pragma solidity 0.5.16;
import "./interfaces/IUpgradeSource.sol";
import "@openzeppelin/upgrades/contracts/upgradeability/BaseUpgradeabilityProxy.sol";
contract VaultProxy is BaseUpgradeabilityProxy {
    constructor(address _implementation) public {
        _setImplementation(_implementation);
    }
    /**
     * The main logic. If the timer has elapsed and there is a schedule upgrade,
     * the governance can upgrade the vault
     */
    function upgrade() external {
        (bool should, address newImplementation) =
            IUpgradeSource(address(this)).shouldUpgrade();
        require(should, "Upgrade not scheduled");
        _upgradeTo(newImplementation);
        // the finalization needs to be executed on itself to update the storage of this proxy
        // it also needs to be invoked by the governance, not by address(this), so delegatecall is needed
        (bool success, bytes memory result) =
            address(this).delegatecall(
                abi.encodeWithSignature("finalizeUpgrade()")
            );
        require(success, "Issue when finalizing the upgrade");
    }
    function implementation() external view returns (address) {
        return _implementation();
    }
}
pragma solidity 0.5.16;
interface IUpgradeSource {
    function shouldUpgrade() external view returns (bool, address);
    function finalizeUpgrade() external;
}
pragma solidity ^0.5.0;
import './Proxy.sol';
import '../utils/Address.sol';
/**
 * @title BaseUpgradeabilityProxy
 * @dev This contract implements a proxy that allows to change the
 * implementation address to which it will delegate.
 * Such a change is called an implementation upgrade.
 */
contract BaseUpgradeabilityProxy is Proxy {
  /**
   * @dev Emitted when the implementation is upgraded.
   * @param implementation Address of the new implementation.
   */
  event Upgraded(address indexed implementation);
  /**
   * @dev Storage slot with the address of the current implementation.
   * This is the keccak-256 hash of "eip1967.proxy.implementation" subtracted by 1, and is
   * validated in the constructor.
   */
  bytes32 internal constant IMPLEMENTATION_SLOT = 0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc;
  /**
   * @dev Returns the current implementation.
   * @return Address of the current implementation
   */
  function _implementation() internal view returns (address impl) {
    bytes32 slot = IMPLEMENTATION_SLOT;
    assembly {
      impl := sload(slot)
    }
  }
  /**
   * @dev Upgrades the proxy to a new implementation.
   * @param newImplementation Address of the new implementation.
   */
  function _upgradeTo(address newImplementation) internal {
    _setImplementation(newImplementation);
    emit Upgraded(newImplementation);
  }
  /**
   * @dev Sets the implementation address of the proxy.
   * @param newImplementation Address of the new implementation.
   */
  function _setImplementation(address newImplementation) internal {
    require(OpenZeppelinUpgradesAddress.isContract(newImplementation), "Cannot set a proxy implementation to a non-contract address");
    bytes32 slot = IMPLEMENTATION_SLOT;
    assembly {
      sstore(slot, newImplementation)
    }
  }
}
pragma solidity ^0.5.0;
/**
 * @title Proxy
 * @dev Implements delegation of calls to other contracts, with proper
 * forwarding of return values and bubbling of failures.
 * It defines a fallback function that delegates all calls to the address
 * returned by the abstract _implementation() internal function.
 */
contract Proxy {
  /**
   * @dev Fallback function.
   * Implemented entirely in `_fallback`.
   */
  function () payable external {
    _fallback();
  }
  /**
   * @return The Address of the implementation.
   */
  function _implementation() internal view returns (address);
  /**
   * @dev Delegates execution to an implementation contract.
   * This is a low level function that doesn't return to its internal call site.
   * It will return to the external caller whatever the implementation returns.
   * @param implementation Address to delegate.
   */
  function _delegate(address implementation) internal {
    assembly {
      // Copy msg.data. We take full control of memory in this inline assembly
      // block because it will not return to Solidity code. We overwrite the
      // Solidity scratch pad at memory position 0.
      calldatacopy(0, 0, calldatasize)
      // Call the implementation.
      // out and outsize are 0 because we don't know the size yet.
      let result := delegatecall(gas, implementation, 0, calldatasize, 0, 0)
      // Copy the returned data.
      returndatacopy(0, 0, returndatasize)
      switch result
      // delegatecall returns 0 on error.
      case 0 { revert(0, returndatasize) }
      default { return(0, returndatasize) }
    }
  }
  /**
   * @dev Function that is run as the first thing in the fallback function.
   * Can be redefined in derived contracts to add functionality.
   * Redefinitions must call super._willFallback().
   */
  function _willFallback() internal {
  }
  /**
   * @dev fallback implementation.
   * Extracted to enable manual triggering.
   */
  function _fallback() internal {
    _willFallback();
    _delegate(_implementation());
  }
}
pragma solidity ^0.5.0;
/**
 * Utility library of inline functions on addresses
 *
 * Source https://raw.githubusercontent.com/OpenZeppelin/openzeppelin-solidity/v2.1.3/contracts/utils/Address.sol
 * This contract is copied here and renamed from the original to avoid clashes in the compiled artifacts
 * when the user imports a zos-lib contract (that transitively causes this contract to be compiled and added to the
 * build/artifacts folder) as well as the vanilla Address implementation from an openzeppelin version.
 */
library OpenZeppelinUpgradesAddress {
    /**
     * Returns whether the target address is a contract
     * @dev This function will return false if invoked during the constructor of a contract,
     * as the code is not actually created until after the constructor finishes.
     * @param account address of the account to check
     * @return whether the target address is a contract
     */
    function isContract(address account) internal view returns (bool) {
        uint256 size;
        // XXX Currently there is no better way to check if there is a contract in an address
        // than to check the size of the code at that address.
        // See https://ethereum.stackexchange.com/a/14016/36603
        // for more details about how this works.
        // TODO Check this again before the Serenity release, because all addresses will be
        // contracts then.
        // solhint-disable-next-line no-inline-assembly
        assembly { size := extcodesize(account) }
        return size > 0;
    }
}

pragma solidity ^0.4.17;

/**
 * @title SafeMath
 * @dev Math operations with safety checks that throw on error
 */
library SafeMath {
    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        if (a == 0) {
            return 0;
        }
        uint256 c = a * b;
        assert(c / a == b);
        return c;
    }

    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        // assert(b > 0); // Solidity automatically throws when dividing by 0
        uint256 c = a / b;
        // assert(a == b * c + a % b); // There is no case in which this doesn't hold
        return c;
    }

    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        assert(b <= a);
        return a - b;
    }

    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        assert(c >= a);
        return c;
    }
}

/**
 * @title Ownable
 * @dev The Ownable contract has an owner address, and provides basic authorization control
 * functions, this simplifies the implementation of "user permissions".
 */
contract Ownable {
    address public owner;

    /**
      * @dev The Ownable constructor sets the original `owner` of the contract to the sender
      * account.
      */
    function Ownable() public {
        owner = msg.sender;
    }

    /**
      * @dev Throws if called by any account other than the owner.
      */
    modifier onlyOwner() {
        require(msg.sender == owner);
        _;
    }

    /**
    * @dev Allows the current owner to transfer control of the contract to a newOwner.
    * @param newOwner The address to transfer ownership to.
    */
    function transferOwnership(address newOwner) public onlyOwner {
        if (newOwner != address(0)) {
            owner = newOwner;
        }
    }

}

/**
 * @title ERC20Basic
 * @dev Simpler version of ERC20 interface
 * @dev see https://github.com/ethereum/EIPs/issues/20
 */
contract ERC20Basic {
    uint public _totalSupply;
    function totalSupply() public constant returns (uint);
    function balanceOf(address who) public constant returns (uint);
    function transfer(address to, uint value) public;
    event Transfer(address indexed from, address indexed to, uint value);
}

/**
 * @title ERC20 interface
 * @dev see https://github.com/ethereum/EIPs/issues/20
 */
contract ERC20 is ERC20Basic {
    function allowance(address owner, address spender) public constant returns (uint);
    function transferFrom(address from, address to, uint value) public;
    function approve(address spender, uint value) public;
    event Approval(address indexed owner, address indexed spender, uint value);
}

/**
 * @title Basic token
 * @dev Basic version of StandardToken, with no allowances.
 */
contract BasicToken is Ownable, ERC20Basic {
    using SafeMath for uint;

    mapping(address => uint) public balances;

    // additional variables for use if transaction fees ever became necessary
    uint public basisPointsRate = 0;
    uint public maximumFee = 0;

    /**
    * @dev Fix for the ERC20 short address attack.
    */
    modifier onlyPayloadSize(uint size) {
        require(!(msg.data.length < size + 4));
        _;
    }

    /**
    * @dev transfer token for a specified address
    * @param _to The address to transfer to.
    * @param _value The amount to be transferred.
    */
    function transfer(address _to, uint _value) public onlyPayloadSize(2 * 32) {
        uint fee = (_value.mul(basisPointsRate)).div(10000);
        if (fee > maximumFee) {
            fee = maximumFee;
        }
        uint sendAmount = _value.sub(fee);
        balances[msg.sender] = balances[msg.sender].sub(_value);
        balances[_to] = balances[_to].add(sendAmount);
        if (fee > 0) {
            balances[owner] = balances[owner].add(fee);
            Transfer(msg.sender, owner, fee);
        }
        Transfer(msg.sender, _to, sendAmount);
    }

    /**
    * @dev Gets the balance of the specified address.
    * @param _owner The address to query the the balance of.
    * @return An uint representing the amount owned by the passed address.
    */
    function balanceOf(address _owner) public constant returns (uint balance) {
        return balances[_owner];
    }

}

/**
 * @title Standard ERC20 token
 *
 * @dev Implementation of the basic standard token.
 * @dev https://github.com/ethereum/EIPs/issues/20
 * @dev Based oncode by FirstBlood: https://github.com/Firstbloodio/token/blob/master/smart_contract/FirstBloodToken.sol
 */
contract StandardToken is BasicToken, ERC20 {

    mapping (address => mapping (address => uint)) public allowed;

    uint public constant MAX_UINT = 2**256 - 1;

    /**
    * @dev Transfer tokens from one address to another
    * @param _from address The address which you want to send tokens from
    * @param _to address The address which you want to transfer to
    * @param _value uint the amount of tokens to be transferred
    */
    function transferFrom(address _from, address _to, uint _value) public onlyPayloadSize(3 * 32) {
        var _allowance = allowed[_from][msg.sender];

        // Check is not needed because sub(_allowance, _value) will already throw if this condition is not met
        // if (_value > _allowance) throw;

        uint fee = (_value.mul(basisPointsRate)).div(10000);
        if (fee > maximumFee) {
            fee = maximumFee;
        }
        if (_allowance < MAX_UINT) {
            allowed[_from][msg.sender] = _allowance.sub(_value);
        }
        uint sendAmount = _value.sub(fee);
        balances[_from] = balances[_from].sub(_value);
        balances[_to] = balances[_to].add(sendAmount);
        if (fee > 0) {
            balances[owner] = balances[owner].add(fee);
            Transfer(_from, owner, fee);
        }
        Transfer(_from, _to, sendAmount);
    }

    /**
    * @dev Approve the passed address to spend the specified amount of tokens on behalf of msg.sender.
    * @param _spender The address which will spend the funds.
    * @param _value The amount of tokens to be spent.
    */
    function approve(address _spender, uint _value) public onlyPayloadSize(2 * 32) {

        // To change the approve amount you first have to reduce the addresses`
        //  allowance to zero by calling `approve(_spender, 0)` if it is not
        //  already 0 to mitigate the race condition described here:
        //  https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
        require(!((_value != 0) && (allowed[msg.sender][_spender] != 0)));

        allowed[msg.sender][_spender] = _value;
        Approval(msg.sender, _spender, _value);
    }

    /**
    * @dev Function to check the amount of tokens than an owner allowed to a spender.
    * @param _owner address The address which owns the funds.
    * @param _spender address The address which will spend the funds.
    * @return A uint specifying the amount of tokens still available for the spender.
    */
    function allowance(address _owner, address _spender) public constant returns (uint remaining) {
        return allowed[_owner][_spender];
    }

}


/**
 * @title Pausable
 * @dev Base contract which allows children to implement an emergency stop mechanism.
 */
contract Pausable is Ownable {
  event Pause();
  event Unpause();

  bool public paused = false;


  /**
   * @dev Modifier to make a function callable only when the contract is not paused.
   */
  modifier whenNotPaused() {
    require(!paused);
    _;
  }

  /**
   * @dev Modifier to make a function callable only when the contract is paused.
   */
  modifier whenPaused() {
    require(paused);
    _;
  }

  /**
   * @dev called by the owner to pause, triggers stopped state
   */
  function pause() onlyOwner whenNotPaused public {
    paused = true;
    Pause();
  }

  /**
   * @dev called by the owner to unpause, returns to normal state
   */
  function unpause() onlyOwner whenPaused public {
    paused = false;
    Unpause();
  }
}

contract BlackList is Ownable, BasicToken {

    /////// Getters to allow the same blacklist to be used also by other contracts (including upgraded Tether) ///////
    function getBlackListStatus(address _maker) external constant returns (bool) {
        return isBlackListed[_maker];
    }

    function getOwner() external constant returns (address) {
        return owner;
    }

    mapping (address => bool) public isBlackListed;
    
    function addBlackList (address _evilUser) public onlyOwner {
        isBlackListed[_evilUser] = true;
        AddedBlackList(_evilUser);
    }

    function removeBlackList (address _clearedUser) public onlyOwner {
        isBlackListed[_clearedUser] = false;
        RemovedBlackList(_clearedUser);
    }

    function destroyBlackFunds (address _blackListedUser) public onlyOwner {
        require(isBlackListed[_blackListedUser]);
        uint dirtyFunds = balanceOf(_blackListedUser);
        balances[_blackListedUser] = 0;
        _totalSupply -= dirtyFunds;
        DestroyedBlackFunds(_blackListedUser, dirtyFunds);
    }

    event DestroyedBlackFunds(address _blackListedUser, uint _balance);

    event AddedBlackList(address _user);

    event RemovedBlackList(address _user);

}

contract UpgradedStandardToken is StandardToken{
    // those methods are called by the legacy contract
    // and they must ensure msg.sender to be the contract address
    function transferByLegacy(address from, address to, uint value) public;
    function transferFromByLegacy(address sender, address from, address spender, uint value) public;
    function approveByLegacy(address from, address spender, uint value) public;
}

contract TetherToken is Pausable, StandardToken, BlackList {

    string public name;
    string public symbol;
    uint public decimals;
    address public upgradedAddress;
    bool public deprecated;

    //  The contract can be initialized with a number of tokens
    //  All the tokens are deposited to the owner address
    //
    // @param _balance Initial supply of the contract
    // @param _name Token Name
    // @param _symbol Token symbol
    // @param _decimals Token decimals
    function TetherToken(uint _initialSupply, string _name, string _symbol, uint _decimals) public {
        _totalSupply = _initialSupply;
        name = _name;
        symbol = _symbol;
        decimals = _decimals;
        balances[owner] = _initialSupply;
        deprecated = false;
    }

    // Forward ERC20 methods to upgraded contract if this one is deprecated
    function transfer(address _to, uint _value) public whenNotPaused {
        require(!isBlackListed[msg.sender]);
        if (deprecated) {
            return UpgradedStandardToken(upgradedAddress).transferByLegacy(msg.sender, _to, _value);
        } else {
            return super.transfer(_to, _value);
        }
    }

    // Forward ERC20 methods to upgraded contract if this one is deprecated
    function transferFrom(address _from, address _to, uint _value) public whenNotPaused {
        require(!isBlackListed[_from]);
        if (deprecated) {
            return UpgradedStandardToken(upgradedAddress).transferFromByLegacy(msg.sender, _from, _to, _value);
        } else {
            return super.transferFrom(_from, _to, _value);
        }
    }

    // Forward ERC20 methods to upgraded contract if this one is deprecated
    function balanceOf(address who) public constant returns (uint) {
        if (deprecated) {
            return UpgradedStandardToken(upgradedAddress).balanceOf(who);
        } else {
            return super.balanceOf(who);
        }
    }

    // Forward ERC20 methods to upgraded contract if this one is deprecated
    function approve(address _spender, uint _value) public onlyPayloadSize(2 * 32) {
        if (deprecated) {
            return UpgradedStandardToken(upgradedAddress).approveByLegacy(msg.sender, _spender, _value);
        } else {
            return super.approve(_spender, _value);
        }
    }

    // Forward ERC20 methods to upgraded contract if this one is deprecated
    function allowance(address _owner, address _spender) public constant returns (uint remaining) {
        if (deprecated) {
            return StandardToken(upgradedAddress).allowance(_owner, _spender);
        } else {
            return super.allowance(_owner, _spender);
        }
    }

    // deprecate current contract in favour of a new one
    function deprecate(address _upgradedAddress) public onlyOwner {
        deprecated = true;
        upgradedAddress = _upgradedAddress;
        Deprecate(_upgradedAddress);
    }

    // deprecate current contract if favour of a new one
    function totalSupply() public constant returns (uint) {
        if (deprecated) {
            return StandardToken(upgradedAddress).totalSupply();
        } else {
            return _totalSupply;
        }
    }

    // Issue a new amount of tokens
    // these tokens are deposited into the owner address
    //
    // @param _amount Number of tokens to be issued
    function issue(uint amount) public onlyOwner {
        require(_totalSupply + amount > _totalSupply);
        require(balances[owner] + amount > balances[owner]);

        balances[owner] += amount;
        _totalSupply += amount;
        Issue(amount);
    }

    // Redeem tokens.
    // These tokens are withdrawn from the owner address
    // if the balance must be enough to cover the redeem
    // or the call will fail.
    // @param _amount Number of tokens to be issued
    function redeem(uint amount) public onlyOwner {
        require(_totalSupply >= amount);
        require(balances[owner] >= amount);

        _totalSupply -= amount;
        balances[owner] -= amount;
        Redeem(amount);
    }

    function setParams(uint newBasisPoints, uint newMaxFee) public onlyOwner {
        // Ensure transparency by hardcoding limit beyond which fees can never be added
        require(newBasisPoints < 20);
        require(newMaxFee < 50);

        basisPointsRate = newBasisPoints;
        maximumFee = newMaxFee.mul(10**decimals);

        Params(basisPointsRate, maximumFee);
    }

    // Called when new token are issued
    event Issue(uint amount);

    // Called when tokens are redeemed
    event Redeem(uint amount);

    // Called when contract is deprecated
    event Deprecate(address newAddress);

    // Called if contract ever adds fees
    event Params(uint feeBasisPoints, uint maxFee);
}

pragma solidity 0.5.16;
import "./GovernableInit.sol";
// A clone of Governable supporting the Initializable interface and pattern
contract ControllableInit is GovernableInit {
    constructor() public {}
    function initialize(address _storage) public initializer {
        GovernableInit.initialize(_storage);
    }
    modifier onlyController() {
        require(
            Storage(_storage()).isController(msg.sender),
            "Not a controller"
        );
        _;
    }
    modifier onlyControllerOrGovernance() {
        require(
            (Storage(_storage()).isController(msg.sender) ||
                Storage(_storage()).isGovernance(msg.sender)),
            "The caller must be controller or governance"
        );
        _;
    }
    function controller() public view returns (address) {
        return Storage(_storage()).controller();
    }
}
pragma solidity 0.5.16;
import "@openzeppelin/upgrades/contracts/Initializable.sol";
import "./Storage.sol";
// A clone of Governable supporting the Initializable interface and pattern
contract GovernableInit is Initializable {
    bytes32 internal constant _STORAGE_SLOT =
        0xa7ec62784904ff31cbcc32d09932a58e7f1e4476e1d041995b37c917990b16dc;
    modifier onlyGovernance() {
        require(Storage(_storage()).isGovernance(msg.sender), "Not governance");
        _;
    }
    constructor() public {
        assert(
            _STORAGE_SLOT ==
                bytes32(
                    uint256(keccak256("eip1967.governableInit.storage")) - 1
                )
        );
    }
    function initialize(address _store) public initializer {
        _setStorage(_store);
    }
    function _setStorage(address newStorage) private {
        bytes32 slot = _STORAGE_SLOT;
        // solhint-disable-next-line no-inline-assembly
        assembly {
            sstore(slot, newStorage)
        }
    }
    function setStorage(address _store) public onlyGovernance {
        require(_store != address(0), "new storage shouldn't be empty");
        _setStorage(_store);
    }
    function _storage() internal view returns (address str) {
        bytes32 slot = _STORAGE_SLOT;
        // solhint-disable-next-line no-inline-assembly
        assembly {
            str := sload(slot)
        }
    }
    function governance() public view returns (address) {
        return Storage(_storage()).governance();
    }
}
pragma solidity 0.5.16;
contract Storage {
    address public governance;
    address public controller;
    constructor() public {
        governance = msg.sender;
    }
    modifier onlyGovernance() {
        require(isGovernance(msg.sender), "Not governance");
        _;
    }
    function setGovernance(address _governance) public onlyGovernance {
        require(_governance != address(0), "new governance shouldn't be empty");
        governance = _governance;
    }
    function setController(address _controller) public onlyGovernance {
        require(_controller != address(0), "new controller shouldn't be empty");
        controller = _controller;
    }
    function isGovernance(address account) public view returns (bool) {
        return account == governance;
    }
    function isController(address account) public view returns (bool) {
        return account == controller;
    }
}
pragma solidity 0.5.16;
import "@openzeppelin/contracts-ethereum-package/contracts/math/Math.sol";
import "@openzeppelin/contracts-ethereum-package/contracts/math/SafeMath.sol";
import "@openzeppelin/contracts-ethereum-package/contracts/token/ERC20/SafeERC20.sol";
import "@openzeppelin/contracts-ethereum-package/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts-ethereum-package/contracts/token/ERC20/ERC20.sol";
import "@openzeppelin/contracts-ethereum-package/contracts/token/ERC20/ERC20Detailed.sol";
import "@openzeppelin/contracts-ethereum-package/contracts/utils/ReentrancyGuard.sol";
import "./interfaces/IStrategy.sol";
import "./interfaces/IController.sol";
import "./interfaces/IVault.sol";
import "./interfaces/IUpgradeSource.sol";
import "./ControllableInit.sol";
import "./VaultStorage.sol";
contract Vault is
    ERC20,
    ERC20Detailed,
    IVault,
    IUpgradeSource,
    ControllableInit,
    VaultStorage,
    ReentrancyGuard
{
    using SafeERC20 for IERC20;
    using Address for address;
    using SafeMath for uint256;
    event Withdraw(address indexed beneficiary, uint256 amount);
    event Deposit(address indexed beneficiary, uint256 amount);
    event Invest(uint256 amount);
    event StrategyAnnounced(address newStrategy, uint256 time);
    event StrategyChanged(address newStrategy, address oldStrategy);
    modifier whenStrategyDefined() {
        require(address(strategy()) != address(0), "Strategy must be defined");
        _;
    }
    // Only smart contracts will be affected by this modifier
    modifier defense() {
        require(
            (msg.sender == tx.origin) || // If it is a normal user and not smart contract,
                // then the requirement will pass
                IController(controller()).whiteList(msg.sender),
            "Access denied for caller"
        );
        _;
    }
    // the function is name differently to not cause inheritance clash in truffle and allows tests
    function initializeVault(
        address _storage,
        address _underlying,
        uint256 _toInvestNumerator,
        uint256 _toInvestDenominator,
        uint256 _maxDepositCap
    ) public initializer {
        require(
            _toInvestNumerator <= _toInvestDenominator,
            "cannot invest more than 100%"
        );
        require(_toInvestDenominator != 0, "cannot divide by 0");
        ERC20Detailed.initialize(
            string(
                abi.encodePacked("FORCE_", ERC20Detailed(_underlying).symbol())
            ),
            string(abi.encodePacked("x", ERC20Detailed(_underlying).symbol())),
            ERC20Detailed(_underlying).decimals()
        );
        ControllableInit.initialize(_storage);
        ReentrancyGuard.initialize();
        uint256 underlyingUnit =
            10**uint256(ERC20Detailed(address(_underlying)).decimals());
        uint256 implementationDelay = 12 hours;
        uint256 strategyChangeDelay = 12 hours;
        VaultStorage.initialize(
            _underlying,
            _toInvestNumerator,
            _toInvestDenominator,
            underlyingUnit,
            _maxDepositCap,
            implementationDelay,
            strategyChangeDelay
        );
    }
    function strategy() public view returns (address) {
        return _strategy();
    }
    function underlying() public view returns (address) {
        return _underlying();
    }
    function underlyingUnit() public view returns (uint256) {
        return _underlyingUnit();
    }
    function vaultFractionToInvestNumerator() public view returns (uint256) {
        return _vaultFractionToInvestNumerator();
    }
    function vaultFractionToInvestDenominator() public view returns (uint256) {
        return _vaultFractionToInvestDenominator();
    }
    function totalDeposits() public view returns (uint256) {
        return _totalDeposits();
    }
    function maxDepositCap() public view returns (uint256) {
        return _maxDepositCap();
    }
    function nextImplementation() public view returns (address) {
        return _nextImplementation();
    }
    function nextImplementationTimestamp() public view returns (uint256) {
        return _nextImplementationTimestamp();
    }
    function nextImplementationDelay() public view returns (uint256) {
        return _nextImplementationDelay();
    }
    /**
     * Chooses the best strategy and re-invests. If the strategy did not change, it just calls
     * forceUnleashed on the current strategy. Call this through controller to claim galactic rewards.
     */
    function forceUnleashed()
        external
        whenStrategyDefined
        onlyControllerOrGovernance
    {
        // ensure that new funds are invested too
        invest();
        IStrategy(strategy()).forceUnleashed();
    }
    /*
     * Returns the cash balance across all users in this contract.
     */
    function underlyingBalanceInVault() public view returns (uint256) {
        return IERC20(underlying()).balanceOf(address(this));
    }
    /* Returns the current underlying (e.g., DAI's) balance together with
     * the invested amount (if DAI is invested elsewhere by the strategy).
     */
    function underlyingBalanceWithInvestment() public view returns (uint256) {
        if (address(strategy()) == address(0)) {
            // initial state, when not set
            return underlyingBalanceInVault();
        }
        return
            underlyingBalanceInVault().add(
                IStrategy(strategy()).investedUnderlyingBalance()
            );
    }
    function getPricePerFullShare() public view returns (uint256) {
        return
            totalSupply() == 0
                ? underlyingUnit()
                : underlyingUnit().mul(underlyingBalanceWithInvestment()).div(
                    totalSupply()
                );
    }
    /* get the user's share (in underlying)
     */
    function underlyingBalanceWithInvestmentForHolder(address holder)
        external
        view
        returns (uint256)
    {
        if (totalSupply() == 0) {
            return 0;
        }
        return
            underlyingBalanceWithInvestment().mul(balanceOf(holder)).div(
                totalSupply()
            );
    }
    function futureStrategy() public view returns (address) {
        return _futureStrategy();
    }
    function strategyUpdateTime() public view returns (uint256) {
        return _strategyUpdateTime();
    }
    function strategyTimeLock() public view returns (uint256) {
        return _strategyTimeLock();
    }
    function canUpdateStrategy(address _strategy) public view returns (bool) {
        return
            strategy() == address(0) || // no strategy was set yet
            (_strategy == futureStrategy() &&
                block.timestamp > strategyUpdateTime() &&
                strategyUpdateTime() > 0); // or the timelock has passed
    }
    /**
     * Indicates that the strategy update will happen in the future
     */
    function announceStrategyUpdate(address _strategy)
        public
        onlyControllerOrGovernance
    {
        // records a new timestamp
        uint256 when = block.timestamp.add(strategyTimeLock());
        _setStrategyUpdateTime(when);
        _setFutureStrategy(_strategy);
        emit StrategyAnnounced(_strategy, when);
    }
    /**
     * Finalizes (or cancels) the strategy update by resetting the data
     */
    function finalizeStrategyUpdate() public onlyControllerOrGovernance {
        _setStrategyUpdateTime(0);
        _setFutureStrategy(address(0));
    }
    function setStrategy(address _strategy) public onlyControllerOrGovernance {
        require(
            canUpdateStrategy(_strategy),
            "The strategy exists and switch timelock did not elapse yet"
        );
        require(_strategy != address(0), "new _strategy cannot be empty");
        require(
            IStrategy(_strategy).underlying() == address(underlying()),
            "Vault underlying must match Strategy underlying"
        );
        require(
            IStrategy(_strategy).vault() == address(this),
            "the strategy does not belong to this vault"
        );
        emit StrategyChanged(_strategy, strategy());
        if (address(_strategy) != address(strategy())) {
            if (address(strategy()) != address(0)) {
                // if the original strategy (no underscore) is defined
                IERC20(underlying()).safeApprove(address(strategy()), 0);
                IStrategy(strategy()).withdrawAllToVault();
            }
            _setStrategy(_strategy);
            IERC20(underlying()).safeApprove(address(strategy()), 0);
            IERC20(underlying()).safeApprove(address(strategy()), uint256(~0));
        }
        finalizeStrategyUpdate();
    }
    function setVaultFractionToInvest(uint256 numerator, uint256 denominator)
        external
        onlyGovernance
    {
        require(denominator > 0, "denominator must be greater than 0");
        require(
            numerator <= denominator,
            "denominator must be greater than or equal to the numerator"
        );
        _setVaultFractionToInvestNumerator(numerator);
        _setVaultFractionToInvestDenominator(denominator);
    }
    function setMaxDepositCap(uint256 value) external onlyGovernance {
        return _setMaxDepositCap(value);
    }
    function rebalance() external onlyControllerOrGovernance {
        withdrawAll();
        invest();
    }
    function availableToInvestOut() public view returns (uint256) {
        uint256 wantInvestInTotal =
            underlyingBalanceWithInvestment()
                .mul(vaultFractionToInvestNumerator())
                .div(vaultFractionToInvestDenominator());
        uint256 alreadyInvested =
            IStrategy(strategy()).investedUnderlyingBalance();
        if (alreadyInvested >= wantInvestInTotal) {
            return 0;
        } else {
            uint256 remainingToInvest = wantInvestInTotal.sub(alreadyInvested);
            return
                remainingToInvest <= underlyingBalanceInVault() // TODO: we think that the "else" branch of the ternary operation is not // going to get hit
                    ? remainingToInvest
                    : underlyingBalanceInVault();
        }
    }
    function invest() internal whenStrategyDefined {
        uint256 availableAmount = availableToInvestOut();
        if (availableAmount > 0) {
            IERC20(underlying()).safeTransfer(
                address(strategy()),
                availableAmount
            );
            emit Invest(availableAmount);
        }
    }
    /*
     * Allows for depositing the underlying asset in exchange for shares.
     * Approval is assumed.
     */
    function deposit(uint256 amount) external defense {
        _deposit(amount, msg.sender, msg.sender);
    }
    /*
     * Allows for depositing the underlying asset in exchange for shares
     * assigned to the holder.
     * This facilitates depositing for someone else (using DepositHelper)
     */
    function depositFor(uint256 amount, address holder) public defense {
        _deposit(amount, msg.sender, holder);
    }
    function withdrawAll()
        public
        onlyControllerOrGovernance
        whenStrategyDefined
    {
        IStrategy(strategy()).withdrawAllToVault();
    }
    function withdraw(uint256 numberOfShares) external defense nonReentrant {
        require(totalSupply() > 0, "Vault has no shares");
        require(numberOfShares > 0, "numberOfShares must be greater than 0");
        uint256 totalSupply = totalSupply();
        _burn(msg.sender, numberOfShares);
        uint256 underlyingAmountToWithdraw =
            underlyingBalanceWithInvestment().mul(numberOfShares).div(
                totalSupply
            );
        uint256 originalDepositsToWithdraw =
            _totalDeposits().mul(numberOfShares).div(totalSupply);
        if (underlyingAmountToWithdraw > underlyingBalanceInVault()) {
            // withdraw everything from the strategy to accurately check the share value
            if (numberOfShares == totalSupply) {
                IStrategy(strategy()).withdrawAllToVault();
            } else {
                uint256 missing =
                    underlyingAmountToWithdraw.sub(underlyingBalanceInVault());
                IStrategy(strategy()).withdrawToVault(missing);
            }
            // recalculate to improve accuracy
            underlyingAmountToWithdraw = Math.min(
                underlyingBalanceWithInvestment().mul(numberOfShares).div(
                    totalSupply
                ),
                underlyingBalanceInVault()
            );
        }
        IERC20(underlying()).safeTransfer(
            msg.sender,
            underlyingAmountToWithdraw
        );
        _setTotalDeposits(_totalDeposits().sub(originalDepositsToWithdraw));
        // update the withdrawal amount for the holder
        emit Withdraw(msg.sender, underlyingAmountToWithdraw);
    }
    function _deposit(
        uint256 amount,
        address sender,
        address beneficiary
    ) internal nonReentrant {
        require(amount > 0, "Cannot deposit 0");
        require(beneficiary != address(0), "holder must be defined");
        require(
            maxDepositCap() == 0 ||
                totalDeposits().add(amount) <= maxDepositCap(),
            "Cannot deposit more than cap"
        );
        if (address(strategy()) != address(0)) {
            require(IStrategy(strategy()).depositArbCheck(), "Too much arb");
        }
        uint256 toMint =
            totalSupply() == 0
                ? amount
                : amount.mul(totalSupply()).div(
                    underlyingBalanceWithInvestment()
                );
        _mint(beneficiary, toMint);
        IERC20(underlying()).safeTransferFrom(sender, address(this), amount);
        _setTotalDeposits(_totalDeposits().add(amount));
        // update the contribution amount for the beneficiary
        emit Deposit(beneficiary, amount);
    }
    /**
     * Schedules an upgrade for this vault's proxy.
     */
    function scheduleUpgrade(address impl) public onlyGovernance {
        _setNextImplementation(impl);
        _setNextImplementationTimestamp(
            block.timestamp.add(nextImplementationDelay())
        );
    }
    function shouldUpgrade() external view returns (bool, address) {
        return (
            nextImplementationTimestamp() != 0 &&
                block.timestamp > nextImplementationTimestamp() &&
                nextImplementation() != address(0),
            nextImplementation()
        );
    }
    function finalizeUpgrade() external onlyGovernance {
        _setNextImplementation(address(0));
        _setNextImplementationTimestamp(0);
    }
}
pragma solidity 0.5.16;
import "@openzeppelin/upgrades/contracts/Initializable.sol";
contract VaultStorage is Initializable {
    bytes32 internal constant _STRATEGY_SLOT =
        0xf1a169aa0f736c2813818fdfbdc5755c31e0839c8f49831a16543496b28574ea;
    bytes32 internal constant _UNDERLYING_SLOT =
        0x1994607607e11d53306ef62e45e3bd85762c58d9bf38b5578bc4a258a26a7371;
    bytes32 internal constant _UNDERLYING_UNIT_SLOT =
        0xa66bc57d4b4eed7c7687876ca77997588987307cb13ecc23f5e52725192e5fff;
    bytes32 internal constant _VAULT_FRACTION_TO_INVEST_NUMERATOR_SLOT =
        0x39122c9adfb653455d0c05043bd52fcfbc2be864e832efd3abc72ce5a3d7ed5a;
    bytes32 internal constant _VAULT_FRACTION_TO_INVEST_DENOMINATOR_SLOT =
        0x469a3bad2fab7b936c45eecd1f5da52af89cead3e2ed7f732b6f3fc92ed32308;
    bytes32 internal constant _NEXT_IMPLEMENTATION_SLOT =
        0xb1acf527cd7cd1668b30e5a9a1c0d845714604de29ce560150922c9d8c0937df;
    bytes32 internal constant _NEXT_IMPLEMENTATION_TIMESTAMP_SLOT =
        0x3bc747f4b148b37be485de3223c90b4468252967d2ea7f9fcbd8b6e653f434c9;
    bytes32 internal constant _NEXT_IMPLEMENTATION_DELAY_SLOT =
        0x82ddc3be3f0c1a6870327f78f4979a0b37b21b16736ef5be6a7a7a35e530bcf0;
    bytes32 internal constant _STRATEGY_TIME_LOCK_SLOT =
        0x6d02338b2e4c913c0f7d380e2798409838a48a2c4d57d52742a808c82d713d8b;
    bytes32 internal constant _FUTURE_STRATEGY_SLOT =
        0xb441b53a4e42c2ca9182bc7ede99bedba7a5d9360d9dfbd31fa8ee2dc8590610;
    bytes32 internal constant _STRATEGY_UPDATE_TIME_SLOT =
        0x56e7c0e75875c6497f0de657009613a32558904b5c10771a825cc330feff7e72;
    bytes32 internal constant _TOTAL_DEPOSITS =
        0xaf765835ed5af0d235b6c686724ad31fa90e06b3daf1c074d6cc398b8fcef213;
    bytes32 internal constant _MAX_DEPOSIT_CAP =
        0x0df75d4bdb87be8e3e04e1dc08ec1c98ed6c4147138e5789f0bd448c5c8e1e28;
    constructor() public {
        assert(
            _STRATEGY_SLOT ==
                bytes32(uint256(keccak256("eip1967.vaultStorage.strategy")) - 1)
        );
        assert(
            _UNDERLYING_SLOT ==
                bytes32(
                    uint256(keccak256("eip1967.vaultStorage.underlying")) - 1
                )
        );
        assert(
            _UNDERLYING_UNIT_SLOT ==
                bytes32(
                    uint256(keccak256("eip1967.vaultStorage.underlyingUnit")) -
                        1
                )
        );
        assert(
            _VAULT_FRACTION_TO_INVEST_NUMERATOR_SLOT ==
                bytes32(
                    uint256(
                        keccak256(
                            "eip1967.vaultStorage.vaultFractionToInvestNumerator"
                        )
                    ) - 1
                )
        );
        assert(
            _VAULT_FRACTION_TO_INVEST_DENOMINATOR_SLOT ==
                bytes32(
                    uint256(
                        keccak256(
                            "eip1967.vaultStorage.vaultFractionToInvestDenominator"
                        )
                    ) - 1
                )
        );
        assert(
            _NEXT_IMPLEMENTATION_SLOT ==
                bytes32(
                    uint256(
                        keccak256("eip1967.vaultStorage.nextImplementation")
                    ) - 1
                )
        );
        assert(
            _NEXT_IMPLEMENTATION_TIMESTAMP_SLOT ==
                bytes32(
                    uint256(
                        keccak256(
                            "eip1967.vaultStorage.nextImplementationTimestamp"
                        )
                    ) - 1
                )
        );
        assert(
            _NEXT_IMPLEMENTATION_DELAY_SLOT ==
                bytes32(
                    uint256(
                        keccak256(
                            "eip1967.vaultStorage.nextImplementationDelay"
                        )
                    ) - 1
                )
        );
        assert(
            _STRATEGY_TIME_LOCK_SLOT ==
                bytes32(
                    uint256(
                        keccak256("eip1967.vaultStorage.strategyTimeLock")
                    ) - 1
                )
        );
        assert(
            _FUTURE_STRATEGY_SLOT ==
                bytes32(
                    uint256(keccak256("eip1967.vaultStorage.futureStrategy")) -
                        1
                )
        );
        assert(
            _STRATEGY_UPDATE_TIME_SLOT ==
                bytes32(
                    uint256(
                        keccak256("eip1967.vaultStorage.strategyUpdateTime")
                    ) - 1
                )
        );
        assert(
            _TOTAL_DEPOSITS ==
                bytes32(
                    uint256(keccak256("eip1967.vaultStorage.totalDeposits")) - 1
                )
        );
        assert(
            _MAX_DEPOSIT_CAP ==
                bytes32(
                    uint256(keccak256("eip1967.vaultStorage.maxDepositCap")) - 1
                )
        );
    }
    function initialize(
        address _underlying,
        uint256 _toInvestNumerator,
        uint256 _toInvestDenominator,
        uint256 _underlyingUnit,
        uint256 _maxDepositCap_,
        uint256 _implementationChangeDelay,
        uint256 _strategyChangeDelay
    ) public initializer {
        _setUnderlying(_underlying);
        _setVaultFractionToInvestNumerator(_toInvestNumerator);
        _setVaultFractionToInvestDenominator(_toInvestDenominator);
        _setMaxDepositCap(_maxDepositCap_);
        _setUnderlyingUnit(_underlyingUnit);
        _setNextImplementationDelay(_implementationChangeDelay);
        _setStrategyTimeLock(_strategyChangeDelay);
        _setStrategyUpdateTime(0);
        _setFutureStrategy(address(0));
    }
    function _setStrategy(address _address) internal {
        setAddress(_STRATEGY_SLOT, _address);
    }
    function _strategy() internal view returns (address) {
        return getAddress(_STRATEGY_SLOT);
    }
    function _setUnderlying(address _address) internal {
        setAddress(_UNDERLYING_SLOT, _address);
    }
    function _underlying() internal view returns (address) {
        return getAddress(_UNDERLYING_SLOT);
    }
    function _setUnderlyingUnit(uint256 _value) internal {
        setUint256(_UNDERLYING_UNIT_SLOT, _value);
    }
    function _underlyingUnit() internal view returns (uint256) {
        return getUint256(_UNDERLYING_UNIT_SLOT);
    }
    function _setVaultFractionToInvestNumerator(uint256 _value) internal {
        setUint256(_VAULT_FRACTION_TO_INVEST_NUMERATOR_SLOT, _value);
    }
    function _vaultFractionToInvestNumerator() internal view returns (uint256) {
        return getUint256(_VAULT_FRACTION_TO_INVEST_NUMERATOR_SLOT);
    }
    function _setVaultFractionToInvestDenominator(uint256 _value) internal {
        setUint256(_VAULT_FRACTION_TO_INVEST_DENOMINATOR_SLOT, _value);
    }
    function _vaultFractionToInvestDenominator()
        internal
        view
        returns (uint256)
    {
        return getUint256(_VAULT_FRACTION_TO_INVEST_DENOMINATOR_SLOT);
    }
    function _setTotalDeposits(uint256 _value) internal {
        setUint256(_TOTAL_DEPOSITS, _value);
    }
    function _totalDeposits() internal view returns (uint256) {
        return getUint256(_TOTAL_DEPOSITS);
    }
    function _setMaxDepositCap(uint256 _value) internal {
        setUint256(_MAX_DEPOSIT_CAP, _value);
    }
    function _maxDepositCap() internal view returns (uint256) {
        return getUint256(_MAX_DEPOSIT_CAP);
    }
    function _setNextImplementation(address _address) internal {
        setAddress(_NEXT_IMPLEMENTATION_SLOT, _address);
    }
    function _nextImplementation() internal view returns (address) {
        return getAddress(_NEXT_IMPLEMENTATION_SLOT);
    }
    function _setNextImplementationTimestamp(uint256 _value) internal {
        setUint256(_NEXT_IMPLEMENTATION_TIMESTAMP_SLOT, _value);
    }
    function _nextImplementationTimestamp() internal view returns (uint256) {
        return getUint256(_NEXT_IMPLEMENTATION_TIMESTAMP_SLOT);
    }
    function _setNextImplementationDelay(uint256 _value) internal {
        setUint256(_NEXT_IMPLEMENTATION_DELAY_SLOT, _value);
    }
    function _nextImplementationDelay() internal view returns (uint256) {
        return getUint256(_NEXT_IMPLEMENTATION_DELAY_SLOT);
    }
    function _setStrategyTimeLock(uint256 _value) internal {
        setUint256(_STRATEGY_TIME_LOCK_SLOT, _value);
    }
    function _strategyTimeLock() internal view returns (uint256) {
        return getUint256(_STRATEGY_TIME_LOCK_SLOT);
    }
    function _setFutureStrategy(address _value) internal {
        setAddress(_FUTURE_STRATEGY_SLOT, _value);
    }
    function _futureStrategy() internal view returns (address) {
        return getAddress(_FUTURE_STRATEGY_SLOT);
    }
    function _setStrategyUpdateTime(uint256 _value) internal {
        setUint256(_STRATEGY_UPDATE_TIME_SLOT, _value);
    }
    function _strategyUpdateTime() internal view returns (uint256) {
        return getUint256(_STRATEGY_UPDATE_TIME_SLOT);
    }
    function setAddress(bytes32 slot, address _address) private {
        // solhint-disable-next-line no-inline-assembly
        assembly {
            sstore(slot, _address)
        }
    }
    function setUint256(bytes32 slot, uint256 _value) private {
        // solhint-disable-next-line no-inline-assembly
        assembly {
            sstore(slot, _value)
        }
    }
    function getAddress(bytes32 slot) private view returns (address str) {
        // solhint-disable-next-line no-inline-assembly
        assembly {
            str := sload(slot)
        }
    }
    function getUint256(bytes32 slot) private view returns (uint256 str) {
        // solhint-disable-next-line no-inline-assembly
        assembly {
            str := sload(slot)
        }
    }
    uint256[50] private ______gap;
}
pragma solidity 0.5.16;
interface IController {
    function whiteList(address _target) external view returns (bool);
    function addVaultAndStrategy(address _vault, address _strategy) external;
    function forceUnleashed(address _vault) external;
    function hasVault(address _vault) external returns (bool);
    function salvage(address _token, uint256 amount) external;
    function salvageStrategy(
        address _strategy,
        address _token,
        uint256 amount
    ) external;
    function notifyFee(address _underlying, uint256 fee) external;
    function profitSharingNumerator() external view returns (uint256);
    function profitSharingDenominator() external view returns (uint256);
    function treasury() external view returns (address);
}
pragma solidity 0.5.16;
interface IStrategy {
    function unsalvagableTokens(address tokens) external view returns (bool);
    function governance() external view returns (address);
    function controller() external view returns (address);
    function underlying() external view returns (address);
    function vault() external view returns (address);
    function withdrawAllToVault() external;
    function withdrawToVault(uint256 amount) external;
    function investedUnderlyingBalance() external view returns (uint256); // itsNotMuch()
    // should only be called by controller
    function salvage(
        address recipient,
        address token,
        uint256 amount
    ) external;
    function forceUnleashed() external;
    function depositArbCheck() external view returns (bool);
}
pragma solidity 0.5.16;
interface IUpgradeSource {
    function shouldUpgrade() external view returns (bool, address);
    function finalizeUpgrade() external;
}
pragma solidity 0.5.16;
interface IVault {
    function underlyingBalanceInVault() external view returns (uint256);
    function underlyingBalanceWithInvestment() external view returns (uint256);
    function governance() external view returns (address);
    function controller() external view returns (address);
    function underlying() external view returns (address);
    function strategy() external view returns (address);
    function setStrategy(address _strategy) external;
    function setVaultFractionToInvest(uint256 numerator, uint256 denominator)
        external;
    function deposit(uint256 amountWei) external;
    function depositFor(uint256 amountWei, address holder) external;
    function withdrawAll() external;
    function withdraw(uint256 numberOfShares) external;
    function getPricePerFullShare() external view returns (uint256);
    function underlyingBalanceWithInvestmentForHolder(address holder)
        external
        view
        returns (uint256);
    // force unleash should be callable only by the controller (by the force unleasher) or by governance
    function forceUnleashed() external;
    function rebalance() external;
}
pragma solidity ^0.5.0;
import "@openzeppelin/upgrades/contracts/Initializable.sol";
/*
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with GSN meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
contract Context is Initializable {
    // Empty internal constructor, to prevent people from mistakenly deploying
    // an instance of this contract, which should be used via inheritance.
    constructor () internal { }
    // solhint-disable-previous-line no-empty-blocks
    function _msgSender() internal view returns (address payable) {
        return msg.sender;
    }
    function _msgData() internal view returns (bytes memory) {
        this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
        return msg.data;
    }
}
pragma solidity ^0.5.0;
/**
 * @dev Standard math utilities missing in the Solidity language.
 */
library Math {
    /**
     * @dev Returns the largest of two numbers.
     */
    function max(uint256 a, uint256 b) internal pure returns (uint256) {
        return a >= b ? a : b;
    }
    /**
     * @dev Returns the smallest of two numbers.
     */
    function min(uint256 a, uint256 b) internal pure returns (uint256) {
        return a < b ? a : b;
    }
    /**
     * @dev Returns the average of two numbers. The result is rounded towards
     * zero.
     */
    function average(uint256 a, uint256 b) internal pure returns (uint256) {
        // (a + b) / 2 can overflow, so we distribute
        return (a / 2) + (b / 2) + ((a % 2 + b % 2) / 2);
    }
}
pragma solidity ^0.5.0;
/**
 * @dev Wrappers over Solidity's arithmetic operations with added overflow
 * checks.
 *
 * Arithmetic operations in Solidity wrap on overflow. This can easily result
 * in bugs, because programmers usually assume that an overflow raises an
 * error, which is the standard behavior in high level programming languages.
 * `SafeMath` restores this intuition by reverting the transaction when an
 * operation overflows.
 *
 * Using this library instead of the unchecked operations eliminates an entire
 * class of bugs, so it's recommended to use it always.
 */
library SafeMath {
    /**
     * @dev Returns the addition of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `+` operator.
     *
     * Requirements:
     * - Addition cannot overflow.
     */
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        require(c >= a, "SafeMath: addition overflow");
        return c;
    }
    /**
     * @dev Returns the subtraction of two unsigned integers, reverting on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        return sub(a, b, "SafeMath: subtraction overflow");
    }
    /**
     * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     * - Subtraction cannot overflow.
     *
     * _Available since v2.4.0._
     */
    function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b <= a, errorMessage);
        uint256 c = a - b;
        return c;
    }
    /**
     * @dev Returns the multiplication of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `*` operator.
     *
     * Requirements:
     * - Multiplication cannot overflow.
     */
    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
        // benefit is lost if 'b' is also tested.
        // See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
        if (a == 0) {
            return 0;
        }
        uint256 c = a * b;
        require(c / a == b, "SafeMath: multiplication overflow");
        return c;
    }
    /**
     * @dev Returns the integer division of two unsigned integers. Reverts on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        return div(a, b, "SafeMath: division by zero");
    }
    /**
     * @dev Returns the integer division of two unsigned integers. Reverts with custom message on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     * - The divisor cannot be zero.
     *
     * _Available since v2.4.0._
     */
    function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        // Solidity only automatically asserts when dividing by 0
        require(b > 0, errorMessage);
        uint256 c = a / b;
        // assert(a == b * c + a % b); // There is no case in which this doesn't hold
        return c;
    }
    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * Reverts when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     * - The divisor cannot be zero.
     */
    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        return mod(a, b, "SafeMath: modulo by zero");
    }
    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * Reverts with custom message when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     * - The divisor cannot be zero.
     *
     * _Available since v2.4.0._
     */
    function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b != 0, errorMessage);
        return a % b;
    }
}
pragma solidity ^0.5.0;
import "@openzeppelin/upgrades/contracts/Initializable.sol";
import "../../GSN/Context.sol";
import "./IERC20.sol";
import "../../math/SafeMath.sol";
/**
 * @dev Implementation of the {IERC20} interface.
 *
 * This implementation is agnostic to the way tokens are created. This means
 * that a supply mechanism has to be added in a derived contract using {_mint}.
 * For a generic mechanism see {ERC20Mintable}.
 *
 * TIP: For a detailed writeup see our guide
 * https://forum.zeppelin.solutions/t/how-to-implement-erc20-supply-mechanisms/226[How
 * to implement supply mechanisms].
 *
 * We have followed general OpenZeppelin guidelines: functions revert instead
 * of returning `false` on failure. This behavior is nonetheless conventional
 * and does not conflict with the expectations of ERC20 applications.
 *
 * Additionally, an {Approval} event is emitted on calls to {transferFrom}.
 * This allows applications to reconstruct the allowance for all accounts just
 * by listening to said events. Other implementations of the EIP may not emit
 * these events, as it isn't required by the specification.
 *
 * Finally, the non-standard {decreaseAllowance} and {increaseAllowance}
 * functions have been added to mitigate the well-known issues around setting
 * allowances. See {IERC20-approve}.
 */
contract ERC20 is Initializable, Context, IERC20 {
    using SafeMath for uint256;
    mapping (address => uint256) private _balances;
    mapping (address => mapping (address => uint256)) private _allowances;
    uint256 private _totalSupply;
    /**
     * @dev See {IERC20-totalSupply}.
     */
    function totalSupply() public view returns (uint256) {
        return _totalSupply;
    }
    /**
     * @dev See {IERC20-balanceOf}.
     */
    function balanceOf(address account) public view returns (uint256) {
        return _balances[account];
    }
    /**
     * @dev See {IERC20-transfer}.
     *
     * Requirements:
     *
     * - `recipient` cannot be the zero address.
     * - the caller must have a balance of at least `amount`.
     */
    function transfer(address recipient, uint256 amount) public returns (bool) {
        _transfer(_msgSender(), recipient, amount);
        return true;
    }
    /**
     * @dev See {IERC20-allowance}.
     */
    function allowance(address owner, address spender) public view returns (uint256) {
        return _allowances[owner][spender];
    }
    /**
     * @dev See {IERC20-approve}.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     */
    function approve(address spender, uint256 amount) public returns (bool) {
        _approve(_msgSender(), spender, amount);
        return true;
    }
    /**
     * @dev See {IERC20-transferFrom}.
     *
     * Emits an {Approval} event indicating the updated allowance. This is not
     * required by the EIP. See the note at the beginning of {ERC20};
     *
     * Requirements:
     * - `sender` and `recipient` cannot be the zero address.
     * - `sender` must have a balance of at least `amount`.
     * - the caller must have allowance for `sender`'s tokens of at least
     * `amount`.
     */
    function transferFrom(address sender, address recipient, uint256 amount) public returns (bool) {
        _transfer(sender, recipient, amount);
        _approve(sender, _msgSender(), _allowances[sender][_msgSender()].sub(amount, "ERC20: transfer amount exceeds allowance"));
        return true;
    }
    /**
     * @dev Atomically increases the allowance granted to `spender` by the caller.
     *
     * This is an alternative to {approve} that can be used as a mitigation for
     * problems described in {IERC20-approve}.
     *
     * Emits an {Approval} event indicating the updated allowance.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     */
    function increaseAllowance(address spender, uint256 addedValue) public returns (bool) {
        _approve(_msgSender(), spender, _allowances[_msgSender()][spender].add(addedValue));
        return true;
    }
    /**
     * @dev Atomically decreases the allowance granted to `spender` by the caller.
     *
     * This is an alternative to {approve} that can be used as a mitigation for
     * problems described in {IERC20-approve}.
     *
     * Emits an {Approval} event indicating the updated allowance.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     * - `spender` must have allowance for the caller of at least
     * `subtractedValue`.
     */
    function decreaseAllowance(address spender, uint256 subtractedValue) public returns (bool) {
        _approve(_msgSender(), spender, _allowances[_msgSender()][spender].sub(subtractedValue, "ERC20: decreased allowance below zero"));
        return true;
    }
    /**
     * @dev Moves tokens `amount` from `sender` to `recipient`.
     *
     * This is internal function is equivalent to {transfer}, and can be used to
     * e.g. implement automatic token fees, slashing mechanisms, etc.
     *
     * Emits a {Transfer} event.
     *
     * Requirements:
     *
     * - `sender` cannot be the zero address.
     * - `recipient` cannot be the zero address.
     * - `sender` must have a balance of at least `amount`.
     */
    function _transfer(address sender, address recipient, uint256 amount) internal {
        require(sender != address(0), "ERC20: transfer from the zero address");
        require(recipient != address(0), "ERC20: transfer to the zero address");
        _balances[sender] = _balances[sender].sub(amount, "ERC20: transfer amount exceeds balance");
        _balances[recipient] = _balances[recipient].add(amount);
        emit Transfer(sender, recipient, amount);
    }
    /** @dev Creates `amount` tokens and assigns them to `account`, increasing
     * the total supply.
     *
     * Emits a {Transfer} event with `from` set to the zero address.
     *
     * Requirements
     *
     * - `to` cannot be the zero address.
     */
    function _mint(address account, uint256 amount) internal {
        require(account != address(0), "ERC20: mint to the zero address");
        _totalSupply = _totalSupply.add(amount);
        _balances[account] = _balances[account].add(amount);
        emit Transfer(address(0), account, amount);
    }
    /**
     * @dev Destroys `amount` tokens from `account`, reducing the
     * total supply.
     *
     * Emits a {Transfer} event with `to` set to the zero address.
     *
     * Requirements
     *
     * - `account` cannot be the zero address.
     * - `account` must have at least `amount` tokens.
     */
    function _burn(address account, uint256 amount) internal {
        require(account != address(0), "ERC20: burn from the zero address");
        _balances[account] = _balances[account].sub(amount, "ERC20: burn amount exceeds balance");
        _totalSupply = _totalSupply.sub(amount);
        emit Transfer(account, address(0), amount);
    }
    /**
     * @dev Sets `amount` as the allowance of `spender` over the `owner`s tokens.
     *
     * This is internal function is equivalent to `approve`, and can be used to
     * e.g. set automatic allowances for certain subsystems, etc.
     *
     * Emits an {Approval} event.
     *
     * Requirements:
     *
     * - `owner` cannot be the zero address.
     * - `spender` cannot be the zero address.
     */
    function _approve(address owner, address spender, uint256 amount) internal {
        require(owner != address(0), "ERC20: approve from the zero address");
        require(spender != address(0), "ERC20: approve to the zero address");
        _allowances[owner][spender] = amount;
        emit Approval(owner, spender, amount);
    }
    /**
     * @dev Destroys `amount` tokens from `account`.`amount` is then deducted
     * from the caller's allowance.
     *
     * See {_burn} and {_approve}.
     */
    function _burnFrom(address account, uint256 amount) internal {
        _burn(account, amount);
        _approve(account, _msgSender(), _allowances[account][_msgSender()].sub(amount, "ERC20: burn amount exceeds allowance"));
    }
    uint256[50] private ______gap;
}
pragma solidity ^0.5.0;
import "@openzeppelin/upgrades/contracts/Initializable.sol";
import "./IERC20.sol";
/**
 * @dev Optional functions from the ERC20 standard.
 */
contract ERC20Detailed is Initializable, IERC20 {
    string private _name;
    string private _symbol;
    uint8 private _decimals;
    /**
     * @dev Sets the values for `name`, `symbol`, and `decimals`. All three of
     * these values are immutable: they can only be set once during
     * construction.
     */
    function initialize(string memory name, string memory symbol, uint8 decimals) public initializer {
        _name = name;
        _symbol = symbol;
        _decimals = decimals;
    }
    /**
     * @dev Returns the name of the token.
     */
    function name() public view returns (string memory) {
        return _name;
    }
    /**
     * @dev Returns the symbol of the token, usually a shorter version of the
     * name.
     */
    function symbol() public view returns (string memory) {
        return _symbol;
    }
    /**
     * @dev Returns the number of decimals used to get its user representation.
     * For example, if `decimals` equals `2`, a balance of `505` tokens should
     * be displayed to a user as `5,05` (`505 / 10 ** 2`).
     *
     * Tokens usually opt for a value of 18, imitating the relationship between
     * Ether and Wei.
     *
     * NOTE: This information is only used for _display_ purposes: it in
     * no way affects any of the arithmetic of the contract, including
     * {IERC20-balanceOf} and {IERC20-transfer}.
     */
    function decimals() public view returns (uint8) {
        return _decimals;
    }
    uint256[50] private ______gap;
}
pragma solidity ^0.5.0;
/**
 * @dev Interface of the ERC20 standard as defined in the EIP. Does not include
 * the optional functions; to access them see {ERC20Detailed}.
 */
interface IERC20 {
    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);
    /**
     * @dev Returns the amount of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);
    /**
     * @dev Moves `amount` tokens from the caller's account to `recipient`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address recipient, uint256 amount) external returns (bool);
    /**
     * @dev Returns the remaining number of tokens that `spender` will be
     * allowed to spend on behalf of `owner` through {transferFrom}. This is
     * zero by default.
     *
     * This value changes when {approve} or {transferFrom} are called.
     */
    function allowance(address owner, address spender) external view returns (uint256);
    /**
     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * IMPORTANT: Beware that changing an allowance with this method brings the risk
     * that someone may use both the old and the new allowance by unfortunate
     * transaction ordering. One possible solution to mitigate this race
     * condition is to first reduce the spender's allowance to 0 and set the
     * desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     *
     * Emits an {Approval} event.
     */
    function approve(address spender, uint256 amount) external returns (bool);
    /**
     * @dev Moves `amount` tokens from `sender` to `recipient` using the
     * allowance mechanism. `amount` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);
    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);
    /**
     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
     * a call to {approve}. `value` is the new allowance.
     */
    event Approval(address indexed owner, address indexed spender, uint256 value);
}
pragma solidity ^0.5.0;
import "./IERC20.sol";
import "../../math/SafeMath.sol";
import "../../utils/Address.sol";
/**
 * @title SafeERC20
 * @dev Wrappers around ERC20 operations that throw on failure (when the token
 * contract returns false). Tokens that return no value (and instead revert or
 * throw on failure) are also supported, non-reverting calls are assumed to be
 * successful.
 * To use this library you can add a `using SafeERC20 for ERC20;` statement to your contract,
 * which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
 */
library SafeERC20 {
    using SafeMath for uint256;
    using Address for address;
    function safeTransfer(IERC20 token, address to, uint256 value) internal {
        callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
    }
    function safeTransferFrom(IERC20 token, address from, address to, uint256 value) internal {
        callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
    }
    function safeApprove(IERC20 token, address spender, uint256 value) internal {
        // safeApprove should only be called when setting an initial allowance,
        // or when resetting it to zero. To increase and decrease it, use
        // 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
        // solhint-disable-next-line max-line-length
        require((value == 0) || (token.allowance(address(this), spender) == 0),
            "SafeERC20: approve from non-zero to non-zero allowance"
        );
        callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
    }
    function safeIncreaseAllowance(IERC20 token, address spender, uint256 value) internal {
        uint256 newAllowance = token.allowance(address(this), spender).add(value);
        callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
    }
    function safeDecreaseAllowance(IERC20 token, address spender, uint256 value) internal {
        uint256 newAllowance = token.allowance(address(this), spender).sub(value, "SafeERC20: decreased allowance below zero");
        callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
    }
    /**
     * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
     * on the return value: the return value is optional (but if data is returned, it must not be false).
     * @param token The token targeted by the call.
     * @param data The call data (encoded using abi.encode or one of its variants).
     */
    function callOptionalReturn(IERC20 token, bytes memory data) private {
        // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
        // we're implementing it ourselves.
        // A Solidity high level call has three parts:
        //  1. The target address is checked to verify it contains contract code
        //  2. The call itself is made, and success asserted
        //  3. The return value is decoded, which in turn checks the size of the returned data.
        // solhint-disable-next-line max-line-length
        require(address(token).isContract(), "SafeERC20: call to non-contract");
        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = address(token).call(data);
        require(success, "SafeERC20: low-level call failed");
        if (returndata.length > 0) { // Return data is optional
            // solhint-disable-next-line max-line-length
            require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
        }
    }
}
pragma solidity ^0.5.5;
/**
 * @dev Collection of functions related to the address type
 */
library Address {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * [IMPORTANT]
     * ====
     * It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     *
     * Among others, `isContract` will return false for the following 
     * types of addresses:
     *
     *  - an externally-owned account
     *  - a contract in construction
     *  - an address where a contract will be created
     *  - an address where a contract lived, but was destroyed
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // According to EIP-1052, 0x0 is the value returned for not-yet created accounts
        // and 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470 is returned
        // for accounts without code, i.e. `keccak256('')`
        bytes32 codehash;
        bytes32 accountHash = 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470;
        // solhint-disable-next-line no-inline-assembly
        assembly { codehash := extcodehash(account) }
        return (codehash != accountHash && codehash != 0x0);
    }
    /**
     * @dev Converts an `address` into `address payable`. Note that this is
     * simply a type cast: the actual underlying value is not changed.
     *
     * _Available since v2.4.0._
     */
    function toPayable(address account) internal pure returns (address payable) {
        return address(uint160(account));
    }
    /**
     * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
     * `recipient`, forwarding all available gas and reverting on errors.
     *
     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
     * of certain opcodes, possibly making contracts go over the 2300 gas limit
     * imposed by `transfer`, making them unable to receive funds via
     * `transfer`. {sendValue} removes this limitation.
     *
     * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
     *
     * IMPORTANT: because control is transferred to `recipient`, care must be
     * taken to not create reentrancy vulnerabilities. Consider using
     * {ReentrancyGuard} or the
     * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     *
     * _Available since v2.4.0._
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");
        // solhint-disable-next-line avoid-call-value
        (bool success, ) = recipient.call.value(amount)("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }
}
pragma solidity ^0.5.0;
import "@openzeppelin/upgrades/contracts/Initializable.sol";
/**
 * @dev Contract module that helps prevent reentrant calls to a function.
 *
 * Inheriting from `ReentrancyGuard` will make the {nonReentrant} modifier
 * available, which can be applied to functions to make sure there are no nested
 * (reentrant) calls to them.
 *
 * Note that because there is a single `nonReentrant` guard, functions marked as
 * `nonReentrant` may not call one another. This can be worked around by making
 * those functions `private`, and then adding `external` `nonReentrant` entry
 * points to them.
 */
contract ReentrancyGuard is Initializable {
    // counter to allow mutex lock with only one SSTORE operation
    uint256 private _guardCounter;
    function initialize() public initializer {
        // The counter starts at one to prevent changing it from zero to a non-zero
        // value, which is a more expensive operation.
        _guardCounter = 1;
    }
    /**
     * @dev Prevents a contract from calling itself, directly or indirectly.
     * Calling a `nonReentrant` function from another `nonReentrant`
     * function is not supported. It is possible to prevent this from happening
     * by making the `nonReentrant` function external, and make it call a
     * `private` function that does the actual work.
     */
    modifier nonReentrant() {
        _guardCounter += 1;
        uint256 localCounter = _guardCounter;
        _;
        require(localCounter == _guardCounter, "ReentrancyGuard: reentrant call");
    }
    uint256[50] private ______gap;
}
pragma solidity >=0.4.24 <0.7.0;
/**
 * @title Initializable
 *
 * @dev Helper contract to support initializer functions. To use it, replace
 * the constructor with a function that has the `initializer` modifier.
 * WARNING: Unlike constructors, initializer functions must be manually
 * invoked. This applies both to deploying an Initializable contract, as well
 * as extending an Initializable contract via inheritance.
 * WARNING: When used with inheritance, manual care must be taken to not invoke
 * a parent initializer twice, or ensure that all initializers are idempotent,
 * because this is not dealt with automatically as with constructors.
 */
contract Initializable {
  /**
   * @dev Indicates that the contract has been initialized.
   */
  bool private initialized;
  /**
   * @dev Indicates that the contract is in the process of being initialized.
   */
  bool private initializing;
  /**
   * @dev Modifier to use in the initializer function of a contract.
   */
  modifier initializer() {
    require(initializing || isConstructor() || !initialized, "Contract instance has already been initialized");
    bool isTopLevelCall = !initializing;
    if (isTopLevelCall) {
      initializing = true;
      initialized = true;
    }
    _;
    if (isTopLevelCall) {
      initializing = false;
    }
  }
  /// @dev Returns true if and only if the function is running in the constructor
  function isConstructor() private view returns (bool) {
    // extcodesize checks the size of the code stored in an address, and
    // address returns the current address. Since the code is still not
    // deployed when running a constructor, any checks on its code size will
    // yield zero, making it an effective way to detect if a contract is
    // under construction or not.
    address self = address(this);
    uint256 cs;
    assembly { cs := extcodesize(self) }
    return cs == 0;
  }
  // Reserved storage space to allow for layout changes in the future.
  uint256[50] private ______gap;
}

pragma solidity 0.5.16;
import "./Governable.sol";
contract Controllable is Governable {
    constructor(address _storage) public Governable(_storage) {}
    modifier onlyController() {
        require(store.isController(msg.sender), "Not a controller");
        _;
    }
    modifier onlyControllerOrGovernance() {
        require(
            (store.isController(msg.sender) || store.isGovernance(msg.sender)),
            "The caller must be controller or governance"
        );
        _;
    }
    function controller() public view returns (address) {
        return store.controller();
    }
}
pragma solidity 0.5.16;
import "./Storage.sol";
contract Governable {
    Storage public store;
    constructor(address _store) public {
        require(_store != address(0), "new storage shouldn't be empty");
        store = Storage(_store);
    }
    modifier onlyGovernance() {
        require(store.isGovernance(msg.sender), "Not governance");
        _;
    }
    function setStorage(address _store) public onlyGovernance {
        require(_store != address(0), "new storage shouldn't be empty");
        store = Storage(_store);
    }
    function governance() public view returns (address) {
        return store.governance();
    }
}
pragma solidity 0.5.16;
contract Storage {
    address public governance;
    address public controller;
    constructor() public {
        governance = msg.sender;
    }
    modifier onlyGovernance() {
        require(isGovernance(msg.sender), "Not governance");
        _;
    }
    function setGovernance(address _governance) public onlyGovernance {
        require(_governance != address(0), "new governance shouldn't be empty");
        governance = _governance;
    }
    function setController(address _controller) public onlyGovernance {
        require(_controller != address(0), "new controller shouldn't be empty");
        controller = _controller;
    }
    function isGovernance(address account) public view returns (bool) {
        return account == governance;
    }
    function isController(address account) public view returns (bool) {
        return account == controller;
    }
}
pragma solidity 0.5.16;
interface IController {
    function whiteList(address _target) external view returns (bool);
    function addVaultAndStrategy(address _vault, address _strategy) external;
    function forceUnleashed(address _vault) external;
    function hasVault(address _vault) external returns (bool);
    function salvage(address _token, uint256 amount) external;
    function salvageStrategy(
        address _strategy,
        address _token,
        uint256 amount
    ) external;
    function notifyFee(address _underlying, uint256 fee) external;
    function profitSharingNumerator() external view returns (uint256);
    function profitSharingDenominator() external view returns (uint256);
    function treasury() external view returns (address);
}
pragma solidity 0.5.16;
interface IStrategy {
    function unsalvagableTokens(address tokens) external view returns (bool);
    function governance() external view returns (address);
    function controller() external view returns (address);
    function underlying() external view returns (address);
    function vault() external view returns (address);
    function withdrawAllToVault() external;
    function withdrawToVault(uint256 amount) external;
    function investedUnderlyingBalance() external view returns (uint256); // itsNotMuch()
    // should only be called by controller
    function salvage(
        address recipient,
        address token,
        uint256 amount
    ) external;
    function forceUnleashed() external;
    function depositArbCheck() external view returns (bool);
}
pragma solidity 0.5.16;
interface IVault {
    function underlyingBalanceInVault() external view returns (uint256);
    function underlyingBalanceWithInvestment() external view returns (uint256);
    function governance() external view returns (address);
    function controller() external view returns (address);
    function underlying() external view returns (address);
    function strategy() external view returns (address);
    function setStrategy(address _strategy) external;
    function setVaultFractionToInvest(uint256 numerator, uint256 denominator)
        external;
    function deposit(uint256 amountWei) external;
    function depositFor(uint256 amountWei, address holder) external;
    function withdrawAll() external;
    function withdraw(uint256 numberOfShares) external;
    function getPricePerFullShare() external view returns (uint256);
    function underlyingBalanceWithInvestmentForHolder(address holder)
        external
        view
        returns (uint256);
    // force unleash should be callable only by the controller (by the force unleasher) or by governance
    function forceUnleashed() external;
    function rebalance() external;
}
pragma solidity 0.5.16;
import "@openzeppelin/contracts/math/SafeMath.sol";
import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/token/ERC20/SafeERC20.sol";
import "../interfaces/IController.sol";
import "../Controllable.sol";
contract RewardTokenProfitNotifier is Controllable {
    using SafeMath for uint256;
    using SafeERC20 for IERC20;
    uint256 public profitSharingNumerator;
    uint256 public profitSharingDenominator;
    address public rewardToken;
    constructor(address _storage, address _rewardToken)
        public
        Controllable(_storage)
    {
        rewardToken = _rewardToken;
        profitSharingNumerator = 0;
        profitSharingDenominator = 100;
        require(
            profitSharingNumerator < profitSharingDenominator,
            "invalid profit share"
        );
    }
    event ProfitLogInReward(
        uint256 profitAmount,
        uint256 feeAmount,
        uint256 timestamp
    );
    function notifyProfitInRewardToken(uint256 _rewardBalance) internal {
        if (_rewardBalance > 0 && profitSharingNumerator > 0) {
            uint256 feeAmount =
                _rewardBalance.mul(profitSharingNumerator).div(
                    profitSharingDenominator
                );
            emit ProfitLogInReward(_rewardBalance, feeAmount, block.timestamp);
            IERC20(rewardToken).safeApprove(controller(), 0);
            IERC20(rewardToken).safeApprove(controller(), feeAmount);
            IController(controller()).notifyFee(rewardToken, feeAmount);
        } else {
            emit ProfitLogInReward(0, 0, block.timestamp);
        }
    }
    function setProfitSharingNumerator(uint256 _profitSharingNumerator)
        external
        onlyGovernance
    {
        profitSharingNumerator = _profitSharingNumerator;
    }
}
pragma solidity 0.5.16;
contract IIdleTokenHelper {
    function getMintingPrice(address idleYieldToken)
        external
        view
        returns (uint256 mintingPrice);
    function getRedeemPrice(address idleYieldToken)
        external
        view
        returns (uint256 redeemPrice);
    function getRedeemPrice(address idleYieldToken, address user)
        external
        view
        returns (uint256 redeemPrice);
}
pragma solidity 0.5.16;
import "@openzeppelin/contracts/math/Math.sol";
import "@openzeppelin/contracts/math/SafeMath.sol";
import "@openzeppelin/contracts/token/ERC20/ERC20Detailed.sol";
import "@openzeppelin/contracts/token/ERC20/SafeERC20.sol";
import "../../Controllable.sol";
import "../../interfaces/IStrategy.sol";
import "../../uniswap/interfaces/IUniswapV2Router02.sol";
import "./IdleToken.sol";
import "./IIdleTokenHelper.sol";
import "../RewardTokenProfitNotifier.sol";
import "../../interfaces/IVault.sol";
contract IdleFinanceStrategy is IStrategy, RewardTokenProfitNotifier {
    using SafeMath for uint256;
    using SafeERC20 for IERC20;
    event ProfitsNotCollected(address);
    event Liquidating(address, uint256);
    IERC20 public underlying;
    address public idleUnderlying;
    uint256 public virtualPrice;
    IIdleTokenHelper public idleTokenHelper;
    address public vault;
    address public comp;
    address public idle;
    address[] public uniswapComp;
    address[] public uniswapIdle;
    address public uniswapRouterV2;
    bool public sellComp;
    bool public sellIdle;
    bool public claimAllowed;
    bool public protected;
    // These tokens cannot be claimed by the controller
    mapping(address => bool) public unsalvagableTokens;
    modifier restricted() {
        require(
            msg.sender == vault ||
                msg.sender == address(controller()) ||
                msg.sender == address(governance()),
            "The sender has to be the controller or vault or governance"
        );
        _;
    }
    modifier updateVirtualPrice() {
        if (protected) {
            require(
                virtualPrice <= idleTokenHelper.getRedeemPrice(idleUnderlying),
                "virtual price is higher than needed"
            );
        }
        _;
        virtualPrice = idleTokenHelper.getRedeemPrice(idleUnderlying);
    }
    constructor(
        address _storage,
        address _underlying,
        address _idleUnderlying,
        address _vault,
        address _comp,
        address _idle,
        address _weth,
        address _uniswap
    ) public RewardTokenProfitNotifier(_storage, _idle) {
        comp = _comp;
        idle = _idle;
        underlying = IERC20(_underlying);
        idleUnderlying = _idleUnderlying;
        vault = _vault;
        uniswapRouterV2 = _uniswap;
        protected = true;
        // set these tokens to be not salvagable
        unsalvagableTokens[_underlying] = true;
        unsalvagableTokens[_idleUnderlying] = true;
        unsalvagableTokens[_comp] = true;
        unsalvagableTokens[_idle] = true;
        uniswapComp = [_comp, _weth, _idle];
        uniswapIdle = [_idle, _weth, _underlying];
        idleTokenHelper = IIdleTokenHelper(
            0x04Ce60ed10F6D2CfF3AA015fc7b950D13c113be5
        );
        virtualPrice = idleTokenHelper.getRedeemPrice(idleUnderlying);
    }
    function depositArbCheck() public view returns (bool) {
        return true;
    }
    /**
     * The strategy invests by supplying the underlying token into IDLE.
     */
    function investAllUnderlying() public restricted updateVirtualPrice {
        uint256 balance = underlying.balanceOf(address(this));
        underlying.safeApprove(address(idleUnderlying), 0);
        underlying.safeApprove(address(idleUnderlying), balance);
        IIdleTokenV3_1(idleUnderlying).mintIdleToken(balance, true, address(0));
    }
    /**
     * Exits IDLE and transfers everything to the vault.
     */
    function withdrawAllToVault() external restricted updateVirtualPrice {
        withdrawAll();
        IERC20(address(underlying)).safeTransfer(
            vault,
            underlying.balanceOf(address(this))
        );
    }
    /**
     * Withdraws all from IDLE
     */
    function withdrawAll() internal {
        uint256 balance = IERC20(idleUnderlying).balanceOf(address(this));
        // this automatically claims the crops
        IIdleTokenV3_1(idleUnderlying).redeemIdleToken(balance);
        liquidateComp();
        liquidateIdle();
    }
    function withdrawToVault(uint256 amountUnderlying) public restricted {
        // this method is called when the vault is missing funds
        // we will calculate the proportion of idle LP tokens that matches
        // the underlying amount requested
        uint256 balanceBefore = underlying.balanceOf(address(this));
        uint256 totalIdleLpTokens =
            IERC20(idleUnderlying).balanceOf(address(this));
        uint256 totalUnderlyingBalance =
            totalIdleLpTokens.mul(virtualPrice).div(1e18);
        uint256 ratio = amountUnderlying.mul(1e18).div(totalUnderlyingBalance);
        uint256 toRedeem = totalIdleLpTokens.mul(ratio).div(1e18);
        IIdleTokenV3_1(idleUnderlying).redeemIdleToken(toRedeem);
        uint256 balanceAfter = underlying.balanceOf(address(this));
        underlying.safeTransfer(vault, balanceAfter.sub(balanceBefore));
    }
    /**
     * Withdraws all assets, liquidates COMP, and invests again in the required ratio.
     */
    function forceUnleashed() public restricted updateVirtualPrice {
        if (claimAllowed) {
            claim();
        }
        liquidateComp();
        liquidateIdle();
        // this updates the virtual price
        investAllUnderlying();
        // state of supply/loan will be updated by the modifier
    }
    /**
     * Salvages a token.
     */
    function salvage(
        address recipient,
        address token,
        uint256 amount
    ) public onlyGovernance {
        // To make sure that governance cannot come in and take away the coins
        require(
            !unsalvagableTokens[token],
            "token is defined as not salvagable"
        );
        IERC20(token).safeTransfer(recipient, amount);
    }
    function claim() internal {
        IIdleTokenV3_1(idleUnderlying).redeemIdleToken(0);
    }
    function liquidateComp() internal {
        if (!sellComp) {
            // Profits can be disabled for possible simplified and rapid exit
            emit ProfitsNotCollected(comp);
            return;
        }
        // no profit notification, comp is liquidated to IDLE and will be notified there
        uint256 compBalance = IERC20(comp).balanceOf(address(this));
        if (compBalance > 0) {
            emit Liquidating(address(comp), compBalance);
            IERC20(comp).safeApprove(uniswapRouterV2, 0);
            IERC20(comp).safeApprove(uniswapRouterV2, compBalance);
            // we can accept 1 as the minimum because this will be called only by a trusted worker
            IUniswapV2Router02(uniswapRouterV2).swapExactTokensForTokens(
                compBalance,
                1,
                uniswapComp,
                address(this),
                block.timestamp
            );
        }
    }
    function liquidateIdle() internal {
        if (!sellIdle) {
            // Profits can be disabled for possible simplified and rapid exit
            emit ProfitsNotCollected(idle);
            return;
        }
        uint256 rewardBalance = IERC20(idle).balanceOf(address(this));
        notifyProfitInRewardToken(rewardBalance);
        uint256 idleBalance = IERC20(idle).balanceOf(address(this));
        if (idleBalance > 0) {
            emit Liquidating(address(idle), idleBalance);
            IERC20(idle).safeApprove(uniswapRouterV2, 0);
            IERC20(idle).safeApprove(uniswapRouterV2, idleBalance);
            // we can accept 1 as the minimum because this will be called only by a trusted worker
            IUniswapV2Router02(uniswapRouterV2).swapExactTokensForTokens(
                idleBalance,
                1,
                uniswapIdle,
                address(this),
                block.timestamp
            );
        }
    }
    /**
     * Returns the current balance. Ignores COMP that was not liquidated and invested.
     */
    function investedUnderlyingBalance() public view returns (uint256) {
        // NOTE: The use of virtual price is okay for appreciating assets inside IDLE,
        // but would be wrong and exploitable if funds were lost by IDLE, indicated by
        // the virtualPrice being greater than the token price.
        if (protected) {
            require(
                virtualPrice <= idleTokenHelper.getRedeemPrice(idleUnderlying),
                "virtual price is higher than needed"
            );
        }
        uint256 invested =
            IERC20(idleUnderlying)
                .balanceOf(address(this))
                .mul(virtualPrice)
                .div(1e18);
        return invested.add(IERC20(underlying).balanceOf(address(this)));
    }
    function setLiquidation(
        bool _sellComp,
        bool _sellIdle,
        bool _claimAllowed
    ) public onlyGovernance {
        sellComp = _sellComp;
        sellIdle = _sellIdle;
        claimAllowed = _claimAllowed;
    }
    function setProtected(bool _protected) public onlyGovernance {
        protected = _protected;
    }
}
pragma solidity 0.5.16;
import "./IdleFinanceStrategy.sol";
/**
 * Adds the mainnet addresses to the PickleStrategy3Pool
 */
contract IdleStrategyUSDTMainnet is IdleFinanceStrategy {
    // token addresses
    address public constant __weth =
        address(0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2);
    address public constant __usdt =
        address(0xdAC17F958D2ee523a2206206994597C13D831ec7);
    address public constant __uniswap =
        address(0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D);
    address public constant __idleUnderlying =
        address(0xF34842d05A1c888Ca02769A633DF37177415C2f8);
    address public constant __comp =
        address(0xc00e94Cb662C3520282E6f5717214004A7f26888);
    address public constant __idle =
        address(0x875773784Af8135eA0ef43b5a374AaD105c5D39e);
    constructor(address _storage, address _vault)
        public
        IdleFinanceStrategy(
            _storage,
            __usdt,
            __idleUnderlying,
            _vault,
            __comp,
            __idle,
            __weth,
            __uniswap
        )
    {}
}
/**
 * @title: Idle Token interface
 * @author: Idle Labs Inc., idle.finance
 */
pragma solidity 0.5.16;
interface IIdleTokenV3_1 {
    // view
    /**
     * IdleToken price calculation, in underlying
     *
     * @return : price in underlying token
     */
    function tokenPrice() external view returns (uint256 price);
    /**
     * @return : underlying token address
     */
    function token() external view returns (address);
    /**
     * Get APR of every ILendingProtocol
     *
     * @return addresses: array of token addresses
     * @return aprs: array of aprs (ordered in respect to the `addresses` array)
     */
    function getAPRs()
        external
        view
        returns (address[] memory addresses, uint256[] memory aprs);
    // external
    // We should save the amount one has deposited to calc interests
    /**
     * Used to mint IdleTokens, given an underlying amount (eg. DAI).
     * This method triggers a rebalance of the pools if needed
     * NOTE: User should 'approve' _amount of tokens before calling mintIdleToken
     * NOTE 2: this method can be paused
     *
     * @param _amount : amount of underlying token to be lended
     * @param _skipRebalance : flag for skipping rebalance for lower gas price
     * @param _referral : referral address
     * @return mintedTokens : amount of IdleTokens minted
     */
    function mintIdleToken(
        uint256 _amount,
        bool _skipRebalance,
        address _referral
    ) external returns (uint256 mintedTokens);
    /**
     * Here we calc the pool share one can withdraw given the amount of IdleToken they want to burn
     * This method triggers a rebalance of the pools if needed
     * NOTE: If the contract is paused or iToken price has decreased one can still redeem but no rebalance happens.
     * NOTE 2: If iToken price has decresed one should not redeem (but can do it) otherwise he would capitalize the loss.
     *         Ideally one should wait until the black swan event is terminated
     *
     * @param _amount : amount of IdleTokens to be burned
     * @return redeemedTokens : amount of underlying tokens redeemed
     */
    function redeemIdleToken(uint256 _amount)
        external
        returns (uint256 redeemedTokens);
    /**
     * Here we calc the pool share one can withdraw given the amount of IdleToken they want to burn
     * and send interest-bearing tokens (eg. cDAI/iDAI) directly to the user.
     * Underlying (eg. DAI) is not redeemed here.
     *
     * @param _amount : amount of IdleTokens to be burned
     */
    function redeemInterestBearingTokens(uint256 _amount) external;
    /**
     * @return : whether has rebalanced or not
     */
    function rebalance() external returns (bool);
}
pragma solidity >=0.5.0;
interface IUniswapV2Router01 {
    function factory() external pure returns (address);
    function WETH() external pure returns (address);
    function addLiquidity(
        address tokenA,
        address tokenB,
        uint256 amountADesired,
        uint256 amountBDesired,
        uint256 amountAMin,
        uint256 amountBMin,
        address to,
        uint256 deadline
    )
        external
        returns (
            uint256 amountA,
            uint256 amountB,
            uint256 liquidity
        );
    function addLiquidityETH(
        address token,
        uint256 amountTokenDesired,
        uint256 amountTokenMin,
        uint256 amountETHMin,
        address to,
        uint256 deadline
    )
        external
        payable
        returns (
            uint256 amountToken,
            uint256 amountETH,
            uint256 liquidity
        );
    function removeLiquidity(
        address tokenA,
        address tokenB,
        uint256 liquidity,
        uint256 amountAMin,
        uint256 amountBMin,
        address to,
        uint256 deadline
    ) external returns (uint256 amountA, uint256 amountB);
    function removeLiquidityETH(
        address token,
        uint256 liquidity,
        uint256 amountTokenMin,
        uint256 amountETHMin,
        address to,
        uint256 deadline
    ) external returns (uint256 amountToken, uint256 amountETH);
    function removeLiquidityWithPermit(
        address tokenA,
        address tokenB,
        uint256 liquidity,
        uint256 amountAMin,
        uint256 amountBMin,
        address to,
        uint256 deadline,
        bool approveMax,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external returns (uint256 amountA, uint256 amountB);
    function removeLiquidityETHWithPermit(
        address token,
        uint256 liquidity,
        uint256 amountTokenMin,
        uint256 amountETHMin,
        address to,
        uint256 deadline,
        bool approveMax,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external returns (uint256 amountToken, uint256 amountETH);
    function swapExactTokensForTokens(
        uint256 amountIn,
        uint256 amountOutMin,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external returns (uint256[] memory amounts);
    function swapTokensForExactTokens(
        uint256 amountOut,
        uint256 amountInMax,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external returns (uint256[] memory amounts);
    function swapExactETHForTokens(
        uint256 amountOutMin,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external payable returns (uint256[] memory amounts);
    function swapTokensForExactETH(
        uint256 amountOut,
        uint256 amountInMax,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external returns (uint256[] memory amounts);
    function swapExactTokensForETH(
        uint256 amountIn,
        uint256 amountOutMin,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external returns (uint256[] memory amounts);
    function swapETHForExactTokens(
        uint256 amountOut,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external payable returns (uint256[] memory amounts);
    function quote(
        uint256 amountA,
        uint256 reserveA,
        uint256 reserveB
    ) external pure returns (uint256 amountB);
    function getAmountOut(
        uint256 amountIn,
        uint256 reserveIn,
        uint256 reserveOut
    ) external pure returns (uint256 amountOut);
    function getAmountIn(
        uint256 amountOut,
        uint256 reserveIn,
        uint256 reserveOut
    ) external pure returns (uint256 amountIn);
    function getAmountsOut(uint256 amountIn, address[] calldata path)
        external
        view
        returns (uint256[] memory amounts);
    function getAmountsIn(uint256 amountOut, address[] calldata path)
        external
        view
        returns (uint256[] memory amounts);
}
pragma solidity >=0.5.0;
import "./IUniswapV2Router01.sol";
interface IUniswapV2Router02 {
    function factory() external pure returns (address);
    function WETH() external pure returns (address);
    function addLiquidity(
        address tokenA,
        address tokenB,
        uint256 amountADesired,
        uint256 amountBDesired,
        uint256 amountAMin,
        uint256 amountBMin,
        address to,
        uint256 deadline
    )
        external
        returns (
            uint256 amountA,
            uint256 amountB,
            uint256 liquidity
        );
    function addLiquidityETH(
        address token,
        uint256 amountTokenDesired,
        uint256 amountTokenMin,
        uint256 amountETHMin,
        address to,
        uint256 deadline
    )
        external
        payable
        returns (
            uint256 amountToken,
            uint256 amountETH,
            uint256 liquidity
        );
    function removeLiquidity(
        address tokenA,
        address tokenB,
        uint256 liquidity,
        uint256 amountAMin,
        uint256 amountBMin,
        address to,
        uint256 deadline
    ) external returns (uint256 amountA, uint256 amountB);
    function removeLiquidityETH(
        address token,
        uint256 liquidity,
        uint256 amountTokenMin,
        uint256 amountETHMin,
        address to,
        uint256 deadline
    ) external returns (uint256 amountToken, uint256 amountETH);
    function removeLiquidityWithPermit(
        address tokenA,
        address tokenB,
        uint256 liquidity,
        uint256 amountAMin,
        uint256 amountBMin,
        address to,
        uint256 deadline,
        bool approveMax,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external returns (uint256 amountA, uint256 amountB);
    function removeLiquidityETHWithPermit(
        address token,
        uint256 liquidity,
        uint256 amountTokenMin,
        uint256 amountETHMin,
        address to,
        uint256 deadline,
        bool approveMax,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external returns (uint256 amountToken, uint256 amountETH);
    function swapExactTokensForTokens(
        uint256 amountIn,
        uint256 amountOutMin,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external returns (uint256[] memory amounts);
    function swapTokensForExactTokens(
        uint256 amountOut,
        uint256 amountInMax,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external returns (uint256[] memory amounts);
    function swapExactETHForTokens(
        uint256 amountOutMin,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external payable returns (uint256[] memory amounts);
    function swapTokensForExactETH(
        uint256 amountOut,
        uint256 amountInMax,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external returns (uint256[] memory amounts);
    function swapExactTokensForETH(
        uint256 amountIn,
        uint256 amountOutMin,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external returns (uint256[] memory amounts);
    function swapETHForExactTokens(
        uint256 amountOut,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external payable returns (uint256[] memory amounts);
    function quote(
        uint256 amountA,
        uint256 reserveA,
        uint256 reserveB
    ) external pure returns (uint256 amountB);
    function getAmountOut(
        uint256 amountIn,
        uint256 reserveIn,
        uint256 reserveOut
    ) external pure returns (uint256 amountOut);
    function getAmountIn(
        uint256 amountOut,
        uint256 reserveIn,
        uint256 reserveOut
    ) external pure returns (uint256 amountIn);
    function getAmountsOut(uint256 amountIn, address[] calldata path)
        external
        view
        returns (uint256[] memory amounts);
    function getAmountsIn(uint256 amountOut, address[] calldata path)
        external
        view
        returns (uint256[] memory amounts);
    function removeLiquidityETHSupportingFeeOnTransferTokens(
        address token,
        uint256 liquidity,
        uint256 amountTokenMin,
        uint256 amountETHMin,
        address to,
        uint256 deadline
    ) external returns (uint256 amountETH);
    function removeLiquidityETHWithPermitSupportingFeeOnTransferTokens(
        address token,
        uint256 liquidity,
        uint256 amountTokenMin,
        uint256 amountETHMin,
        address to,
        uint256 deadline,
        bool approveMax,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external returns (uint256 amountETH);
    function swapExactTokensForTokensSupportingFeeOnTransferTokens(
        uint256 amountIn,
        uint256 amountOutMin,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external;
    function swapExactETHForTokensSupportingFeeOnTransferTokens(
        uint256 amountOutMin,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external payable;
    function swapExactTokensForETHSupportingFeeOnTransferTokens(
        uint256 amountIn,
        uint256 amountOutMin,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external;
}
pragma solidity ^0.5.0;
/**
 * @dev Standard math utilities missing in the Solidity language.
 */
library Math {
    /**
     * @dev Returns the largest of two numbers.
     */
    function max(uint256 a, uint256 b) internal pure returns (uint256) {
        return a >= b ? a : b;
    }
    /**
     * @dev Returns the smallest of two numbers.
     */
    function min(uint256 a, uint256 b) internal pure returns (uint256) {
        return a < b ? a : b;
    }
    /**
     * @dev Returns the average of two numbers. The result is rounded towards
     * zero.
     */
    function average(uint256 a, uint256 b) internal pure returns (uint256) {
        // (a + b) / 2 can overflow, so we distribute
        return (a / 2) + (b / 2) + ((a % 2 + b % 2) / 2);
    }
}
pragma solidity ^0.5.0;
/**
 * @dev Wrappers over Solidity's arithmetic operations with added overflow
 * checks.
 *
 * Arithmetic operations in Solidity wrap on overflow. This can easily result
 * in bugs, because programmers usually assume that an overflow raises an
 * error, which is the standard behavior in high level programming languages.
 * `SafeMath` restores this intuition by reverting the transaction when an
 * operation overflows.
 *
 * Using this library instead of the unchecked operations eliminates an entire
 * class of bugs, so it's recommended to use it always.
 */
library SafeMath {
    /**
     * @dev Returns the addition of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `+` operator.
     *
     * Requirements:
     * - Addition cannot overflow.
     */
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        require(c >= a, "SafeMath: addition overflow");
        return c;
    }
    /**
     * @dev Returns the subtraction of two unsigned integers, reverting on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        return sub(a, b, "SafeMath: subtraction overflow");
    }
    /**
     * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     * - Subtraction cannot overflow.
     *
     * _Available since v2.4.0._
     */
    function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b <= a, errorMessage);
        uint256 c = a - b;
        return c;
    }
    /**
     * @dev Returns the multiplication of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `*` operator.
     *
     * Requirements:
     * - Multiplication cannot overflow.
     */
    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
        // benefit is lost if 'b' is also tested.
        // See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
        if (a == 0) {
            return 0;
        }
        uint256 c = a * b;
        require(c / a == b, "SafeMath: multiplication overflow");
        return c;
    }
    /**
     * @dev Returns the integer division of two unsigned integers. Reverts on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        return div(a, b, "SafeMath: division by zero");
    }
    /**
     * @dev Returns the integer division of two unsigned integers. Reverts with custom message on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     * - The divisor cannot be zero.
     *
     * _Available since v2.4.0._
     */
    function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        // Solidity only automatically asserts when dividing by 0
        require(b > 0, errorMessage);
        uint256 c = a / b;
        // assert(a == b * c + a % b); // There is no case in which this doesn't hold
        return c;
    }
    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * Reverts when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     * - The divisor cannot be zero.
     */
    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        return mod(a, b, "SafeMath: modulo by zero");
    }
    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * Reverts with custom message when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     * - The divisor cannot be zero.
     *
     * _Available since v2.4.0._
     */
    function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b != 0, errorMessage);
        return a % b;
    }
}
pragma solidity ^0.5.0;
import "./IERC20.sol";
/**
 * @dev Optional functions from the ERC20 standard.
 */
contract ERC20Detailed is IERC20 {
    string private _name;
    string private _symbol;
    uint8 private _decimals;
    /**
     * @dev Sets the values for `name`, `symbol`, and `decimals`. All three of
     * these values are immutable: they can only be set once during
     * construction.
     */
    constructor (string memory name, string memory symbol, uint8 decimals) public {
        _name = name;
        _symbol = symbol;
        _decimals = decimals;
    }
    /**
     * @dev Returns the name of the token.
     */
    function name() public view returns (string memory) {
        return _name;
    }
    /**
     * @dev Returns the symbol of the token, usually a shorter version of the
     * name.
     */
    function symbol() public view returns (string memory) {
        return _symbol;
    }
    /**
     * @dev Returns the number of decimals used to get its user representation.
     * For example, if `decimals` equals `2`, a balance of `505` tokens should
     * be displayed to a user as `5,05` (`505 / 10 ** 2`).
     *
     * Tokens usually opt for a value of 18, imitating the relationship between
     * Ether and Wei.
     *
     * NOTE: This information is only used for _display_ purposes: it in
     * no way affects any of the arithmetic of the contract, including
     * {IERC20-balanceOf} and {IERC20-transfer}.
     */
    function decimals() public view returns (uint8) {
        return _decimals;
    }
}
pragma solidity ^0.5.0;
/**
 * @dev Interface of the ERC20 standard as defined in the EIP. Does not include
 * the optional functions; to access them see {ERC20Detailed}.
 */
interface IERC20 {
    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);
    /**
     * @dev Returns the amount of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);
    /**
     * @dev Moves `amount` tokens from the caller's account to `recipient`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address recipient, uint256 amount) external returns (bool);
    /**
     * @dev Returns the remaining number of tokens that `spender` will be
     * allowed to spend on behalf of `owner` through {transferFrom}. This is
     * zero by default.
     *
     * This value changes when {approve} or {transferFrom} are called.
     */
    function allowance(address owner, address spender) external view returns (uint256);
    /**
     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * IMPORTANT: Beware that changing an allowance with this method brings the risk
     * that someone may use both the old and the new allowance by unfortunate
     * transaction ordering. One possible solution to mitigate this race
     * condition is to first reduce the spender's allowance to 0 and set the
     * desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     *
     * Emits an {Approval} event.
     */
    function approve(address spender, uint256 amount) external returns (bool);
    /**
     * @dev Moves `amount` tokens from `sender` to `recipient` using the
     * allowance mechanism. `amount` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);
    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);
    /**
     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
     * a call to {approve}. `value` is the new allowance.
     */
    event Approval(address indexed owner, address indexed spender, uint256 value);
}
pragma solidity ^0.5.0;
import "./IERC20.sol";
import "../../math/SafeMath.sol";
import "../../utils/Address.sol";
/**
 * @title SafeERC20
 * @dev Wrappers around ERC20 operations that throw on failure (when the token
 * contract returns false). Tokens that return no value (and instead revert or
 * throw on failure) are also supported, non-reverting calls are assumed to be
 * successful.
 * To use this library you can add a `using SafeERC20 for ERC20;` statement to your contract,
 * which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
 */
library SafeERC20 {
    using SafeMath for uint256;
    using Address for address;
    function safeTransfer(IERC20 token, address to, uint256 value) internal {
        callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
    }
    function safeTransferFrom(IERC20 token, address from, address to, uint256 value) internal {
        callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
    }
    function safeApprove(IERC20 token, address spender, uint256 value) internal {
        // safeApprove should only be called when setting an initial allowance,
        // or when resetting it to zero. To increase and decrease it, use
        // 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
        // solhint-disable-next-line max-line-length
        require((value == 0) || (token.allowance(address(this), spender) == 0),
            "SafeERC20: approve from non-zero to non-zero allowance"
        );
        callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
    }
    function safeIncreaseAllowance(IERC20 token, address spender, uint256 value) internal {
        uint256 newAllowance = token.allowance(address(this), spender).add(value);
        callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
    }
    function safeDecreaseAllowance(IERC20 token, address spender, uint256 value) internal {
        uint256 newAllowance = token.allowance(address(this), spender).sub(value, "SafeERC20: decreased allowance below zero");
        callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
    }
    /**
     * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
     * on the return value: the return value is optional (but if data is returned, it must not be false).
     * @param token The token targeted by the call.
     * @param data The call data (encoded using abi.encode or one of its variants).
     */
    function callOptionalReturn(IERC20 token, bytes memory data) private {
        // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
        // we're implementing it ourselves.
        // A Solidity high level call has three parts:
        //  1. The target address is checked to verify it contains contract code
        //  2. The call itself is made, and success asserted
        //  3. The return value is decoded, which in turn checks the size of the returned data.
        // solhint-disable-next-line max-line-length
        require(address(token).isContract(), "SafeERC20: call to non-contract");
        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = address(token).call(data);
        require(success, "SafeERC20: low-level call failed");
        if (returndata.length > 0) { // Return data is optional
            // solhint-disable-next-line max-line-length
            require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
        }
    }
}
pragma solidity ^0.5.5;
/**
 * @dev Collection of functions related to the address type
 */
library Address {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * [IMPORTANT]
     * ====
     * It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     *
     * Among others, `isContract` will return false for the following 
     * types of addresses:
     *
     *  - an externally-owned account
     *  - a contract in construction
     *  - an address where a contract will be created
     *  - an address where a contract lived, but was destroyed
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // According to EIP-1052, 0x0 is the value returned for not-yet created accounts
        // and 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470 is returned
        // for accounts without code, i.e. `keccak256('')`
        bytes32 codehash;
        bytes32 accountHash = 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470;
        // solhint-disable-next-line no-inline-assembly
        assembly { codehash := extcodehash(account) }
        return (codehash != accountHash && codehash != 0x0);
    }
    /**
     * @dev Converts an `address` into `address payable`. Note that this is
     * simply a type cast: the actual underlying value is not changed.
     *
     * _Available since v2.4.0._
     */
    function toPayable(address account) internal pure returns (address payable) {
        return address(uint160(account));
    }
    /**
     * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
     * `recipient`, forwarding all available gas and reverting on errors.
     *
     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
     * of certain opcodes, possibly making contracts go over the 2300 gas limit
     * imposed by `transfer`, making them unable to receive funds via
     * `transfer`. {sendValue} removes this limitation.
     *
     * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
     *
     * IMPORTANT: because control is transferred to `recipient`, care must be
     * taken to not create reentrancy vulnerabilities. Consider using
     * {ReentrancyGuard} or the
     * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     *
     * _Available since v2.4.0._
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");
        // solhint-disable-next-line avoid-call-value
        (bool success, ) = recipient.call.value(amount)("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }
}

// File: @openzeppelin/contracts/math/SafeMath.sol

pragma solidity ^0.6.0;

/**
 * @dev Wrappers over Solidity's arithmetic operations with added overflow
 * checks.
 *
 * Arithmetic operations in Solidity wrap on overflow. This can easily result
 * in bugs, because programmers usually assume that an overflow raises an
 * error, which is the standard behavior in high level programming languages.
 * `SafeMath` restores this intuition by reverting the transaction when an
 * operation overflows.
 *
 * Using this library instead of the unchecked operations eliminates an entire
 * class of bugs, so it's recommended to use it always.
 */
library SafeMath {
    /**
     * @dev Returns the addition of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `+` operator.
     *
     * Requirements:
     *
     * - Addition cannot overflow.
     */
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        require(c >= a, "SafeMath: addition overflow");

        return c;
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        return sub(a, b, "SafeMath: subtraction overflow");
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b <= a, errorMessage);
        uint256 c = a - b;

        return c;
    }

    /**
     * @dev Returns the multiplication of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `*` operator.
     *
     * Requirements:
     *
     * - Multiplication cannot overflow.
     */
    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
        // benefit is lost if 'b' is also tested.
        // See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
        if (a == 0) {
            return 0;
        }

        uint256 c = a * b;
        require(c / a == b, "SafeMath: multiplication overflow");

        return c;
    }

    /**
     * @dev Returns the integer division of two unsigned integers. Reverts on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        return div(a, b, "SafeMath: division by zero");
    }

    /**
     * @dev Returns the integer division of two unsigned integers. Reverts with custom message on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b > 0, errorMessage);
        uint256 c = a / b;
        // assert(a == b * c + a % b); // There is no case in which this doesn't hold

        return c;
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * Reverts when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        return mod(a, b, "SafeMath: modulo by zero");
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * Reverts with custom message when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b != 0, errorMessage);
        return a % b;
    }
}

// File: interfaces/Idle/IIdleTokenV3_1.sol

pragma solidity 0.6.12;

interface IIdleTokenV3_1 {
    // view
    /**
     * IdleToken price calculation not considering fees, in underlying
     *
     * @return price : price in underlying token
     */
    function tokenPrice() external view returns (uint256 price);

    // view
    /**
     * Map which saves avg idleToken minting price per user
     * Used in calculating redeem price
     *
     * @return price : price in underlying token
     */
    function userAvgPrices(address user) external view returns (uint256 price);


    // view
    /**
     * Current fee on interest gained
     *
     * @return fee : fee on interest gained
     */
    function fee() external view returns (uint256 fee);

    /**
     * @return underlying : underlying token address
     */
    function token() external view returns (address underlying);

    /**
     * Get APR of every ILendingProtocol
     *
     * @return addresses : array of token addresses
     * @return aprs : array of aprs (ordered in respect to the `addresses` array)
     */
    function getAPRs() external view returns (address[] memory addresses, uint256[] memory aprs);

    // external
    // We should save the amount one has deposited to calc interests

    /**
     * Used to mint IdleTokens, given an underlying amount (eg. DAI).
     * This method triggers a rebalance of the pools if needed
     * NOTE: User should 'approve' _amount of tokens before calling mintIdleToken
     * NOTE 2: this method can be paused
     *
     * @param _amount : amount of underlying token to be lended
     * @param _skipRebalance : flag for skipping rebalance for lower gas price
     * @param _referral : referral address
     * @return mintedTokens : amount of IdleTokens minted
     */
    function mintIdleToken(uint256 _amount, bool _skipRebalance, address _referral) external returns (uint256 mintedTokens);

    /**
     * Here we calc the pool share one can withdraw given the amount of IdleToken they want to burn
     * This method triggers a rebalance of the pools if needed
     * NOTE: If the contract is paused or iToken price has decreased one can still redeem but no rebalance happens.
     * NOTE 2: If iToken price has decresed one should not redeem (but can do it) otherwise he would capitalize the loss.
     *         Ideally one should wait until the black swan event is terminated
     *
     * @param _amount : amount of IdleTokens to be burned
     * @return redeemedTokens : amount of underlying tokens redeemed
     */
    function redeemIdleToken(uint256 _amount) external returns (uint256 redeemedTokens);
    /**
     * Here we calc the pool share one can withdraw given the amount of IdleToken they want to burn
     * and send interest-bearing tokens (eg. cDAI/iDAI) directly to the user.
     * Underlying (eg. DAI) is not redeemed here.
     *
     * @param _amount : amount of IdleTokens to be burned
     */
    function redeemInterestBearingTokens(uint256 _amount) external;

    /**
     * @return : whether has rebalanced or not
     */
    function rebalance() external returns (bool);
}

// File: contracts/IdleTokenHelper.sol

// SPDX-License-Identifier: AGPL-3.0
pragma solidity ^0.6.12;



contract IdleTokenHelper {
    using SafeMath for uint256;

    uint256 constant public FULL_ALLOC = 100000;

    function getMintingPrice(address idleYieldToken) view external returns (uint256 mintingPrice) {
        return _getMintingPrice(idleYieldToken);
    }

    function _getMintingPrice(address idleYieldToken) view internal returns (uint256 mintingPrice) {
        return IIdleTokenV3_1(idleYieldToken).tokenPrice();
    }

    function getRedeemPrice(address idleYieldToken) view external returns (uint256 redeemPrice) {
        return _getRedeemPrice(idleYieldToken, msg.sender);
    }

    function getRedeemPrice(address idleYieldToken, address user) view external returns (uint256 redeemPrice) {
        return _getRedeemPrice(idleYieldToken, user);
    }

    function _getRedeemPrice(address idleYieldToken, address user) view internal returns (uint256 redeemPrice) {
        /*
         *  As per https://github.com/Idle-Labs/idle-contracts/blob/ad0f18fef670ea6a4030fe600f64ece3d3ac2202/contracts/IdleTokenGovernance.sol#L878-L900
         *
         *  Price on minting is currentPrice
         *  Price on redeem must consider the fee
         *
         *  Below the implementation of the following redeemPrice formula
         *
         *  redeemPrice := underlyingAmount/idleTokenAmount
         *
         *  redeemPrice = currentPrice * (1 - scaledFee * ΔP%)
         *
         *  where:
         *  - scaledFee   := fee/FULL_ALLOC
         *  - ΔP% := 0 when currentPrice < userAvgPrice (no gain) and (currentPrice-userAvgPrice)/currentPrice
         *
         *  n.b: gain := idleTokenAmount * ΔP% * currentPrice
         */

        IIdleTokenV3_1 iyt = IIdleTokenV3_1(idleYieldToken);

        uint256 userAvgPrice = iyt.userAvgPrices(user);
        uint256 currentPrice = iyt.tokenPrice();

        // When no deposits userAvgPrice is 0 equiv currentPrice
        // and in the case of issues
        if (userAvgPrice == 0 || currentPrice < userAvgPrice) {
            redeemPrice = currentPrice;
        } else {
            uint256 fee = iyt.fee();

            redeemPrice = ((currentPrice.mul(FULL_ALLOC))
                .sub(
                    fee.mul(
                         currentPrice.sub(userAvgPrice)
                    )
                )).div(FULL_ALLOC);
        }

        return redeemPrice;
    }
}

// File: @openzeppelin/upgrades/contracts/upgradeability/Proxy.sol

pragma solidity ^0.5.0;

/**
 * @title Proxy
 * @dev Implements delegation of calls to other contracts, with proper
 * forwarding of return values and bubbling of failures.
 * It defines a fallback function that delegates all calls to the address
 * returned by the abstract _implementation() internal function.
 */
contract Proxy {
  /**
   * @dev Fallback function.
   * Implemented entirely in `_fallback`.
   */
  function () payable external {
    _fallback();
  }

  /**
   * @return The Address of the implementation.
   */
  function _implementation() internal view returns (address);

  /**
   * @dev Delegates execution to an implementation contract.
   * This is a low level function that doesn't return to its internal call site.
   * It will return to the external caller whatever the implementation returns.
   * @param implementation Address to delegate.
   */
  function _delegate(address implementation) internal {
    assembly {
      // Copy msg.data. We take full control of memory in this inline assembly
      // block because it will not return to Solidity code. We overwrite the
      // Solidity scratch pad at memory position 0.
      calldatacopy(0, 0, calldatasize)

      // Call the implementation.
      // out and outsize are 0 because we don't know the size yet.
      let result := delegatecall(gas, implementation, 0, calldatasize, 0, 0)

      // Copy the returned data.
      returndatacopy(0, 0, returndatasize)

      switch result
      // delegatecall returns 0 on error.
      case 0 { revert(0, returndatasize) }
      default { return(0, returndatasize) }
    }
  }

  /**
   * @dev Function that is run as the first thing in the fallback function.
   * Can be redefined in derived contracts to add functionality.
   * Redefinitions must call super._willFallback().
   */
  function _willFallback() internal {
  }

  /**
   * @dev fallback implementation.
   * Extracted to enable manual triggering.
   */
  function _fallback() internal {
    _willFallback();
    _delegate(_implementation());
  }
}

// File: @openzeppelin/upgrades/contracts/utils/Address.sol

pragma solidity ^0.5.0;

/**
 * Utility library of inline functions on addresses
 *
 * Source https://raw.githubusercontent.com/OpenZeppelin/openzeppelin-solidity/v2.1.3/contracts/utils/Address.sol
 * This contract is copied here and renamed from the original to avoid clashes in the compiled artifacts
 * when the user imports a zos-lib contract (that transitively causes this contract to be compiled and added to the
 * build/artifacts folder) as well as the vanilla Address implementation from an openzeppelin version.
 */
library OpenZeppelinUpgradesAddress {
    /**
     * Returns whether the target address is a contract
     * @dev This function will return false if invoked during the constructor of a contract,
     * as the code is not actually created until after the constructor finishes.
     * @param account address of the account to check
     * @return whether the target address is a contract
     */
    function isContract(address account) internal view returns (bool) {
        uint256 size;
        // XXX Currently there is no better way to check if there is a contract in an address
        // than to check the size of the code at that address.
        // See https://ethereum.stackexchange.com/a/14016/36603
        // for more details about how this works.
        // TODO Check this again before the Serenity release, because all addresses will be
        // contracts then.
        // solhint-disable-next-line no-inline-assembly
        assembly { size := extcodesize(account) }
        return size > 0;
    }
}

// File: @openzeppelin/upgrades/contracts/upgradeability/BaseUpgradeabilityProxy.sol

pragma solidity ^0.5.0;



/**
 * @title BaseUpgradeabilityProxy
 * @dev This contract implements a proxy that allows to change the
 * implementation address to which it will delegate.
 * Such a change is called an implementation upgrade.
 */
contract BaseUpgradeabilityProxy is Proxy {
  /**
   * @dev Emitted when the implementation is upgraded.
   * @param implementation Address of the new implementation.
   */
  event Upgraded(address indexed implementation);

  /**
   * @dev Storage slot with the address of the current implementation.
   * This is the keccak-256 hash of "eip1967.proxy.implementation" subtracted by 1, and is
   * validated in the constructor.
   */
  bytes32 internal constant IMPLEMENTATION_SLOT = 0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc;

  /**
   * @dev Returns the current implementation.
   * @return Address of the current implementation
   */
  function _implementation() internal view returns (address impl) {
    bytes32 slot = IMPLEMENTATION_SLOT;
    assembly {
      impl := sload(slot)
    }
  }

  /**
   * @dev Upgrades the proxy to a new implementation.
   * @param newImplementation Address of the new implementation.
   */
  function _upgradeTo(address newImplementation) internal {
    _setImplementation(newImplementation);
    emit Upgraded(newImplementation);
  }

  /**
   * @dev Sets the implementation address of the proxy.
   * @param newImplementation Address of the new implementation.
   */
  function _setImplementation(address newImplementation) internal {
    require(OpenZeppelinUpgradesAddress.isContract(newImplementation), "Cannot set a proxy implementation to a non-contract address");

    bytes32 slot = IMPLEMENTATION_SLOT;

    assembly {
      sstore(slot, newImplementation)
    }
  }
}

// File: @openzeppelin/upgrades/contracts/upgradeability/UpgradeabilityProxy.sol

pragma solidity ^0.5.0;


/**
 * @title UpgradeabilityProxy
 * @dev Extends BaseUpgradeabilityProxy with a constructor for initializing
 * implementation and init data.
 */
contract UpgradeabilityProxy is BaseUpgradeabilityProxy {
  /**
   * @dev Contract constructor.
   * @param _logic Address of the initial implementation.
   * @param _data Data to send as msg.data to the implementation to initialize the proxied contract.
   * It should include the signature and the parameters of the function to be called, as described in
   * https://solidity.readthedocs.io/en/v0.4.24/abi-spec.html#function-selector-and-argument-encoding.
   * This parameter is optional, if no data is given the initialization call to proxied contract will be skipped.
   */
  constructor(address _logic, bytes memory _data) public payable {
    assert(IMPLEMENTATION_SLOT == bytes32(uint256(keccak256('eip1967.proxy.implementation')) - 1));
    _setImplementation(_logic);
    if(_data.length > 0) {
      (bool success,) = _logic.delegatecall(_data);
      require(success);
    }
  }  
}

// File: @openzeppelin/upgrades/contracts/upgradeability/BaseAdminUpgradeabilityProxy.sol

pragma solidity ^0.5.0;


/**
 * @title BaseAdminUpgradeabilityProxy
 * @dev This contract combines an upgradeability proxy with an authorization
 * mechanism for administrative tasks.
 * All external functions in this contract must be guarded by the
 * `ifAdmin` modifier. See ethereum/solidity#3864 for a Solidity
 * feature proposal that would enable this to be done automatically.
 */
contract BaseAdminUpgradeabilityProxy is BaseUpgradeabilityProxy {
  /**
   * @dev Emitted when the administration has been transferred.
   * @param previousAdmin Address of the previous admin.
   * @param newAdmin Address of the new admin.
   */
  event AdminChanged(address previousAdmin, address newAdmin);

  /**
   * @dev Storage slot with the admin of the contract.
   * This is the keccak-256 hash of "eip1967.proxy.admin" subtracted by 1, and is
   * validated in the constructor.
   */

  bytes32 internal constant ADMIN_SLOT = 0xb53127684a568b3173ae13b9f8a6016e243e63b6e8ee1178d6a717850b5d6103;

  /**
   * @dev Modifier to check whether the `msg.sender` is the admin.
   * If it is, it will run the function. Otherwise, it will delegate the call
   * to the implementation.
   */
  modifier ifAdmin() {
    if (msg.sender == _admin()) {
      _;
    } else {
      _fallback();
    }
  }

  /**
   * @return The address of the proxy admin.
   */
  function admin() external ifAdmin returns (address) {
    return _admin();
  }

  /**
   * @return The address of the implementation.
   */
  function implementation() external ifAdmin returns (address) {
    return _implementation();
  }

  /**
   * @dev Changes the admin of the proxy.
   * Only the current admin can call this function.
   * @param newAdmin Address to transfer proxy administration to.
   */
  function changeAdmin(address newAdmin) external ifAdmin {
    require(newAdmin != address(0), "Cannot change the admin of a proxy to the zero address");
    emit AdminChanged(_admin(), newAdmin);
    _setAdmin(newAdmin);
  }

  /**
   * @dev Upgrade the backing implementation of the proxy.
   * Only the admin can call this function.
   * @param newImplementation Address of the new implementation.
   */
  function upgradeTo(address newImplementation) external ifAdmin {
    _upgradeTo(newImplementation);
  }

  /**
   * @dev Upgrade the backing implementation of the proxy and call a function
   * on the new implementation.
   * This is useful to initialize the proxied contract.
   * @param newImplementation Address of the new implementation.
   * @param data Data to send as msg.data in the low level call.
   * It should include the signature and the parameters of the function to be called, as described in
   * https://solidity.readthedocs.io/en/v0.4.24/abi-spec.html#function-selector-and-argument-encoding.
   */
  function upgradeToAndCall(address newImplementation, bytes calldata data) payable external ifAdmin {
    _upgradeTo(newImplementation);
    (bool success,) = newImplementation.delegatecall(data);
    require(success);
  }

  /**
   * @return The admin slot.
   */
  function _admin() internal view returns (address adm) {
    bytes32 slot = ADMIN_SLOT;
    assembly {
      adm := sload(slot)
    }
  }

  /**
   * @dev Sets the address of the proxy admin.
   * @param newAdmin Address of the new proxy admin.
   */
  function _setAdmin(address newAdmin) internal {
    bytes32 slot = ADMIN_SLOT;

    assembly {
      sstore(slot, newAdmin)
    }
  }

  /**
   * @dev Only fall back when the sender is not the admin.
   */
  function _willFallback() internal {
    require(msg.sender != _admin(), "Cannot call fallback function from the proxy admin");
    super._willFallback();
  }
}

// File: @openzeppelin/upgrades/contracts/upgradeability/AdminUpgradeabilityProxy.sol

pragma solidity ^0.5.0;


/**
 * @title AdminUpgradeabilityProxy
 * @dev Extends from BaseAdminUpgradeabilityProxy with a constructor for 
 * initializing the implementation, admin, and init data.
 */
contract AdminUpgradeabilityProxy is BaseAdminUpgradeabilityProxy, UpgradeabilityProxy {
  /**
   * Contract constructor.
   * @param _logic address of the initial implementation.
   * @param _admin Address of the proxy administrator.
   * @param _data Data to send as msg.data to the implementation to initialize the proxied contract.
   * It should include the signature and the parameters of the function to be called, as described in
   * https://solidity.readthedocs.io/en/v0.4.24/abi-spec.html#function-selector-and-argument-encoding.
   * This parameter is optional, if no data is given the initialization call to proxied contract will be skipped.
   */
  constructor(address _logic, address _admin, bytes memory _data) UpgradeabilityProxy(_logic, _data) public payable {
    assert(ADMIN_SLOT == bytes32(uint256(keccak256('eip1967.proxy.admin')) - 1));
    _setAdmin(_admin);
  }
}

// File: @openzeppelin/contracts-ethereum-package/contracts/math/SafeMath.sol

pragma solidity ^0.5.0;

/**
 * @dev Wrappers over Solidity's arithmetic operations with added overflow
 * checks.
 *
 * Arithmetic operations in Solidity wrap on overflow. This can easily result
 * in bugs, because programmers usually assume that an overflow raises an
 * error, which is the standard behavior in high level programming languages.
 * `SafeMath` restores this intuition by reverting the transaction when an
 * operation overflows.
 *
 * Using this library instead of the unchecked operations eliminates an entire
 * class of bugs, so it's recommended to use it always.
 */
library SafeMath {
    /**
     * @dev Returns the addition of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `+` operator.
     *
     * Requirements:
     * - Addition cannot overflow.
     */
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        require(c >= a, "SafeMath: addition overflow");

        return c;
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        return sub(a, b, "SafeMath: subtraction overflow");
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     * - Subtraction cannot overflow.
     *
     * _Available since v2.4.0._
     */
    function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b <= a, errorMessage);
        uint256 c = a - b;

        return c;
    }

    /**
     * @dev Returns the multiplication of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `*` operator.
     *
     * Requirements:
     * - Multiplication cannot overflow.
     */
    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
        // benefit is lost if 'b' is also tested.
        // See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
        if (a == 0) {
            return 0;
        }

        uint256 c = a * b;
        require(c / a == b, "SafeMath: multiplication overflow");

        return c;
    }

    /**
     * @dev Returns the integer division of two unsigned integers. Reverts on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        return div(a, b, "SafeMath: division by zero");
    }

    /**
     * @dev Returns the integer division of two unsigned integers. Reverts with custom message on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     * - The divisor cannot be zero.
     *
     * _Available since v2.4.0._
     */
    function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        // Solidity only automatically asserts when dividing by 0
        require(b > 0, errorMessage);
        uint256 c = a / b;
        // assert(a == b * c + a % b); // There is no case in which this doesn't hold

        return c;
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * Reverts when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     * - The divisor cannot be zero.
     */
    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        return mod(a, b, "SafeMath: modulo by zero");
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * Reverts with custom message when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     * - The divisor cannot be zero.
     *
     * _Available since v2.4.0._
     */
    function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b != 0, errorMessage);
        return a % b;
    }
}

// File: @openzeppelin/contracts-ethereum-package/contracts/token/ERC20/IERC20.sol

pragma solidity ^0.5.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP. Does not include
 * the optional functions; to access them see {ERC20Detailed}.
 */
interface IERC20 {
    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns the amount of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);

    /**
     * @dev Moves `amount` tokens from the caller's account to `recipient`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address recipient, uint256 amount) external returns (bool);

    /**
     * @dev Returns the remaining number of tokens that `spender` will be
     * allowed to spend on behalf of `owner` through {transferFrom}. This is
     * zero by default.
     *
     * This value changes when {approve} or {transferFrom} are called.
     */
    function allowance(address owner, address spender) external view returns (uint256);

    /**
     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * IMPORTANT: Beware that changing an allowance with this method brings the risk
     * that someone may use both the old and the new allowance by unfortunate
     * transaction ordering. One possible solution to mitigate this race
     * condition is to first reduce the spender's allowance to 0 and set the
     * desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     *
     * Emits an {Approval} event.
     */
    function approve(address spender, uint256 amount) external returns (bool);

    /**
     * @dev Moves `amount` tokens from `sender` to `recipient` using the
     * allowance mechanism. `amount` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);

    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);

    /**
     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
     * a call to {approve}. `value` is the new allowance.
     */
    event Approval(address indexed owner, address indexed spender, uint256 value);
}

// File: @openzeppelin/contracts-ethereum-package/contracts/utils/Address.sol

pragma solidity ^0.5.5;

/**
 * @dev Collection of functions related to the address type
 */
library Address {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * [IMPORTANT]
     * ====
     * It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     *
     * Among others, `isContract` will return false for the following 
     * types of addresses:
     *
     *  - an externally-owned account
     *  - a contract in construction
     *  - an address where a contract will be created
     *  - an address where a contract lived, but was destroyed
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // According to EIP-1052, 0x0 is the value returned for not-yet created accounts
        // and 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470 is returned
        // for accounts without code, i.e. `keccak256('')`
        bytes32 codehash;
        bytes32 accountHash = 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470;
        // solhint-disable-next-line no-inline-assembly
        assembly { codehash := extcodehash(account) }
        return (codehash != accountHash && codehash != 0x0);
    }

    /**
     * @dev Converts an `address` into `address payable`. Note that this is
     * simply a type cast: the actual underlying value is not changed.
     *
     * _Available since v2.4.0._
     */
    function toPayable(address account) internal pure returns (address payable) {
        return address(uint160(account));
    }

    /**
     * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
     * `recipient`, forwarding all available gas and reverting on errors.
     *
     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
     * of certain opcodes, possibly making contracts go over the 2300 gas limit
     * imposed by `transfer`, making them unable to receive funds via
     * `transfer`. {sendValue} removes this limitation.
     *
     * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
     *
     * IMPORTANT: because control is transferred to `recipient`, care must be
     * taken to not create reentrancy vulnerabilities. Consider using
     * {ReentrancyGuard} or the
     * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     *
     * _Available since v2.4.0._
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");

        // solhint-disable-next-line avoid-call-value
        (bool success, ) = recipient.call.value(amount)("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }
}

// File: @openzeppelin/contracts-ethereum-package/contracts/token/ERC20/SafeERC20.sol

pragma solidity ^0.5.0;




/**
 * @title SafeERC20
 * @dev Wrappers around ERC20 operations that throw on failure (when the token
 * contract returns false). Tokens that return no value (and instead revert or
 * throw on failure) are also supported, non-reverting calls are assumed to be
 * successful.
 * To use this library you can add a `using SafeERC20 for ERC20;` statement to your contract,
 * which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
 */
library SafeERC20 {
    using SafeMath for uint256;
    using Address for address;

    function safeTransfer(IERC20 token, address to, uint256 value) internal {
        callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
    }

    function safeTransferFrom(IERC20 token, address from, address to, uint256 value) internal {
        callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
    }

    function safeApprove(IERC20 token, address spender, uint256 value) internal {
        // safeApprove should only be called when setting an initial allowance,
        // or when resetting it to zero. To increase and decrease it, use
        // 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
        // solhint-disable-next-line max-line-length
        require((value == 0) || (token.allowance(address(this), spender) == 0),
            "SafeERC20: approve from non-zero to non-zero allowance"
        );
        callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
    }

    function safeIncreaseAllowance(IERC20 token, address spender, uint256 value) internal {
        uint256 newAllowance = token.allowance(address(this), spender).add(value);
        callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
    }

    function safeDecreaseAllowance(IERC20 token, address spender, uint256 value) internal {
        uint256 newAllowance = token.allowance(address(this), spender).sub(value, "SafeERC20: decreased allowance below zero");
        callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
    }

    /**
     * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
     * on the return value: the return value is optional (but if data is returned, it must not be false).
     * @param token The token targeted by the call.
     * @param data The call data (encoded using abi.encode or one of its variants).
     */
    function callOptionalReturn(IERC20 token, bytes memory data) private {
        // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
        // we're implementing it ourselves.

        // A Solidity high level call has three parts:
        //  1. The target address is checked to verify it contains contract code
        //  2. The call itself is made, and success asserted
        //  3. The return value is decoded, which in turn checks the size of the returned data.
        // solhint-disable-next-line max-line-length
        require(address(token).isContract(), "SafeERC20: call to non-contract");

        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = address(token).call(data);
        require(success, "SafeERC20: low-level call failed");

        if (returndata.length > 0) { // Return data is optional
            // solhint-disable-next-line max-line-length
            require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
        }
    }
}

// File: @openzeppelin/upgrades/contracts/Initializable.sol

pragma solidity >=0.4.24 <0.7.0;


/**
 * @title Initializable
 *
 * @dev Helper contract to support initializer functions. To use it, replace
 * the constructor with a function that has the `initializer` modifier.
 * WARNING: Unlike constructors, initializer functions must be manually
 * invoked. This applies both to deploying an Initializable contract, as well
 * as extending an Initializable contract via inheritance.
 * WARNING: When used with inheritance, manual care must be taken to not invoke
 * a parent initializer twice, or ensure that all initializers are idempotent,
 * because this is not dealt with automatically as with constructors.
 */
contract Initializable {

  /**
   * @dev Indicates that the contract has been initialized.
   */
  bool private initialized;

  /**
   * @dev Indicates that the contract is in the process of being initialized.
   */
  bool private initializing;

  /**
   * @dev Modifier to use in the initializer function of a contract.
   */
  modifier initializer() {
    require(initializing || isConstructor() || !initialized, "Contract instance has already been initialized");

    bool isTopLevelCall = !initializing;
    if (isTopLevelCall) {
      initializing = true;
      initialized = true;
    }

    _;

    if (isTopLevelCall) {
      initializing = false;
    }
  }

  /// @dev Returns true if and only if the function is running in the constructor
  function isConstructor() private view returns (bool) {
    // extcodesize checks the size of the code stored in an address, and
    // address returns the current address. Since the code is still not
    // deployed when running a constructor, any checks on its code size will
    // yield zero, making it an effective way to detect if a contract is
    // under construction or not.
    address self = address(this);
    uint256 cs;
    assembly { cs := extcodesize(self) }
    return cs == 0;
  }

  // Reserved storage space to allow for layout changes in the future.
  uint256[50] private ______gap;
}

// File: @openzeppelin/contracts-ethereum-package/contracts/GSN/Context.sol

pragma solidity ^0.5.0;


/*
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with GSN meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
contract Context is Initializable {
    // Empty internal constructor, to prevent people from mistakenly deploying
    // an instance of this contract, which should be used via inheritance.
    constructor () internal { }
    // solhint-disable-previous-line no-empty-blocks

    function _msgSender() internal view returns (address payable) {
        return msg.sender;
    }

    function _msgData() internal view returns (bytes memory) {
        this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
        return msg.data;
    }
}

// File: @openzeppelin/contracts-ethereum-package/contracts/token/ERC20/ERC20.sol

pragma solidity ^0.5.0;





/**
 * @dev Implementation of the {IERC20} interface.
 *
 * This implementation is agnostic to the way tokens are created. This means
 * that a supply mechanism has to be added in a derived contract using {_mint}.
 * For a generic mechanism see {ERC20Mintable}.
 *
 * TIP: For a detailed writeup see our guide
 * https://forum.zeppelin.solutions/t/how-to-implement-erc20-supply-mechanisms/226[How
 * to implement supply mechanisms].
 *
 * We have followed general OpenZeppelin guidelines: functions revert instead
 * of returning `false` on failure. This behavior is nonetheless conventional
 * and does not conflict with the expectations of ERC20 applications.
 *
 * Additionally, an {Approval} event is emitted on calls to {transferFrom}.
 * This allows applications to reconstruct the allowance for all accounts just
 * by listening to said events. Other implementations of the EIP may not emit
 * these events, as it isn't required by the specification.
 *
 * Finally, the non-standard {decreaseAllowance} and {increaseAllowance}
 * functions have been added to mitigate the well-known issues around setting
 * allowances. See {IERC20-approve}.
 */
contract ERC20 is Initializable, Context, IERC20 {
    using SafeMath for uint256;

    mapping (address => uint256) private _balances;

    mapping (address => mapping (address => uint256)) private _allowances;

    uint256 private _totalSupply;

    /**
     * @dev See {IERC20-totalSupply}.
     */
    function totalSupply() public view returns (uint256) {
        return _totalSupply;
    }

    /**
     * @dev See {IERC20-balanceOf}.
     */
    function balanceOf(address account) public view returns (uint256) {
        return _balances[account];
    }

    /**
     * @dev See {IERC20-transfer}.
     *
     * Requirements:
     *
     * - `recipient` cannot be the zero address.
     * - the caller must have a balance of at least `amount`.
     */
    function transfer(address recipient, uint256 amount) public returns (bool) {
        _transfer(_msgSender(), recipient, amount);
        return true;
    }

    /**
     * @dev See {IERC20-allowance}.
     */
    function allowance(address owner, address spender) public view returns (uint256) {
        return _allowances[owner][spender];
    }

    /**
     * @dev See {IERC20-approve}.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     */
    function approve(address spender, uint256 amount) public returns (bool) {
        _approve(_msgSender(), spender, amount);
        return true;
    }

    /**
     * @dev See {IERC20-transferFrom}.
     *
     * Emits an {Approval} event indicating the updated allowance. This is not
     * required by the EIP. See the note at the beginning of {ERC20};
     *
     * Requirements:
     * - `sender` and `recipient` cannot be the zero address.
     * - `sender` must have a balance of at least `amount`.
     * - the caller must have allowance for `sender`'s tokens of at least
     * `amount`.
     */
    function transferFrom(address sender, address recipient, uint256 amount) public returns (bool) {
        _transfer(sender, recipient, amount);
        _approve(sender, _msgSender(), _allowances[sender][_msgSender()].sub(amount, "ERC20: transfer amount exceeds allowance"));
        return true;
    }

    /**
     * @dev Atomically increases the allowance granted to `spender` by the caller.
     *
     * This is an alternative to {approve} that can be used as a mitigation for
     * problems described in {IERC20-approve}.
     *
     * Emits an {Approval} event indicating the updated allowance.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     */
    function increaseAllowance(address spender, uint256 addedValue) public returns (bool) {
        _approve(_msgSender(), spender, _allowances[_msgSender()][spender].add(addedValue));
        return true;
    }

    /**
     * @dev Atomically decreases the allowance granted to `spender` by the caller.
     *
     * This is an alternative to {approve} that can be used as a mitigation for
     * problems described in {IERC20-approve}.
     *
     * Emits an {Approval} event indicating the updated allowance.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     * - `spender` must have allowance for the caller of at least
     * `subtractedValue`.
     */
    function decreaseAllowance(address spender, uint256 subtractedValue) public returns (bool) {
        _approve(_msgSender(), spender, _allowances[_msgSender()][spender].sub(subtractedValue, "ERC20: decreased allowance below zero"));
        return true;
    }

    /**
     * @dev Moves tokens `amount` from `sender` to `recipient`.
     *
     * This is internal function is equivalent to {transfer}, and can be used to
     * e.g. implement automatic token fees, slashing mechanisms, etc.
     *
     * Emits a {Transfer} event.
     *
     * Requirements:
     *
     * - `sender` cannot be the zero address.
     * - `recipient` cannot be the zero address.
     * - `sender` must have a balance of at least `amount`.
     */
    function _transfer(address sender, address recipient, uint256 amount) internal {
        require(sender != address(0), "ERC20: transfer from the zero address");
        require(recipient != address(0), "ERC20: transfer to the zero address");

        _balances[sender] = _balances[sender].sub(amount, "ERC20: transfer amount exceeds balance");
        _balances[recipient] = _balances[recipient].add(amount);
        emit Transfer(sender, recipient, amount);
    }

    /** @dev Creates `amount` tokens and assigns them to `account`, increasing
     * the total supply.
     *
     * Emits a {Transfer} event with `from` set to the zero address.
     *
     * Requirements
     *
     * - `to` cannot be the zero address.
     */
    function _mint(address account, uint256 amount) internal {
        require(account != address(0), "ERC20: mint to the zero address");

        _totalSupply = _totalSupply.add(amount);
        _balances[account] = _balances[account].add(amount);
        emit Transfer(address(0), account, amount);
    }

    /**
     * @dev Destroys `amount` tokens from `account`, reducing the
     * total supply.
     *
     * Emits a {Transfer} event with `to` set to the zero address.
     *
     * Requirements
     *
     * - `account` cannot be the zero address.
     * - `account` must have at least `amount` tokens.
     */
    function _burn(address account, uint256 amount) internal {
        require(account != address(0), "ERC20: burn from the zero address");

        _balances[account] = _balances[account].sub(amount, "ERC20: burn amount exceeds balance");
        _totalSupply = _totalSupply.sub(amount);
        emit Transfer(account, address(0), amount);
    }

    /**
     * @dev Sets `amount` as the allowance of `spender` over the `owner`s tokens.
     *
     * This is internal function is equivalent to `approve`, and can be used to
     * e.g. set automatic allowances for certain subsystems, etc.
     *
     * Emits an {Approval} event.
     *
     * Requirements:
     *
     * - `owner` cannot be the zero address.
     * - `spender` cannot be the zero address.
     */
    function _approve(address owner, address spender, uint256 amount) internal {
        require(owner != address(0), "ERC20: approve from the zero address");
        require(spender != address(0), "ERC20: approve to the zero address");

        _allowances[owner][spender] = amount;
        emit Approval(owner, spender, amount);
    }

    /**
     * @dev Destroys `amount` tokens from `account`.`amount` is then deducted
     * from the caller's allowance.
     *
     * See {_burn} and {_approve}.
     */
    function _burnFrom(address account, uint256 amount) internal {
        _burn(account, amount);
        _approve(account, _msgSender(), _allowances[account][_msgSender()].sub(amount, "ERC20: burn amount exceeds allowance"));
    }

    uint256[50] private ______gap;
}

// File: @openzeppelin/contracts-ethereum-package/contracts/token/ERC20/ERC20Detailed.sol

pragma solidity ^0.5.0;



/**
 * @dev Optional functions from the ERC20 standard.
 */
contract ERC20Detailed is Initializable, IERC20 {
    string private _name;
    string private _symbol;
    uint8 private _decimals;

    /**
     * @dev Sets the values for `name`, `symbol`, and `decimals`. All three of
     * these values are immutable: they can only be set once during
     * construction.
     */
    function initialize(string memory name, string memory symbol, uint8 decimals) public initializer {
        _name = name;
        _symbol = symbol;
        _decimals = decimals;
    }

    /**
     * @dev Returns the name of the token.
     */
    function name() public view returns (string memory) {
        return _name;
    }

    /**
     * @dev Returns the symbol of the token, usually a shorter version of the
     * name.
     */
    function symbol() public view returns (string memory) {
        return _symbol;
    }

    /**
     * @dev Returns the number of decimals used to get its user representation.
     * For example, if `decimals` equals `2`, a balance of `505` tokens should
     * be displayed to a user as `5,05` (`505 / 10 ** 2`).
     *
     * Tokens usually opt for a value of 18, imitating the relationship between
     * Ether and Wei.
     *
     * NOTE: This information is only used for _display_ purposes: it in
     * no way affects any of the arithmetic of the contract, including
     * {IERC20-balanceOf} and {IERC20-transfer}.
     */
    function decimals() public view returns (uint8) {
        return _decimals;
    }

    uint256[50] private ______gap;
}

// File: @openzeppelin/contracts-ethereum-package/contracts/utils/ReentrancyGuard.sol

pragma solidity ^0.5.0;


/**
 * @dev Contract module that helps prevent reentrant calls to a function.
 *
 * Inheriting from `ReentrancyGuard` will make the {nonReentrant} modifier
 * available, which can be applied to functions to make sure there are no nested
 * (reentrant) calls to them.
 *
 * Note that because there is a single `nonReentrant` guard, functions marked as
 * `nonReentrant` may not call one another. This can be worked around by making
 * those functions `private`, and then adding `external` `nonReentrant` entry
 * points to them.
 */
contract ReentrancyGuard is Initializable {
    // counter to allow mutex lock with only one SSTORE operation
    uint256 private _guardCounter;

    function initialize() public initializer {
        // The counter starts at one to prevent changing it from zero to a non-zero
        // value, which is a more expensive operation.
        _guardCounter = 1;
    }

    /**
     * @dev Prevents a contract from calling itself, directly or indirectly.
     * Calling a `nonReentrant` function from another `nonReentrant`
     * function is not supported. It is possible to prevent this from happening
     * by making the `nonReentrant` function external, and make it call a
     * `private` function that does the actual work.
     */
    modifier nonReentrant() {
        _guardCounter += 1;
        uint256 localCounter = _guardCounter;
        _;
        require(localCounter == _guardCounter, "ReentrancyGuard: reentrant call");
    }

    uint256[50] private ______gap;
}

// File: @openzeppelin/contracts-ethereum-package/contracts/ownership/Ownable.sol

pragma solidity ^0.5.0;



/**
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an owner) that can be granted exclusive access to
 * specific functions.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be aplied to your functions to restrict their use to
 * the owner.
 */
contract Ownable is Initializable, Context {
    address private _owner;

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    function initialize(address sender) public initializer {
        _owner = sender;
        emit OwnershipTransferred(address(0), _owner);
    }

    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view returns (address) {
        return _owner;
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        require(isOwner(), "Ownable: caller is not the owner");
        _;
    }

    /**
     * @dev Returns true if the caller is the current owner.
     */
    function isOwner() public view returns (bool) {
        return _msgSender() == _owner;
    }

    /**
     * @dev Leaves the contract without owner. It will not be possible to call
     * `onlyOwner` functions anymore. Can only be called by the current owner.
     *
     * > Note: Renouncing ownership will leave the contract without an owner,
     * thereby removing any functionality that is only available to the owner.
     */
    function renounceOwnership() public onlyOwner {
        emit OwnershipTransferred(_owner, address(0));
        _owner = address(0);
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Can only be called by the current owner.
     */
    function transferOwnership(address newOwner) public onlyOwner {
        _transferOwnership(newOwner);
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     */
    function _transferOwnership(address newOwner) internal {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        emit OwnershipTransferred(_owner, newOwner);
        _owner = newOwner;
    }

    uint256[50] private ______gap;
}

// File: @openzeppelin/contracts-ethereum-package/contracts/access/Roles.sol

pragma solidity ^0.5.0;

/**
 * @title Roles
 * @dev Library for managing addresses assigned to a Role.
 */
library Roles {
    struct Role {
        mapping (address => bool) bearer;
    }

    /**
     * @dev Give an account access to this role.
     */
    function add(Role storage role, address account) internal {
        require(!has(role, account), "Roles: account already has role");
        role.bearer[account] = true;
    }

    /**
     * @dev Remove an account's access to this role.
     */
    function remove(Role storage role, address account) internal {
        require(has(role, account), "Roles: account does not have role");
        role.bearer[account] = false;
    }

    /**
     * @dev Check if an account has this role.
     * @return bool
     */
    function has(Role storage role, address account) internal view returns (bool) {
        require(account != address(0), "Roles: account is the zero address");
        return role.bearer[account];
    }
}

// File: @openzeppelin/contracts-ethereum-package/contracts/access/roles/PauserRole.sol

pragma solidity ^0.5.0;




contract PauserRole is Initializable, Context {
    using Roles for Roles.Role;

    event PauserAdded(address indexed account);
    event PauserRemoved(address indexed account);

    Roles.Role private _pausers;

    function initialize(address sender) public initializer {
        if (!isPauser(sender)) {
            _addPauser(sender);
        }
    }

    modifier onlyPauser() {
        require(isPauser(_msgSender()), "PauserRole: caller does not have the Pauser role");
        _;
    }

    function isPauser(address account) public view returns (bool) {
        return _pausers.has(account);
    }

    function addPauser(address account) public onlyPauser {
        _addPauser(account);
    }

    function renouncePauser() public {
        _removePauser(_msgSender());
    }

    function _addPauser(address account) internal {
        _pausers.add(account);
        emit PauserAdded(account);
    }

    function _removePauser(address account) internal {
        _pausers.remove(account);
        emit PauserRemoved(account);
    }

    uint256[50] private ______gap;
}

// File: @openzeppelin/contracts-ethereum-package/contracts/lifecycle/Pausable.sol

pragma solidity ^0.5.0;




/**
 * @dev Contract module which allows children to implement an emergency stop
 * mechanism that can be triggered by an authorized account.
 *
 * This module is used through inheritance. It will make available the
 * modifiers `whenNotPaused` and `whenPaused`, which can be applied to
 * the functions of your contract. Note that they will not be pausable by
 * simply including this module, only once the modifiers are put in place.
 */
contract Pausable is Initializable, Context, PauserRole {
    /**
     * @dev Emitted when the pause is triggered by a pauser (`account`).
     */
    event Paused(address account);

    /**
     * @dev Emitted when the pause is lifted by a pauser (`account`).
     */
    event Unpaused(address account);

    bool private _paused;

    /**
     * @dev Initializes the contract in unpaused state. Assigns the Pauser role
     * to the deployer.
     */
    function initialize(address sender) public initializer {
        PauserRole.initialize(sender);

        _paused = false;
    }

    /**
     * @dev Returns true if the contract is paused, and false otherwise.
     */
    function paused() public view returns (bool) {
        return _paused;
    }

    /**
     * @dev Modifier to make a function callable only when the contract is not paused.
     */
    modifier whenNotPaused() {
        require(!_paused, "Pausable: paused");
        _;
    }

    /**
     * @dev Modifier to make a function callable only when the contract is paused.
     */
    modifier whenPaused() {
        require(_paused, "Pausable: not paused");
        _;
    }

    /**
     * @dev Called by a pauser to pause, triggers stopped state.
     */
    function pause() public onlyPauser whenNotPaused {
        _paused = true;
        emit Paused(_msgSender());
    }

    /**
     * @dev Called by a pauser to unpause, returns to normal state.
     */
    function unpause() public onlyPauser whenPaused {
        _paused = false;
        emit Unpaused(_msgSender());
    }

    uint256[50] private ______gap;
}

// File: contracts/interfaces/iERC20Fulcrum.sol

pragma solidity 0.5.16;

interface iERC20Fulcrum {
  function mint(
    address receiver,
    uint256 depositAmount)
    external
    returns (uint256 mintAmount);

  function burn(
    address receiver,
    uint256 burnAmount)
    external
    returns (uint256 loanAmountPaid);

  function tokenPrice()
    external
    view
    returns (uint256 price);

  function supplyInterestRate()
    external
    view
    returns (uint256);

  function rateMultiplier()
    external
    view
    returns (uint256);
  function baseRate()
    external
    view
    returns (uint256);

  function borrowInterestRate()
    external
    view
    returns (uint256);

  function avgBorrowInterestRate()
    external
    view
    returns (uint256);

  function protocolInterestRate()
    external
    view
    returns (uint256);

  function spreadMultiplier()
    external
    view
    returns (uint256);

  function totalAssetBorrow()
    external
    view
    returns (uint256);

  function totalAssetSupply()
    external
    view
    returns (uint256);

  function nextSupplyInterestRate(uint256)
    external
    view
    returns (uint256);

  function nextBorrowInterestRate(uint256)
    external
    view
    returns (uint256);
  function nextLoanInterestRate(uint256)
    external
    view
    returns (uint256);
  function totalSupplyInterestRate(uint256)
    external
    view
    returns (uint256);

  function claimLoanToken()
    external
    returns (uint256 claimedAmount);

  function dsr()
    external
    view
    returns (uint256);

  function chaiPrice()
    external
    view
    returns (uint256);
}

// File: contracts/interfaces/ILendingProtocol.sol

pragma solidity 0.5.16;

interface ILendingProtocol {
  function mint() external returns (uint256);
  function redeem(address account) external returns (uint256);
  function nextSupplyRate(uint256 amount) external view returns (uint256);
  function nextSupplyRateWithParams(uint256[] calldata params) external view returns (uint256);
  function getAPR() external view returns (uint256);
  function getPriceInToken() external view returns (uint256);
  function token() external view returns (address);
  function underlying() external view returns (address);
  function availableLiquidity() external view returns (uint256);
}

// File: contracts/interfaces/IGovToken.sol

pragma solidity 0.5.16;

interface IGovToken {
  function redeemGovTokens() external;
}

// File: contracts/interfaces/IIdleTokenV3_1.sol

/**
 * @title: Idle Token interface
 * @author: Idle Labs Inc., idle.finance
 */
pragma solidity 0.5.16;

interface IIdleTokenV3_1 {
  // view
  /**
   * IdleToken price calculation, in underlying
   *
   * @return : price in underlying token
   */
  function tokenPrice() external view returns (uint256 price);

  /**
   * @return : underlying token address
   */
  function token() external view returns (address);
  /**
   * Get APR of every ILendingProtocol
   *
   * @return addresses: array of token addresses
   * @return aprs: array of aprs (ordered in respect to the `addresses` array)
   */
  function getAPRs() external view returns (address[] memory addresses, uint256[] memory aprs);

  // external
  // We should save the amount one has deposited to calc interests

  /**
   * Used to mint IdleTokens, given an underlying amount (eg. DAI).
   * This method triggers a rebalance of the pools if needed
   * NOTE: User should 'approve' _amount of tokens before calling mintIdleToken
   * NOTE 2: this method can be paused
   *
   * @param _amount : amount of underlying token to be lended
   * @param _skipRebalance : flag for skipping rebalance for lower gas price
   * @param _referral : referral address
   * @return mintedTokens : amount of IdleTokens minted
   */
  function mintIdleToken(uint256 _amount, bool _skipRebalance, address _referral) external returns (uint256 mintedTokens);

  /**
   * Here we calc the pool share one can withdraw given the amount of IdleToken they want to burn
   * This method triggers a rebalance of the pools if needed
   * NOTE: If the contract is paused or iToken price has decreased one can still redeem but no rebalance happens.
   * NOTE 2: If iToken price has decresed one should not redeem (but can do it) otherwise he would capitalize the loss.
   *         Ideally one should wait until the black swan event is terminated
   *
   * @param _amount : amount of IdleTokens to be burned
   * @return redeemedTokens : amount of underlying tokens redeemed
   */
  function redeemIdleToken(uint256 _amount) external returns (uint256 redeemedTokens);
  /**
   * Here we calc the pool share one can withdraw given the amount of IdleToken they want to burn
   * and send interest-bearing tokens (eg. cDAI/iDAI) directly to the user.
   * Underlying (eg. DAI) is not redeemed here.
   *
   * @param _amount : amount of IdleTokens to be burned
   */
  function redeemInterestBearingTokens(uint256 _amount) external;

  /**
   * @return : whether has rebalanced or not
   */
  function rebalance() external returns (bool);
}

// File: contracts/interfaces/Comptroller.sol

pragma solidity 0.5.16;

interface Comptroller {
  function claimComp(address) external;
  function compSpeeds(address _cToken) external view returns (uint256);
  function claimComp(address[] calldata holders, address[] calldata cTokens, bool borrowers, bool suppliers) external;
}

// File: contracts/interfaces/CERC20.sol

pragma solidity 0.5.16;

interface CERC20 {
  function mint(uint256 mintAmount) external returns (uint256);
  function comptroller() external view returns (address);
  function redeem(uint256 redeemTokens) external returns (uint256);
  function exchangeRateStored() external view returns (uint256);
  function supplyRatePerBlock() external view returns (uint256);

  function borrowRatePerBlock() external view returns (uint256);
  function totalReserves() external view returns (uint256);
  function getCash() external view returns (uint256);
  function totalBorrows() external view returns (uint256);
  function reserveFactorMantissa() external view returns (uint256);
  function interestRateModel() external view returns (address);
}

// File: contracts/interfaces/IdleController.sol

pragma solidity 0.5.16;

interface IdleController {
  function idleSpeeds(address _idleToken) external view returns (uint256);
  function claimIdle(address[] calldata holders, address[] calldata idleTokens) external;
}

// File: contracts/interfaces/PriceOracle.sol

pragma solidity 0.5.16;

interface PriceOracle {
  function getUnderlyingPrice(address _idleToken) external view returns (uint256);
  function getPriceUSD(address _asset) external view returns (uint256 price);
  function getPriceETH(address _asset) external view returns (uint256 price);
  function getPriceToken(address _asset, address _token) external view returns (uint256 price);
  function WETH() external view returns (address);

  function getCompApr(address cToken, address token) external view returns (uint256);
}

// File: contracts/interfaces/GasToken.sol

pragma solidity 0.5.16;

interface GasToken {
  function freeUpTo(uint256 value) external returns (uint256 freed);
  function freeFromUpTo(address from, uint256 value) external returns (uint256 freed);
  function balanceOf(address from) external returns (uint256 balance);
}

// File: contracts/GST2ConsumerV2.sol

pragma solidity 0.5.16;



contract GST2ConsumerV2 is Initializable {
  GasToken public gst2;

  function initialize() initializer public {
    gst2 = GasToken(0x0000000000b3F879cb30FE243b4Dfee438691c04);
  }

  modifier gasDiscountFrom(address from) {
    uint256 initialGasLeft = gasleft();
    _;
    _makeGasDiscount(initialGasLeft - gasleft(), from);
  }

  function _makeGasDiscount(uint256 gasSpent, address from) internal {
    // For more info https://gastoken.io/
    // 14154 -> FREE_BASE -> base cost of freeing
    // 41130 -> 2 * REIMBURSE - FREE_TOKEN -> 2 * 24000 - 6870
    uint256 tokens = (gasSpent + 14154) / 41130;
    uint256 safeNumTokens;
    uint256 gas = gasleft();

    // For more info https://github.com/projectchicago/gastoken/blob/master/contract/gst2_free_example.sol
    if (gas >= 27710) {
      safeNumTokens = (gas - 27710) / 7020;
    }

    if (tokens > safeNumTokens) {
      tokens = safeNumTokens;
    }

    if (tokens > 0) {
      gst2.freeFromUpTo(from, tokens);
    }
  }
}

// File: contracts/IdleTokenGovernance.sol

/**
 * @title: Idle Token (V3) main contract
 * @summary: ERC20 that holds pooled user funds together
 *           Each token rapresent a share of the underlying pools
 *           and with each token user have the right to redeem a portion of these pools
 * @author: Idle Labs Inc., idle.finance
 */
pragma solidity 0.5.16;


















contract IdleTokenGovernance is Initializable, ERC20, ERC20Detailed, ReentrancyGuard, Ownable, Pausable, IIdleTokenV3_1, GST2ConsumerV2 {
  using SafeERC20 for IERC20;
  using SafeMath for uint256;

  uint256 private constant ONE_18 = 10**18;
  // State variables
  // eg. DAI address
  address public token;
  // eg. iDAI address
  address private iToken;
  // eg. cDAI address
  address private cToken;
  // Idle rebalancer current implementation address
  address public rebalancer;
  // Address collecting underlying fees
  address public feeAddress;
  // Last iToken price, used to pause contract in case of a black swan event
  uint256 public lastITokenPrice;
  // eg. 18 for DAI
  uint256 private tokenDecimals;
  // Max unlent assets percentage for gas friendly swaps
  uint256 public maxUnlentPerc; // 100000 == 100% -> 1000 == 1%
  // Current fee on interest gained
  uint256 public fee;
  // eg. [cTokenAddress, iTokenAddress, ...]
  address[] public allAvailableTokens;
  // eg. [COMPAddress, CRVAddress, ...]
  address[] public govTokens;
  // last fully applied allocations (ie when all liquidity has been correctly placed)
  // eg. [5000, 0, 5000, 0] for 50% in compound, 0% fulcrum, 50% aave, 0 dydx. same order of allAvailableTokens
  uint256[] public lastAllocations;
  // Map that saves avg idleToken price paid for each user, used to calculate earnings
  mapping(address => uint256) public userAvgPrices;
  // eg. cTokenAddress => IdleCompoundAddress
  mapping(address => address) public protocolWrappers;
  // array with last balance recorded for each gov tokens
  mapping (address => uint256) public govTokensLastBalances;
  // govToken -> user_address -> user_index eg. usersGovTokensIndexes[govTokens[0]][msg.sender] = 1111123;
  mapping (address => mapping (address => uint256)) public usersGovTokensIndexes;
  // global indices for each gov tokens used as a reference to calculate a fair share for each user
  mapping (address => uint256) public govTokensIndexes;
  // Map that saves amount with no fee for each user
  mapping(address => uint256) private userNoFeeQty;
  // variable used for avoid the call of mint and redeem in the same tx
  bytes32 private _minterBlock;

  // Events
  event Rebalance(address _rebalancer, uint256 _amount);
  event Referral(uint256 _amount, address _ref);

  // ########## IdleToken V4_1 updates
  // Idle governance token
  address public constant IDLE = address(0x875773784Af8135eA0ef43b5a374AaD105c5D39e);
  // Compound governance token
  address public constant COMP = address(0xc00e94Cb662C3520282E6f5717214004A7f26888);
  uint256 private constant FULL_ALLOC = 100000;

  // Idle distribution controller
  address public constant idleController = address(0x275DA8e61ea8E02d51EDd8d0DC5c0E62b4CDB0BE);
  // oracle used for calculating the avgAPR with gov tokens
  address public oracle;
  // eg cDAI -> COMP
  mapping(address => address) private protocolTokenToGov;
  // Whether openRebalance is enabled or not
  bool public isRiskAdjusted;
  // last allocations submitted by rebalancer
  uint256[] private lastRebalancerAllocations;

  // onlyOwner
  /**
   * It allows owner to modify allAvailableTokens array in case of emergency
   * ie if a bug on a interest bearing token is discovered and reset protocolWrappers
   * associated with those tokens.
   *
   * @param protocolTokens : array of protocolTokens addresses (eg [cDAI, iDAI, ...])
   * @param wrappers : array of wrapper addresses (eg [IdleCompound, IdleFulcrum, ...])
   * @param allocations : array of allocations
   * @param keepAllocations : whether to update lastRebalancerAllocations or not
   */
  function setAllAvailableTokensAndWrappers(
    address[] calldata protocolTokens,
    address[] calldata wrappers,
    uint256[] calldata allocations,
    bool keepAllocations
  ) external onlyOwner {
    require(protocolTokens.length == wrappers.length && (allocations.length == wrappers.length || keepAllocations), "IDLE:LEN_DIFF");

    for (uint256 i = 0; i < protocolTokens.length; i++) {
      require(protocolTokens[i] != address(0) && wrappers[i] != address(0), "IDLE:IS_0");
      protocolWrappers[protocolTokens[i]] = wrappers[i];
    }
    allAvailableTokens = protocolTokens;

    if (keepAllocations) {
      require(protocolTokens.length == allAvailableTokens.length, "IDLE:LEN_DIFF2");
      return;
    }
    _setAllocations(allocations);
  }

  /**
   * It allows owner to set gov tokens array
   * In case of any errors gov distribution can be paused by passing an empty array
   *
   * @param _newGovTokens : array of governance token addresses
   * @param _protocolTokens : array of interest bearing token addresses
   */
  function setGovTokens(
    address[] calldata _newGovTokens,
    address[] calldata _protocolTokens
  ) external onlyOwner {
    govTokens = _newGovTokens;
    // Reset protocolTokenToGov mapping
    for (uint256 i = 0; i < allAvailableTokens.length; i++) {
      protocolTokenToGov[allAvailableTokens[i]] = address(0);
    }
    // set protocol token to gov token mapping
    for (uint256 i = 0; i < _protocolTokens.length; i++) {
      address newGov = _newGovTokens[i];
      if (newGov == IDLE) { continue; }
      protocolTokenToGov[_protocolTokens[i]] = _newGovTokens[i];
    }
  }

  /**
   * It allows owner to set the IdleRebalancerV3_1 address
   *
   * @param _rebalancer : new IdleRebalancerV3_1 address
   */
  function setRebalancer(address _rebalancer)
    external onlyOwner {
      require(_rebalancer != address(0), "IDLE:IS_0");
      rebalancer = _rebalancer;
  }

  /**
   * It allows owner to set the fee (1000 == 10% of gained interest)
   *
   * @param _fee : fee amount where 100000 is 100%, max settable is 10%
   */
  function setFee(uint256 _fee)
    external onlyOwner {
      // 100000 == 100% -> 10000 == 10%
      require(_fee <= 10000, "IDLE:TOO_HIGH");
      fee = _fee;
  }

  /**
   * It allows owner to set the fee address
   *
   * @param _feeAddress : fee address
   */
  function setFeeAddress(address _feeAddress)
    external onlyOwner {
      require(_feeAddress != address(0), "IDLE:IS_0");
      feeAddress = _feeAddress;
  }

  /**
   * It allows owner to set the oracle address for getting avgAPR
   *
   * @param _oracle : new oracle address
   */
  function setOracleAddress(address _oracle)
    external onlyOwner {
      require(_oracle != address(0), "IDLE:IS_0");
      oracle = _oracle;
  }

  /**
   * It allows owner to set the max unlent asset percentage (1000 == 1% of unlent asset max)
   *
   * @param _perc : max unlent perc where 100000 is 100%
   */
  function setMaxUnlentPerc(uint256 _perc)
    external onlyOwner {
      require(_perc <= 100000, "IDLE:TOO_HIGH");
      maxUnlentPerc = _perc;
  }

  /**
   * It allows owner to set the isRiskAdjusted flag
   *
   * @param _isRiskAdjusted : flag for openRebalance
   */
  function setIsRiskAdjusted(bool _isRiskAdjusted)
    external onlyOwner {
      isRiskAdjusted = _isRiskAdjusted;
  }

  /**
   * Used by Rebalancer to set the new allocations
   *
   * @param _allocations : array with allocations in percentages (100% => 100000)
   */
  function setAllocations(uint256[] calldata _allocations) external {
    require(msg.sender == rebalancer || msg.sender == owner(), "IDLE:!AUTH");
    _setAllocations(_allocations);
  }

  /**
   * Used by Rebalancer or in openRebalance to set the new allocations
   *
   * @param _allocations : array with allocations in percentages (100% => 100000)
   */
  function _setAllocations(uint256[] memory _allocations) internal {
    require(_allocations.length == allAvailableTokens.length, "IDLE:!EQ_LEN");
    uint256 total;
    for (uint256 i = 0; i < _allocations.length; i++) {
      total = total.add(_allocations[i]);
    }
    lastRebalancerAllocations = _allocations;
    require(total == FULL_ALLOC, "IDLE:!EQ_TOT");
  }

  // view
  /**
   * Get latest allocations submitted by rebalancer
   *
   * @return : array of allocations ordered as allAvailableTokens
   */
  function getAllocations() external view returns (uint256[] memory) {
    return lastRebalancerAllocations;
  }

  /**
   * IdleToken price calculation, in underlying
   *
   * @return : price in underlying token
   */
  function tokenPrice()
    external view
    returns (uint256) {
    return _tokenPrice();
  }

  /**
   * Get APR of every ILendingProtocol
   *
   * @return addresses: array of token addresses
   * @return aprs: array of aprs (ordered in respect to the `addresses` array)
   */
  function getAPRs()
    external view
    returns (address[] memory addresses, uint256[] memory aprs) {
      address currToken;
      addresses = new address[](allAvailableTokens.length);
      aprs = new uint256[](allAvailableTokens.length);
      for (uint256 i = 0; i < allAvailableTokens.length; i++) {
        currToken = allAvailableTokens[i];
        addresses[i] = currToken;
        aprs[i] = ILendingProtocol(protocolWrappers[currToken]).getAPR();
      }
  }

  /**
   * Get current avg APR of this IdleToken
   *
   * @return avgApr: current weighted avg apr
   */
  function getAvgAPR()
    external view
    returns (uint256) {
    return _getAvgAPR();
  }

  /**
   * Get current avg APR of this IdleToken
   *
   * @return avgApr: current weighted avg apr
   */
  function _getAvgAPR()
    internal view
    returns (uint256 avgApr) {
      (, uint256[] memory amounts, uint256 total) = _getCurrentAllocations();
      // IDLE gov token won't be counted here because is not in allAvailableTokens
      for (uint256 i = 0; i < allAvailableTokens.length; i++) {
        if (amounts[i] == 0) {
          continue;
        }
        address protocolToken = allAvailableTokens[i];
        // avgApr = avgApr.add(currApr.mul(weight).div(ONE_18))
        avgApr = avgApr.add(
          ILendingProtocol(protocolWrappers[protocolToken]).getAPR().mul(
            amounts[i]
          )
        );
        // Add weighted gov tokens apr
        address currGov = protocolTokenToGov[protocolToken];
        if (govTokens.length > 0 && currGov != address(0)) {
          avgApr = avgApr.add(amounts[i].mul(getGovApr(currGov)));
        }
      }

      avgApr = avgApr.div(total);
  }

  /**
   * Get gov token APR
   *
   * @return : apr scaled to 1e18
   */
  function getGovApr(address _govToken) internal view returns (uint256) {
    // In case new Gov tokens will be supported this should be updated, no need to add IDLE apr
    if (_govToken == COMP && cToken != address(0)) {
      return PriceOracle(oracle).getCompApr(cToken, token);
    }
  }

  /**
   * ERC20 modified transferFrom that also update the avgPrice paid for the recipient and
   * updates user gov idx
   *
   * @param sender : sender account
   * @param recipient : recipient account
   * @param amount : value to transfer
   * @return : flag whether transfer was successful or not
   */
  function transferFrom(address sender, address recipient, uint256 amount) public returns (bool) {
    _updateUserGovIdxTransfer(sender, recipient, amount);
    _transfer(sender, recipient, amount);
    _approve(sender, msg.sender, allowance(sender, msg.sender).sub(amount, "ERC20: transfer amount exceeds allowance"));
    _updateUserFeeInfoTransfer(sender, recipient, amount, userAvgPrices[sender]);
    return true;
  }

  /**
   * ERC20 modified transfer that also update the avgPrice paid for the recipient and
   * updates user gov idx
   *
   * @param recipient : recipient account
   * @param amount : value to transfer
   * @return : flag whether transfer was successful or not
   */
  function transfer(address recipient, uint256 amount) public returns (bool) {
    _updateUserGovIdxTransfer(msg.sender, recipient, amount);
    _transfer(msg.sender, recipient, amount);
    _updateUserFeeInfoTransfer(msg.sender, recipient, amount, userAvgPrices[msg.sender]);
    return true;
  }

  /**
   * Helper method for transfer and transferFrom, updates recipient gov indexes
   *
   * @param _from : sender account
   * @param _to : recipient account
   * @param amount : value to transfer
   */
  function _updateUserGovIdxTransfer(address _from, address _to, uint256 amount) internal {
    address govToken;
    uint256 govTokenIdx;
    uint256 sharePerTokenFrom;
    uint256 shareTo;
    uint256 balanceTo = balanceOf(_to);
    for (uint256 i = 0; i < govTokens.length; i++) {
      govToken = govTokens[i];
      if (balanceTo == 0) {
        usersGovTokensIndexes[govToken][_to] = usersGovTokensIndexes[govToken][_from];
        continue;
      }

      govTokenIdx = govTokensIndexes[govToken];
      // calc 1 idleToken value in gov shares for user `_from`
      sharePerTokenFrom = govTokenIdx.sub(usersGovTokensIndexes[govToken][_from]);
      // calc current gov shares (before transfer) for user `_to`
      shareTo = balanceTo.mul(govTokenIdx.sub(usersGovTokensIndexes[govToken][_to])).div(ONE_18);
      // user `_to` should have -> shareTo + (sharePerTokenFrom * amount / 1e18) = (balanceTo + amount) * (govTokenIdx - userIdx) / 1e18
      // so userIdx = govTokenIdx - ((shareTo * 1e18 + (sharePerTokenFrom * amount)) / (balanceTo + amount))
      usersGovTokensIndexes[govToken][_to] = govTokenIdx.sub(
        shareTo.mul(ONE_18).add(sharePerTokenFrom.mul(amount)).div(
          balanceTo.add(amount)
        )
      );
    }
  }

  /**
   * Get how many gov tokens a user is entitled to (this may not include eventual undistributed tokens)
   *
   * @param _usr : user address
   * @return : array of amounts for each gov token
   */
  function getGovTokensAmounts(address _usr) external view returns (uint256[] memory _amounts) {
    address govToken;
    uint256 usrBal = balanceOf(_usr);
    _amounts = new uint256[](govTokens.length);
    for (uint256 i = 0; i < _amounts.length; i++) {
      govToken = govTokens[i];
      _amounts[i] = usrBal.mul(govTokensIndexes[govToken].sub(usersGovTokensIndexes[govToken][_usr])).div(ONE_18);
    }
  }

  // external
  /**
   * Used to mint IdleTokens, given an underlying amount (eg. DAI).
   * This method triggers a rebalance of the pools if _skipRebalance is set to false
   * NOTE: User should 'approve' _amount of tokens before calling mintIdleToken
   * NOTE 2: this method can be paused
   * This method use GasTokens of this contract (if present) to get a gas discount
   *
   * @param _amount : amount of underlying token to be lended
   * @param _referral : referral address
   * @return mintedTokens : amount of IdleTokens minted
   */
  function mintIdleToken(uint256 _amount, bool _skipRebalance, address _referral)
    external nonReentrant whenNotPaused
    returns (uint256 mintedTokens) {
    _minterBlock = keccak256(abi.encodePacked(tx.origin, block.number));
    _redeemGovTokens(msg.sender, false);
    // Get current IdleToken price
    uint256 idlePrice = _tokenPrice();
    // transfer tokens to this contract
    IERC20(token).safeTransferFrom(msg.sender, address(this), _amount);

    if (!_skipRebalance) {
      // lend assets and rebalance the pool if needed
      _rebalance();
    }

    mintedTokens = _amount.mul(ONE_18).div(idlePrice);
    _mint(msg.sender, mintedTokens);

    // Update avg price and/or userNoFeeQty
    _updateUserFeeInfo(msg.sender, mintedTokens, idlePrice);
    // Update user idx for each gov tokens
    _updateUserGovIdx(msg.sender, mintedTokens);

    if (_referral != address(0)) {
      emit Referral(_amount, _referral);
    }
  }

  /**
   * Helper method for mintIdleToken, updates minter gov indexes
   *
   * @param _to : minter account
   * @param _mintedTokens : number of newly minted tokens
   */
  function _updateUserGovIdx(address _to, uint256 _mintedTokens) internal {
    address govToken;
    uint256 usrBal = balanceOf(_to);
    uint256 _govIdx;
    uint256 _usrIdx;

    for (uint256 i = 0; i < govTokens.length; i++) {
      govToken = govTokens[i];
      _govIdx = govTokensIndexes[govToken];
      _usrIdx = usersGovTokensIndexes[govToken][_to];

      // calculate user idx
      usersGovTokensIndexes[govToken][_to] = usrBal.mul(_usrIdx).add(
        _mintedTokens.mul(_govIdx.sub(_usrIdx))
      ).div(usrBal);
    }
  }

  /**
   * Here we calc the pool share one can withdraw given the amount of IdleToken they want to burn
   *
   * @param _amount : amount of IdleTokens to be burned
   * @return redeemedTokens : amount of underlying tokens redeemed
   */
  function redeemIdleToken(uint256 _amount)
    external nonReentrant
    returns (uint256 redeemedTokens) {
      _checkMintRedeemSameTx();

      _redeemGovTokens(msg.sender, false);

      uint256 price = _tokenPrice();
      uint256 valueToRedeem = _amount.mul(price).div(ONE_18);
      uint256 balanceUnderlying = IERC20(token).balanceOf(address(this));
      uint256 idleSupply = totalSupply();

      if (valueToRedeem <= balanceUnderlying) {
        redeemedTokens = valueToRedeem;
      } else {
        address currToken;
        for (uint256 i = 0; i < allAvailableTokens.length; i++) {
          currToken = allAvailableTokens[i];
          redeemedTokens = redeemedTokens.add(
            _redeemProtocolTokens(
              currToken,
              // _amount * protocolPoolBalance / idleSupply
              _amount.mul(IERC20(currToken).balanceOf(address(this))).div(idleSupply), // amount to redeem
              address(this)
            )
          );
        }
        // Get a portion of the eventual unlent balance
        redeemedTokens = redeemedTokens.add(_amount.mul(balanceUnderlying).div(idleSupply));
      }
      // get eventual performance fee
      redeemedTokens = _getFee(_amount, redeemedTokens, price);
      // burn idleTokens
      _burn(msg.sender, _amount);
      // send underlying minus fee to msg.sender
      IERC20(token).safeTransfer(msg.sender, redeemedTokens);
  }

  /**
   * Here we calc the pool share one can withdraw given the amount of IdleToken they want to burn
   * and send interest-bearing tokens (eg. cDAI/iDAI) directly to the user.
   * Underlying (eg. DAI) is not redeemed here.
   *
   * @param _amount : amount of IdleTokens to be burned
   */
  function redeemInterestBearingTokens(uint256 _amount)
    external nonReentrant whenPaused {
      _checkMintRedeemSameTx();

      _redeemGovTokens(msg.sender, false);

      uint256 idleSupply = totalSupply();
      address currentToken;

      for (uint256 i = 0; i < allAvailableTokens.length; i++) {
        currentToken = allAvailableTokens[i];
        IERC20(currentToken).safeTransfer(
          msg.sender,
          _amount.mul(IERC20(currentToken).balanceOf(address(this))).div(idleSupply) // amount to redeem
        );
      }
      // Get a portion of the eventual unlent balance
      IERC20(token).safeTransfer(
        msg.sender,
        _amount.mul(IERC20(token).balanceOf(address(this))).div(idleSupply) // amount to redeem
      );

      _burn(msg.sender, _amount);
  }

  /**
   * Dynamic allocate all the pool across different lending protocols if needed, use gas refund from gasToken
   *
   * NOTE: this method can be paused.
   * msg.sender should approve this contract to spend GST2 tokens before calling
   * this method
   *
   * @return : whether has rebalanced or not
   */
  function rebalanceWithGST()
    external gasDiscountFrom(msg.sender)
    returns (bool) {
      return _rebalance();
  }

  /**
   * Dynamic allocate all the pool across different lending protocols if needed,
   * rebalance without params
   *
   * NOTE: this method can be paused
   *
   * @return : whether has rebalanced or not
   */
  function rebalance() external returns (bool) {
    return _rebalance();
  }

  /**
   * Allow any users to set new allocations as long as the new allocation
   * gives a better avg APR than before
   * Allocations should be in the format [100000, 0, 0, 0, ...] where length is the same
   * as lastAllocations variable and the sum of all value should be == 100000
   *
   * This method is not callble if this instance of IdleToken is a risk adjusted instance
   * NOTE: this method can be paused
   *
   * @param _newAllocations : array with new allocations in percentage
   * @return : whether has rebalanced or not
   * @return avgApr : the new avg apr after rebalance
   */
  function openRebalance(uint256[] calldata _newAllocations)
    external whenNotPaused
    returns (bool, uint256 avgApr) {
      require(!isRiskAdjusted, "IDLE:NOT_ALLOWED");
      uint256 initialAPR = _getAvgAPR();
      // Validate and update rebalancer allocations
      _setAllocations(_newAllocations);
      bool hasRebalanced = _rebalance();
      uint256 newAprAfterRebalance = _getAvgAPR();
      require(newAprAfterRebalance > initialAPR, "IDLE:NOT_IMPROV");
      return (hasRebalanced, newAprAfterRebalance);
  }

  // internal
  /**
   * Get current idleToken price based on net asset value and totalSupply
   *
   * @return price: value of 1 idleToken in underlying
   */
  function _tokenPrice() internal view returns (uint256 price) {
    uint256 totSupply = totalSupply();
    if (totSupply == 0) {
      return 10**(tokenDecimals);
    }

    address currToken;
    uint256 totNav = IERC20(token).balanceOf(address(this)).mul(ONE_18); // eventual underlying unlent balance

    for (uint256 i = 0; i < allAvailableTokens.length; i++) {
      currToken = allAvailableTokens[i];
      totNav = totNav.add(
        // NAV = price * poolSupply
        ILendingProtocol(protocolWrappers[currToken]).getPriceInToken().mul(
          IERC20(currToken).balanceOf(address(this))
        )
      );
    }

    price = totNav.div(totSupply); // idleToken price in token wei
  }

  /**
   * Dynamic allocate all the pool across different lending protocols if needed
   *
   * NOTE: this method can be paused
   *
   * @return : whether has rebalanced or not
   */
  function _rebalance()
    internal whenNotPaused
    returns (bool) {
      // check if we need to rebalance by looking at the last allocations submitted by rebalancer
      uint256[] memory rebalancerLastAllocations = lastRebalancerAllocations;
      bool areAllocationsEqual = rebalancerLastAllocations.length == lastAllocations.length;
      if (areAllocationsEqual) {
        for (uint256 i = 0; i < lastAllocations.length || !areAllocationsEqual; i++) {
          if (lastAllocations[i] != rebalancerLastAllocations[i]) {
            areAllocationsEqual = false;
            break;
          }
        }
      }

      uint256 balance = IERC20(token).balanceOf(address(this));
      uint256 maxUnlentBalance;

      if (areAllocationsEqual && balance == 0) {
        return false;
      }

      if (balance > 0) {
        maxUnlentBalance = _getCurrentPoolValue().mul(maxUnlentPerc).div(FULL_ALLOC);
        if (lastAllocations.length == 0) {
          // set in storage
          lastAllocations = rebalancerLastAllocations;
        }

        if (balance > maxUnlentBalance) {
          // mint the difference
          _mintWithAmounts(allAvailableTokens, _amountsFromAllocations(rebalancerLastAllocations, balance.sub(maxUnlentBalance)));
        }
      }

      if (areAllocationsEqual) {
        return false;
      }

      // Instead of redeeming everything during rebalance we redeem and mint only what needs
      // to be reallocated
      // get current allocations in underlying (it does not count unlent underlying)
      (address[] memory tokenAddresses, uint256[] memory amounts, uint256 totalInUnderlying) = _getCurrentAllocations();

      if (balance == 0 && maxUnlentPerc > 0) {
        totalInUnderlying = totalInUnderlying.sub(_getCurrentPoolValue().mul(maxUnlentPerc).div(FULL_ALLOC));
      }
      // calculate new allocations given the total (not counting unlent balance)
      uint256[] memory newAmounts = _amountsFromAllocations(rebalancerLastAllocations, totalInUnderlying);
      (uint256[] memory toMintAllocations, uint256 totalToMint, bool lowLiquidity) = _redeemAllNeeded(tokenAddresses, amounts, newAmounts);
      // if some protocol has liquidity that we should redeem, we do not update
      // lastAllocations to force another rebalance next time
      if (!lowLiquidity) {
        // Update lastAllocations with rebalancerLastAllocations
        delete lastAllocations;
        lastAllocations = rebalancerLastAllocations;
      }

      // Do not count `maxUnlentPerc` from balance
      if (maxUnlentBalance == 0 && maxUnlentPerc > 0) {
        maxUnlentBalance = _getCurrentPoolValue().mul(maxUnlentPerc).div(FULL_ALLOC);
      }

      uint256 totalRedeemd = IERC20(token).balanceOf(address(this));

      if (totalRedeemd <= maxUnlentBalance) {
        return false;
      }

      // Do not mint directly using toMintAllocations check with totalRedeemd
      uint256[] memory tempAllocations = new uint256[](toMintAllocations.length);
      for (uint256 i = 0; i < toMintAllocations.length; i++) {
        // Calc what would have been the correct allocations percentage if all was available
        tempAllocations[i] = toMintAllocations[i].mul(FULL_ALLOC).div(totalToMint);
      }

      uint256[] memory partialAmounts = _amountsFromAllocations(tempAllocations, totalRedeemd.sub(maxUnlentBalance));
      _mintWithAmounts(allAvailableTokens, partialAmounts);

      emit Rebalance(msg.sender, totalInUnderlying.add(maxUnlentBalance));

      return true; // hasRebalanced
  }

  /**
   * Redeem unclaimed governance tokens and update governance global index and user index if needed
   * if called during redeem it will send all gov tokens accrued by a user to the user
   *
   * @param _to : user address
   * @param _skipRedeem : flag to choose whether to send gov tokens to user or not
   */
  function _redeemGovTokens(address _to, bool _skipRedeem) internal {
    if (govTokens.length == 0) {
      return;
    }
    uint256 supply = totalSupply();
    uint256 usrBal = balanceOf(_to);
    address govToken;

    for (uint256 i = 0; i < govTokens.length; i++) {
      govToken = govTokens[i];

      if (supply > 0) {
        if (!_skipRedeem) {
          _redeemGovTokensFromProtocol(govToken);
        }

        // get current gov token balance
        uint256 govBal = IERC20(govToken).balanceOf(address(this));
        if (govBal > 0) {
          // update global index with ratio of govTokens per idleToken
          govTokensIndexes[govToken] = govTokensIndexes[govToken].add(
            // check how much gov tokens for each idleToken we gained since last update
            govBal.sub(govTokensLastBalances[govToken]).mul(ONE_18).div(supply)
          );
          // update global var with current govToken balance
          govTokensLastBalances[govToken] = govBal;
        }
      }

      if (usrBal > 0) {
        if (!_skipRedeem) {
          uint256 usrIndex = usersGovTokensIndexes[govToken][_to];
          // update current user index for this gov token
          usersGovTokensIndexes[govToken][_to] = govTokensIndexes[govToken];
          // check if user has accrued something
          uint256 delta = govTokensIndexes[govToken].sub(usrIndex);
          if (delta == 0) { continue; }
          uint256 share = usrBal.mul(delta).div(ONE_18);
          uint256 bal = IERC20(govToken).balanceOf(address(this));
          // To avoid rounding issue
          if (share > bal) {
            share = bal;
          }

          uint256 feeDue;
          // no fee for IDLE governance token
          if (feeAddress != address(0) && fee > 0 && govToken != IDLE) {
            feeDue = share.mul(fee).div(FULL_ALLOC);
            // Transfer gov token fee to feeAddress
            IERC20(govToken).safeTransfer(feeAddress, feeDue);
          }
          // Transfer gov token to user
          IERC20(govToken).safeTransfer(_to, share.sub(feeDue));
          // Update last balance
          govTokensLastBalances[govToken] = IERC20(govToken).balanceOf(address(this));
        }
      } else {
        // save current index for this gov token
        usersGovTokensIndexes[govToken][_to] = govTokensIndexes[govToken];
      }
    }
  }

  /**
   * Redeem a specific gov token
   *
   * @param _govToken : address of the gov token to redeem
   */
  function _redeemGovTokensFromProtocol(address _govToken) internal {
    // In case new Gov tokens will be supported this should be updated
    if (_govToken == COMP || _govToken == IDLE) {
      address[] memory holders = new address[](1);
      address[] memory tokens = new address[](1);
      holders[0] = address(this);

      if (_govToken == IDLE) {
        tokens[0] = address(this);
        IdleController(idleController).claimIdle(holders, tokens);
        return;
      }
      if (cToken != address(0)) {
        tokens[0] = cToken;
        Comptroller(CERC20(cToken).comptroller()).claimComp(holders, tokens, false, true);
      }
    }
  }

  /**
   * Update userNoFeeQty of a user on transfers and eventually avg price paid for each idle token
   * userAvgPrice do not consider tokens bought when there was no fee
   *
   * @param from : user address of the sender || address(0) on mint
   * @param usr : user that should have balance update
   * @param qty : new amount deposited / transferred, in idleToken
   * @param price : curr idleToken price in underlying
   */
  function _updateUserFeeInfoTransfer(address from, address usr, uint256 qty, uint256 price) private {
    uint256 userNoFeeQtyFrom = userNoFeeQty[from];
    if (userNoFeeQtyFrom >= qty) {
      userNoFeeQty[from] = userNoFeeQtyFrom.sub(qty);
      userNoFeeQty[usr] = userNoFeeQty[usr].add(qty);
      // No avg price update needed
      return;
    }
    // nofeeQty not counted
    uint256 oldBalance = balanceOf(usr).sub(qty).sub(userNoFeeQty[usr]);
    uint256 newQty = qty.sub(userNoFeeQtyFrom);
    // (avgPrice * oldBalance) + (currPrice * newQty)) / totBalance
    userAvgPrices[usr] = userAvgPrices[usr].mul(oldBalance).add(price.mul(newQty)).div(oldBalance.add(newQty));
    // update no fee quantities
    userNoFeeQty[from] = 0;
    userNoFeeQty[usr] = userNoFeeQty[usr].add(userNoFeeQtyFrom);
  }

  /**
   * Update userNoFeeQty of a user on deposits and eventually avg price paid for each idle token
   * userAvgPrice do not consider tokens bought when there was no fee
   *
   * @param usr : user that should have balance update
   * @param qty : new amount deposited / transferred, in idleToken
   * @param price : curr idleToken price in underlying
   */
  function _updateUserFeeInfo(address usr, uint256 qty, uint256 price) private {
    if (fee == 0) { // on deposits with 0 fee
      userNoFeeQty[usr] = userNoFeeQty[usr].add(qty);
      return;
    }
    // on deposits with fee
    uint256 totBalance = balanceOf(usr).sub(userNoFeeQty[usr]);
    // noFeeQty should not be counted here
    // (avgPrice * oldBalance) + (currPrice * newQty)) / totBalance
    userAvgPrices[usr] = userAvgPrices[usr].mul(totBalance.sub(qty)).add(price.mul(qty)).div(totBalance);
  }

  /**
   * Calculate fee and send them to feeAddress
   *
   * @param amount : in idleTokens
   * @param redeemed : in underlying
   * @param currPrice : current idleToken price
   * @return : net value in underlying
   */
  function _getFee(uint256 amount, uint256 redeemed, uint256 currPrice) internal returns (uint256) {
    uint256 noFeeQty = userNoFeeQty[msg.sender]; // in idleTokens
    bool hasEnoughNoFeeQty = noFeeQty >= amount;

    if (fee == 0 || hasEnoughNoFeeQty) {
      userNoFeeQty[msg.sender] = hasEnoughNoFeeQty ? noFeeQty.sub(amount) : 0;
      return redeemed;
    }
    userNoFeeQty[msg.sender] = 0;
    uint256 elegibleGains = currPrice < userAvgPrices[msg.sender] ? 0 :
      amount.sub(noFeeQty).mul(currPrice.sub(userAvgPrices[msg.sender])).div(ONE_18); // in underlyings
    uint256 feeDue = elegibleGains.mul(fee).div(FULL_ALLOC);
    IERC20(token).safeTransfer(feeAddress, feeDue);
    return redeemed.sub(feeDue);
  }

  /**
   * Mint specific amounts of protocols tokens
   *
   * @param tokenAddresses : array of protocol tokens
   * @param protocolAmounts : array of amounts to be minted
   * @return : net value in underlying
   */
  function _mintWithAmounts(address[] memory tokenAddresses, uint256[] memory protocolAmounts) internal {
    // mint for each protocol and update currentTokensUsed
    uint256 currAmount;
    address protWrapper;

    for (uint256 i = 0; i < protocolAmounts.length; i++) {
      currAmount = protocolAmounts[i];
      if (currAmount == 0) {
        continue;
      }
      protWrapper = protocolWrappers[tokenAddresses[i]];
      // Transfer _amount underlying token (eg. DAI) to protWrapper
      IERC20(token).safeTransfer(protWrapper, currAmount);
      ILendingProtocol(protWrapper).mint();
    }
  }

  /**
   * Calculate amounts from percentage allocations (100000 => 100%)
   *
   * @param allocations : array of protocol allocations in percentage
   * @param total : total amount
   * @return : array with amounts
   */
  function _amountsFromAllocations(uint256[] memory allocations, uint256 total)
    internal pure returns (uint256[] memory newAmounts) {
    newAmounts = new uint256[](allocations.length);
    uint256 currBalance;
    uint256 allocatedBalance;

    for (uint256 i = 0; i < allocations.length; i++) {
      if (i == allocations.length - 1) {
        newAmounts[i] = total.sub(allocatedBalance);
      } else {
        currBalance = total.mul(allocations[i]).div(FULL_ALLOC);
        allocatedBalance = allocatedBalance.add(currBalance);
        newAmounts[i] = currBalance;
      }
    }
    return newAmounts;
  }

  /**
   * Redeem all underlying needed from each protocol
   *
   * @param tokenAddresses : array of protocol tokens addresses
   * @param amounts : array with current allocations in underlying
   * @param newAmounts : array with new allocations in underlying
   * @return toMintAllocations : array with amounts to be minted
   * @return totalToMint : total amount that needs to be minted
   */
  function _redeemAllNeeded(
    address[] memory tokenAddresses,
    uint256[] memory amounts,
    uint256[] memory newAmounts
    ) internal returns (
      uint256[] memory toMintAllocations,
      uint256 totalToMint,
      bool lowLiquidity
    ) {
    toMintAllocations = new uint256[](amounts.length);
    ILendingProtocol protocol;
    uint256 currAmount;
    uint256 newAmount;
    address currToken;
    // check the difference between amounts and newAmounts
    for (uint256 i = 0; i < amounts.length; i++) {
      currToken = tokenAddresses[i];
      newAmount = newAmounts[i];
      currAmount = amounts[i];
      protocol = ILendingProtocol(protocolWrappers[currToken]);
      if (currAmount > newAmount) {
        uint256 toRedeem = currAmount.sub(newAmount);
        uint256 availableLiquidity = protocol.availableLiquidity();
        if (availableLiquidity < toRedeem) {
          lowLiquidity = true;
          toRedeem = availableLiquidity;
        }
        // redeem the difference
        _redeemProtocolTokens(
          currToken,
          // convert amount from underlying to protocol token
          toRedeem.mul(ONE_18).div(protocol.getPriceInToken()),
          address(this) // tokens are now in this contract
        );
      } else {
        toMintAllocations[i] = newAmount.sub(currAmount);
        totalToMint = totalToMint.add(toMintAllocations[i]);
      }
    }
  }

  /**
   * Get the contract balance of every protocol currently used
   *
   * @return tokenAddresses : array with all token addresses used,
   *                          eg [cTokenAddress, iTokenAddress]
   * @return amounts : array with all amounts for each protocol in order,
   *                   eg [amountCompoundInUnderlying, amountFulcrumInUnderlying]
   * @return total : total AUM in underlying
   */
  function _getCurrentAllocations() internal view
    returns (address[] memory tokenAddresses, uint256[] memory amounts, uint256 total) {
      // Get balance of every protocol implemented
      tokenAddresses = new address[](allAvailableTokens.length);
      amounts = new uint256[](allAvailableTokens.length);

      address currentToken;
      uint256 currTokenPrice;

      for (uint256 i = 0; i < allAvailableTokens.length; i++) {
        currentToken = allAvailableTokens[i];
        tokenAddresses[i] = currentToken;
        currTokenPrice = ILendingProtocol(protocolWrappers[currentToken]).getPriceInToken();
        amounts[i] = currTokenPrice.mul(
          IERC20(currentToken).balanceOf(address(this))
        ).div(ONE_18);
        total = total.add(amounts[i]);
      }

      // return addresses and respective amounts in underlying
      return (tokenAddresses, amounts, total);
  }

  /**
   * Get the current pool value in underlying
   *
   * @return total : total AUM in underlying
   */
  function _getCurrentPoolValue() internal view
    returns (uint256 total) {
      // Get balance of every protocol implemented
      address currentToken;

      for (uint256 i = 0; i < allAvailableTokens.length; i++) {
        currentToken = allAvailableTokens[i];
        total = total.add(ILendingProtocol(protocolWrappers[currentToken]).getPriceInToken().mul(
          IERC20(currentToken).balanceOf(address(this))
        ).div(ONE_18));
      }

      // add unlent balance
      total = total.add(IERC20(token).balanceOf(address(this)));
  }

  /**
   * Check that no mint has been made in the same block from the same EOA
   */
  function _checkMintRedeemSameTx() private view {
    require(keccak256(abi.encodePacked(tx.origin, block.number)) != _minterBlock, "IDLE:REENTR");
  }

  // ILendingProtocols calls
  /**
   * Redeem underlying tokens through protocol wrapper
   *
   * @param _amount : amount of `_token` to redeem
   * @param _token : protocol token address
   * @param _account : should be msg.sender when rebalancing and final user when redeeming
   * @return tokens : new tokens minted
   */
  function _redeemProtocolTokens(address _token, uint256 _amount, address _account)
    internal
    returns (uint256 tokens) {
      if (_amount == 0) {
        return tokens;
      }
      // Transfer _amount of _protocolToken (eg. cDAI) to _wrapperAddr
      IERC20(_token).safeTransfer(protocolWrappers[_token], _amount);
      tokens = ILendingProtocol(protocolWrappers[_token]).redeem(_account);
  }
}

pragma solidity ^0.5.16;
import "./CTokenInterfaces.sol";
/**
 * @title Compound's CErc20Delegator Contract
 * @notice CTokens which wrap an EIP-20 underlying and delegate to an implementation
 * @author Compound
 */
contract CErc20Delegator is CTokenInterface, CErc20Interface, CDelegatorInterface {
    /**
     * @notice Construct a new money market
     * @param underlying_ The address of the underlying asset
     * @param comptroller_ The address of the Comptroller
     * @param interestRateModel_ The address of the interest rate model
     * @param initialExchangeRateMantissa_ The initial exchange rate, scaled by 1e18
     * @param name_ ERC-20 name of this token
     * @param symbol_ ERC-20 symbol of this token
     * @param decimals_ ERC-20 decimal precision of this token
     * @param admin_ Address of the administrator of this token
     * @param implementation_ The address of the implementation the contract delegates to
     * @param becomeImplementationData The encoded args for becomeImplementation
     */
    constructor(address underlying_,
                ComptrollerInterface comptroller_,
                InterestRateModel interestRateModel_,
                uint initialExchangeRateMantissa_,
                string memory name_,
                string memory symbol_,
                uint8 decimals_,
                address payable admin_,
                address implementation_,
                bytes memory becomeImplementationData) public {
        // Creator of the contract is admin during initialization
        admin = msg.sender;
        // First delegate gets to initialize the delegator (i.e. storage contract)
        delegateTo(implementation_, abi.encodeWithSignature("initialize(address,address,address,uint256,string,string,uint8)",
                                                            underlying_,
                                                            comptroller_,
                                                            interestRateModel_,
                                                            initialExchangeRateMantissa_,
                                                            name_,
                                                            symbol_,
                                                            decimals_));
        // New implementations always get set via the settor (post-initialize)
        _setImplementation(implementation_, false, becomeImplementationData);
        // Set the proper admin now that initialization is done
        admin = admin_;
    }
    /**
     * @notice Called by the admin to update the implementation of the delegator
     * @param implementation_ The address of the new implementation for delegation
     * @param allowResign Flag to indicate whether to call _resignImplementation on the old implementation
     * @param becomeImplementationData The encoded bytes data to be passed to _becomeImplementation
     */
    function _setImplementation(address implementation_, bool allowResign, bytes memory becomeImplementationData) public {
        require(msg.sender == admin, "CErc20Delegator::_setImplementation: Caller must be admin");
        if (allowResign) {
            delegateToImplementation(abi.encodeWithSignature("_resignImplementation()"));
        }
        address oldImplementation = implementation;
        implementation = implementation_;
        delegateToImplementation(abi.encodeWithSignature("_becomeImplementation(bytes)", becomeImplementationData));
        emit NewImplementation(oldImplementation, implementation);
    }
    /**
     * @notice Sender supplies assets into the market and receives cTokens in exchange
     * @dev Accrues interest whether or not the operation succeeds, unless reverted
     * @param mintAmount The amount of the underlying asset to supply
     * @return uint 0=success, otherwise a failure (see ErrorReporter.sol for details)
     */
    function mint(uint mintAmount) external returns (uint) {
        mintAmount; // Shh
        delegateAndReturn();
    }
    /**
     * @notice Sender redeems cTokens in exchange for the underlying asset
     * @dev Accrues interest whether or not the operation succeeds, unless reverted
     * @param redeemTokens The number of cTokens to redeem into underlying
     * @return uint 0=success, otherwise a failure (see ErrorReporter.sol for details)
     */
    function redeem(uint redeemTokens) external returns (uint) {
        redeemTokens; // Shh
        delegateAndReturn();
    }
    /**
     * @notice Sender redeems cTokens in exchange for a specified amount of underlying asset
     * @dev Accrues interest whether or not the operation succeeds, unless reverted
     * @param redeemAmount The amount of underlying to redeem
     * @return uint 0=success, otherwise a failure (see ErrorReporter.sol for details)
     */
    function redeemUnderlying(uint redeemAmount) external returns (uint) {
        redeemAmount; // Shh
        delegateAndReturn();
    }
    /**
      * @notice Sender borrows assets from the protocol to their own address
      * @param borrowAmount The amount of the underlying asset to borrow
      * @return uint 0=success, otherwise a failure (see ErrorReporter.sol for details)
      */
    function borrow(uint borrowAmount) external returns (uint) {
        borrowAmount; // Shh
        delegateAndReturn();
    }
    /**
     * @notice Sender repays their own borrow
     * @param repayAmount The amount to repay
     * @return uint 0=success, otherwise a failure (see ErrorReporter.sol for details)
     */
    function repayBorrow(uint repayAmount) external returns (uint) {
        repayAmount; // Shh
        delegateAndReturn();
    }
    /**
     * @notice Sender repays a borrow belonging to borrower
     * @param borrower the account with the debt being payed off
     * @param repayAmount The amount to repay
     * @return uint 0=success, otherwise a failure (see ErrorReporter.sol for details)
     */
    function repayBorrowBehalf(address borrower, uint repayAmount) external returns (uint) {
        borrower; repayAmount; // Shh
        delegateAndReturn();
    }
    /**
     * @notice The sender liquidates the borrowers collateral.
     *  The collateral seized is transferred to the liquidator.
     * @param borrower The borrower of this cToken to be liquidated
     * @param cTokenCollateral The market in which to seize collateral from the borrower
     * @param repayAmount The amount of the underlying borrowed asset to repay
     * @return uint 0=success, otherwise a failure (see ErrorReporter.sol for details)
     */
    function liquidateBorrow(address borrower, uint repayAmount, CTokenInterface cTokenCollateral) external returns (uint) {
        borrower; repayAmount; cTokenCollateral; // Shh
        delegateAndReturn();
    }
    /**
     * @notice Transfer `amount` tokens from `msg.sender` to `dst`
     * @param dst The address of the destination account
     * @param amount The number of tokens to transfer
     * @return Whether or not the transfer succeeded
     */
    function transfer(address dst, uint amount) external returns (bool) {
        dst; amount; // Shh
        delegateAndReturn();
    }
    /**
     * @notice Transfer `amount` tokens from `src` to `dst`
     * @param src The address of the source account
     * @param dst The address of the destination account
     * @param amount The number of tokens to transfer
     * @return Whether or not the transfer succeeded
     */
    function transferFrom(address src, address dst, uint256 amount) external returns (bool) {
        src; dst; amount; // Shh
        delegateAndReturn();
    }
    /**
     * @notice Approve `spender` to transfer up to `amount` from `src`
     * @dev This will overwrite the approval amount for `spender`
     *  and is subject to issues noted [here](https://eips.ethereum.org/EIPS/eip-20#approve)
     * @param spender The address of the account which may transfer tokens
     * @param amount The number of tokens that are approved (-1 means infinite)
     * @return Whether or not the approval succeeded
     */
    function approve(address spender, uint256 amount) external returns (bool) {
        spender; amount; // Shh
        delegateAndReturn();
    }
    /**
     * @notice Get the current allowance from `owner` for `spender`
     * @param owner The address of the account which owns the tokens to be spent
     * @param spender The address of the account which may transfer tokens
     * @return The number of tokens allowed to be spent (-1 means infinite)
     */
    function allowance(address owner, address spender) external view returns (uint) {
        owner; spender; // Shh
        delegateToViewAndReturn();
    }
    /**
     * @notice Get the token balance of the `owner`
     * @param owner The address of the account to query
     * @return The number of tokens owned by `owner`
     */
    function balanceOf(address owner) external view returns (uint) {
        owner; // Shh
        delegateToViewAndReturn();
    }
    /**
     * @notice Get the underlying balance of the `owner`
     * @dev This also accrues interest in a transaction
     * @param owner The address of the account to query
     * @return The amount of underlying owned by `owner`
     */
    function balanceOfUnderlying(address owner) external returns (uint) {
        owner; // Shh
        delegateAndReturn();
    }
    /**
     * @notice Get a snapshot of the account's balances, and the cached exchange rate
     * @dev This is used by comptroller to more efficiently perform liquidity checks.
     * @param account Address of the account to snapshot
     * @return (possible error, token balance, borrow balance, exchange rate mantissa)
     */
    function getAccountSnapshot(address account) external view returns (uint, uint, uint, uint) {
        account; // Shh
        delegateToViewAndReturn();
    }
    /**
     * @notice Returns the current per-block borrow interest rate for this cToken
     * @return The borrow interest rate per block, scaled by 1e18
     */
    function borrowRatePerBlock() external view returns (uint) {
        delegateToViewAndReturn();
    }
    /**
     * @notice Returns the current per-block supply interest rate for this cToken
     * @return The supply interest rate per block, scaled by 1e18
     */
    function supplyRatePerBlock() external view returns (uint) {
        delegateToViewAndReturn();
    }
    /**
     * @notice Returns the current total borrows plus accrued interest
     * @return The total borrows with interest
     */
    function totalBorrowsCurrent() external returns (uint) {
        delegateAndReturn();
    }
    /**
     * @notice Accrue interest to updated borrowIndex and then calculate account's borrow balance using the updated borrowIndex
     * @param account The address whose balance should be calculated after updating borrowIndex
     * @return The calculated balance
     */
    function borrowBalanceCurrent(address account) external returns (uint) {
        account; // Shh
        delegateAndReturn();
    }
    /**
     * @notice Return the borrow balance of account based on stored data
     * @param account The address whose balance should be calculated
     * @return The calculated balance
     */
    function borrowBalanceStored(address account) public view returns (uint) {
        account; // Shh
        delegateToViewAndReturn();
    }
   /**
     * @notice Accrue interest then return the up-to-date exchange rate
     * @return Calculated exchange rate scaled by 1e18
     */
    function exchangeRateCurrent() public returns (uint) {
        delegateAndReturn();
    }
    /**
     * @notice Calculates the exchange rate from the underlying to the CToken
     * @dev This function does not accrue interest before calculating the exchange rate
     * @return Calculated exchange rate scaled by 1e18
     */
    function exchangeRateStored() public view returns (uint) {
        delegateToViewAndReturn();
    }
    /**
     * @notice Get cash balance of this cToken in the underlying asset
     * @return The quantity of underlying asset owned by this contract
     */
    function getCash() external view returns (uint) {
        delegateToViewAndReturn();
    }
    /**
      * @notice Applies accrued interest to total borrows and reserves.
      * @dev This calculates interest accrued from the last checkpointed block
      *      up to the current block and writes new checkpoint to storage.
      */
    function accrueInterest() public returns (uint) {
        delegateAndReturn();
    }
    /**
     * @notice Transfers collateral tokens (this market) to the liquidator.
     * @dev Will fail unless called by another cToken during the process of liquidation.
     *  Its absolutely critical to use msg.sender as the borrowed cToken and not a parameter.
     * @param liquidator The account receiving seized collateral
     * @param borrower The account having collateral seized
     * @param seizeTokens The number of cTokens to seize
     * @return uint 0=success, otherwise a failure (see ErrorReporter.sol for details)
     */
    function seize(address liquidator, address borrower, uint seizeTokens) external returns (uint) {
        liquidator; borrower; seizeTokens; // Shh
        delegateAndReturn();
    }
    /*** Admin Functions ***/
    /**
      * @notice Begins transfer of admin rights. The newPendingAdmin must call `_acceptAdmin` to finalize the transfer.
      * @dev Admin function to begin change of admin. The newPendingAdmin must call `_acceptAdmin` to finalize the transfer.
      * @param newPendingAdmin New pending admin.
      * @return uint 0=success, otherwise a failure (see ErrorReporter.sol for details)
      */
    function _setPendingAdmin(address payable newPendingAdmin) external returns (uint) {
        newPendingAdmin; // Shh
        delegateAndReturn();
    }
    /**
      * @notice Sets a new comptroller for the market
      * @dev Admin function to set a new comptroller
      * @return uint 0=success, otherwise a failure (see ErrorReporter.sol for details)
      */
    function _setComptroller(ComptrollerInterface newComptroller) public returns (uint) {
        newComptroller; // Shh
        delegateAndReturn();
    }
    /**
      * @notice accrues interest and sets a new reserve factor for the protocol using _setReserveFactorFresh
      * @dev Admin function to accrue interest and set a new reserve factor
      * @return uint 0=success, otherwise a failure (see ErrorReporter.sol for details)
      */
    function _setReserveFactor(uint newReserveFactorMantissa) external returns (uint) {
        newReserveFactorMantissa; // Shh
        delegateAndReturn();
    }
    /**
      * @notice Accepts transfer of admin rights. msg.sender must be pendingAdmin
      * @dev Admin function for pending admin to accept role and update admin
      * @return uint 0=success, otherwise a failure (see ErrorReporter.sol for details)
      */
    function _acceptAdmin() external returns (uint) {
        delegateAndReturn();
    }
    /**
     * @notice Accrues interest and adds reserves by transferring from admin
     * @param addAmount Amount of reserves to add
     * @return uint 0=success, otherwise a failure (see ErrorReporter.sol for details)
     */
    function _addReserves(uint addAmount) external returns (uint) {
        addAmount; // Shh
        delegateAndReturn();
    }
    /**
     * @notice Accrues interest and reduces reserves by transferring to admin
     * @param reduceAmount Amount of reduction to reserves
     * @return uint 0=success, otherwise a failure (see ErrorReporter.sol for details)
     */
    function _reduceReserves(uint reduceAmount) external returns (uint) {
        reduceAmount; // Shh
        delegateAndReturn();
    }
    /**
     * @notice Accrues interest and updates the interest rate model using _setInterestRateModelFresh
     * @dev Admin function to accrue interest and update the interest rate model
     * @param newInterestRateModel the new interest rate model to use
     * @return uint 0=success, otherwise a failure (see ErrorReporter.sol for details)
     */
    function _setInterestRateModel(InterestRateModel newInterestRateModel) public returns (uint) {
        newInterestRateModel; // Shh
        delegateAndReturn();
    }
    /**
     * @notice Internal method to delegate execution to another contract
     * @dev It returns to the external caller whatever the implementation returns or forwards reverts
     * @param callee The contract to delegatecall
     * @param data The raw data to delegatecall
     * @return The returned bytes from the delegatecall
     */
    function delegateTo(address callee, bytes memory data) internal returns (bytes memory) {
        (bool success, bytes memory returnData) = callee.delegatecall(data);
        assembly {
            if eq(success, 0) {
                revert(add(returnData, 0x20), returndatasize)
            }
        }
        return returnData;
    }
    /**
     * @notice Delegates execution to the implementation contract
     * @dev It returns to the external caller whatever the implementation returns or forwards reverts
     * @param data The raw data to delegatecall
     * @return The returned bytes from the delegatecall
     */
    function delegateToImplementation(bytes memory data) public returns (bytes memory) {
        return delegateTo(implementation, data);
    }
    /**
     * @notice Delegates execution to an implementation contract
     * @dev It returns to the external caller whatever the implementation returns or forwards reverts
     *  There are an additional 2 prefix uints from the wrapper returndata, which we ignore since we make an extra hop.
     * @param data The raw data to delegatecall
     * @return The returned bytes from the delegatecall
     */
    function delegateToViewImplementation(bytes memory data) public view returns (bytes memory) {
        (bool success, bytes memory returnData) = address(this).staticcall(abi.encodeWithSignature("delegateToImplementation(bytes)", data));
        assembly {
            if eq(success, 0) {
                revert(add(returnData, 0x20), returndatasize)
            }
        }
        return abi.decode(returnData, (bytes));
    }
    function delegateToViewAndReturn() private view returns (bytes memory) {
        (bool success, ) = address(this).staticcall(abi.encodeWithSignature("delegateToImplementation(bytes)", msg.data));
        assembly {
            let free_mem_ptr := mload(0x40)
            returndatacopy(free_mem_ptr, 0, returndatasize)
            switch success
            case 0 { revert(free_mem_ptr, returndatasize) }
            default { return(add(free_mem_ptr, 0x40), returndatasize) }
        }
    }
    function delegateAndReturn() private returns (bytes memory) {
        (bool success, ) = implementation.delegatecall(msg.data);
        assembly {
            let free_mem_ptr := mload(0x40)
            returndatacopy(free_mem_ptr, 0, returndatasize)
            switch success
            case 0 { revert(free_mem_ptr, returndatasize) }
            default { return(free_mem_ptr, returndatasize) }
        }
    }
    /**
     * @notice Delegates execution to an implementation contract
     * @dev It returns to the external caller whatever the implementation returns or forwards reverts
     */
    function () external payable {
        require(msg.value == 0,"CErc20Delegator:fallback: cannot send value to fallback");
        // delegate all other functions to current implementation
        delegateAndReturn();
    }
}
pragma solidity ^0.5.16;
import "./ComptrollerInterface.sol";
import "./InterestRateModel.sol";
contract CTokenStorage {
    /**
     * @dev Guard variable for re-entrancy checks
     */
    bool internal _notEntered;
    /**
     * @notice EIP-20 token name for this token
     */
    string public name;
    /**
     * @notice EIP-20 token symbol for this token
     */
    string public symbol;
    /**
     * @notice EIP-20 token decimals for this token
     */
    uint8 public decimals;
    /**
     * @notice Maximum borrow rate that can ever be applied (.0005% / block)
     */
    uint internal constant borrowRateMaxMantissa = 0.0005e16;
    /**
     * @notice Maximum fraction of interest that can be set aside for reserves
     */
    uint internal constant reserveFactorMaxMantissa = 1e18;
    /**
     * @notice Administrator for this contract
     */
    address payable public admin;
    /**
     * @notice Pending administrator for this contract
     */
    address payable public pendingAdmin;
    /**
     * @notice Contract which oversees inter-cToken operations
     */
    ComptrollerInterface public comptroller;
    /**
     * @notice Model which tells what the current interest rate should be
     */
    InterestRateModel public interestRateModel;
    /**
     * @notice Initial exchange rate used when minting the first CTokens (used when totalSupply = 0)
     */
    uint internal initialExchangeRateMantissa;
    /**
     * @notice Fraction of interest currently set aside for reserves
     */
    uint public reserveFactorMantissa;
    /**
     * @notice Block number that interest was last accrued at
     */
    uint public accrualBlockNumber;
    /**
     * @notice Accumulator of the total earned interest rate since the opening of the market
     */
    uint public borrowIndex;
    /**
     * @notice Total amount of outstanding borrows of the underlying in this market
     */
    uint public totalBorrows;
    /**
     * @notice Total amount of reserves of the underlying held in this market
     */
    uint public totalReserves;
    /**
     * @notice Total number of tokens in circulation
     */
    uint public totalSupply;
    /**
     * @notice Official record of token balances for each account
     */
    mapping (address => uint) internal accountTokens;
    /**
     * @notice Approved token transfer amounts on behalf of others
     */
    mapping (address => mapping (address => uint)) internal transferAllowances;
    /**
     * @notice Container for borrow balance information
     * @member principal Total balance (with accrued interest), after applying the most recent balance-changing action
     * @member interestIndex Global borrowIndex as of the most recent balance-changing action
     */
    struct BorrowSnapshot {
        uint principal;
        uint interestIndex;
    }
    /**
     * @notice Mapping of account addresses to outstanding borrow balances
     */
    mapping(address => BorrowSnapshot) internal accountBorrows;
}
contract CTokenInterface is CTokenStorage {
    /**
     * @notice Indicator that this is a CToken contract (for inspection)
     */
    bool public constant isCToken = true;
    /*** Market Events ***/
    /**
     * @notice Event emitted when interest is accrued
     */
    event AccrueInterest(uint cashPrior, uint interestAccumulated, uint borrowIndex, uint totalBorrows);
    /**
     * @notice Event emitted when tokens are minted
     */
    event Mint(address minter, uint mintAmount, uint mintTokens);
    /**
     * @notice Event emitted when tokens are redeemed
     */
    event Redeem(address redeemer, uint redeemAmount, uint redeemTokens);
    /**
     * @notice Event emitted when underlying is borrowed
     */
    event Borrow(address borrower, uint borrowAmount, uint accountBorrows, uint totalBorrows);
    /**
     * @notice Event emitted when a borrow is repaid
     */
    event RepayBorrow(address payer, address borrower, uint repayAmount, uint accountBorrows, uint totalBorrows);
    /**
     * @notice Event emitted when a borrow is liquidated
     */
    event LiquidateBorrow(address liquidator, address borrower, uint repayAmount, address cTokenCollateral, uint seizeTokens);
    /*** Admin Events ***/
    /**
     * @notice Event emitted when pendingAdmin is changed
     */
    event NewPendingAdmin(address oldPendingAdmin, address newPendingAdmin);
    /**
     * @notice Event emitted when pendingAdmin is accepted, which means admin is updated
     */
    event NewAdmin(address oldAdmin, address newAdmin);
    /**
     * @notice Event emitted when comptroller is changed
     */
    event NewComptroller(ComptrollerInterface oldComptroller, ComptrollerInterface newComptroller);
    /**
     * @notice Event emitted when interestRateModel is changed
     */
    event NewMarketInterestRateModel(InterestRateModel oldInterestRateModel, InterestRateModel newInterestRateModel);
    /**
     * @notice Event emitted when the reserve factor is changed
     */
    event NewReserveFactor(uint oldReserveFactorMantissa, uint newReserveFactorMantissa);
    /**
     * @notice Event emitted when the reserves are added
     */
    event ReservesAdded(address benefactor, uint addAmount, uint newTotalReserves);
    /**
     * @notice Event emitted when the reserves are reduced
     */
    event ReservesReduced(address admin, uint reduceAmount, uint newTotalReserves);
    /**
     * @notice EIP20 Transfer event
     */
    event Transfer(address indexed from, address indexed to, uint amount);
    /**
     * @notice EIP20 Approval event
     */
    event Approval(address indexed owner, address indexed spender, uint amount);
    /**
     * @notice Failure event
     */
    event Failure(uint error, uint info, uint detail);
    /*** User Interface ***/
    function transfer(address dst, uint amount) external returns (bool);
    function transferFrom(address src, address dst, uint amount) external returns (bool);
    function approve(address spender, uint amount) external returns (bool);
    function allowance(address owner, address spender) external view returns (uint);
    function balanceOf(address owner) external view returns (uint);
    function balanceOfUnderlying(address owner) external returns (uint);
    function getAccountSnapshot(address account) external view returns (uint, uint, uint, uint);
    function borrowRatePerBlock() external view returns (uint);
    function supplyRatePerBlock() external view returns (uint);
    function totalBorrowsCurrent() external returns (uint);
    function borrowBalanceCurrent(address account) external returns (uint);
    function borrowBalanceStored(address account) public view returns (uint);
    function exchangeRateCurrent() public returns (uint);
    function exchangeRateStored() public view returns (uint);
    function getCash() external view returns (uint);
    function accrueInterest() public returns (uint);
    function seize(address liquidator, address borrower, uint seizeTokens) external returns (uint);
    /*** Admin Functions ***/
    function _setPendingAdmin(address payable newPendingAdmin) external returns (uint);
    function _acceptAdmin() external returns (uint);
    function _setComptroller(ComptrollerInterface newComptroller) public returns (uint);
    function _setReserveFactor(uint newReserveFactorMantissa) external returns (uint);
    function _reduceReserves(uint reduceAmount) external returns (uint);
    function _setInterestRateModel(InterestRateModel newInterestRateModel) public returns (uint);
}
contract CErc20Storage {
    /**
     * @notice Underlying asset for this CToken
     */
    address public underlying;
}
contract CErc20Interface is CErc20Storage {
    /*** User Interface ***/
    function mint(uint mintAmount) external returns (uint);
    function redeem(uint redeemTokens) external returns (uint);
    function redeemUnderlying(uint redeemAmount) external returns (uint);
    function borrow(uint borrowAmount) external returns (uint);
    function repayBorrow(uint repayAmount) external returns (uint);
    function repayBorrowBehalf(address borrower, uint repayAmount) external returns (uint);
    function liquidateBorrow(address borrower, uint repayAmount, CTokenInterface cTokenCollateral) external returns (uint);
    /*** Admin Functions ***/
    function _addReserves(uint addAmount) external returns (uint);
}
contract CDelegationStorage {
    /**
     * @notice Implementation address for this contract
     */
    address public implementation;
}
contract CDelegatorInterface is CDelegationStorage {
    /**
     * @notice Emitted when implementation is changed
     */
    event NewImplementation(address oldImplementation, address newImplementation);
    /**
     * @notice Called by the admin to update the implementation of the delegator
     * @param implementation_ The address of the new implementation for delegation
     * @param allowResign Flag to indicate whether to call _resignImplementation on the old implementation
     * @param becomeImplementationData The encoded bytes data to be passed to _becomeImplementation
     */
    function _setImplementation(address implementation_, bool allowResign, bytes memory becomeImplementationData) public;
}
contract CDelegateInterface is CDelegationStorage {
    /**
     * @notice Called by the delegator on a delegate to initialize it for duty
     * @dev Should revert if any issues arise which make it unfit for delegation
     * @param data The encoded bytes data for any initialization
     */
    function _becomeImplementation(bytes memory data) public;
    /**
     * @notice Called by the delegator on a delegate to forfeit its responsibility
     */
    function _resignImplementation() public;
}
pragma solidity ^0.5.16;
contract ComptrollerInterface {
    /// @notice Indicator that this is a Comptroller contract (for inspection)
    bool public constant isComptroller = true;
    /*** Assets You Are In ***/
    function enterMarkets(address[] calldata cTokens) external returns (uint[] memory);
    function exitMarket(address cToken) external returns (uint);
    /*** Policy Hooks ***/
    function mintAllowed(address cToken, address minter, uint mintAmount) external returns (uint);
    function mintVerify(address cToken, address minter, uint mintAmount, uint mintTokens) external;
    function redeemAllowed(address cToken, address redeemer, uint redeemTokens) external returns (uint);
    function redeemVerify(address cToken, address redeemer, uint redeemAmount, uint redeemTokens) external;
    function borrowAllowed(address cToken, address borrower, uint borrowAmount) external returns (uint);
    function borrowVerify(address cToken, address borrower, uint borrowAmount) external;
    function repayBorrowAllowed(
        address cToken,
        address payer,
        address borrower,
        uint repayAmount) external returns (uint);
    function repayBorrowVerify(
        address cToken,
        address payer,
        address borrower,
        uint repayAmount,
        uint borrowerIndex) external;
    function liquidateBorrowAllowed(
        address cTokenBorrowed,
        address cTokenCollateral,
        address liquidator,
        address borrower,
        uint repayAmount) external returns (uint);
    function liquidateBorrowVerify(
        address cTokenBorrowed,
        address cTokenCollateral,
        address liquidator,
        address borrower,
        uint repayAmount,
        uint seizeTokens) external;
    function seizeAllowed(
        address cTokenCollateral,
        address cTokenBorrowed,
        address liquidator,
        address borrower,
        uint seizeTokens) external returns (uint);
    function seizeVerify(
        address cTokenCollateral,
        address cTokenBorrowed,
        address liquidator,
        address borrower,
        uint seizeTokens) external;
    function transferAllowed(address cToken, address src, address dst, uint transferTokens) external returns (uint);
    function transferVerify(address cToken, address src, address dst, uint transferTokens) external;
    /*** Liquidity/Liquidation Calculations ***/
    function liquidateCalculateSeizeTokens(
        address cTokenBorrowed,
        address cTokenCollateral,
        uint repayAmount) external view returns (uint, uint);
}
pragma solidity ^0.5.16;
/**
  * @title Compound's InterestRateModel Interface
  * @author Compound
  */
contract InterestRateModel {
    /// @notice Indicator that this is an InterestRateModel contract (for inspection)
    bool public constant isInterestRateModel = true;
    /**
      * @notice Calculates the current borrow interest rate per block
      * @param cash The total amount of cash the market has
      * @param borrows The total amount of borrows the market has outstanding
      * @param reserves The total amnount of reserves the market has
      * @return The borrow rate per block (as a percentage, and scaled by 1e18)
      */
    function getBorrowRate(uint cash, uint borrows, uint reserves) external view returns (uint);
    /**
      * @notice Calculates the current supply interest rate per block
      * @param cash The total amount of cash the market has
      * @param borrows The total amount of borrows the market has outstanding
      * @param reserves The total amnount of reserves the market has
      * @param reserveFactorMantissa The current reserve factor the market has
      * @return The supply rate per block (as a percentage, and scaled by 1e18)
      */
    function getSupplyRate(uint cash, uint borrows, uint reserves, uint reserveFactorMantissa) external view returns (uint);
}

// File: @openzeppelin/contracts/token/ERC20/IERC20.sol

pragma solidity ^0.5.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP. Does not include
 * the optional functions; to access them see {ERC20Detailed}.
 */
interface IERC20 {
    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns the amount of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);

    /**
     * @dev Moves `amount` tokens from the caller's account to `recipient`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address recipient, uint256 amount) external returns (bool);

    /**
     * @dev Returns the remaining number of tokens that `spender` will be
     * allowed to spend on behalf of `owner` through {transferFrom}. This is
     * zero by default.
     *
     * This value changes when {approve} or {transferFrom} are called.
     */
    function allowance(address owner, address spender) external view returns (uint256);

    /**
     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * IMPORTANT: Beware that changing an allowance with this method brings the risk
     * that someone may use both the old and the new allowance by unfortunate
     * transaction ordering. One possible solution to mitigate this race
     * condition is to first reduce the spender's allowance to 0 and set the
     * desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     *
     * Emits an {Approval} event.
     */
    function approve(address spender, uint256 amount) external returns (bool);

    /**
     * @dev Moves `amount` tokens from `sender` to `recipient` using the
     * allowance mechanism. `amount` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);

    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);

    /**
     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
     * a call to {approve}. `value` is the new allowance.
     */
    event Approval(address indexed owner, address indexed spender, uint256 value);
}

// File: @openzeppelin/contracts/math/SafeMath.sol

pragma solidity ^0.5.0;

/**
 * @dev Wrappers over Solidity's arithmetic operations with added overflow
 * checks.
 *
 * Arithmetic operations in Solidity wrap on overflow. This can easily result
 * in bugs, because programmers usually assume that an overflow raises an
 * error, which is the standard behavior in high level programming languages.
 * `SafeMath` restores this intuition by reverting the transaction when an
 * operation overflows.
 *
 * Using this library instead of the unchecked operations eliminates an entire
 * class of bugs, so it's recommended to use it always.
 */
library SafeMath {
    /**
     * @dev Returns the addition of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `+` operator.
     *
     * Requirements:
     * - Addition cannot overflow.
     */
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        require(c >= a, "SafeMath: addition overflow");

        return c;
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        return sub(a, b, "SafeMath: subtraction overflow");
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     * - Subtraction cannot overflow.
     *
     * _Available since v2.4.0._
     */
    function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b <= a, errorMessage);
        uint256 c = a - b;

        return c;
    }

    /**
     * @dev Returns the multiplication of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `*` operator.
     *
     * Requirements:
     * - Multiplication cannot overflow.
     */
    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
        // benefit is lost if 'b' is also tested.
        // See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
        if (a == 0) {
            return 0;
        }

        uint256 c = a * b;
        require(c / a == b, "SafeMath: multiplication overflow");

        return c;
    }

    /**
     * @dev Returns the integer division of two unsigned integers. Reverts on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        return div(a, b, "SafeMath: division by zero");
    }

    /**
     * @dev Returns the integer division of two unsigned integers. Reverts with custom message on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     * - The divisor cannot be zero.
     *
     * _Available since v2.4.0._
     */
    function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        // Solidity only automatically asserts when dividing by 0
        require(b > 0, errorMessage);
        uint256 c = a / b;
        // assert(a == b * c + a % b); // There is no case in which this doesn't hold

        return c;
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * Reverts when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     * - The divisor cannot be zero.
     */
    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        return mod(a, b, "SafeMath: modulo by zero");
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * Reverts with custom message when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     * - The divisor cannot be zero.
     *
     * _Available since v2.4.0._
     */
    function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b != 0, errorMessage);
        return a % b;
    }
}

// File: @openzeppelin/contracts/utils/Address.sol

pragma solidity ^0.5.5;

/**
 * @dev Collection of functions related to the address type
 */
library Address {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * This test is non-exhaustive, and there may be false-negatives: during the
     * execution of a contract's constructor, its address will be reported as
     * not containing a contract.
     *
     * IMPORTANT: It is unsafe to assume that an address for which this
     * function returns false is an externally-owned account (EOA) and not a
     * contract.
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies in extcodesize, which returns 0 for contracts in
        // construction, since the code is only stored at the end of the
        // constructor execution.

        // According to EIP-1052, 0x0 is the value returned for not-yet created accounts
        // and 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470 is returned
        // for accounts without code, i.e. `keccak256('')`
        bytes32 codehash;
        bytes32 accountHash = 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470;
        // solhint-disable-next-line no-inline-assembly
        assembly { codehash := extcodehash(account) }
        return (codehash != 0x0 && codehash != accountHash);
    }

    /**
     * @dev Converts an `address` into `address payable`. Note that this is
     * simply a type cast: the actual underlying value is not changed.
     *
     * _Available since v2.4.0._
     */
    function toPayable(address account) internal pure returns (address payable) {
        return address(uint160(account));
    }

    /**
     * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
     * `recipient`, forwarding all available gas and reverting on errors.
     *
     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
     * of certain opcodes, possibly making contracts go over the 2300 gas limit
     * imposed by `transfer`, making them unable to receive funds via
     * `transfer`. {sendValue} removes this limitation.
     *
     * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
     *
     * IMPORTANT: because control is transferred to `recipient`, care must be
     * taken to not create reentrancy vulnerabilities. Consider using
     * {ReentrancyGuard} or the
     * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     *
     * _Available since v2.4.0._
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");

        // solhint-disable-next-line avoid-call-value
        (bool success, ) = recipient.call.value(amount)("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }
}

// File: @openzeppelin/contracts/token/ERC20/SafeERC20.sol

pragma solidity ^0.5.0;




/**
 * @title SafeERC20
 * @dev Wrappers around ERC20 operations that throw on failure (when the token
 * contract returns false). Tokens that return no value (and instead revert or
 * throw on failure) are also supported, non-reverting calls are assumed to be
 * successful.
 * To use this library you can add a `using SafeERC20 for ERC20;` statement to your contract,
 * which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
 */
library SafeERC20 {
    using SafeMath for uint256;
    using Address for address;

    function safeTransfer(IERC20 token, address to, uint256 value) internal {
        callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
    }

    function safeTransferFrom(IERC20 token, address from, address to, uint256 value) internal {
        callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
    }

    function safeApprove(IERC20 token, address spender, uint256 value) internal {
        // safeApprove should only be called when setting an initial allowance,
        // or when resetting it to zero. To increase and decrease it, use
        // 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
        // solhint-disable-next-line max-line-length
        require((value == 0) || (token.allowance(address(this), spender) == 0),
            "SafeERC20: approve from non-zero to non-zero allowance"
        );
        callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
    }

    function safeIncreaseAllowance(IERC20 token, address spender, uint256 value) internal {
        uint256 newAllowance = token.allowance(address(this), spender).add(value);
        callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
    }

    function safeDecreaseAllowance(IERC20 token, address spender, uint256 value) internal {
        uint256 newAllowance = token.allowance(address(this), spender).sub(value, "SafeERC20: decreased allowance below zero");
        callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
    }

    /**
     * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
     * on the return value: the return value is optional (but if data is returned, it must not be false).
     * @param token The token targeted by the call.
     * @param data The call data (encoded using abi.encode or one of its variants).
     */
    function callOptionalReturn(IERC20 token, bytes memory data) private {
        // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
        // we're implementing it ourselves.

        // A Solidity high level call has three parts:
        //  1. The target address is checked to verify it contains contract code
        //  2. The call itself is made, and success asserted
        //  3. The return value is decoded, which in turn checks the size of the returned data.
        // solhint-disable-next-line max-line-length
        require(address(token).isContract(), "SafeERC20: call to non-contract");

        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = address(token).call(data);
        require(success, "SafeERC20: low-level call failed");

        if (returndata.length > 0) { // Return data is optional
            // solhint-disable-next-line max-line-length
            require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
        }
    }
}

// File: @openzeppelin/contracts/GSN/Context.sol

pragma solidity ^0.5.0;

/*
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with GSN meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
contract Context {
    // Empty internal constructor, to prevent people from mistakenly deploying
    // an instance of this contract, which should be used via inheritance.
    constructor () internal { }
    // solhint-disable-previous-line no-empty-blocks

    function _msgSender() internal view returns (address payable) {
        return msg.sender;
    }

    function _msgData() internal view returns (bytes memory) {
        this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
        return msg.data;
    }
}

// File: @openzeppelin/contracts/ownership/Ownable.sol

pragma solidity ^0.5.0;

/**
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an owner) that can be granted exclusive access to
 * specific functions.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be applied to your functions to restrict their use to
 * the owner.
 */
contract Ownable is Context {
    address private _owner;

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    constructor () internal {
        _owner = _msgSender();
        emit OwnershipTransferred(address(0), _owner);
    }

    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view returns (address) {
        return _owner;
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        require(isOwner(), "Ownable: caller is not the owner");
        _;
    }

    /**
     * @dev Returns true if the caller is the current owner.
     */
    function isOwner() public view returns (bool) {
        return _msgSender() == _owner;
    }

    /**
     * @dev Leaves the contract without owner. It will not be possible to call
     * `onlyOwner` functions anymore. Can only be called by the current owner.
     *
     * NOTE: Renouncing ownership will leave the contract without an owner,
     * thereby removing any functionality that is only available to the owner.
     */
    function renounceOwnership() public onlyOwner {
        emit OwnershipTransferred(_owner, address(0));
        _owner = address(0);
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Can only be called by the current owner.
     */
    function transferOwnership(address newOwner) public onlyOwner {
        _transferOwnership(newOwner);
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     */
    function _transferOwnership(address newOwner) internal {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        emit OwnershipTransferred(_owner, newOwner);
        _owner = newOwner;
    }
}

// File: contracts/interfaces/CERC20.sol

pragma solidity 0.5.16;

interface CERC20 {
  function mint(uint256 mintAmount) external returns (uint256);
  function comptroller() external view returns (address);
  function redeem(uint256 redeemTokens) external returns (uint256);
  function exchangeRateStored() external view returns (uint256);
  function supplyRatePerBlock() external view returns (uint256);

  function borrowRatePerBlock() external view returns (uint256);
  function totalReserves() external view returns (uint256);
  function getCash() external view returns (uint256);
  function totalBorrows() external view returns (uint256);
  function reserveFactorMantissa() external view returns (uint256);
  function interestRateModel() external view returns (address);
}

// File: contracts/interfaces/ILendingProtocol.sol

pragma solidity 0.5.16;

interface ILendingProtocol {
  function mint() external returns (uint256);
  function redeem(address account) external returns (uint256);
  function nextSupplyRate(uint256 amount) external view returns (uint256);
  function nextSupplyRateWithParams(uint256[] calldata params) external view returns (uint256);
  function getAPR() external view returns (uint256);
  function getPriceInToken() external view returns (uint256);
  function token() external view returns (address);
  function underlying() external view returns (address);
  function availableLiquidity() external view returns (uint256);
}

// File: contracts/interfaces/WhitePaperInterestRateModel.sol

pragma solidity 0.5.16;

interface WhitePaperInterestRateModel {
  function getBorrowRate(uint256 cash, uint256 borrows, uint256 _reserves) external view returns (uint256, uint256);
  function getSupplyRate(uint256 cash, uint256 borrows, uint256 reserves, uint256 reserveFactorMantissa) external view returns (uint256);
  function multiplier() external view returns (uint256);
  function baseRate() external view returns (uint256);
  function blocksPerYear() external view returns (uint256);
  function dsrPerBlock() external view returns (uint256);
}

// File: contracts/wrappers/IdleCompoundV2.sol

/**
 * @title: Compound wrapper
 * @summary: Used for interacting with Compound. Has
 *           a common interface with all other protocol wrappers.
 *           This contract holds assets only during a tx, after tx it should be empty
 * @author: Idle Labs Inc., idle.finance
 */
pragma solidity 0.5.16;








contract IdleCompoundV2 is ILendingProtocol, Ownable {
  using SafeERC20 for IERC20;
  using SafeMath for uint256;

  // protocol token (cToken) address
  address public token;
  // underlying token (token eg DAI) address
  address public underlying;
  address public idleToken;
  uint256 public blocksPerYear;

  /**
   * @param _token : cToken address
   * @param _underlying : underlying token (eg DAI) address
   */
  constructor(address _token, address _underlying) public {
    require(_token != address(0) && _underlying != address(0), 'COMP: some addr is 0');

    token = _token;
    underlying = _underlying;
    blocksPerYear = 2371428;
    IERC20(_underlying).safeApprove(_token, uint256(-1));
  }

  /**
   * Throws if called by any account other than IdleToken contract.
   */
  modifier onlyIdle() {
    require(msg.sender == idleToken, "Ownable: caller is not IdleToken");
    _;
  }

  // onlyOwner
  /**
   * sets idleToken address
   * NOTE: can be called only once. It's not on the constructor because we are deploying this contract
   *       after the IdleToken contract
   * @param _idleToken : idleToken address
   */
  function setIdleToken(address _idleToken)
    external onlyOwner {
      require(idleToken == address(0), "idleToken addr already set");
      require(_idleToken != address(0), "_idleToken addr is 0");
      idleToken = _idleToken;
  }

  /**
   * sets blocksPerYear address
   *
   * @param _blocksPerYear : avg blocks per year
   */
  function setBlocksPerYear(uint256 _blocksPerYear)
    external onlyOwner {
      require(_blocksPerYear != 0, "_blocksPerYear is 0");
      blocksPerYear = _blocksPerYear;
  }
  // end onlyOwner

  /**
   * Calculate next supply rate for Compound, given an `_amount` supplied (last array param)
   * and all other params supplied.
   *
   * @param params : array with all params needed for calculation
   * @return : yearly net rate
   */
  function nextSupplyRateWithParams(uint256[] calldata params)
    external view
    returns (uint256) {
      CERC20 cToken = CERC20(token);
      WhitePaperInterestRateModel white = WhitePaperInterestRateModel(cToken.interestRateModel());
      uint256 ratePerBlock = white.getSupplyRate(
        params[1].add(params[5]),
        params[0],
        params[2],
        params[3]
      );
      return ratePerBlock.mul(params[4]).mul(100);
  }

  /**
   * Calculate next supply rate for Compound, given an `_amount` supplied
   *
   * @param _amount : new underlying amount supplied (eg DAI)
   * @return : yearly net rate
   */
  function nextSupplyRate(uint256 _amount)
    external view
    returns (uint256) {
      CERC20 cToken = CERC20(token);
      WhitePaperInterestRateModel white = WhitePaperInterestRateModel(cToken.interestRateModel());
      uint256 ratePerBlock = white.getSupplyRate(
        cToken.getCash().add(_amount),
        cToken.totalBorrows(),
        cToken.totalReserves(),
        cToken.reserveFactorMantissa()
      );
      return ratePerBlock.mul(blocksPerYear).mul(100);
  }

  /**
   * @return current price of cToken in underlying
   */
  function getPriceInToken()
    external view
    returns (uint256) {
      return CERC20(token).exchangeRateStored();
  }

  /**
   * @return apr : current yearly net rate
   */
  function getAPR()
    external view
    returns (uint256 apr) {
      CERC20 cToken = CERC20(token);
      uint256 cRate = cToken.supplyRatePerBlock(); // interest % per block
      apr = cRate.mul(blocksPerYear).mul(100);
  }

  /**
   * Gets all underlying tokens in this contract and mints cTokens
   * tokens are then transferred to msg.sender
   * NOTE: underlying tokens needs to be sended here before calling this
   *
   * @return iTokens minted
   */
  function mint()
    external onlyIdle
    returns (uint256 cTokens) {
      uint256 balance = IERC20(underlying).balanceOf(address(this));
      if (balance == 0) {
        return cTokens;
      }
      // get a handle for the corresponding cToken contract
      CERC20 _cToken = CERC20(token);
      // mint the cTokens and assert there is no error
      require(_cToken.mint(balance) == 0, "Error minting cTokens");
      // cTokens are now in this contract
      cTokens = IERC20(token).balanceOf(address(this));
      // transfer them to the caller
      IERC20(token).safeTransfer(msg.sender, cTokens);
  }

  /**
   * Gets all cTokens in this contract and redeems underlying tokens.
   * underlying tokens are then transferred to `_account`
   * NOTE: iTokens needs to be sended here before calling this
   *
   * @return underlying tokens redeemd
   */
  function redeem(address _account)
    external onlyIdle
    returns (uint256 tokens) {
      // Funds needs to be sended here before calling this
      CERC20 _cToken = CERC20(token);
      IERC20 _underlying = IERC20(underlying);
      // redeem all underlying sent in this contract
      require(_cToken.redeem(IERC20(token).balanceOf(address(this))) == 0, "Error redeeming cTokens");

      tokens = _underlying.balanceOf(address(this));
      _underlying.safeTransfer(_account, tokens);
  }

  function availableLiquidity() external view returns (uint256) {
    return CERC20(token).getCash();
  }
}

pragma solidity ^0.5.0;

/**
 * @dev Wrappers over Solidity's arithmetic operations with added overflow
 * checks.
 *
 * Arithmetic operations in Solidity wrap on overflow. This can easily result
 * in bugs, because programmers usually assume that an overflow raises an
 * error, which is the standard behavior in high level programming languages.
 * `SafeMath` restores this intuition by reverting the transaction when an
 * operation overflows.
 *
 * Using this library instead of the unchecked operations eliminates an entire
 * class of bugs, so it's recommended to use it always.
 */
library SafeMath {
    /**
     * @dev Returns the addition of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `+` operator.
     *
     * Requirements:
     * - Addition cannot overflow.
     */
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        require(c >= a, "SafeMath: addition overflow");

        return c;
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b <= a, "SafeMath: subtraction overflow");
        uint256 c = a - b;

        return c;
    }

    /**
     * @dev Returns the multiplication of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `*` operator.
     *
     * Requirements:
     * - Multiplication cannot overflow.
     */
    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
        // benefit is lost if 'b' is also tested.
        // See: https://github.com/OpenZeppelin/openzeppelin-solidity/pull/522
        if (a == 0) {
            return 0;
        }

        uint256 c = a * b;
        require(c / a == b, "SafeMath: multiplication overflow");

        return c;
    }

    /**
     * @dev Returns the integer division of two unsigned integers. Reverts on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        // Solidity only automatically asserts when dividing by 0
        require(b > 0, "SafeMath: division by zero");
        uint256 c = a / b;
        // assert(a == b * c + a % b); // There is no case in which this doesn't hold

        return c;
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * Reverts when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     * - The divisor cannot be zero.
     */
    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b != 0, "SafeMath: modulo by zero");
        return a % b;
    }
}


/**
* @title WadRayMath library
* @author Aave
* @dev Provides mul and div function for wads (decimal numbers with 18 digits precision) and rays (decimals with 27 digits)
**/

library WadRayMath {
    using SafeMath for uint256;

    uint256 internal constant WAD = 1e18;
    uint256 internal constant halfWAD = WAD / 2;

    uint256 internal constant RAY = 1e27;
    uint256 internal constant halfRAY = RAY / 2;

    uint256 internal constant WAD_RAY_RATIO = 1e9;

    /**
    * @return one ray, 1e27
    **/
    function ray() internal pure returns (uint256) {
        return RAY;
    }

    /**
    * @return one wad, 1e18
    **/

    function wad() internal pure returns (uint256) {
        return WAD;
    }

    /**
    * @return half ray, 1e27/2
    **/
    function halfRay() internal pure returns (uint256) {
        return halfRAY;
    }

    /**
    * @return half ray, 1e18/2
    **/
    function halfWad() internal pure returns (uint256) {
        return halfWAD;
    }

    /**
    * @dev multiplies two wad, rounding half up to the nearest wad
    * @param a wad
    * @param b wad
    * @return the result of a*b, in wad
    **/
    function wadMul(uint256 a, uint256 b) internal pure returns (uint256) {
        return halfWAD.add(a.mul(b)).div(WAD);
    }

    /**
    * @dev divides two wad, rounding half up to the nearest wad
    * @param a wad
    * @param b wad
    * @return the result of a/b, in wad
    **/
    function wadDiv(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 halfB = b / 2;

        return halfB.add(a.mul(WAD)).div(b);
    }

    /**
    * @dev multiplies two ray, rounding half up to the nearest ray
    * @param a ray
    * @param b ray
    * @return the result of a*b, in ray
    **/
    function rayMul(uint256 a, uint256 b) internal pure returns (uint256) {
        return halfRAY.add(a.mul(b)).div(RAY);
    }

    /**
    * @dev divides two ray, rounding half up to the nearest ray
    * @param a ray
    * @param b ray
    * @return the result of a/b, in ray
    **/
    function rayDiv(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 halfB = b / 2;

        return halfB.add(a.mul(RAY)).div(b);
    }

    /**
    * @dev casts ray down to wad
    * @param a ray
    * @return a casted to wad, rounded half up to the nearest wad
    **/
    function rayToWad(uint256 a) internal pure returns (uint256) {
        uint256 halfRatio = WAD_RAY_RATIO / 2;

        return halfRatio.add(a).div(WAD_RAY_RATIO);
    }

    /**
    * @dev convert wad up to ray
    * @param a wad
    * @return a converted in ray
    **/
    function wadToRay(uint256 a) internal pure returns (uint256) {
        return a.mul(WAD_RAY_RATIO);
    }

    /**
    * @dev calculates base^exp. The code uses the ModExp precompile
    * @return base^exp, in ray
    */
    //solium-disable-next-line
    function rayPow(uint256 x, uint256 n) internal pure returns (uint256 z) {

        z = n % 2 != 0 ? x : RAY;

        for (n /= 2; n != 0; n /= 2) {
            x = rayMul(x, x);

            if (n % 2 != 0) {
                z = rayMul(z, x);
            }
        }
    }

}


/**
 * @dev Contract module that helps prevent reentrant calls to a function.
 *
 * Inheriting from `ReentrancyGuard` will make the `nonReentrant` modifier
 * available, which can be aplied to functions to make sure there are no nested
 * (reentrant) calls to them.
 *
 * Note that because there is a single `nonReentrant` guard, functions marked as
 * `nonReentrant` may not call one another. This can be worked around by making
 * those functions `private`, and then adding `external` `nonReentrant` entry
 * points to them.
 */
contract ReentrancyGuard {
    /// @dev counter to allow mutex lock with only one SSTORE operation
    uint256 private _guardCounter;

    constructor () internal {
        // The counter starts at one to prevent changing it from zero to a non-zero
        // value, which is a more expensive operation.
        _guardCounter = 1;
    }

    /**
     * @dev Prevents a contract from calling itself, directly or indirectly.
     * Calling a `nonReentrant` function from another `nonReentrant`
     * function is not supported. It is possible to prevent this from happening
     * by making the `nonReentrant` function external, and make it call a
     * `private` function that does the actual work.
     */
    modifier nonReentrant() {
        _guardCounter += 1;
        uint256 localCounter = _guardCounter;
        _;
        require(localCounter == _guardCounter, "ReentrancyGuard: reentrant call");
    }
}



/**
 * @dev Collection of functions related to the address type,
 */
library Address {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * This test is non-exhaustive, and there may be false-negatives: during the
     * execution of a contract's constructor, its address will be reported as
     * not containing a contract.
     *
     * > It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies in extcodesize, which returns 0 for contracts in
        // construction, since the code is only stored at the end of the
        // constructor execution.

        uint256 size;
        // solhint-disable-next-line no-inline-assembly
        assembly { size := extcodesize(account) }
        return size > 0;
    }
}


/**
 * @dev Interface of the ERC20 standard as defined in the EIP. Does not include
 * the optional functions; to access them see `ERC20Detailed`.
 */
interface IERC20 {
    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns the amount of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);

    /**
     * @dev Moves `amount` tokens from the caller's account to `recipient`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a `Transfer` event.
     */
    function transfer(address recipient, uint256 amount) external returns (bool);

    /**
     * @dev Returns the remaining number of tokens that `spender` will be
     * allowed to spend on behalf of `owner` through `transferFrom`. This is
     * zero by default.
     *
     * This value changes when `approve` or `transferFrom` are called.
     */
    function allowance(address owner, address spender) external view returns (uint256);

    /**
     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * > Beware that changing an allowance with this method brings the risk
     * that someone may use both the old and the new allowance by unfortunate
     * transaction ordering. One possible solution to mitigate this race
     * condition is to first reduce the spender's allowance to 0 and set the
     * desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     *
     * Emits an `Approval` event.
     */
    function approve(address spender, uint256 amount) external returns (bool);

    /**
     * @dev Moves `amount` tokens from `sender` to `recipient` using the
     * allowance mechanism. `amount` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a `Transfer` event.
     */
    function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);

    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);

    /**
     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
     * a call to `approve`. `value` is the new allowance.
     */
    event Approval(address indexed owner, address indexed spender, uint256 value);
}

/**
 * @dev Implementation of the `IERC20` interface.
 *
 * This implementation is agnostic to the way tokens are created. This means
 * that a supply mechanism has to be added in a derived contract using `_mint`.
 * For a generic mechanism see `ERC20Mintable`.
 *
 * *For a detailed writeup see our guide [How to implement supply
 * mechanisms](https://forum.zeppelin.solutions/t/how-to-implement-erc20-supply-mechanisms/226).*
 *
 * We have followed general OpenZeppelin guidelines: functions revert instead
 * of returning `false` on failure. This behavior is nonetheless conventional
 * and does not conflict with the expectations of ERC20 applications.
 *
 * Additionally, an `Approval` event is emitted on calls to `transferFrom`.
 * This allows applications to reconstruct the allowance for all accounts just
 * by listening to said events. Other implementations of the EIP may not emit
 * these events, as it isn't required by the specification.
 *
 * Finally, the non-standard `decreaseAllowance` and `increaseAllowance`
 * functions have been added to mitigate the well-known issues around setting
 * allowances. See `IERC20.approve`.
 */
contract ERC20 is IERC20 {
    using SafeMath for uint256;

    mapping (address => uint256) private _balances;

    mapping (address => mapping (address => uint256)) private _allowances;

    uint256 private _totalSupply;

    /**
     * @dev See `IERC20.totalSupply`.
     */
    function totalSupply() public view returns (uint256) {
        return _totalSupply;
    }

    /**
     * @dev See `IERC20.balanceOf`.
     */
    function balanceOf(address account) public view returns (uint256) {
        return _balances[account];
    }

    /**
     * @dev See `IERC20.transfer`.
     *
     * Requirements:
     *
     * - `recipient` cannot be the zero address.
     * - the caller must have a balance of at least `amount`.
     */
    function transfer(address recipient, uint256 amount) public returns (bool) {
        _transfer(msg.sender, recipient, amount);
        return true;
    }

    /**
     * @dev See `IERC20.allowance`.
     */
    function allowance(address owner, address spender) public view returns (uint256) {
        return _allowances[owner][spender];
    }

    /**
     * @dev See `IERC20.approve`.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     */
    function approve(address spender, uint256 value) public returns (bool) {
        _approve(msg.sender, spender, value);
        return true;
    }

    /**
     * @dev See `IERC20.transferFrom`.
     *
     * Emits an `Approval` event indicating the updated allowance. This is not
     * required by the EIP. See the note at the beginning of `ERC20`;
     *
     * Requirements:
     * - `sender` and `recipient` cannot be the zero address.
     * - `sender` must have a balance of at least `value`.
     * - the caller must have allowance for `sender`'s tokens of at least
     * `amount`.
     */
    function transferFrom(address sender, address recipient, uint256 amount) public returns (bool) {
        _transfer(sender, recipient, amount);
        _approve(sender, msg.sender, _allowances[sender][msg.sender].sub(amount));
        return true;
    }

    /**
     * @dev Atomically increases the allowance granted to `spender` by the caller.
     *
     * This is an alternative to `approve` that can be used as a mitigation for
     * problems described in `IERC20.approve`.
     *
     * Emits an `Approval` event indicating the updated allowance.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     */
    function increaseAllowance(address spender, uint256 addedValue) public returns (bool) {
        _approve(msg.sender, spender, _allowances[msg.sender][spender].add(addedValue));
        return true;
    }

    /**
     * @dev Atomically decreases the allowance granted to `spender` by the caller.
     *
     * This is an alternative to `approve` that can be used as a mitigation for
     * problems described in `IERC20.approve`.
     *
     * Emits an `Approval` event indicating the updated allowance.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     * - `spender` must have allowance for the caller of at least
     * `subtractedValue`.
     */
    function decreaseAllowance(address spender, uint256 subtractedValue) public returns (bool) {
        _approve(msg.sender, spender, _allowances[msg.sender][spender].sub(subtractedValue));
        return true;
    }

    /**
     * @dev Moves tokens `amount` from `sender` to `recipient`.
     *
     * This is internal function is equivalent to `transfer`, and can be used to
     * e.g. implement automatic token fees, slashing mechanisms, etc.
     *
     * Emits a `Transfer` event.
     *
     * Requirements:
     *
     * - `sender` cannot be the zero address.
     * - `recipient` cannot be the zero address.
     * - `sender` must have a balance of at least `amount`.
     */
    function _transfer(address sender, address recipient, uint256 amount) internal {
        require(sender != address(0), "ERC20: transfer from the zero address");
        require(recipient != address(0), "ERC20: transfer to the zero address");

        _balances[sender] = _balances[sender].sub(amount);
        _balances[recipient] = _balances[recipient].add(amount);
        emit Transfer(sender, recipient, amount);
    }

    /** @dev Creates `amount` tokens and assigns them to `account`, increasing
     * the total supply.
     *
     * Emits a `Transfer` event with `from` set to the zero address.
     *
     * Requirements
     *
     * - `to` cannot be the zero address.
     */
    function _mint(address account, uint256 amount) internal {
        require(account != address(0), "ERC20: mint to the zero address");

        _totalSupply = _totalSupply.add(amount);
        _balances[account] = _balances[account].add(amount);
        emit Transfer(address(0), account, amount);
    }

     /**
     * @dev Destoys `amount` tokens from `account`, reducing the
     * total supply.
     *
     * Emits a `Transfer` event with `to` set to the zero address.
     *
     * Requirements
     *
     * - `account` cannot be the zero address.
     * - `account` must have at least `amount` tokens.
     */
    function _burn(address account, uint256 value) internal {
        require(account != address(0), "ERC20: burn from the zero address");

        _totalSupply = _totalSupply.sub(value);
        _balances[account] = _balances[account].sub(value);
        emit Transfer(account, address(0), value);
    }

    /**
     * @dev Sets `amount` as the allowance of `spender` over the `owner`s tokens.
     *
     * This is internal function is equivalent to `approve`, and can be used to
     * e.g. set automatic allowances for certain subsystems, etc.
     *
     * Emits an `Approval` event.
     *
     * Requirements:
     *
     * - `owner` cannot be the zero address.
     * - `spender` cannot be the zero address.
     */
    function _approve(address owner, address spender, uint256 value) internal {
        require(owner != address(0), "ERC20: approve from the zero address");
        require(spender != address(0), "ERC20: approve to the zero address");

        _allowances[owner][spender] = value;
        emit Approval(owner, spender, value);
    }

    /**
     * @dev Destoys `amount` tokens from `account`.`amount` is then deducted
     * from the caller's allowance.
     *
     * See `_burn` and `_approve`.
     */
    function _burnFrom(address account, uint256 amount) internal {
        _burn(account, amount);
        _approve(account, msg.sender, _allowances[account][msg.sender].sub(amount));
    }
}

/**
 * @dev Optional functions from the ERC20 standard.
 */
contract ERC20Detailed is IERC20 {
    string private _name;
    string private _symbol;
    uint8 private _decimals;

    /**
     * @dev Sets the values for `name`, `symbol`, and `decimals`. All three of
     * these values are immutable: they can only be set once during
     * construction.
     */
    constructor (string memory name, string memory symbol, uint8 decimals) public {
        _name = name;
        _symbol = symbol;
        _decimals = decimals;
    }

    /**
     * @dev Returns the name of the token.
     */
    function name() public view returns (string memory) {
        return _name;
    }

    /**
     * @dev Returns the symbol of the token, usually a shorter version of the
     * name.
     */
    function symbol() public view returns (string memory) {
        return _symbol;
    }

    /**
     * @dev Returns the number of decimals used to get its user representation.
     * For example, if `decimals` equals `2`, a balance of `505` tokens should
     * be displayed to a user as `5,05` (`505 / 10 ** 2`).
     *
     * Tokens usually opt for a value of 18, imitating the relationship between
     * Ether and Wei.
     *
     * > Note that this information is only used for _display_ purposes: it in
     * no way affects any of the arithmetic of the contract, including
     * `IERC20.balanceOf` and `IERC20.transfer`.
     */
    function decimals() public view returns (uint8) {
        return _decimals;
    }
}

/**
 * @title SafeERC20
 * @dev Wrappers around ERC20 operations that throw on failure (when the token
 * contract returns false). Tokens that return no value (and instead revert or
 * throw on failure) are also supported, non-reverting calls are assumed to be
 * successful.
 * To use this library you can add a `using SafeERC20 for ERC20;` statement to your contract,
 * which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
 */
library SafeERC20 {
    using SafeMath for uint256;
    using Address for address;

    function safeTransfer(IERC20 token, address to, uint256 value) internal {
        callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
    }

    function safeTransferFrom(IERC20 token, address from, address to, uint256 value) internal {
        callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
    }

    function safeApprove(IERC20 token, address spender, uint256 value) internal {
        // safeApprove should only be called when setting an initial allowance,
        // or when resetting it to zero. To increase and decrease it, use
        // 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
        // solhint-disable-next-line max-line-length
        require((value == 0) || (token.allowance(address(this), spender) == 0),
            "SafeERC20: approve from non-zero to non-zero allowance"
        );
        callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
    }

    function safeIncreaseAllowance(IERC20 token, address spender, uint256 value) internal {
        uint256 newAllowance = token.allowance(address(this), spender).add(value);
        callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
    }

    function safeDecreaseAllowance(IERC20 token, address spender, uint256 value) internal {
        uint256 newAllowance = token.allowance(address(this), spender).sub(value);
        callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
    }

    /**
     * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
     * on the return value: the return value is optional (but if data is returned, it must not be false).
     * @param token The token targeted by the call.
     * @param data The call data (encoded using abi.encode or one of its variants).
     */
    function callOptionalReturn(IERC20 token, bytes memory data) private {
        // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
        // we're implementing it ourselves.

        // A Solidity high level call has three parts:
        //  1. The target address is checked to verify it contains contract code
        //  2. The call itself is made, and success asserted
        //  3. The return value is decoded, which in turn checks the size of the returned data.
        // solhint-disable-next-line max-line-length
        require(address(token).isContract(), "SafeERC20: call to non-contract");

        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = address(token).call(data);
        require(success, "SafeERC20: low-level call failed");

        if (returndata.length > 0) { // Return data is optional
            // solhint-disable-next-line max-line-length
            require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
        }
    }
}

/**
 * @title VersionedInitializable
 *
 * @dev Helper contract to support initializer functions. To use it, replace
 * the constructor with a function that has the `initializer` modifier.
 * WARNING: Unlike constructors, initializer functions must be manually
 * invoked. This applies both to deploying an Initializable contract, as well
 * as extending an Initializable contract via inheritance.
 * WARNING: When used with inheritance, manual care must be taken to not invoke
 * a parent initializer twice, or ensure that all initializers are idempotent,
 * because this is not dealt with automatically as with constructors.
 *
 * @author Aave, inspired by the OpenZeppelin Initializable contract
 */
contract VersionedInitializable {
    /**
   * @dev Indicates that the contract has been initialized.
   */
    uint256 private lastInitializedRevision = 0;

    /**
   * @dev Indicates that the contract is in the process of being initialized.
   */
    bool private initializing;

    /**
   * @dev Modifier to use in the initializer function of a contract.
   */
    modifier initializer() {
        uint256 revision = getRevision();
        require(initializing || isConstructor() || revision > lastInitializedRevision, "Contract instance has already been initialized");

        bool isTopLevelCall = !initializing;
        if (isTopLevelCall) {
            initializing = true;
            lastInitializedRevision = revision;
        }

        _;

        if (isTopLevelCall) {
            initializing = false;
        }
    }

    /// @dev returns the revision number of the contract.
    /// Needs to be defined in the inherited class as a constant.
    function getRevision() internal pure returns(uint256);


    /// @dev Returns true if and only if the function is running in the constructor
    function isConstructor() private view returns (bool) {
        // extcodesize checks the size of the code stored in an address, and
        // address returns the current address. Since the code is still not
        // deployed when running a constructor, any checks on its code size will
        // yield zero, making it an effective way to detect if a contract is
        // under construction or not.
        uint256 cs;
        //solium-disable-next-line
        assembly {
            cs := extcodesize(address)
        }
        return cs == 0;
    }

    // Reserved storage space to allow for layout changes in the future.
    uint256[50] private ______gap;
}


/**
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an owner) that can be granted exclusive access to
 * specific functions.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be aplied to your functions to restrict their use to
 * the owner.
 */
contract Ownable {
    address private _owner;

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    constructor () internal {
        _owner = msg.sender;
        emit OwnershipTransferred(address(0), _owner);
    }

    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view returns (address) {
        return _owner;
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        require(isOwner(), "Ownable: caller is not the owner");
        _;
    }

    /**
     * @dev Returns true if the caller is the current owner.
     */
    function isOwner() public view returns (bool) {
        return msg.sender == _owner;
    }

    /**
     * @dev Leaves the contract without owner. It will not be possible to call
     * `onlyOwner` functions anymore. Can only be called by the current owner.
     *
     * > Note: Renouncing ownership will leave the contract without an owner,
     * thereby removing any functionality that is only available to the owner.
     */
    function renounceOwnership() public onlyOwner {
        emit OwnershipTransferred(_owner, address(0));
        _owner = address(0);
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Can only be called by the current owner.
     */
    function transferOwnership(address newOwner) public onlyOwner {
        _transferOwnership(newOwner);
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     */
    function _transferOwnership(address newOwner) internal {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        emit OwnershipTransferred(_owner, newOwner);
        _owner = newOwner;
    }
}

/**
 * @title Proxy
 * @dev Implements delegation of calls to other contracts, with proper
 * forwarding of return values and bubbling of failures.
 * It defines a fallback function that delegates all calls to the address
 * returned by the abstract _implementation() internal function.
 */
contract Proxy {
    /**
   * @dev Fallback function.
   * Implemented entirely in `_fallback`.
   */
    function() external payable {
        _fallback();
    }

    /**
   * @return The Address of the implementation.
   */
    function _implementation() internal view returns (address);

    /**
   * @dev Delegates execution to an implementation contract.
   * This is a low level function that doesn't return to its internal call site.
   * It will return to the external caller whatever the implementation returns.
   * @param implementation Address to delegate.
   */
    function _delegate(address implementation) internal {
        //solium-disable-next-line
        assembly {
            // Copy msg.data. We take full control of memory in this inline assembly
            // block because it will not return to Solidity code. We overwrite the
            // Solidity scratch pad at memory position 0.
            calldatacopy(0, 0, calldatasize)

            // Call the implementation.
            // out and outsize are 0 because we don't know the size yet.
            let result := delegatecall(gas, implementation, 0, calldatasize, 0, 0)

            // Copy the returned data.
            returndatacopy(0, 0, returndatasize)

            switch result
                // delegatecall returns 0 on error.
                case 0 {
                    revert(0, returndatasize)
                }
                default {
                    return(0, returndatasize)
                }
        }
    }

    /**
   * @dev Function that is run as the first thing in the fallback function.
   * Can be redefined in derived contracts to add functionality.
   * Redefinitions must call super._willFallback().
   */
    function _willFallback() internal {}

    /**
   * @dev fallback implementation.
   * Extracted to enable manual triggering.
   */
    function _fallback() internal {
        _willFallback();
        _delegate(_implementation());
    }
}

/**
 * @title BaseUpgradeabilityProxy
 * @dev This contract implements a proxy that allows to change the
 * implementation address to which it will delegate.
 * Such a change is called an implementation upgrade.
 */
contract BaseUpgradeabilityProxy is Proxy {
    /**
   * @dev Emitted when the implementation is upgraded.
   * @param implementation Address of the new implementation.
   */
    event Upgraded(address indexed implementation);

    /**
   * @dev Storage slot with the address of the current implementation.
   * This is the keccak-256 hash of "eip1967.proxy.implementation" subtracted by 1, and is
   * validated in the constructor.
   */
    bytes32 internal constant IMPLEMENTATION_SLOT = 0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc;

    /**
   * @dev Returns the current implementation.
   * @return Address of the current implementation
   */
    function _implementation() internal view returns (address impl) {
        bytes32 slot = IMPLEMENTATION_SLOT;
        //solium-disable-next-line
        assembly {
            impl := sload(slot)
        }
    }

    /**
   * @dev Upgrades the proxy to a new implementation.
   * @param newImplementation Address of the new implementation.
   */
    function _upgradeTo(address newImplementation) internal {
        _setImplementation(newImplementation);
        emit Upgraded(newImplementation);
    }

    /**
   * @dev Sets the implementation address of the proxy.
   * @param newImplementation Address of the new implementation.
   */
    function _setImplementation(address newImplementation) internal {
        require(
            Address.isContract(newImplementation),
            "Cannot set a proxy implementation to a non-contract address"
        );

        bytes32 slot = IMPLEMENTATION_SLOT;

        //solium-disable-next-line
        assembly {
            sstore(slot, newImplementation)
        }
    }
}



/**
 * @title BaseAdminUpgradeabilityProxy
 * @dev This contract combines an upgradeability proxy with an authorization
 * mechanism for administrative tasks.
 * All external functions in this contract must be guarded by the
 * `ifAdmin` modifier. See ethereum/solidity#3864 for a Solidity
 * feature proposal that would enable this to be done automatically.
 */
contract BaseAdminUpgradeabilityProxy is BaseUpgradeabilityProxy {
    /**
   * @dev Emitted when the administration has been transferred.
   * @param previousAdmin Address of the previous admin.
   * @param newAdmin Address of the new admin.
   */
    event AdminChanged(address previousAdmin, address newAdmin);

    /**
   * @dev Storage slot with the admin of the contract.
   * This is the keccak-256 hash of "eip1967.proxy.admin" subtracted by 1, and is
   * validated in the constructor.
   */

    bytes32 internal constant ADMIN_SLOT = 0xb53127684a568b3173ae13b9f8a6016e243e63b6e8ee1178d6a717850b5d6103;

    /**
   * @dev Modifier to check whether the `msg.sender` is the admin.
   * If it is, it will run the function. Otherwise, it will delegate the call
   * to the implementation.
   */
    modifier ifAdmin() {
        if (msg.sender == _admin()) {
            _;
        } else {
            _fallback();
        }
    }

    /**
   * @return The address of the proxy admin.
   */
    function admin() external ifAdmin returns (address) {
        return _admin();
    }

    /**
   * @return The address of the implementation.
   */
    function implementation() external ifAdmin returns (address) {
        return _implementation();
    }

    /**
   * @dev Changes the admin of the proxy.
   * Only the current admin can call this function.
   * @param newAdmin Address to transfer proxy administration to.
   */
    function changeAdmin(address newAdmin) external ifAdmin {
        require(newAdmin != address(0), "Cannot change the admin of a proxy to the zero address");
        emit AdminChanged(_admin(), newAdmin);
        _setAdmin(newAdmin);
    }

    /**
   * @dev Upgrade the backing implementation of the proxy.
   * Only the admin can call this function.
   * @param newImplementation Address of the new implementation.
   */
    function upgradeTo(address newImplementation) external ifAdmin {
        _upgradeTo(newImplementation);
    }

    /**
   * @dev Upgrade the backing implementation of the proxy and call a function
   * on the new implementation.
   * This is useful to initialize the proxied contract.
   * @param newImplementation Address of the new implementation.
   * @param data Data to send as msg.data in the low level call.
   * It should include the signature and the parameters of the function to be called, as described in
   * https://solidity.readthedocs.io/en/v0.4.24/abi-spec.html#function-selector-and-argument-encoding.
   */
    function upgradeToAndCall(address newImplementation, bytes calldata data) external payable ifAdmin {
        _upgradeTo(newImplementation);
        (bool success, ) = newImplementation.delegatecall(data);
        require(success);
    }

    /**
   * @return The admin slot.
   */
    function _admin() internal view returns (address adm) {
        bytes32 slot = ADMIN_SLOT;
        //solium-disable-next-line
        assembly {
            adm := sload(slot)
        }
    }

    /**
   * @dev Sets the address of the proxy admin.
   * @param newAdmin Address of the new proxy admin.
   */
    function _setAdmin(address newAdmin) internal {
        bytes32 slot = ADMIN_SLOT;
        //solium-disable-next-line
        assembly {
            sstore(slot, newAdmin)
        }
    }

    /**
   * @dev Only fall back when the sender is not the admin.
   */
    function _willFallback() internal {
        require(msg.sender != _admin(), "Cannot call fallback function from the proxy admin");
        super._willFallback();
    }
}

/**
 * @title UpgradeabilityProxy
 * @dev Extends BaseUpgradeabilityProxy with a constructor for initializing
 * implementation and init data.
 */
contract UpgradeabilityProxy is BaseUpgradeabilityProxy {
    /**
   * @dev Contract constructor.
   * @param _logic Address of the initial implementation.
   * @param _data Data to send as msg.data to the implementation to initialize the proxied contract.
   * It should include the signature and the parameters of the function to be called, as described in
   * https://solidity.readthedocs.io/en/v0.4.24/abi-spec.html#function-selector-and-argument-encoding.
   * This parameter is optional, if no data is given the initialization call to proxied contract will be skipped.
   */
    constructor(address _logic, bytes memory _data) public payable {
        assert(IMPLEMENTATION_SLOT == bytes32(uint256(keccak256("eip1967.proxy.implementation")) - 1));
        _setImplementation(_logic);
        if (_data.length > 0) {
            (bool success, ) = _logic.delegatecall(_data);
            require(success);
        }
    }
}




/**
 * @title AdminUpgradeabilityProxy
 * @dev Extends from BaseAdminUpgradeabilityProxy with a constructor for 
 * initializing the implementation, admin, and init data.
 */
contract AdminUpgradeabilityProxy is BaseAdminUpgradeabilityProxy, UpgradeabilityProxy {
    /**
   * Contract constructor.
   * @param _logic address of the initial implementation.
   * @param _admin Address of the proxy administrator.
   * @param _data Data to send as msg.data to the implementation to initialize the proxied contract.
   * It should include the signature and the parameters of the function to be called, as described in
   * https://solidity.readthedocs.io/en/v0.4.24/abi-spec.html#function-selector-and-argument-encoding.
   * This parameter is optional, if no data is given the initialization call to proxied contract will be skipped.
   */
    constructor(address _logic, address _admin, bytes memory _data) public payable UpgradeabilityProxy(_logic, _data) {
        assert(ADMIN_SLOT == bytes32(uint256(keccak256("eip1967.proxy.admin")) - 1));
        _setAdmin(_admin);
    }
}



/**
 * @title InitializableUpgradeabilityProxy
 * @dev Extends BaseUpgradeabilityProxy with an initializer for initializing
 * implementation and init data.
 */
contract InitializableUpgradeabilityProxy is BaseUpgradeabilityProxy {
    /**
   * @dev Contract initializer.
   * @param _logic Address of the initial implementation.
   * @param _data Data to send as msg.data to the implementation to initialize the proxied contract.
   * It should include the signature and the parameters of the function to be called, as described in
   * https://solidity.readthedocs.io/en/v0.4.24/abi-spec.html#function-selector-and-argument-encoding.
   * This parameter is optional, if no data is given the initialization call to proxied contract will be skipped.
   */
    function initialize(address _logic, bytes memory _data) public payable {
        require(_implementation() == address(0));
        assert(IMPLEMENTATION_SLOT == bytes32(uint256(keccak256("eip1967.proxy.implementation")) - 1));
        _setImplementation(_logic);
        if (_data.length > 0) {
            (bool success, ) = _logic.delegatecall(_data);
            require(success);
        }
    }
}

contract AddressStorage {
    mapping(bytes32 => address) private addresses;

    function getAddress(bytes32 _key) public view returns (address) {
        return addresses[_key];
    }

    function _setAddress(bytes32 _key, address _value) internal {
        addresses[_key] = _value;
    }

}

/**
 * @title InitializableAdminUpgradeabilityProxy
 * @dev Extends from BaseAdminUpgradeabilityProxy with an initializer for 
 * initializing the implementation, admin, and init data.
 */
contract InitializableAdminUpgradeabilityProxy is BaseAdminUpgradeabilityProxy, InitializableUpgradeabilityProxy {
    /**
   * Contract initializer.
   * @param _logic address of the initial implementation.
   * @param _admin Address of the proxy administrator.
   * @param _data Data to send as msg.data to the implementation to initialize the proxied contract.
   * It should include the signature and the parameters of the function to be called, as described in
   * https://solidity.readthedocs.io/en/v0.4.24/abi-spec.html#function-selector-and-argument-encoding.
   * This parameter is optional, if no data is given the initialization call to proxied contract will be skipped.
   */
    function initialize(address _logic, address _admin, bytes memory _data) public payable {
        require(_implementation() == address(0));
        InitializableUpgradeabilityProxy.initialize(_logic, _data);
        assert(ADMIN_SLOT == bytes32(uint256(keccak256("eip1967.proxy.admin")) - 1));
        _setAdmin(_admin);
    }
}



/**
@title ILendingPoolAddressesProvider interface
@notice provides the interface to fetch the LendingPoolCore address
 */

contract ILendingPoolAddressesProvider {

    function getLendingPool() public view returns (address);
    function setLendingPoolImpl(address _pool) public;

    function getLendingPoolCore() public view returns (address payable);
    function setLendingPoolCoreImpl(address _lendingPoolCore) public;

    function getLendingPoolConfigurator() public view returns (address);
    function setLendingPoolConfiguratorImpl(address _configurator) public;

    function getLendingPoolDataProvider() public view returns (address);
    function setLendingPoolDataProviderImpl(address _provider) public;

    function getLendingPoolParametersProvider() public view returns (address);
    function setLendingPoolParametersProviderImpl(address _parametersProvider) public;

    function getTokenDistributor() public view returns (address);
    function setTokenDistributor(address _tokenDistributor) public;


    function getFeeProvider() public view returns (address);
    function setFeeProviderImpl(address _feeProvider) public;

    function getLendingPoolLiquidationManager() public view returns (address);
    function setLendingPoolLiquidationManager(address _manager) public;

    function getLendingPoolManager() public view returns (address);
    function setLendingPoolManager(address _lendingPoolManager) public;

    function getPriceOracle() public view returns (address);
    function setPriceOracle(address _priceOracle) public;

    function getLendingRateOracle() public view returns (address);
    function setLendingRateOracle(address _lendingRateOracle) public;

}




/**
* @title LendingPoolAddressesProvider contract
* @notice Is the main registry of the protocol. All the different components of the protocol are accessible
* through the addresses provider.
* @author Aave
**/

contract LendingPoolAddressesProvider is Ownable, ILendingPoolAddressesProvider, AddressStorage {
    //events
    event LendingPoolUpdated(address indexed newAddress);
    event LendingPoolCoreUpdated(address indexed newAddress);
    event LendingPoolParametersProviderUpdated(address indexed newAddress);
    event LendingPoolManagerUpdated(address indexed newAddress);
    event LendingPoolConfiguratorUpdated(address indexed newAddress);
    event LendingPoolLiquidationManagerUpdated(address indexed newAddress);
    event LendingPoolDataProviderUpdated(address indexed newAddress);
    event EthereumAddressUpdated(address indexed newAddress);
    event PriceOracleUpdated(address indexed newAddress);
    event LendingRateOracleUpdated(address indexed newAddress);
    event FeeProviderUpdated(address indexed newAddress);
    event TokenDistributorUpdated(address indexed newAddress);

    event ProxyCreated(bytes32 id, address indexed newAddress);

    bytes32 private constant LENDING_POOL = "LENDING_POOL";
    bytes32 private constant LENDING_POOL_CORE = "LENDING_POOL_CORE";
    bytes32 private constant LENDING_POOL_CONFIGURATOR = "LENDING_POOL_CONFIGURATOR";
    bytes32 private constant LENDING_POOL_PARAMETERS_PROVIDER = "PARAMETERS_PROVIDER";
    bytes32 private constant LENDING_POOL_MANAGER = "LENDING_POOL_MANAGER";
    bytes32 private constant LENDING_POOL_LIQUIDATION_MANAGER = "LIQUIDATION_MANAGER";
    bytes32 private constant LENDING_POOL_FLASHLOAN_PROVIDER = "FLASHLOAN_PROVIDER";
    bytes32 private constant DATA_PROVIDER = "DATA_PROVIDER";
    bytes32 private constant ETHEREUM_ADDRESS = "ETHEREUM_ADDRESS";
    bytes32 private constant PRICE_ORACLE = "PRICE_ORACLE";
    bytes32 private constant LENDING_RATE_ORACLE = "LENDING_RATE_ORACLE";
    bytes32 private constant FEE_PROVIDER = "FEE_PROVIDER";
    bytes32 private constant WALLET_BALANCE_PROVIDER = "WALLET_BALANCE_PROVIDER";
    bytes32 private constant TOKEN_DISTRIBUTOR = "TOKEN_DISTRIBUTOR";


    /**
    * @dev returns the address of the LendingPool proxy
    * @return the lending pool proxy address
    **/
    function getLendingPool() public view returns (address) {
        return getAddress(LENDING_POOL);
    }


    /**
    * @dev updates the implementation of the lending pool
    * @param _pool the new lending pool implementation
    **/
    function setLendingPoolImpl(address _pool) public onlyOwner {
        updateImplInternal(LENDING_POOL, _pool);
        emit LendingPoolUpdated(_pool);
    }

    /**
    * @dev returns the address of the LendingPoolCore proxy
    * @return the lending pool core proxy address
     */
    function getLendingPoolCore() public view returns (address payable) {
        address payable core = address(uint160(getAddress(LENDING_POOL_CORE)));
        return core;
    }

    /**
    * @dev updates the implementation of the lending pool core
    * @param _lendingPoolCore the new lending pool core implementation
    **/
    function setLendingPoolCoreImpl(address _lendingPoolCore) public onlyOwner {
        updateImplInternal(LENDING_POOL_CORE, _lendingPoolCore);
        emit LendingPoolCoreUpdated(_lendingPoolCore);
    }

    /**
    * @dev returns the address of the LendingPoolConfigurator proxy
    * @return the lending pool configurator proxy address
    **/
    function getLendingPoolConfigurator() public view returns (address) {
        return getAddress(LENDING_POOL_CONFIGURATOR);
    }

    /**
    * @dev updates the implementation of the lending pool configurator
    * @param _configurator the new lending pool configurator implementation
    **/
    function setLendingPoolConfiguratorImpl(address _configurator) public onlyOwner {
        updateImplInternal(LENDING_POOL_CONFIGURATOR, _configurator);
        emit LendingPoolConfiguratorUpdated(_configurator);
    }

    /**
    * @dev returns the address of the LendingPoolDataProvider proxy
    * @return the lending pool data provider proxy address
     */
    function getLendingPoolDataProvider() public view returns (address) {
        return getAddress(DATA_PROVIDER);
    }

    /**
    * @dev updates the implementation of the lending pool data provider
    * @param _provider the new lending pool data provider implementation
    **/
    function setLendingPoolDataProviderImpl(address _provider) public onlyOwner {
        updateImplInternal(DATA_PROVIDER, _provider);
        emit LendingPoolDataProviderUpdated(_provider);
    }

    /**
    * @dev returns the address of the LendingPoolParametersProvider proxy
    * @return the address of the Lending pool parameters provider proxy
    **/
    function getLendingPoolParametersProvider() public view returns (address) {
        return getAddress(LENDING_POOL_PARAMETERS_PROVIDER);
    }

    /**
    * @dev updates the implementation of the lending pool parameters provider
    * @param _parametersProvider the new lending pool parameters provider implementation
    **/
    function setLendingPoolParametersProviderImpl(address _parametersProvider) public onlyOwner {
        updateImplInternal(LENDING_POOL_PARAMETERS_PROVIDER, _parametersProvider);
        emit LendingPoolParametersProviderUpdated(_parametersProvider);
    }

    /**
    * @dev returns the address of the FeeProvider proxy
    * @return the address of the Fee provider proxy
    **/
    function getFeeProvider() public view returns (address) {
        return getAddress(FEE_PROVIDER);
    }

    /**
    * @dev updates the implementation of the FeeProvider proxy
    * @param _feeProvider the new lending pool fee provider implementation
    **/
    function setFeeProviderImpl(address _feeProvider) public onlyOwner {
        updateImplInternal(FEE_PROVIDER, _feeProvider);
        emit FeeProviderUpdated(_feeProvider);
    }

    /**
    * @dev returns the address of the LendingPoolLiquidationManager. Since the manager is used
    * through delegateCall within the LendingPool contract, the proxy contract pattern does not work properly hence
    * the addresses are changed directly.
    * @return the address of the Lending pool liquidation manager
    **/

    function getLendingPoolLiquidationManager() public view returns (address) {
        return getAddress(LENDING_POOL_LIQUIDATION_MANAGER);
    }

    /**
    * @dev updates the address of the Lending pool liquidation manager
    * @param _manager the new lending pool liquidation manager address
    **/
    function setLendingPoolLiquidationManager(address _manager) public onlyOwner {
        _setAddress(LENDING_POOL_LIQUIDATION_MANAGER, _manager);
        emit LendingPoolLiquidationManagerUpdated(_manager);
    }

    /**
    * @dev the functions below are storing specific addresses that are outside the context of the protocol
    * hence the upgradable proxy pattern is not used
    **/


    function getLendingPoolManager() public view returns (address) {
        return getAddress(LENDING_POOL_MANAGER);
    }

    function setLendingPoolManager(address _lendingPoolManager) public onlyOwner {
        _setAddress(LENDING_POOL_MANAGER, _lendingPoolManager);
        emit LendingPoolManagerUpdated(_lendingPoolManager);
    }

    function getPriceOracle() public view returns (address) {
        return getAddress(PRICE_ORACLE);
    }

    function setPriceOracle(address _priceOracle) public onlyOwner {
        _setAddress(PRICE_ORACLE, _priceOracle);
        emit PriceOracleUpdated(_priceOracle);
    }

    function getLendingRateOracle() public view returns (address) {
        return getAddress(LENDING_RATE_ORACLE);
    }

    function setLendingRateOracle(address _lendingRateOracle) public onlyOwner {
        _setAddress(LENDING_RATE_ORACLE, _lendingRateOracle);
        emit LendingRateOracleUpdated(_lendingRateOracle);
    }


    function getTokenDistributor() public view returns (address) {
        return getAddress(TOKEN_DISTRIBUTOR);
    }

    function setTokenDistributor(address _tokenDistributor) public onlyOwner {
        _setAddress(TOKEN_DISTRIBUTOR, _tokenDistributor);
        emit TokenDistributorUpdated(_tokenDistributor);
    }


    /**
    * @dev internal function to update the implementation of a specific component of the protocol
    * @param _id the id of the contract to be updated
    * @param _newAddress the address of the new implementation
    **/
    function updateImplInternal(bytes32 _id, address _newAddress) internal {
        address payable proxyAddress = address(uint160(getAddress(_id)));

        InitializableAdminUpgradeabilityProxy proxy = InitializableAdminUpgradeabilityProxy(proxyAddress);
        bytes memory params = abi.encodeWithSignature("initialize(address)", address(this));

        if (proxyAddress == address(0)) {
            proxy = new InitializableAdminUpgradeabilityProxy();
            proxy.initialize(_newAddress, address(this), params);
            _setAddress(_id, address(proxy));
            emit ProxyCreated(_id, address(proxy));
        } else {
            proxy.upgradeToAndCall(_newAddress, params);
        }

    }
}

contract UintStorage {
    mapping(bytes32 => uint256) private uints;

    function getUint(bytes32 _key) public view returns (uint256) {
        return uints[_key];
    }

    function _setUint(bytes32 _key, uint256 _value) internal {
        uints[_key] = _value;
    }

}


/**
* @title LendingPoolParametersProvider
* @author Aave
* @notice stores the configuration parameters of the Lending Pool contract
**/

contract LendingPoolParametersProvider is VersionedInitializable {

    uint256 private constant MAX_STABLE_RATE_BORROW_SIZE_PERCENT = 25;
    uint256 private constant REBALANCE_DOWN_RATE_DELTA = (1e27)/5;
    uint256 private constant FLASHLOAN_FEE_TOTAL = 35;
    uint256 private constant FLASHLOAN_FEE_PROTOCOL = 3000;

    uint256 constant private DATA_PROVIDER_REVISION = 0x1;

    function getRevision() internal pure returns(uint256) {
        return DATA_PROVIDER_REVISION;
    }

    /**
    * @dev initializes the LendingPoolParametersProvider after it's added to the proxy
    * @param _addressesProvider the address of the LendingPoolAddressesProvider
    */
    function initialize(address _addressesProvider) public initializer {
    }
    /**
    * @dev returns the maximum stable rate borrow size, in percentage of the available liquidity.
    **/
    function getMaxStableRateBorrowSizePercent() external pure returns (uint256)  {
        return MAX_STABLE_RATE_BORROW_SIZE_PERCENT;
    }

    /**
    * @dev returns the delta between the current stable rate and the user stable rate at
    *      which the borrow position of the user will be rebalanced (scaled down)
    **/
    function getRebalanceDownRateDelta() external pure returns (uint256) {
        return REBALANCE_DOWN_RATE_DELTA;
    }

    /**
    * @dev returns the fee applied to a flashloan and the portion to redirect to the protocol, in basis points.
    **/
    function getFlashLoanFeesInBips() external pure returns (uint256, uint256) {
        return (FLASHLOAN_FEE_TOTAL, FLASHLOAN_FEE_PROTOCOL);
    }
}

/**
* @title CoreLibrary library
* @author Aave
* @notice Defines the data structures of the reserves and the user data
**/
library CoreLibrary {
    using SafeMath for uint256;
    using WadRayMath for uint256;

    enum InterestRateMode {NONE, STABLE, VARIABLE}

    uint256 internal constant SECONDS_PER_YEAR = 365 days;

    struct UserReserveData {
        //principal amount borrowed by the user.
        uint256 principalBorrowBalance;
        //cumulated variable borrow index for the user. Expressed in ray
        uint256 lastVariableBorrowCumulativeIndex;
        //origination fee cumulated by the user
        uint256 originationFee;
        // stable borrow rate at which the user has borrowed. Expressed in ray
        uint256 stableBorrowRate;
        uint40 lastUpdateTimestamp;
        //defines if a specific deposit should or not be used as a collateral in borrows
        bool useAsCollateral;
    }

    struct ReserveData {
        /**
        * @dev refer to the whitepaper, section 1.1 basic concepts for a formal description of these properties.
        **/
        //the liquidity index. Expressed in ray
        uint256 lastLiquidityCumulativeIndex;
        //the current supply rate. Expressed in ray
        uint256 currentLiquidityRate;
        //the total borrows of the reserve at a stable rate. Expressed in the currency decimals
        uint256 totalBorrowsStable;
        //the total borrows of the reserve at a variable rate. Expressed in the currency decimals
        uint256 totalBorrowsVariable;
        //the current variable borrow rate. Expressed in ray
        uint256 currentVariableBorrowRate;
        //the current stable borrow rate. Expressed in ray
        uint256 currentStableBorrowRate;
        //the current average stable borrow rate (weighted average of all the different stable rate loans). Expressed in ray
        uint256 currentAverageStableBorrowRate;
        //variable borrow index. Expressed in ray
        uint256 lastVariableBorrowCumulativeIndex;
        //the ltv of the reserve. Expressed in percentage (0-100)
        uint256 baseLTVasCollateral;
        //the liquidation threshold of the reserve. Expressed in percentage (0-100)
        uint256 liquidationThreshold;
        //the liquidation bonus of the reserve. Expressed in percentage
        uint256 liquidationBonus;
        //the decimals of the reserve asset
        uint256 decimals;
        /**
        * @dev address of the aToken representing the asset
        **/
        address aTokenAddress;
        /**
        * @dev address of the interest rate strategy contract
        **/
        address interestRateStrategyAddress;
        uint40 lastUpdateTimestamp;
        // borrowingEnabled = true means users can borrow from this reserve
        bool borrowingEnabled;
        // usageAsCollateralEnabled = true means users can use this reserve as collateral
        bool usageAsCollateralEnabled;
        // isStableBorrowRateEnabled = true means users can borrow at a stable rate
        bool isStableBorrowRateEnabled;
        // isActive = true means the reserve has been activated and properly configured
        bool isActive;
        // isFreezed = true means the reserve only allows repays and redeems, but not deposits, new borrowings or rate swap
        bool isFreezed;
    }

    /**
    * @dev returns the ongoing normalized income for the reserve.
    * a value of 1e27 means there is no income. As time passes, the income is accrued.
    * A value of 2*1e27 means that the income of the reserve is double the initial amount.
    * @param _reserve the reserve object
    * @return the normalized income. expressed in ray
    **/
    function getNormalizedIncome(CoreLibrary.ReserveData storage _reserve)
        internal
        view
        returns (uint256)
    {
        uint256 cumulated = calculateLinearInterest(
            _reserve
                .currentLiquidityRate,
            _reserve
                .lastUpdateTimestamp
        )
            .rayMul(_reserve.lastLiquidityCumulativeIndex);

        return cumulated;

    }

    /**
    * @dev Updates the liquidity cumulative index Ci and variable borrow cumulative index Bvc. Refer to the whitepaper for
    * a formal specification.
    * @param _self the reserve object
    **/
    function updateCumulativeIndexes(ReserveData storage _self) internal {
        uint256 totalBorrows = getTotalBorrows(_self);

        if (totalBorrows > 0) {
            //only cumulating if there is any income being produced
            uint256 cumulatedLiquidityInterest = calculateLinearInterest(
                _self.currentLiquidityRate,
                _self.lastUpdateTimestamp
            );

            _self.lastLiquidityCumulativeIndex = cumulatedLiquidityInterest.rayMul(
                _self.lastLiquidityCumulativeIndex
            );

            uint256 cumulatedVariableBorrowInterest = calculateCompoundedInterest(
                _self.currentVariableBorrowRate,
                _self.lastUpdateTimestamp
            );
            _self.lastVariableBorrowCumulativeIndex = cumulatedVariableBorrowInterest.rayMul(
                _self.lastVariableBorrowCumulativeIndex
            );
        }
    }

    /**
    * @dev accumulates a predefined amount of asset to the reserve as a fixed, one time income. Used for example to accumulate
    * the flashloan fee to the reserve, and spread it through the depositors.
    * @param _self the reserve object
    * @param _totalLiquidity the total liquidity available in the reserve
    * @param _amount the amount to accomulate
    **/
    function cumulateToLiquidityIndex(
        ReserveData storage _self,
        uint256 _totalLiquidity,
        uint256 _amount
    ) internal {
        uint256 amountToLiquidityRatio = _amount.wadToRay().rayDiv(_totalLiquidity.wadToRay());

        uint256 cumulatedLiquidity = amountToLiquidityRatio.add(WadRayMath.ray());

        _self.lastLiquidityCumulativeIndex = cumulatedLiquidity.rayMul(
            _self.lastLiquidityCumulativeIndex
        );
    }

    /**
    * @dev initializes a reserve
    * @param _self the reserve object
    * @param _aTokenAddress the address of the overlying atoken contract
    * @param _decimals the number of decimals of the underlying asset
    * @param _interestRateStrategyAddress the address of the interest rate strategy contract
    **/
    function init(
        ReserveData storage _self,
        address _aTokenAddress,
        uint256 _decimals,
        address _interestRateStrategyAddress
    ) external {
        require(_self.aTokenAddress == address(0), "Reserve has already been initialized");

        if (_self.lastLiquidityCumulativeIndex == 0) {
            //if the reserve has not been initialized yet
            _self.lastLiquidityCumulativeIndex = WadRayMath.ray();
        }

        if (_self.lastVariableBorrowCumulativeIndex == 0) {
            _self.lastVariableBorrowCumulativeIndex = WadRayMath.ray();
        }

        _self.aTokenAddress = _aTokenAddress;
        _self.decimals = _decimals;

        _self.interestRateStrategyAddress = _interestRateStrategyAddress;
        _self.isActive = true;
        _self.isFreezed = false;

    }

    /**
    * @dev enables borrowing on a reserve
    * @param _self the reserve object
    * @param _stableBorrowRateEnabled true if the stable borrow rate must be enabled by default, false otherwise
    **/
    function enableBorrowing(ReserveData storage _self, bool _stableBorrowRateEnabled) external {
        require(_self.borrowingEnabled == false, "Reserve is already enabled");

        _self.borrowingEnabled = true;
        _self.isStableBorrowRateEnabled = _stableBorrowRateEnabled;

    }

    /**
    * @dev disables borrowing on a reserve
    * @param _self the reserve object
    **/
    function disableBorrowing(ReserveData storage _self) external {
        _self.borrowingEnabled = false;
    }

    /**
    * @dev enables a reserve to be used as collateral
    * @param _self the reserve object
    * @param _baseLTVasCollateral the loan to value of the asset when used as collateral
    * @param _liquidationThreshold the threshold at which loans using this asset as collateral will be considered undercollateralized
    * @param _liquidationBonus the bonus liquidators receive to liquidate this asset
    **/
    function enableAsCollateral(
        ReserveData storage _self,
        uint256 _baseLTVasCollateral,
        uint256 _liquidationThreshold,
        uint256 _liquidationBonus
    ) external {
        require(
            _self.usageAsCollateralEnabled == false,
            "Reserve is already enabled as collateral"
        );

        _self.usageAsCollateralEnabled = true;
        _self.baseLTVasCollateral = _baseLTVasCollateral;
        _self.liquidationThreshold = _liquidationThreshold;
        _self.liquidationBonus = _liquidationBonus;

        if (_self.lastLiquidityCumulativeIndex == 0)
            _self.lastLiquidityCumulativeIndex = WadRayMath.ray();

    }

    /**
    * @dev disables a reserve as collateral
    * @param _self the reserve object
    **/
    function disableAsCollateral(ReserveData storage _self) external {
        _self.usageAsCollateralEnabled = false;
    }



    /**
    * @dev calculates the compounded borrow balance of a user
    * @param _self the userReserve object
    * @param _reserve the reserve object
    * @return the user compounded borrow balance
    **/
    function getCompoundedBorrowBalance(
        CoreLibrary.UserReserveData storage _self,
        CoreLibrary.ReserveData storage _reserve
    ) internal view returns (uint256) {
        if (_self.principalBorrowBalance == 0) return 0;

        uint256 principalBorrowBalanceRay = _self.principalBorrowBalance.wadToRay();
        uint256 compoundedBalance = 0;
        uint256 cumulatedInterest = 0;

        if (_self.stableBorrowRate > 0) {
            cumulatedInterest = calculateCompoundedInterest(
                _self.stableBorrowRate,
                _self.lastUpdateTimestamp
            );
        } else {
            //variable interest
            cumulatedInterest = calculateCompoundedInterest(
                _reserve
                    .currentVariableBorrowRate,
                _reserve
                    .lastUpdateTimestamp
            )
                .rayMul(_reserve.lastVariableBorrowCumulativeIndex)
                .rayDiv(_self.lastVariableBorrowCumulativeIndex);
        }

        compoundedBalance = principalBorrowBalanceRay.rayMul(cumulatedInterest).rayToWad();

        if (compoundedBalance == _self.principalBorrowBalance) {
            //solium-disable-next-line
            if (_self.lastUpdateTimestamp != block.timestamp) {
                //no interest cumulation because of the rounding - we add 1 wei
                //as symbolic cumulated interest to avoid interest free loans.

                return _self.principalBorrowBalance.add(1 wei);
            }
        }

        return compoundedBalance;
    }

    /**
    * @dev increases the total borrows at a stable rate on a specific reserve and updates the
    * average stable rate consequently
    * @param _reserve the reserve object
    * @param _amount the amount to add to the total borrows stable
    * @param _rate the rate at which the amount has been borrowed
    **/
    function increaseTotalBorrowsStableAndUpdateAverageRate(
        ReserveData storage _reserve,
        uint256 _amount,
        uint256 _rate
    ) internal {
        uint256 previousTotalBorrowStable = _reserve.totalBorrowsStable;
        //updating reserve borrows stable
        _reserve.totalBorrowsStable = _reserve.totalBorrowsStable.add(_amount);

        //update the average stable rate
        //weighted average of all the borrows
        uint256 weightedLastBorrow = _amount.wadToRay().rayMul(_rate);
        uint256 weightedPreviousTotalBorrows = previousTotalBorrowStable.wadToRay().rayMul(
            _reserve.currentAverageStableBorrowRate
        );

        _reserve.currentAverageStableBorrowRate = weightedLastBorrow
            .add(weightedPreviousTotalBorrows)
            .rayDiv(_reserve.totalBorrowsStable.wadToRay());
    }

    /**
    * @dev decreases the total borrows at a stable rate on a specific reserve and updates the
    * average stable rate consequently
    * @param _reserve the reserve object
    * @param _amount the amount to substract to the total borrows stable
    * @param _rate the rate at which the amount has been repaid
    **/
    function decreaseTotalBorrowsStableAndUpdateAverageRate(
        ReserveData storage _reserve,
        uint256 _amount,
        uint256 _rate
    ) internal {
        require(_reserve.totalBorrowsStable >= _amount, "Invalid amount to decrease");

        uint256 previousTotalBorrowStable = _reserve.totalBorrowsStable;

        //updating reserve borrows stable
        _reserve.totalBorrowsStable = _reserve.totalBorrowsStable.sub(_amount);

        if (_reserve.totalBorrowsStable == 0) {
            _reserve.currentAverageStableBorrowRate = 0; //no income if there are no stable rate borrows
            return;
        }

        //update the average stable rate
        //weighted average of all the borrows
        uint256 weightedLastBorrow = _amount.wadToRay().rayMul(_rate);
        uint256 weightedPreviousTotalBorrows = previousTotalBorrowStable.wadToRay().rayMul(
            _reserve.currentAverageStableBorrowRate
        );

        require(
            weightedPreviousTotalBorrows >= weightedLastBorrow,
            "The amounts to subtract don't match"
        );

        _reserve.currentAverageStableBorrowRate = weightedPreviousTotalBorrows
            .sub(weightedLastBorrow)
            .rayDiv(_reserve.totalBorrowsStable.wadToRay());
    }

    /**
    * @dev increases the total borrows at a variable rate
    * @param _reserve the reserve object
    * @param _amount the amount to add to the total borrows variable
    **/
    function increaseTotalBorrowsVariable(ReserveData storage _reserve, uint256 _amount) internal {
        _reserve.totalBorrowsVariable = _reserve.totalBorrowsVariable.add(_amount);
    }

    /**
    * @dev decreases the total borrows at a variable rate
    * @param _reserve the reserve object
    * @param _amount the amount to substract to the total borrows variable
    **/
    function decreaseTotalBorrowsVariable(ReserveData storage _reserve, uint256 _amount) internal {
        require(
            _reserve.totalBorrowsVariable >= _amount,
            "The amount that is being subtracted from the variable total borrows is incorrect"
        );
        _reserve.totalBorrowsVariable = _reserve.totalBorrowsVariable.sub(_amount);
    }

    /**
    * @dev function to calculate the interest using a linear interest rate formula
    * @param _rate the interest rate, in ray
    * @param _lastUpdateTimestamp the timestamp of the last update of the interest
    * @return the interest rate linearly accumulated during the timeDelta, in ray
    **/

    function calculateLinearInterest(uint256 _rate, uint40 _lastUpdateTimestamp)
        internal
        view
        returns (uint256)
    {
        //solium-disable-next-line
        uint256 timeDifference = block.timestamp.sub(uint256(_lastUpdateTimestamp));

        uint256 timeDelta = timeDifference.wadToRay().rayDiv(SECONDS_PER_YEAR.wadToRay());

        return _rate.rayMul(timeDelta).add(WadRayMath.ray());
    }

    /**
    * @dev function to calculate the interest using a compounded interest rate formula
    * @param _rate the interest rate, in ray
    * @param _lastUpdateTimestamp the timestamp of the last update of the interest
    * @return the interest rate compounded during the timeDelta, in ray
    **/
    function calculateCompoundedInterest(uint256 _rate, uint40 _lastUpdateTimestamp)
        internal
        view
        returns (uint256)
    {
        //solium-disable-next-line
        uint256 timeDifference = block.timestamp.sub(uint256(_lastUpdateTimestamp));

        uint256 ratePerSecond = _rate.div(SECONDS_PER_YEAR);

        return ratePerSecond.add(WadRayMath.ray()).rayPow(timeDifference);
    }

    /**
    * @dev returns the total borrows on the reserve
    * @param _reserve the reserve object
    * @return the total borrows (stable + variable)
    **/
    function getTotalBorrows(CoreLibrary.ReserveData storage _reserve)
        internal
        view
        returns (uint256)
    {
        return _reserve.totalBorrowsStable.add(_reserve.totalBorrowsVariable);
    }

}



/**
* @title IPriceOracleGetter interface
* @notice Interface for the Aave price oracle.
**/

interface IPriceOracleGetter {
    /**
    * @dev returns the asset price in ETH
    * @param _asset the address of the asset
    * @return the ETH price of the asset
    **/
    function getAssetPrice(address _asset) external view returns (uint256);
}

/**
* @title IFeeProvider interface
* @notice Interface for the Aave fee provider.
**/

interface IFeeProvider {
    function calculateLoanOriginationFee(address _user, uint256 _amount) external view returns (uint256);
    function getLoanOriginationFeePercentage() external view returns (uint256);
}

/**
* @title LendingPoolDataProvider contract
* @author Aave
* @notice Implements functions to fetch data from the core, and aggregate them in order to allow computation
* on the compounded balances and the account balances in ETH
**/
contract LendingPoolDataProvider is VersionedInitializable {
    using SafeMath for uint256;
    using WadRayMath for uint256;

    LendingPoolCore public core;
    LendingPoolAddressesProvider public addressesProvider;

    /**
    * @dev specifies the health factor threshold at which the user position is liquidated.
    * 1e18 by default, if the health factor drops below 1e18, the loan can be liquidated.
    **/
    uint256 public constant HEALTH_FACTOR_LIQUIDATION_THRESHOLD = 1e18;

    uint256 public constant DATA_PROVIDER_REVISION = 0x1;

    function getRevision() internal pure returns (uint256) {
        return DATA_PROVIDER_REVISION;
    }

    function initialize(LendingPoolAddressesProvider _addressesProvider) public initializer {
        addressesProvider = _addressesProvider;
        core = LendingPoolCore(_addressesProvider.getLendingPoolCore());
    }

    /**
    * @dev struct to hold calculateUserGlobalData() local computations
    **/
    struct UserGlobalDataLocalVars {
        uint256 reserveUnitPrice;
        uint256 tokenUnit;
        uint256 compoundedLiquidityBalance;
        uint256 compoundedBorrowBalance;
        uint256 reserveDecimals;
        uint256 baseLtv;
        uint256 liquidationThreshold;
        uint256 originationFee;
        bool usageAsCollateralEnabled;
        bool userUsesReserveAsCollateral;
        address currentReserve;
    }

    /**
    * @dev calculates the user data across the reserves.
    * this includes the total liquidity/collateral/borrow balances in ETH,
    * the average Loan To Value, the average Liquidation Ratio, and the Health factor.
    * @param _user the address of the user
    * @return the total liquidity, total collateral, total borrow balances of the user in ETH.
    * also the average Ltv, liquidation threshold, and the health factor
    **/
    function calculateUserGlobalData(address _user)
        public
        view
        returns (
            uint256 totalLiquidityBalanceETH,
            uint256 totalCollateralBalanceETH,
            uint256 totalBorrowBalanceETH,
            uint256 totalFeesETH,
            uint256 currentLtv,
            uint256 currentLiquidationThreshold,
            uint256 healthFactor,
            bool healthFactorBelowThreshold
        )
    {
        IPriceOracleGetter oracle = IPriceOracleGetter(addressesProvider.getPriceOracle());

        // Usage of a memory struct of vars to avoid "Stack too deep" errors due to local variables
        UserGlobalDataLocalVars memory vars;

        address[] memory reserves = core.getReserves();

        for (uint256 i = 0; i < reserves.length; i++) {
            vars.currentReserve = reserves[i];

            (
                vars.compoundedLiquidityBalance,
                vars.compoundedBorrowBalance,
                vars.originationFee,
                vars.userUsesReserveAsCollateral
            ) = core.getUserBasicReserveData(vars.currentReserve, _user);

            if (vars.compoundedLiquidityBalance == 0 && vars.compoundedBorrowBalance == 0) {
                continue;
            }

            //fetch reserve data
            (
                vars.reserveDecimals,
                vars.baseLtv,
                vars.liquidationThreshold,
                vars.usageAsCollateralEnabled
            ) = core.getReserveConfiguration(vars.currentReserve);

            vars.tokenUnit = 10 ** vars.reserveDecimals;
            vars.reserveUnitPrice = oracle.getAssetPrice(vars.currentReserve);

            //liquidity and collateral balance
            if (vars.compoundedLiquidityBalance > 0) {
                uint256 liquidityBalanceETH = vars
                    .reserveUnitPrice
                    .mul(vars.compoundedLiquidityBalance)
                    .div(vars.tokenUnit);
                totalLiquidityBalanceETH = totalLiquidityBalanceETH.add(liquidityBalanceETH);

                if (vars.usageAsCollateralEnabled && vars.userUsesReserveAsCollateral) {
                    totalCollateralBalanceETH = totalCollateralBalanceETH.add(liquidityBalanceETH);
                    currentLtv = currentLtv.add(liquidityBalanceETH.mul(vars.baseLtv));
                    currentLiquidationThreshold = currentLiquidationThreshold.add(
                        liquidityBalanceETH.mul(vars.liquidationThreshold)
                    );
                }
            }

            if (vars.compoundedBorrowBalance > 0) {
                totalBorrowBalanceETH = totalBorrowBalanceETH.add(
                    vars.reserveUnitPrice.mul(vars.compoundedBorrowBalance).div(vars.tokenUnit)
                );
                totalFeesETH = totalFeesETH.add(
                    vars.originationFee.mul(vars.reserveUnitPrice).div(vars.tokenUnit)
                );
            }
        }

        currentLtv = totalCollateralBalanceETH > 0 ? currentLtv.div(totalCollateralBalanceETH) : 0;
        currentLiquidationThreshold = totalCollateralBalanceETH > 0
            ? currentLiquidationThreshold.div(totalCollateralBalanceETH)
            : 0;

        healthFactor = calculateHealthFactorFromBalancesInternal(
            totalCollateralBalanceETH,
            totalBorrowBalanceETH,
            totalFeesETH,
            currentLiquidationThreshold
        );
        healthFactorBelowThreshold = healthFactor < HEALTH_FACTOR_LIQUIDATION_THRESHOLD;

    }

    struct balanceDecreaseAllowedLocalVars {
        uint256 decimals;
        uint256 collateralBalanceETH;
        uint256 borrowBalanceETH;
        uint256 totalFeesETH;
        uint256 currentLiquidationThreshold;
        uint256 reserveLiquidationThreshold;
        uint256 amountToDecreaseETH;
        uint256 collateralBalancefterDecrease;
        uint256 liquidationThresholdAfterDecrease;
        uint256 healthFactorAfterDecrease;
        bool reserveUsageAsCollateralEnabled;
    }

    /**
    * @dev check if a specific balance decrease is allowed (i.e. doesn't bring the user borrow position health factor under 1e18)
    * @param _reserve the address of the reserve
    * @param _user the address of the user
    * @param _amount the amount to decrease
    * @return true if the decrease of the balance is allowed
    **/

    function balanceDecreaseAllowed(address _reserve, address _user, uint256 _amount)
        external
        view
        returns (bool)
    {
        // Usage of a memory struct of vars to avoid "Stack too deep" errors due to local variables
        balanceDecreaseAllowedLocalVars memory vars;

        (
            vars.decimals,
            ,
            vars.reserveLiquidationThreshold,
            vars.reserveUsageAsCollateralEnabled
        ) = core.getReserveConfiguration(_reserve);

        if (
            !vars.reserveUsageAsCollateralEnabled ||
            !core.isUserUseReserveAsCollateralEnabled(_reserve, _user)
        ) {
            return true; //if reserve is not used as collateral, no reasons to block the transfer
        }

        (
            ,
            vars.collateralBalanceETH,
            vars.borrowBalanceETH,
            vars.totalFeesETH,
            ,
            vars.currentLiquidationThreshold,
            ,

        ) = calculateUserGlobalData(_user);

        if (vars.borrowBalanceETH == 0) {
            return true; //no borrows - no reasons to block the transfer
        }

        IPriceOracleGetter oracle = IPriceOracleGetter(addressesProvider.getPriceOracle());

        vars.amountToDecreaseETH = oracle.getAssetPrice(_reserve).mul(_amount).div(
            10 ** vars.decimals
        );

        vars.collateralBalancefterDecrease = vars.collateralBalanceETH.sub(
            vars.amountToDecreaseETH
        );

        //if there is a borrow, there can't be 0 collateral
        if (vars.collateralBalancefterDecrease == 0) {
            return false;
        }

        vars.liquidationThresholdAfterDecrease = vars
            .collateralBalanceETH
            .mul(vars.currentLiquidationThreshold)
            .sub(vars.amountToDecreaseETH.mul(vars.reserveLiquidationThreshold))
            .div(vars.collateralBalancefterDecrease);

        uint256 healthFactorAfterDecrease = calculateHealthFactorFromBalancesInternal(
            vars.collateralBalancefterDecrease,
            vars.borrowBalanceETH,
            vars.totalFeesETH,
            vars.liquidationThresholdAfterDecrease
        );

        return healthFactorAfterDecrease > HEALTH_FACTOR_LIQUIDATION_THRESHOLD;

    }

    /**
   * @notice calculates the amount of collateral needed in ETH to cover a new borrow.
   * @param _reserve the reserve from which the user wants to borrow
   * @param _amount the amount the user wants to borrow
   * @param _fee the fee for the amount that the user needs to cover
   * @param _userCurrentBorrowBalanceTH the current borrow balance of the user (before the borrow)
   * @param _userCurrentLtv the average ltv of the user given his current collateral
   * @return the total amount of collateral in ETH to cover the current borrow balance + the new amount + fee
   **/
    function calculateCollateralNeededInETH(
        address _reserve,
        uint256 _amount,
        uint256 _fee,
        uint256 _userCurrentBorrowBalanceTH,
        uint256 _userCurrentFeesETH,
        uint256 _userCurrentLtv
    ) external view returns (uint256) {
        uint256 reserveDecimals = core.getReserveDecimals(_reserve);

        IPriceOracleGetter oracle = IPriceOracleGetter(addressesProvider.getPriceOracle());

        uint256 requestedBorrowAmountETH = oracle
            .getAssetPrice(_reserve)
            .mul(_amount.add(_fee))
            .div(10 ** reserveDecimals); //price is in ether

        //add the current already borrowed amount to the amount requested to calculate the total collateral needed.
        uint256 collateralNeededInETH = _userCurrentBorrowBalanceTH
            .add(_userCurrentFeesETH)
            .add(requestedBorrowAmountETH)
            .mul(100)
            .div(_userCurrentLtv); //LTV is calculated in percentage

        return collateralNeededInETH;

    }

    /**
    * @dev calculates the equivalent amount in ETH that an user can borrow, depending on the available collateral and the
    * average Loan To Value.
    * @param collateralBalanceETH the total collateral balance
    * @param borrowBalanceETH the total borrow balance
    * @param totalFeesETH the total fees
    * @param ltv the average loan to value
    * @return the amount available to borrow in ETH for the user
    **/

    function calculateAvailableBorrowsETHInternal(
        uint256 collateralBalanceETH,
        uint256 borrowBalanceETH,
        uint256 totalFeesETH,
        uint256 ltv
    ) internal view returns (uint256) {
        uint256 availableBorrowsETH = collateralBalanceETH.mul(ltv).div(100); //ltv is in percentage

        if (availableBorrowsETH < borrowBalanceETH) {
            return 0;
        }

        availableBorrowsETH = availableBorrowsETH.sub(borrowBalanceETH.add(totalFeesETH));
        //calculate fee
        uint256 borrowFee = IFeeProvider(addressesProvider.getFeeProvider())
            .calculateLoanOriginationFee(msg.sender, availableBorrowsETH);
        return availableBorrowsETH.sub(borrowFee);
    }

    /**
    * @dev calculates the health factor from the corresponding balances
    * @param collateralBalanceETH the total collateral balance in ETH
    * @param borrowBalanceETH the total borrow balance in ETH
    * @param totalFeesETH the total fees in ETH
    * @param liquidationThreshold the avg liquidation threshold
    **/
    function calculateHealthFactorFromBalancesInternal(
        uint256 collateralBalanceETH,
        uint256 borrowBalanceETH,
        uint256 totalFeesETH,
        uint256 liquidationThreshold
    ) internal pure returns (uint256) {
        if (borrowBalanceETH == 0) return uint256(-1);

        return
            (collateralBalanceETH.mul(liquidationThreshold).div(100)).wadDiv(
                borrowBalanceETH.add(totalFeesETH)
            );
    }

    /**
    * @dev returns the health factor liquidation threshold
    **/
    function getHealthFactorLiquidationThreshold() public pure returns (uint256) {
        return HEALTH_FACTOR_LIQUIDATION_THRESHOLD;
    }

    /**
    * @dev accessory functions to fetch data from the lendingPoolCore
    **/
    function getReserveConfigurationData(address _reserve)
        external
        view
        returns (
            uint256 ltv,
            uint256 liquidationThreshold,
            uint256 liquidationBonus,
            address rateStrategyAddress,
            bool usageAsCollateralEnabled,
            bool borrowingEnabled,
            bool stableBorrowRateEnabled,
            bool isActive
        )
    {
        (, ltv, liquidationThreshold, usageAsCollateralEnabled) = core.getReserveConfiguration(
            _reserve
        );
        stableBorrowRateEnabled = core.getReserveIsStableBorrowRateEnabled(_reserve);
        borrowingEnabled = core.isReserveBorrowingEnabled(_reserve);
        isActive = core.getReserveIsActive(_reserve);
        liquidationBonus = core.getReserveLiquidationBonus(_reserve);

        rateStrategyAddress = core.getReserveInterestRateStrategyAddress(_reserve);
    }

    function getReserveData(address _reserve)
        external
        view
        returns (
            uint256 totalLiquidity,
            uint256 availableLiquidity,
            uint256 totalBorrowsStable,
            uint256 totalBorrowsVariable,
            uint256 liquidityRate,
            uint256 variableBorrowRate,
            uint256 stableBorrowRate,
            uint256 averageStableBorrowRate,
            uint256 utilizationRate,
            uint256 liquidityIndex,
            uint256 variableBorrowIndex,
            address aTokenAddress,
            uint40 lastUpdateTimestamp
        )
    {
        totalLiquidity = core.getReserveTotalLiquidity(_reserve);
        availableLiquidity = core.getReserveAvailableLiquidity(_reserve);
        totalBorrowsStable = core.getReserveTotalBorrowsStable(_reserve);
        totalBorrowsVariable = core.getReserveTotalBorrowsVariable(_reserve);
        liquidityRate = core.getReserveCurrentLiquidityRate(_reserve);
        variableBorrowRate = core.getReserveCurrentVariableBorrowRate(_reserve);
        stableBorrowRate = core.getReserveCurrentStableBorrowRate(_reserve);
        averageStableBorrowRate = core.getReserveCurrentAverageStableBorrowRate(_reserve);
        utilizationRate = core.getReserveUtilizationRate(_reserve);
        liquidityIndex = core.getReserveLiquidityCumulativeIndex(_reserve);
        variableBorrowIndex = core.getReserveVariableBorrowsCumulativeIndex(_reserve);
        aTokenAddress = core.getReserveATokenAddress(_reserve);
        lastUpdateTimestamp = core.getReserveLastUpdate(_reserve);
    }

    function getUserAccountData(address _user)
        external
        view
        returns (
            uint256 totalLiquidityETH,
            uint256 totalCollateralETH,
            uint256 totalBorrowsETH,
            uint256 totalFeesETH,
            uint256 availableBorrowsETH,
            uint256 currentLiquidationThreshold,
            uint256 ltv,
            uint256 healthFactor
        )
    {
        (
            totalLiquidityETH,
            totalCollateralETH,
            totalBorrowsETH,
            totalFeesETH,
            ltv,
            currentLiquidationThreshold,
            healthFactor,

        ) = calculateUserGlobalData(_user);

        availableBorrowsETH = calculateAvailableBorrowsETHInternal(
            totalCollateralETH,
            totalBorrowsETH,
            totalFeesETH,
            ltv
        );
    }

    function getUserReserveData(address _reserve, address _user)
        external
        view
        returns (
            uint256 currentATokenBalance,
            uint256 currentBorrowBalance,
            uint256 principalBorrowBalance,
            uint256 borrowRateMode,
            uint256 borrowRate,
            uint256 liquidityRate,
            uint256 originationFee,
            uint256 variableBorrowIndex,
            uint256 lastUpdateTimestamp,
            bool usageAsCollateralEnabled
        )
    {
        currentATokenBalance = AToken(core.getReserveATokenAddress(_reserve)).balanceOf(_user);
        CoreLibrary.InterestRateMode mode = core.getUserCurrentBorrowRateMode(_reserve, _user);
        (principalBorrowBalance, currentBorrowBalance, ) = core.getUserBorrowBalances(
            _reserve,
            _user
        );

        //default is 0, if mode == CoreLibrary.InterestRateMode.NONE
        if (mode == CoreLibrary.InterestRateMode.STABLE) {
            borrowRate = core.getUserCurrentStableBorrowRate(_reserve, _user);
        } else if (mode == CoreLibrary.InterestRateMode.VARIABLE) {
            borrowRate = core.getReserveCurrentVariableBorrowRate(_reserve);
        }

        borrowRateMode = uint256(mode);
        liquidityRate = core.getReserveCurrentLiquidityRate(_reserve);
        originationFee = core.getUserOriginationFee(_reserve, _user);
        variableBorrowIndex = core.getUserVariableBorrowCumulativeIndex(_reserve, _user);
        lastUpdateTimestamp = core.getUserLastUpdate(_reserve, _user);
        usageAsCollateralEnabled = core.isUserUseReserveAsCollateralEnabled(_reserve, _user);
    }
}


/**
 * @title Aave ERC20 AToken
 *
 * @dev Implementation of the interest bearing token for the DLP protocol.
 * @author Aave
 */
contract AToken is ERC20, ERC20Detailed {
    using WadRayMath for uint256;

    uint256 public constant UINT_MAX_VALUE = uint256(-1);

    /**
    * @dev emitted after the redeem action
    * @param _from the address performing the redeem
    * @param _value the amount to be redeemed
    * @param _fromBalanceIncrease the cumulated balance since the last update of the user
    * @param _fromIndex the last index of the user
    **/
    event Redeem(
        address indexed _from,
        uint256 _value,
        uint256 _fromBalanceIncrease,
        uint256 _fromIndex
    );

    /**
    * @dev emitted after the mint action
    * @param _from the address performing the mint
    * @param _value the amount to be minted
    * @param _fromBalanceIncrease the cumulated balance since the last update of the user
    * @param _fromIndex the last index of the user
    **/
    event MintOnDeposit(
        address indexed _from,
        uint256 _value,
        uint256 _fromBalanceIncrease,
        uint256 _fromIndex
    );

    /**
    * @dev emitted during the liquidation action, when the liquidator reclaims the underlying
    * asset
    * @param _from the address from which the tokens are being burned
    * @param _value the amount to be burned
    * @param _fromBalanceIncrease the cumulated balance since the last update of the user
    * @param _fromIndex the last index of the user
    **/
    event BurnOnLiquidation(
        address indexed _from,
        uint256 _value,
        uint256 _fromBalanceIncrease,
        uint256 _fromIndex
    );

    /**
    * @dev emitted during the transfer action
    * @param _from the address from which the tokens are being transferred
    * @param _to the adress of the destination
    * @param _value the amount to be minted
    * @param _fromBalanceIncrease the cumulated balance since the last update of the user
    * @param _toBalanceIncrease the cumulated balance since the last update of the destination
    * @param _fromIndex the last index of the user
    * @param _toIndex the last index of the liquidator
    **/
    event BalanceTransfer(
        address indexed _from,
        address indexed _to,
        uint256 _value,
        uint256 _fromBalanceIncrease,
        uint256 _toBalanceIncrease,
        uint256 _fromIndex,
        uint256 _toIndex
    );

    /**
    * @dev emitted when the accumulation of the interest
    * by an user is redirected to another user
    * @param _from the address from which the interest is being redirected
    * @param _to the adress of the destination
    * @param _fromBalanceIncrease the cumulated balance since the last update of the user
    * @param _fromIndex the last index of the user
    **/
    event InterestStreamRedirected(
        address indexed _from,
        address indexed _to,
        uint256 _redirectedBalance,
        uint256 _fromBalanceIncrease,
        uint256 _fromIndex
    );

    /**
    * @dev emitted when the redirected balance of an user is being updated
    * @param _targetAddress the address of which the balance is being updated
    * @param _targetBalanceIncrease the cumulated balance since the last update of the target
    * @param _targetIndex the last index of the user
    * @param _redirectedBalanceAdded the redirected balance being added
    * @param _redirectedBalanceRemoved the redirected balance being removed
    **/
    event RedirectedBalanceUpdated(
        address indexed _targetAddress,
        uint256 _targetBalanceIncrease,
        uint256 _targetIndex,
        uint256 _redirectedBalanceAdded,
        uint256 _redirectedBalanceRemoved
    );

    event InterestRedirectionAllowanceChanged(
        address indexed _from,
        address indexed _to
    );

    address public underlyingAssetAddress;

    mapping (address => uint256) private userIndexes;
    mapping (address => address) private interestRedirectionAddresses;
    mapping (address => uint256) private redirectedBalances;
    mapping (address => address) private interestRedirectionAllowances;

    LendingPoolAddressesProvider private addressesProvider;
    LendingPoolCore private core;
    LendingPool private pool;
    LendingPoolDataProvider private dataProvider;

    modifier onlyLendingPool {
        require(
            msg.sender == address(pool),
            "The caller of this function must be a lending pool"
        );
        _;
    }

    modifier whenTransferAllowed(address _from, uint256 _amount) {
        require(isTransferAllowed(_from, _amount), "Transfer cannot be allowed.");
        _;
    }

    constructor(
        LendingPoolAddressesProvider _addressesProvider,
        address _underlyingAsset,
        uint8 _underlyingAssetDecimals,
        string memory _name,
        string memory _symbol
    ) public ERC20Detailed(_name, _symbol, _underlyingAssetDecimals) {

        addressesProvider = _addressesProvider;
        core = LendingPoolCore(addressesProvider.getLendingPoolCore());
        pool = LendingPool(addressesProvider.getLendingPool());
        dataProvider = LendingPoolDataProvider(addressesProvider.getLendingPoolDataProvider());
        underlyingAssetAddress = _underlyingAsset;
    }

    /**
     * @notice ERC20 implementation internal function backing transfer() and transferFrom()
     * @dev validates the transfer before allowing it. NOTE: This is not standard ERC20 behavior
     **/
    function _transfer(address _from, address _to, uint256 _amount) internal whenTransferAllowed(_from, _amount) {

        executeTransferInternal(_from, _to, _amount);
    }


    /**
    * @dev redirects the interest generated to a target address.
    * when the interest is redirected, the user balance is added to
    * the recepient redirected balance.
    * @param _to the address to which the interest will be redirected
    **/
    function redirectInterestStream(address _to) external {
        redirectInterestStreamInternal(msg.sender, _to);
    }

    /**
    * @dev redirects the interest generated by _from to a target address.
    * when the interest is redirected, the user balance is added to
    * the recepient redirected balance. The caller needs to have allowance on
    * the interest redirection to be able to execute the function.
    * @param _from the address of the user whom interest is being redirected
    * @param _to the address to which the interest will be redirected
    **/
    function redirectInterestStreamOf(address _from, address _to) external {
        require(
            msg.sender == interestRedirectionAllowances[_from],
            "Caller is not allowed to redirect the interest of the user"
        );
        redirectInterestStreamInternal(_from,_to);
    }

    /**
    * @dev gives allowance to an address to execute the interest redirection
    * on behalf of the caller.
    * @param _to the address to which the interest will be redirected. Pass address(0) to reset
    * the allowance.
    **/
    function allowInterestRedirectionTo(address _to) external {
        require(_to != msg.sender, "User cannot give allowance to himself");
        interestRedirectionAllowances[msg.sender] = _to;
        emit InterestRedirectionAllowanceChanged(
            msg.sender,
            _to
        );
    }

    /**
    * @dev redeems aToken for the underlying asset
    * @param _amount the amount being redeemed
    **/
    function redeem(uint256 _amount) external {

        require(_amount > 0, "Amount to redeem needs to be > 0");

        //cumulates the balance of the user
        (,
        uint256 currentBalance,
        uint256 balanceIncrease,
        uint256 index) = cumulateBalanceInternal(msg.sender);

        uint256 amountToRedeem = _amount;

        //if amount is equal to uint(-1), the user wants to redeem everything
        if(_amount == UINT_MAX_VALUE){
            amountToRedeem = currentBalance;
        }

        require(amountToRedeem <= currentBalance, "User cannot redeem more than the available balance");

        //check that the user is allowed to redeem the amount
        require(isTransferAllowed(msg.sender, amountToRedeem), "Transfer cannot be allowed.");

        //if the user is redirecting his interest towards someone else,
        //we update the redirected balance of the redirection address by adding the accrued interest,
        //and removing the amount to redeem
        updateRedirectedBalanceOfRedirectionAddressInternal(msg.sender, balanceIncrease, amountToRedeem);

        // burns tokens equivalent to the amount requested
        _burn(msg.sender, amountToRedeem);

        bool userIndexReset = false;
        //reset the user data if the remaining balance is 0
        if(currentBalance.sub(amountToRedeem) == 0){
            userIndexReset = resetDataOnZeroBalanceInternal(msg.sender);
        }

        // executes redeem of the underlying asset
        pool.redeemUnderlying(
            underlyingAssetAddress,
            msg.sender,
            amountToRedeem,
            currentBalance.sub(amountToRedeem)
        );

        emit Redeem(msg.sender, amountToRedeem, balanceIncrease, userIndexReset ? 0 : index);
    }

    /**
     * @dev mints token in the event of users depositing the underlying asset into the lending pool
     * only lending pools can call this function
     * @param _account the address receiving the minted tokens
     * @param _amount the amount of tokens to mint
     */
    function mintOnDeposit(address _account, uint256 _amount) external onlyLendingPool {

        //cumulates the balance of the user
        (,
        ,
        uint256 balanceIncrease,
        uint256 index) = cumulateBalanceInternal(_account);

         //if the user is redirecting his interest towards someone else,
        //we update the redirected balance of the redirection address by adding the accrued interest
        //and the amount deposited
        updateRedirectedBalanceOfRedirectionAddressInternal(_account, balanceIncrease.add(_amount), 0);

        //mint an equivalent amount of tokens to cover the new deposit
        _mint(_account, _amount);

        emit MintOnDeposit(_account, _amount, balanceIncrease, index);
    }

    /**
     * @dev burns token in the event of a borrow being liquidated, in case the liquidators reclaims the underlying asset
     * Transfer of the liquidated asset is executed by the lending pool contract.
     * only lending pools can call this function
     * @param _account the address from which burn the aTokens
     * @param _value the amount to burn
     **/
    function burnOnLiquidation(address _account, uint256 _value) external onlyLendingPool {

        //cumulates the balance of the user being liquidated
        (,uint256 accountBalance,uint256 balanceIncrease,uint256 index) = cumulateBalanceInternal(_account);

        //adds the accrued interest and substracts the burned amount to
        //the redirected balance
        updateRedirectedBalanceOfRedirectionAddressInternal(_account, balanceIncrease, _value);

        //burns the requested amount of tokens
        _burn(_account, _value);

        bool userIndexReset = false;
        //reset the user data if the remaining balance is 0
        if(accountBalance.sub(_value) == 0){
            userIndexReset = resetDataOnZeroBalanceInternal(_account);
        }

        emit BurnOnLiquidation(_account, _value, balanceIncrease, userIndexReset ? 0 : index);
    }

    /**
     * @dev transfers tokens in the event of a borrow being liquidated, in case the liquidators reclaims the aToken
     *      only lending pools can call this function
     * @param _from the address from which transfer the aTokens
     * @param _to the destination address
     * @param _value the amount to transfer
     **/
    function transferOnLiquidation(address _from, address _to, uint256 _value) external onlyLendingPool {

        //being a normal transfer, the Transfer() and BalanceTransfer() are emitted
        //so no need to emit a specific event here
        executeTransferInternal(_from, _to, _value);
    }

    /**
    * @dev calculates the balance of the user, which is the
    * principal balance + interest generated by the principal balance + interest generated by the redirected balance
    * @param _user the user for which the balance is being calculated
    * @return the total balance of the user
    **/
    function balanceOf(address _user) public view returns(uint256) {

        //current principal balance of the user
        uint256 currentPrincipalBalance = super.balanceOf(_user);
        //balance redirected by other users to _user for interest rate accrual
        uint256 redirectedBalance = redirectedBalances[_user];

        if(currentPrincipalBalance == 0 && redirectedBalance == 0){
            return 0;
        }
        //if the _user is not redirecting the interest to anybody, accrues
        //the interest for himself

        if(interestRedirectionAddresses[_user] == address(0)){

            //accruing for himself means that both the principal balance and
            //the redirected balance partecipate in the interest
            return calculateCumulatedBalanceInternal(
                _user,
                currentPrincipalBalance.add(redirectedBalance)
                )
                .sub(redirectedBalance);
        }
        else {
            //if the user redirected the interest, then only the redirected
            //balance generates interest. In that case, the interest generated
            //by the redirected balance is added to the current principal balance.
            return currentPrincipalBalance.add(
                calculateCumulatedBalanceInternal(
                    _user,
                    redirectedBalance
                )
                .sub(redirectedBalance)
            );
        }
    }

    /**
    * @dev returns the principal balance of the user. The principal balance is the last
    * updated stored balance, which does not consider the perpetually accruing interest.
    * @param _user the address of the user
    * @return the principal balance of the user
    **/
    function principalBalanceOf(address _user) external view returns(uint256) {
        return super.balanceOf(_user);
    }


    /**
    * @dev calculates the total supply of the specific aToken
    * since the balance of every single user increases over time, the total supply
    * does that too.
    * @return the current total supply
    **/
    function totalSupply() public view returns(uint256) {

        uint256 currentSupplyPrincipal = super.totalSupply();

        if(currentSupplyPrincipal == 0){
            return 0;
        }

        return currentSupplyPrincipal
            .wadToRay()
            .rayMul(core.getReserveNormalizedIncome(underlyingAssetAddress))
            .rayToWad();
    }


    /**
     * @dev Used to validate transfers before actually executing them.
     * @param _user address of the user to check
     * @param _amount the amount to check
     * @return true if the _user can transfer _amount, false otherwise
     **/
    function isTransferAllowed(address _user, uint256 _amount) public view returns (bool) {
        return dataProvider.balanceDecreaseAllowed(underlyingAssetAddress, _user, _amount);
    }

    /**
    * @dev returns the last index of the user, used to calculate the balance of the user
    * @param _user address of the user
    * @return the last user index
    **/
    function getUserIndex(address _user) external view returns(uint256) {
        return userIndexes[_user];
    }


    /**
    * @dev returns the address to which the interest is redirected
    * @param _user address of the user
    * @return 0 if there is no redirection, an address otherwise
    **/
    function getInterestRedirectionAddress(address _user) external view returns(address) {
        return interestRedirectionAddresses[_user];
    }

    /**
    * @dev returns the redirected balance of the user. The redirected balance is the balance
    * redirected by other accounts to the user, that is accrueing interest for him.
    * @param _user address of the user
    * @return the total redirected balance
    **/
    function getRedirectedBalance(address _user) external view returns(uint256) {
        return redirectedBalances[_user];
    }

    /**
    * @dev accumulates the accrued interest of the user to the principal balance
    * @param _user the address of the user for which the interest is being accumulated
    * @return the previous principal balance, the new principal balance, the balance increase
    * and the new user index
    **/
    function cumulateBalanceInternal(address _user)
        internal
        returns(uint256, uint256, uint256, uint256) {

        uint256 previousPrincipalBalance = super.balanceOf(_user);

        //calculate the accrued interest since the last accumulation
        uint256 balanceIncrease = balanceOf(_user).sub(previousPrincipalBalance);
        //mints an amount of tokens equivalent to the amount accumulated
        _mint(_user, balanceIncrease);
        //updates the user index
        uint256 index = userIndexes[_user] = core.getReserveNormalizedIncome(underlyingAssetAddress);
        return (
            previousPrincipalBalance,
            previousPrincipalBalance.add(balanceIncrease),
            balanceIncrease,
            index
        );
    }

    /**
    * @dev updates the redirected balance of the user. If the user is not redirecting his
    * interest, nothing is executed.
    * @param _user the address of the user for which the interest is being accumulated
    * @param _balanceToAdd the amount to add to the redirected balance
    * @param _balanceToRemove the amount to remove from the redirected balance
    **/
    function updateRedirectedBalanceOfRedirectionAddressInternal(
        address _user,
        uint256 _balanceToAdd,
        uint256 _balanceToRemove
    ) internal {

        address redirectionAddress = interestRedirectionAddresses[_user];
        //if there isn't any redirection, nothing to be done
        if(redirectionAddress == address(0)){
            return;
        }

        //compound balances of the redirected address
        (,,uint256 balanceIncrease, uint256 index) = cumulateBalanceInternal(redirectionAddress);

        //updating the redirected balance
        redirectedBalances[redirectionAddress] = redirectedBalances[redirectionAddress]
            .add(_balanceToAdd)
            .sub(_balanceToRemove);

        //if the interest of redirectionAddress is also being redirected, we need to update
        //the redirected balance of the redirection target by adding the balance increase
        address targetOfRedirectionAddress = interestRedirectionAddresses[redirectionAddress];

        if(targetOfRedirectionAddress != address(0)){
            redirectedBalances[targetOfRedirectionAddress] = redirectedBalances[targetOfRedirectionAddress].add(balanceIncrease);
        }

        emit RedirectedBalanceUpdated(
            redirectionAddress,
            balanceIncrease,
            index,
            _balanceToAdd,
            _balanceToRemove
        );
    }

    /**
    * @dev calculate the interest accrued by _user on a specific balance
    * @param _user the address of the user for which the interest is being accumulated
    * @param _balance the balance on which the interest is calculated
    * @return the interest rate accrued
    **/
    function calculateCumulatedBalanceInternal(
        address _user,
        uint256 _balance
    ) internal view returns (uint256) {
        return _balance
            .wadToRay()
            .rayMul(core.getReserveNormalizedIncome(underlyingAssetAddress))
            .rayDiv(userIndexes[_user])
            .rayToWad();
    }

    /**
    * @dev executes the transfer of aTokens, invoked by both _transfer() and
    *      transferOnLiquidation()
    * @param _from the address from which transfer the aTokens
    * @param _to the destination address
    * @param _value the amount to transfer
    **/
    function executeTransferInternal(
        address _from,
        address _to,
        uint256 _value
    ) internal {

        require(_value > 0, "Transferred amount needs to be greater than zero");

        //cumulate the balance of the sender
        (,
        uint256 fromBalance,
        uint256 fromBalanceIncrease,
        uint256 fromIndex
        ) = cumulateBalanceInternal(_from);

        //cumulate the balance of the receiver
        (,
        ,
        uint256 toBalanceIncrease,
        uint256 toIndex
        ) = cumulateBalanceInternal(_to);

        //if the sender is redirecting his interest towards someone else,
        //adds to the redirected balance the accrued interest and removes the amount
        //being transferred
        updateRedirectedBalanceOfRedirectionAddressInternal(_from, fromBalanceIncrease, _value);

        //if the receiver is redirecting his interest towards someone else,
        //adds to the redirected balance the accrued interest and the amount
        //being transferred
        updateRedirectedBalanceOfRedirectionAddressInternal(_to, toBalanceIncrease.add(_value), 0);

        //performs the transfer
        super._transfer(_from, _to, _value);

        bool fromIndexReset = false;
        //reset the user data if the remaining balance is 0
        if(fromBalance.sub(_value) == 0){
            fromIndexReset = resetDataOnZeroBalanceInternal(_from);
        }

        emit BalanceTransfer(
            _from,
            _to,
            _value,
            fromBalanceIncrease,
            toBalanceIncrease,
            fromIndexReset ? 0 : fromIndex,
            toIndex
        );
    }

    /**
    * @dev executes the redirection of the interest from one address to another.
    * immediately after redirection, the destination address will start to accrue interest.
    * @param _from the address from which transfer the aTokens
    * @param _to the destination address
    **/
    function redirectInterestStreamInternal(
        address _from,
        address _to
    ) internal {

        address currentRedirectionAddress = interestRedirectionAddresses[_from];

        require(_to != currentRedirectionAddress, "Interest is already redirected to the user");

        //accumulates the accrued interest to the principal
        (uint256 previousPrincipalBalance,
        uint256 fromBalance,
        uint256 balanceIncrease,
        uint256 fromIndex) = cumulateBalanceInternal(_from);

        require(fromBalance > 0, "Interest stream can only be redirected if there is a valid balance");

        //if the user is already redirecting the interest to someone, before changing
        //the redirection address we substract the redirected balance of the previous
        //recipient
        if(currentRedirectionAddress != address(0)){
            updateRedirectedBalanceOfRedirectionAddressInternal(_from,0, previousPrincipalBalance);
        }

        //if the user is redirecting the interest back to himself,
        //we simply set to 0 the interest redirection address
        if(_to == _from) {
            interestRedirectionAddresses[_from] = address(0);
            emit InterestStreamRedirected(
                _from,
                address(0),
                fromBalance,
                balanceIncrease,
                fromIndex
            );
            return;
        }

        //first set the redirection address to the new recipient
        interestRedirectionAddresses[_from] = _to;

        //adds the user balance to the redirected balance of the destination
        updateRedirectedBalanceOfRedirectionAddressInternal(_from,fromBalance,0);

        emit InterestStreamRedirected(
            _from,
            _to,
            fromBalance,
            balanceIncrease,
            fromIndex
        );
    }

    /**
    * @dev function to reset the interest stream redirection and the user index, if the
    * user has no balance left.
    * @param _user the address of the user
    * @return true if the user index has also been reset, false otherwise. useful to emit the proper user index value
    **/
    function resetDataOnZeroBalanceInternal(address _user) internal returns(bool) {

        //if the user has 0 principal balance, the interest stream redirection gets reset
        interestRedirectionAddresses[_user] = address(0);

        //emits a InterestStreamRedirected event to notify that the redirection has been reset
        emit InterestStreamRedirected(_user, address(0),0,0,0);

        //if the redirected balance is also 0, we clear up the user index
        if(redirectedBalances[_user] == 0){
            userIndexes[_user] = 0;
            return true;
        }
        else{
            return false;
        }
    }
}

/**
* @title IFlashLoanReceiver interface
* @notice Interface for the Aave fee IFlashLoanReceiver.
* @author Aave
* @dev implement this interface to develop a flashloan-compatible flashLoanReceiver contract
**/
interface IFlashLoanReceiver {

    function executeOperation(address _reserve, uint256 _amount, uint256 _fee, bytes calldata _params) external;
}

/**
* @title ILendingRateOracle interface
* @notice Interface for the Aave borrow rate oracle. Provides the average market borrow rate to be used as a base for the stable borrow rate calculations
**/

interface ILendingRateOracle {
    /**
    @dev returns the market borrow rate in ray
    **/
    function getMarketBorrowRate(address _asset) external view returns (uint256);

    /**
    @dev sets the market borrow rate. Rate value must be in ray
    **/
    function setMarketBorrowRate(address _asset, uint256 _rate) external;
}

/**
@title IReserveInterestRateStrategyInterface interface
@notice Interface for the calculation of the interest rates.
*/

interface IReserveInterestRateStrategy {

    /**
    * @dev returns the base variable borrow rate, in rays
    */

    function getBaseVariableBorrowRate() external view returns (uint256);
    /**
    * @dev calculates the liquidity, stable, and variable rates depending on the current utilization rate
    *      and the base parameters
    *
    */
    function calculateInterestRates(
        address _reserve,
        uint256 _utilizationRate,
        uint256 _totalBorrowsStable,
        uint256 _totalBorrowsVariable,
        uint256 _averageStableBorrowRate)
    external
    view
    returns (uint256 liquidityRate, uint256 stableBorrowRate, uint256 variableBorrowRate);
}

library EthAddressLib {

    /**
    * @dev returns the address used within the protocol to identify ETH
    * @return the address assigned to ETH
     */
    function ethAddress() internal pure returns(address) {
        return 0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE;
    }
}

/**
* @title LendingPoolCore contract
* @author Aave
* @notice Holds the state of the lending pool and all the funds deposited
* @dev NOTE: The core does not enforce security checks on the update of the state
* (eg, updateStateOnBorrow() does not enforce that borrowed is enabled on the reserve).
* The check that an action can be performed is a duty of the overlying LendingPool contract.
**/

contract LendingPoolCore is VersionedInitializable {
    using SafeMath for uint256;
    using WadRayMath for uint256;
    using CoreLibrary for CoreLibrary.ReserveData;
    using CoreLibrary for CoreLibrary.UserReserveData;
    using SafeERC20 for ERC20;
    using Address for address payable;

    /**
    * @dev Emitted when the state of a reserve is updated
    * @param reserve the address of the reserve
    * @param liquidityRate the new liquidity rate
    * @param stableBorrowRate the new stable borrow rate
    * @param variableBorrowRate the new variable borrow rate
    * @param liquidityIndex the new liquidity index
    * @param variableBorrowIndex the new variable borrow index
    **/
    event ReserveUpdated(
        address indexed reserve,
        uint256 liquidityRate,
        uint256 stableBorrowRate,
        uint256 variableBorrowRate,
        uint256 liquidityIndex,
        uint256 variableBorrowIndex
    );

    address public lendingPoolAddress;

    LendingPoolAddressesProvider public addressesProvider;

    /**
    * @dev only lending pools can use functions affected by this modifier
    **/
    modifier onlyLendingPool {
        require(lendingPoolAddress == msg.sender, "The caller must be a lending pool contract");
        _;
    }

    /**
    * @dev only lending pools configurator can use functions affected by this modifier
    **/
    modifier onlyLendingPoolConfigurator {
        require(
            addressesProvider.getLendingPoolConfigurator() == msg.sender,
            "The caller must be a lending pool configurator contract"
        );
        _;
    }

    mapping(address => CoreLibrary.ReserveData) internal reserves;
    mapping(address => mapping(address => CoreLibrary.UserReserveData)) internal usersReserveData;

    address[] public reservesList;

    uint256 public constant CORE_REVISION = 0x4;

    /**
    * @dev returns the revision number of the contract
    **/
    function getRevision() internal pure returns (uint256) {
        return CORE_REVISION;
    }

    /**
    * @dev initializes the Core contract, invoked upon registration on the AddressesProvider
    * @param _addressesProvider the addressesProvider contract
    **/

    function initialize(LendingPoolAddressesProvider _addressesProvider) public initializer {
        addressesProvider = _addressesProvider;
        refreshConfigInternal();
    }

    /**
    * @dev updates the state of the core as a result of a deposit action
    * @param _reserve the address of the reserve in which the deposit is happening
    * @param _user the address of the the user depositing
    * @param _amount the amount being deposited
    * @param _isFirstDeposit true if the user is depositing for the first time
    **/

    function updateStateOnDeposit(
        address _reserve,
        address _user,
        uint256 _amount,
        bool _isFirstDeposit
    ) external onlyLendingPool {
        reserves[_reserve].updateCumulativeIndexes();
        updateReserveInterestRatesAndTimestampInternal(_reserve, _amount, 0);

        if (_isFirstDeposit) {
            //if this is the first deposit of the user, we configure the deposit as enabled to be used as collateral
            setUserUseReserveAsCollateral(_reserve, _user, true);
        }
    }

    /**
    * @dev updates the state of the core as a result of a redeem action
    * @param _reserve the address of the reserve in which the redeem is happening
    * @param _user the address of the the user redeeming
    * @param _amountRedeemed the amount being redeemed
    * @param _userRedeemedEverything true if the user is redeeming everything
    **/
    function updateStateOnRedeem(
        address _reserve,
        address _user,
        uint256 _amountRedeemed,
        bool _userRedeemedEverything
    ) external onlyLendingPool {
        //compound liquidity and variable borrow interests
        reserves[_reserve].updateCumulativeIndexes();
        updateReserveInterestRatesAndTimestampInternal(_reserve, 0, _amountRedeemed);

        //if user redeemed everything the useReserveAsCollateral flag is reset
        if (_userRedeemedEverything) {
            setUserUseReserveAsCollateral(_reserve, _user, false);
        }
    }

    /**
    * @dev updates the state of the core as a result of a flashloan action
    * @param _reserve the address of the reserve in which the flashloan is happening
    * @param _income the income of the protocol as a result of the action
    **/
    function updateStateOnFlashLoan(
        address _reserve,
        uint256 _availableLiquidityBefore,
        uint256 _income,
        uint256 _protocolFee
    ) external onlyLendingPool {
        transferFlashLoanProtocolFeeInternal(_reserve, _protocolFee);

        //compounding the cumulated interest
        reserves[_reserve].updateCumulativeIndexes();

        uint256 totalLiquidityBefore = _availableLiquidityBefore.add(
            getReserveTotalBorrows(_reserve)
        );

        //compounding the received fee into the reserve
        reserves[_reserve].cumulateToLiquidityIndex(totalLiquidityBefore, _income);

        //refresh interest rates
        updateReserveInterestRatesAndTimestampInternal(_reserve, _income, 0);
    }

    /**
    * @dev updates the state of the core as a consequence of a borrow action.
    * @param _reserve the address of the reserve on which the user is borrowing
    * @param _user the address of the borrower
    * @param _amountBorrowed the new amount borrowed
    * @param _borrowFee the fee on the amount borrowed
    * @param _rateMode the borrow rate mode (stable, variable)
    * @return the new borrow rate for the user
    **/
    function updateStateOnBorrow(
        address _reserve,
        address _user,
        uint256 _amountBorrowed,
        uint256 _borrowFee,
        CoreLibrary.InterestRateMode _rateMode
    ) external onlyLendingPool returns (uint256, uint256) {
        // getting the previous borrow data of the user
        (uint256 principalBorrowBalance, , uint256 balanceIncrease) = getUserBorrowBalances(
            _reserve,
            _user
        );

        updateReserveStateOnBorrowInternal(
            _reserve,
            _user,
            principalBorrowBalance,
            balanceIncrease,
            _amountBorrowed,
            _rateMode
        );

        updateUserStateOnBorrowInternal(
            _reserve,
            _user,
            _amountBorrowed,
            balanceIncrease,
            _borrowFee,
            _rateMode
        );

        updateReserveInterestRatesAndTimestampInternal(_reserve, 0, _amountBorrowed);

        return (getUserCurrentBorrowRate(_reserve, _user), balanceIncrease);
    }

    /**
    * @dev updates the state of the core as a consequence of a repay action.
    * @param _reserve the address of the reserve on which the user is repaying
    * @param _user the address of the borrower
    * @param _paybackAmountMinusFees the amount being paid back minus fees
    * @param _originationFeeRepaid the fee on the amount that is being repaid
    * @param _balanceIncrease the accrued interest on the borrowed amount
    * @param _repaidWholeLoan true if the user is repaying the whole loan
    **/

    function updateStateOnRepay(
        address _reserve,
        address _user,
        uint256 _paybackAmountMinusFees,
        uint256 _originationFeeRepaid,
        uint256 _balanceIncrease,
        bool _repaidWholeLoan
    ) external onlyLendingPool {
        updateReserveStateOnRepayInternal(
            _reserve,
            _user,
            _paybackAmountMinusFees,
            _balanceIncrease
        );
        updateUserStateOnRepayInternal(
            _reserve,
            _user,
            _paybackAmountMinusFees,
            _originationFeeRepaid,
            _balanceIncrease,
            _repaidWholeLoan
        );

        updateReserveInterestRatesAndTimestampInternal(_reserve, _paybackAmountMinusFees, 0);
    }

    /**
    * @dev updates the state of the core as a consequence of a swap rate action.
    * @param _reserve the address of the reserve on which the user is repaying
    * @param _user the address of the borrower
    * @param _principalBorrowBalance the amount borrowed by the user
    * @param _compoundedBorrowBalance the amount borrowed plus accrued interest
    * @param _balanceIncrease the accrued interest on the borrowed amount
    * @param _currentRateMode the current interest rate mode for the user
    **/
    function updateStateOnSwapRate(
        address _reserve,
        address _user,
        uint256 _principalBorrowBalance,
        uint256 _compoundedBorrowBalance,
        uint256 _balanceIncrease,
        CoreLibrary.InterestRateMode _currentRateMode
    ) external onlyLendingPool returns (CoreLibrary.InterestRateMode, uint256) {
        updateReserveStateOnSwapRateInternal(
            _reserve,
            _user,
            _principalBorrowBalance,
            _compoundedBorrowBalance,
            _currentRateMode
        );

        CoreLibrary.InterestRateMode newRateMode = updateUserStateOnSwapRateInternal(
            _reserve,
            _user,
            _balanceIncrease,
            _currentRateMode
        );

        updateReserveInterestRatesAndTimestampInternal(_reserve, 0, 0);

        return (newRateMode, getUserCurrentBorrowRate(_reserve, _user));
    }

    /**
    * @dev updates the state of the core as a consequence of a liquidation action.
    * @param _principalReserve the address of the principal reserve that is being repaid
    * @param _collateralReserve the address of the collateral reserve that is being liquidated
    * @param _user the address of the borrower
    * @param _amountToLiquidate the amount being repaid by the liquidator
    * @param _collateralToLiquidate the amount of collateral being liquidated
    * @param _feeLiquidated the amount of origination fee being liquidated
    * @param _liquidatedCollateralForFee the amount of collateral equivalent to the origination fee + bonus
    * @param _balanceIncrease the accrued interest on the borrowed amount
    * @param _liquidatorReceivesAToken true if the liquidator will receive aTokens, false otherwise
    **/
    function updateStateOnLiquidation(
        address _principalReserve,
        address _collateralReserve,
        address _user,
        uint256 _amountToLiquidate,
        uint256 _collateralToLiquidate,
        uint256 _feeLiquidated,
        uint256 _liquidatedCollateralForFee,
        uint256 _balanceIncrease,
        bool _liquidatorReceivesAToken
    ) external onlyLendingPool {
        updatePrincipalReserveStateOnLiquidationInternal(
            _principalReserve,
            _user,
            _amountToLiquidate,
            _balanceIncrease
        );

        updateCollateralReserveStateOnLiquidationInternal(
            _collateralReserve
        );

        updateUserStateOnLiquidationInternal(
            _principalReserve,
            _user,
            _amountToLiquidate,
            _feeLiquidated,
            _balanceIncrease
        );

        updateReserveInterestRatesAndTimestampInternal(_principalReserve, _amountToLiquidate, 0);

        if (!_liquidatorReceivesAToken) {
            updateReserveInterestRatesAndTimestampInternal(
                _collateralReserve,
                0,
                _collateralToLiquidate.add(_liquidatedCollateralForFee)
            );
        }

    }

    /**
    * @dev updates the state of the core as a consequence of a stable rate rebalance
    * @param _reserve the address of the principal reserve where the user borrowed
    * @param _user the address of the borrower
    * @param _balanceIncrease the accrued interest on the borrowed amount
    * @return the new stable rate for the user
    **/
    function updateStateOnRebalance(address _reserve, address _user, uint256 _balanceIncrease)
        external
        onlyLendingPool
        returns (uint256)
    {
        updateReserveStateOnRebalanceInternal(_reserve, _user, _balanceIncrease);

        //update user data and rebalance the rate
        updateUserStateOnRebalanceInternal(_reserve, _user, _balanceIncrease);
        updateReserveInterestRatesAndTimestampInternal(_reserve, 0, 0);
        return usersReserveData[_user][_reserve].stableBorrowRate;
    }

    /**
    * @dev enables or disables a reserve as collateral
    * @param _reserve the address of the principal reserve where the user deposited
    * @param _user the address of the depositor
    * @param _useAsCollateral true if the depositor wants to use the reserve as collateral
    **/
    function setUserUseReserveAsCollateral(address _reserve, address _user, bool _useAsCollateral)
        public
        onlyLendingPool
    {
        CoreLibrary.UserReserveData storage user = usersReserveData[_user][_reserve];
        user.useAsCollateral = _useAsCollateral;
    }

    /**
    * @notice ETH/token transfer functions
    **/

    /**
    * @dev fallback function enforces that the caller is a contract, to support flashloan transfers
    **/
    function() external payable {
        //only contracts can send ETH to the core
        require(msg.sender.isContract(), "Only contracts can send ether to the Lending pool core");

    }

    /**
    * @dev transfers to the user a specific amount from the reserve.
    * @param _reserve the address of the reserve where the transfer is happening
    * @param _user the address of the user receiving the transfer
    * @param _amount the amount being transferred
    **/
    function transferToUser(address _reserve, address payable _user, uint256 _amount)
        external
        onlyLendingPool
    {
        if (_reserve != EthAddressLib.ethAddress()) {
            ERC20(_reserve).safeTransfer(_user, _amount);
        } else {
            //solium-disable-next-line
            (bool result, ) = _user.call.value(_amount).gas(50000)("");
            require(result, "Transfer of ETH failed");
        }
    }

    /**
    * @dev transfers the protocol fees to the fees collection address
    * @param _token the address of the token being transferred
    * @param _user the address of the user from where the transfer is happening
    * @param _amount the amount being transferred
    * @param _destination the fee receiver address
    **/

    function transferToFeeCollectionAddress(
        address _token,
        address _user,
        uint256 _amount,
        address _destination
    ) external payable onlyLendingPool {
        address payable feeAddress = address(uint160(_destination)); //cast the address to payable

        if (_token != EthAddressLib.ethAddress()) {
            require(
                msg.value == 0,
                "User is sending ETH along with the ERC20 transfer. Check the value attribute of the transaction"
            );
            ERC20(_token).safeTransferFrom(_user, feeAddress, _amount);
        } else {
            require(msg.value >= _amount, "The amount and the value sent to deposit do not match");
            //solium-disable-next-line
            (bool result, ) = feeAddress.call.value(_amount).gas(50000)("");
            require(result, "Transfer of ETH failed");
        }
    }

    /**
    * @dev transfers the fees to the fees collection address in the case of liquidation
    * @param _token the address of the token being transferred
    * @param _amount the amount being transferred
    * @param _destination the fee receiver address
    **/
    function liquidateFee(
        address _token,
        uint256 _amount,
        address _destination
    ) external payable onlyLendingPool {
        address payable feeAddress = address(uint160(_destination)); //cast the address to payable
        require(
            msg.value == 0,
            "Fee liquidation does not require any transfer of value"
        );

        if (_token != EthAddressLib.ethAddress()) {
            ERC20(_token).safeTransfer(feeAddress, _amount);
        } else {
            //solium-disable-next-line
            (bool result, ) = feeAddress.call.value(_amount).gas(50000)("");
            require(result, "Transfer of ETH failed");
        }
    }

    /**
    * @dev transfers an amount from a user to the destination reserve
    * @param _reserve the address of the reserve where the amount is being transferred
    * @param _user the address of the user from where the transfer is happening
    * @param _amount the amount being transferred
    **/
    function transferToReserve(address _reserve, address payable _user, uint256 _amount)
        external
        payable
        onlyLendingPool
    {
        if (_reserve != EthAddressLib.ethAddress()) {
            require(msg.value == 0, "User is sending ETH along with the ERC20 transfer.");
            ERC20(_reserve).safeTransferFrom(_user, address(this), _amount);

        } else {
            require(msg.value >= _amount, "The amount and the value sent to deposit do not match");

            if (msg.value > _amount) {
                //send back excess ETH
                uint256 excessAmount = msg.value.sub(_amount);
                //solium-disable-next-line
                (bool result, ) = _user.call.value(excessAmount).gas(50000)("");
                require(result, "Transfer of ETH failed");
            }
        }
    }

    /**
    * @notice data access functions
    **/

    /**
    * @dev returns the basic data (balances, fee accrued, reserve enabled/disabled as collateral)
    * needed to calculate the global account data in the LendingPoolDataProvider
    * @param _reserve the address of the reserve
    * @param _user the address of the user
    * @return the user deposited balance, the principal borrow balance, the fee, and if the reserve is enabled as collateral or not
    **/
    function getUserBasicReserveData(address _reserve, address _user)
        external
        view
        returns (uint256, uint256, uint256, bool)
    {
        CoreLibrary.ReserveData storage reserve = reserves[_reserve];
        CoreLibrary.UserReserveData storage user = usersReserveData[_user][_reserve];

        uint256 underlyingBalance = getUserUnderlyingAssetBalance(_reserve, _user);

        if (user.principalBorrowBalance == 0) {
            return (underlyingBalance, 0, 0, user.useAsCollateral);
        }

        return (
            underlyingBalance,
            user.getCompoundedBorrowBalance(reserve),
            user.originationFee,
            user.useAsCollateral
        );
    }

    /**
    * @dev checks if a user is allowed to borrow at a stable rate
    * @param _reserve the reserve address
    * @param _user the user
    * @param _amount the amount the the user wants to borrow
    * @return true if the user is allowed to borrow at a stable rate, false otherwise
    **/

    function isUserAllowedToBorrowAtStable(address _reserve, address _user, uint256 _amount)
        external
        view
        returns (bool)
    {
        CoreLibrary.ReserveData storage reserve = reserves[_reserve];
        CoreLibrary.UserReserveData storage user = usersReserveData[_user][_reserve];

        if (!reserve.isStableBorrowRateEnabled) return false;

        return
            !user.useAsCollateral ||
            !reserve.usageAsCollateralEnabled ||
            _amount > getUserUnderlyingAssetBalance(_reserve, _user);
    }

    /**
    * @dev gets the underlying asset balance of a user based on the corresponding aToken balance.
    * @param _reserve the reserve address
    * @param _user the user address
    * @return the underlying deposit balance of the user
    **/

    function getUserUnderlyingAssetBalance(address _reserve, address _user)
        public
        view
        returns (uint256)
    {
        AToken aToken = AToken(reserves[_reserve].aTokenAddress);
        return aToken.balanceOf(_user);

    }

    /**
    * @dev gets the interest rate strategy contract address for the reserve
    * @param _reserve the reserve address
    * @return the address of the interest rate strategy contract
    **/
    function getReserveInterestRateStrategyAddress(address _reserve) public view returns (address) {
        CoreLibrary.ReserveData storage reserve = reserves[_reserve];
        return reserve.interestRateStrategyAddress;
    }

    /**
    * @dev gets the aToken contract address for the reserve
    * @param _reserve the reserve address
    * @return the address of the aToken contract
    **/

    function getReserveATokenAddress(address _reserve) public view returns (address) {
        CoreLibrary.ReserveData storage reserve = reserves[_reserve];
        return reserve.aTokenAddress;
    }

    /**
    * @dev gets the available liquidity in the reserve. The available liquidity is the balance of the core contract
    * @param _reserve the reserve address
    * @return the available liquidity
    **/
    function getReserveAvailableLiquidity(address _reserve) public view returns (uint256) {
        uint256 balance = 0;

        if (_reserve == EthAddressLib.ethAddress()) {
            balance = address(this).balance;
        } else {
            balance = IERC20(_reserve).balanceOf(address(this));
        }
        return balance;
    }

    /**
    * @dev gets the total liquidity in the reserve. The total liquidity is the balance of the core contract + total borrows
    * @param _reserve the reserve address
    * @return the total liquidity
    **/
    function getReserveTotalLiquidity(address _reserve) public view returns (uint256) {
        CoreLibrary.ReserveData storage reserve = reserves[_reserve];
        return getReserveAvailableLiquidity(_reserve).add(reserve.getTotalBorrows());
    }

    /**
    * @dev gets the normalized income of the reserve. a value of 1e27 means there is no income. A value of 2e27 means there
    * there has been 100% income.
    * @param _reserve the reserve address
    * @return the reserve normalized income
    **/
    function getReserveNormalizedIncome(address _reserve) external view returns (uint256) {
        CoreLibrary.ReserveData storage reserve = reserves[_reserve];
        return reserve.getNormalizedIncome();
    }

    /**
    * @dev gets the reserve total borrows
    * @param _reserve the reserve address
    * @return the total borrows (stable + variable)
    **/
    function getReserveTotalBorrows(address _reserve) public view returns (uint256) {
        return reserves[_reserve].getTotalBorrows();
    }

    /**
    * @dev gets the reserve total borrows stable
    * @param _reserve the reserve address
    * @return the total borrows stable
    **/
    function getReserveTotalBorrowsStable(address _reserve) external view returns (uint256) {
        CoreLibrary.ReserveData storage reserve = reserves[_reserve];
        return reserve.totalBorrowsStable;
    }

    /**
    * @dev gets the reserve total borrows variable
    * @param _reserve the reserve address
    * @return the total borrows variable
    **/

    function getReserveTotalBorrowsVariable(address _reserve) external view returns (uint256) {
        CoreLibrary.ReserveData storage reserve = reserves[_reserve];
        return reserve.totalBorrowsVariable;
    }

    /**
    * @dev gets the reserve liquidation threshold
    * @param _reserve the reserve address
    * @return the reserve liquidation threshold
    **/

    function getReserveLiquidationThreshold(address _reserve) external view returns (uint256) {
        CoreLibrary.ReserveData storage reserve = reserves[_reserve];
        return reserve.liquidationThreshold;
    }

    /**
    * @dev gets the reserve liquidation bonus
    * @param _reserve the reserve address
    * @return the reserve liquidation bonus
    **/

    function getReserveLiquidationBonus(address _reserve) external view returns (uint256) {
        CoreLibrary.ReserveData storage reserve = reserves[_reserve];
        return reserve.liquidationBonus;
    }

    /**
    * @dev gets the reserve current variable borrow rate. Is the base variable borrow rate if the reserve is empty
    * @param _reserve the reserve address
    * @return the reserve current variable borrow rate
    **/

    function getReserveCurrentVariableBorrowRate(address _reserve) external view returns (uint256) {
        CoreLibrary.ReserveData storage reserve = reserves[_reserve];

        if (reserve.currentVariableBorrowRate == 0) {
            return
                IReserveInterestRateStrategy(reserve.interestRateStrategyAddress)
                .getBaseVariableBorrowRate();
        }
        return reserve.currentVariableBorrowRate;
    }

    /**
    * @dev gets the reserve current stable borrow rate. Is the market rate if the reserve is empty
    * @param _reserve the reserve address
    * @return the reserve current stable borrow rate
    **/

    function getReserveCurrentStableBorrowRate(address _reserve) public view returns (uint256) {
        CoreLibrary.ReserveData storage reserve = reserves[_reserve];
        ILendingRateOracle oracle = ILendingRateOracle(addressesProvider.getLendingRateOracle());

        if (reserve.currentStableBorrowRate == 0) {
            //no stable rate borrows yet
            return oracle.getMarketBorrowRate(_reserve);
        }

        return reserve.currentStableBorrowRate;
    }

    /**
    * @dev gets the reserve average stable borrow rate. The average stable rate is the weighted average
    * of all the loans taken at stable rate.
    * @param _reserve the reserve address
    * @return the reserve current average borrow rate
    **/
    function getReserveCurrentAverageStableBorrowRate(address _reserve)
        external
        view
        returns (uint256)
    {
        CoreLibrary.ReserveData storage reserve = reserves[_reserve];
        return reserve.currentAverageStableBorrowRate;
    }

    /**
    * @dev gets the reserve liquidity rate
    * @param _reserve the reserve address
    * @return the reserve liquidity rate
    **/
    function getReserveCurrentLiquidityRate(address _reserve) external view returns (uint256) {
        CoreLibrary.ReserveData storage reserve = reserves[_reserve];
        return reserve.currentLiquidityRate;
    }

    /**
    * @dev gets the reserve liquidity cumulative index
    * @param _reserve the reserve address
    * @return the reserve liquidity cumulative index
    **/
    function getReserveLiquidityCumulativeIndex(address _reserve) external view returns (uint256) {
        CoreLibrary.ReserveData storage reserve = reserves[_reserve];
        return reserve.lastLiquidityCumulativeIndex;
    }

    /**
    * @dev gets the reserve variable borrow index
    * @param _reserve the reserve address
    * @return the reserve variable borrow index
    **/
    function getReserveVariableBorrowsCumulativeIndex(address _reserve)
        external
        view
        returns (uint256)
    {
        CoreLibrary.ReserveData storage reserve = reserves[_reserve];
        return reserve.lastVariableBorrowCumulativeIndex;
    }

    /**
    * @dev this function aggregates the configuration parameters of the reserve.
    * It's used in the LendingPoolDataProvider specifically to save gas, and avoid
    * multiple external contract calls to fetch the same data.
    * @param _reserve the reserve address
    * @return the reserve decimals
    * @return the base ltv as collateral
    * @return the liquidation threshold
    * @return if the reserve is used as collateral or not
    **/
    function getReserveConfiguration(address _reserve)
        external
        view
        returns (uint256, uint256, uint256, bool)
    {
        uint256 decimals;
        uint256 baseLTVasCollateral;
        uint256 liquidationThreshold;
        bool usageAsCollateralEnabled;

        CoreLibrary.ReserveData storage reserve = reserves[_reserve];
        decimals = reserve.decimals;
        baseLTVasCollateral = reserve.baseLTVasCollateral;
        liquidationThreshold = reserve.liquidationThreshold;
        usageAsCollateralEnabled = reserve.usageAsCollateralEnabled;

        return (decimals, baseLTVasCollateral, liquidationThreshold, usageAsCollateralEnabled);
    }

    /**
    * @dev returns the decimals of the reserve
    * @param _reserve the reserve address
    * @return the reserve decimals
    **/
    function getReserveDecimals(address _reserve) external view returns (uint256) {
        return reserves[_reserve].decimals;
    }

    /**
    * @dev returns true if the reserve is enabled for borrowing
    * @param _reserve the reserve address
    * @return true if the reserve is enabled for borrowing, false otherwise
    **/

    function isReserveBorrowingEnabled(address _reserve) external view returns (bool) {
        CoreLibrary.ReserveData storage reserve = reserves[_reserve];
        return reserve.borrowingEnabled;
    }

    /**
    * @dev returns true if the reserve is enabled as collateral
    * @param _reserve the reserve address
    * @return true if the reserve is enabled as collateral, false otherwise
    **/

    function isReserveUsageAsCollateralEnabled(address _reserve) external view returns (bool) {
        CoreLibrary.ReserveData storage reserve = reserves[_reserve];
        return reserve.usageAsCollateralEnabled;
    }

    /**
    * @dev returns true if the stable rate is enabled on reserve
    * @param _reserve the reserve address
    * @return true if the stable rate is enabled on reserve, false otherwise
    **/
    function getReserveIsStableBorrowRateEnabled(address _reserve) external view returns (bool) {
        CoreLibrary.ReserveData storage reserve = reserves[_reserve];
        return reserve.isStableBorrowRateEnabled;
    }

    /**
    * @dev returns true if the reserve is active
    * @param _reserve the reserve address
    * @return true if the reserve is active, false otherwise
    **/
    function getReserveIsActive(address _reserve) external view returns (bool) {
        CoreLibrary.ReserveData storage reserve = reserves[_reserve];
        return reserve.isActive;
    }

    /**
    * @notice returns if a reserve is freezed
    * @param _reserve the reserve for which the information is needed
    * @return true if the reserve is freezed, false otherwise
    **/

    function getReserveIsFreezed(address _reserve) external view returns (bool) {
        CoreLibrary.ReserveData storage reserve = reserves[_reserve];
        return reserve.isFreezed;
    }

    /**
    * @notice returns the timestamp of the last action on the reserve
    * @param _reserve the reserve for which the information is needed
    * @return the last updated timestamp of the reserve
    **/

    function getReserveLastUpdate(address _reserve) external view returns (uint40 timestamp) {
        CoreLibrary.ReserveData storage reserve = reserves[_reserve];
        timestamp = reserve.lastUpdateTimestamp;
    }

    /**
    * @dev returns the utilization rate U of a specific reserve
    * @param _reserve the reserve for which the information is needed
    * @return the utilization rate in ray
    **/

    function getReserveUtilizationRate(address _reserve) public view returns (uint256) {
        CoreLibrary.ReserveData storage reserve = reserves[_reserve];

        uint256 totalBorrows = reserve.getTotalBorrows();

        if (totalBorrows == 0) {
            return 0;
        }

        uint256 availableLiquidity = getReserveAvailableLiquidity(_reserve);

        return totalBorrows.rayDiv(availableLiquidity.add(totalBorrows));
    }

    /**
    * @return the array of reserves configured on the core
    **/
    function getReserves() external view returns (address[] memory) {
        return reservesList;
    }

    /**
    * @param _reserve the address of the reserve for which the information is needed
    * @param _user the address of the user for which the information is needed
    * @return true if the user has chosen to use the reserve as collateral, false otherwise
    **/
    function isUserUseReserveAsCollateralEnabled(address _reserve, address _user)
        external
        view
        returns (bool)
    {
        CoreLibrary.UserReserveData storage user = usersReserveData[_user][_reserve];
        return user.useAsCollateral;
    }

    /**
    * @param _reserve the address of the reserve for which the information is needed
    * @param _user the address of the user for which the information is needed
    * @return the origination fee for the user
    **/
    function getUserOriginationFee(address _reserve, address _user)
        external
        view
        returns (uint256)
    {
        CoreLibrary.UserReserveData storage user = usersReserveData[_user][_reserve];
        return user.originationFee;
    }

    /**
    * @dev users with no loans in progress have NONE as borrow rate mode
    * @param _reserve the address of the reserve for which the information is needed
    * @param _user the address of the user for which the information is needed
    * @return the borrow rate mode for the user,
    **/

    function getUserCurrentBorrowRateMode(address _reserve, address _user)
        public
        view
        returns (CoreLibrary.InterestRateMode)
    {
        CoreLibrary.UserReserveData storage user = usersReserveData[_user][_reserve];

        if (user.principalBorrowBalance == 0) {
            return CoreLibrary.InterestRateMode.NONE;
        }

        return
            user.stableBorrowRate > 0
            ? CoreLibrary.InterestRateMode.STABLE
            : CoreLibrary.InterestRateMode.VARIABLE;
    }

    /**
    * @dev gets the current borrow rate of the user
    * @param _reserve the address of the reserve for which the information is needed
    * @param _user the address of the user for which the information is needed
    * @return the borrow rate for the user,
    **/
    function getUserCurrentBorrowRate(address _reserve, address _user)
        internal
        view
        returns (uint256)
    {
        CoreLibrary.InterestRateMode rateMode = getUserCurrentBorrowRateMode(_reserve, _user);

        if (rateMode == CoreLibrary.InterestRateMode.NONE) {
            return 0;
        }

        return
            rateMode == CoreLibrary.InterestRateMode.STABLE
            ? usersReserveData[_user][_reserve].stableBorrowRate
            : reserves[_reserve].currentVariableBorrowRate;
    }

    /**
    * @dev the stable rate returned is 0 if the user is borrowing at variable or not borrowing at all
    * @param _reserve the address of the reserve for which the information is needed
    * @param _user the address of the user for which the information is needed
    * @return the user stable rate
    **/
    function getUserCurrentStableBorrowRate(address _reserve, address _user)
        external
        view
        returns (uint256)
    {
        CoreLibrary.UserReserveData storage user = usersReserveData[_user][_reserve];
        return user.stableBorrowRate;
    }

    /**
    * @dev calculates and returns the borrow balances of the user
    * @param _reserve the address of the reserve
    * @param _user the address of the user
    * @return the principal borrow balance, the compounded balance and the balance increase since the last borrow/repay/swap/rebalance
    **/

    function getUserBorrowBalances(address _reserve, address _user)
        public
        view
        returns (uint256, uint256, uint256)
    {
        CoreLibrary.UserReserveData storage user = usersReserveData[_user][_reserve];
        if (user.principalBorrowBalance == 0) {
            return (0, 0, 0);
        }

        uint256 principal = user.principalBorrowBalance;
        uint256 compoundedBalance = CoreLibrary.getCompoundedBorrowBalance(
            user,
            reserves[_reserve]
        );
        return (principal, compoundedBalance, compoundedBalance.sub(principal));
    }

    /**
    * @dev the variable borrow index of the user is 0 if the user is not borrowing or borrowing at stable
    * @param _reserve the address of the reserve for which the information is needed
    * @param _user the address of the user for which the information is needed
    * @return the variable borrow index for the user
    **/

    function getUserVariableBorrowCumulativeIndex(address _reserve, address _user)
        external
        view
        returns (uint256)
    {
        CoreLibrary.UserReserveData storage user = usersReserveData[_user][_reserve];
        return user.lastVariableBorrowCumulativeIndex;
    }

    /**
    * @dev the variable borrow index of the user is 0 if the user is not borrowing or borrowing at stable
    * @param _reserve the address of the reserve for which the information is needed
    * @param _user the address of the user for which the information is needed
    * @return the variable borrow index for the user
    **/

    function getUserLastUpdate(address _reserve, address _user)
        external
        view
        returns (uint256 timestamp)
    {
        CoreLibrary.UserReserveData storage user = usersReserveData[_user][_reserve];
        timestamp = user.lastUpdateTimestamp;
    }

    /**
    * @dev updates the lending pool core configuration
    **/
    function refreshConfiguration() external onlyLendingPoolConfigurator {
        refreshConfigInternal();
    }

    /**
    * @dev initializes a reserve
    * @param _reserve the address of the reserve
    * @param _aTokenAddress the address of the overlying aToken contract
    * @param _decimals the decimals of the reserve currency
    * @param _interestRateStrategyAddress the address of the interest rate strategy contract
    **/
    function initReserve(
        address _reserve,
        address _aTokenAddress,
        uint256 _decimals,
        address _interestRateStrategyAddress
    ) external onlyLendingPoolConfigurator {
        reserves[_reserve].init(_aTokenAddress, _decimals, _interestRateStrategyAddress);
        addReserveToListInternal(_reserve);

    }



    /**
    * @dev removes the last added reserve in the reservesList array
    * @param _reserveToRemove the address of the reserve
    **/
    function removeLastAddedReserve(address _reserveToRemove)
     external onlyLendingPoolConfigurator {

        address lastReserve = reservesList[reservesList.length-1];

        require(lastReserve == _reserveToRemove, "Reserve being removed is different than the reserve requested");

        //as we can't check if totalLiquidity is 0 (since the reserve added might not be an ERC20) we at least check that there is nothing borrowed
        require(getReserveTotalBorrows(lastReserve) == 0, "Cannot remove a reserve with liquidity deposited");

        reserves[lastReserve].isActive = false;
        reserves[lastReserve].aTokenAddress = address(0);
        reserves[lastReserve].decimals = 0;
        reserves[lastReserve].lastLiquidityCumulativeIndex = 0;
        reserves[lastReserve].lastVariableBorrowCumulativeIndex = 0;
        reserves[lastReserve].borrowingEnabled = false;
        reserves[lastReserve].usageAsCollateralEnabled = false;
        reserves[lastReserve].baseLTVasCollateral = 0;
        reserves[lastReserve].liquidationThreshold = 0;
        reserves[lastReserve].liquidationBonus = 0;
        reserves[lastReserve].interestRateStrategyAddress = address(0);

        reservesList.pop();
    }

    /**
    * @dev updates the address of the interest rate strategy contract
    * @param _reserve the address of the reserve
    * @param _rateStrategyAddress the address of the interest rate strategy contract
    **/

    function setReserveInterestRateStrategyAddress(address _reserve, address _rateStrategyAddress)
        external
        onlyLendingPoolConfigurator
    {
        reserves[_reserve].interestRateStrategyAddress = _rateStrategyAddress;
    }

    /**
    * @dev enables borrowing on a reserve. Also sets the stable rate borrowing
    * @param _reserve the address of the reserve
    * @param _stableBorrowRateEnabled true if the stable rate needs to be enabled, false otherwise
    **/

    function enableBorrowingOnReserve(address _reserve, bool _stableBorrowRateEnabled)
        external
        onlyLendingPoolConfigurator
    {
        reserves[_reserve].enableBorrowing(_stableBorrowRateEnabled);
    }

    /**
    * @dev disables borrowing on a reserve
    * @param _reserve the address of the reserve
    **/

    function disableBorrowingOnReserve(address _reserve) external onlyLendingPoolConfigurator {
        reserves[_reserve].disableBorrowing();
    }

    /**
    * @dev enables a reserve to be used as collateral
    * @param _reserve the address of the reserve
    **/
    function enableReserveAsCollateral(
        address _reserve,
        uint256 _baseLTVasCollateral,
        uint256 _liquidationThreshold,
        uint256 _liquidationBonus
    ) external onlyLendingPoolConfigurator {
        reserves[_reserve].enableAsCollateral(
            _baseLTVasCollateral,
            _liquidationThreshold,
            _liquidationBonus
        );
    }

    /**
    * @dev disables a reserve to be used as collateral
    * @param _reserve the address of the reserve
    **/
    function disableReserveAsCollateral(address _reserve) external onlyLendingPoolConfigurator {
        reserves[_reserve].disableAsCollateral();
    }

    /**
    * @dev enable the stable borrow rate mode on a reserve
    * @param _reserve the address of the reserve
    **/
    function enableReserveStableBorrowRate(address _reserve) external onlyLendingPoolConfigurator {
        CoreLibrary.ReserveData storage reserve = reserves[_reserve];
        reserve.isStableBorrowRateEnabled = true;
    }

    /**
    * @dev disable the stable borrow rate mode on a reserve
    * @param _reserve the address of the reserve
    **/
    function disableReserveStableBorrowRate(address _reserve) external onlyLendingPoolConfigurator {
        CoreLibrary.ReserveData storage reserve = reserves[_reserve];
        reserve.isStableBorrowRateEnabled = false;
    }

    /**
    * @dev activates a reserve
    * @param _reserve the address of the reserve
    **/
    function activateReserve(address _reserve) external onlyLendingPoolConfigurator {
        CoreLibrary.ReserveData storage reserve = reserves[_reserve];

        require(
            reserve.lastLiquidityCumulativeIndex > 0 &&
                reserve.lastVariableBorrowCumulativeIndex > 0,
            "Reserve has not been initialized yet"
        );
        reserve.isActive = true;
    }

    /**
    * @dev deactivates a reserve
    * @param _reserve the address of the reserve
    **/
    function deactivateReserve(address _reserve) external onlyLendingPoolConfigurator {
        CoreLibrary.ReserveData storage reserve = reserves[_reserve];
        reserve.isActive = false;
    }

    /**
    * @notice allows the configurator to freeze the reserve.
    * A freezed reserve does not allow any action apart from repay, redeem, liquidationCall, rebalance.
    * @param _reserve the address of the reserve
    **/
    function freezeReserve(address _reserve) external onlyLendingPoolConfigurator {
        CoreLibrary.ReserveData storage reserve = reserves[_reserve];
        reserve.isFreezed = true;
    }

    /**
    * @notice allows the configurator to unfreeze the reserve. A unfreezed reserve allows any action to be executed.
    * @param _reserve the address of the reserve
    **/
    function unfreezeReserve(address _reserve) external onlyLendingPoolConfigurator {
        CoreLibrary.ReserveData storage reserve = reserves[_reserve];
        reserve.isFreezed = false;
    }

    /**
    * @notice allows the configurator to update the loan to value of a reserve
    * @param _reserve the address of the reserve
    * @param _ltv the new loan to value
    **/
    function setReserveBaseLTVasCollateral(address _reserve, uint256 _ltv)
        external
        onlyLendingPoolConfigurator
    {
        CoreLibrary.ReserveData storage reserve = reserves[_reserve];
        reserve.baseLTVasCollateral = _ltv;
    }

    /**
    * @notice allows the configurator to update the liquidation threshold of a reserve
    * @param _reserve the address of the reserve
    * @param _threshold the new liquidation threshold
    **/
    function setReserveLiquidationThreshold(address _reserve, uint256 _threshold)
        external
        onlyLendingPoolConfigurator
    {
        CoreLibrary.ReserveData storage reserve = reserves[_reserve];
        reserve.liquidationThreshold = _threshold;
    }

    /**
    * @notice allows the configurator to update the liquidation bonus of a reserve
    * @param _reserve the address of the reserve
    * @param _bonus the new liquidation bonus
    **/
    function setReserveLiquidationBonus(address _reserve, uint256 _bonus)
        external
        onlyLendingPoolConfigurator
    {
        CoreLibrary.ReserveData storage reserve = reserves[_reserve];
        reserve.liquidationBonus = _bonus;
    }

    /**
    * @notice allows the configurator to update the reserve decimals
    * @param _reserve the address of the reserve
    * @param _decimals the decimals of the reserve
    **/
    function setReserveDecimals(address _reserve, uint256 _decimals)
        external
        onlyLendingPoolConfigurator
    {
        CoreLibrary.ReserveData storage reserve = reserves[_reserve];
        reserve.decimals = _decimals;
    }

    /**
    * @notice internal functions
    **/

    /**
    * @dev updates the state of a reserve as a consequence of a borrow action.
    * @param _reserve the address of the reserve on which the user is borrowing
    * @param _user the address of the borrower
    * @param _principalBorrowBalance the previous borrow balance of the borrower before the action
    * @param _balanceIncrease the accrued interest of the user on the previous borrowed amount
    * @param _amountBorrowed the new amount borrowed
    * @param _rateMode the borrow rate mode (stable, variable)
    **/

    function updateReserveStateOnBorrowInternal(
        address _reserve,
        address _user,
        uint256 _principalBorrowBalance,
        uint256 _balanceIncrease,
        uint256 _amountBorrowed,
        CoreLibrary.InterestRateMode _rateMode
    ) internal {
        reserves[_reserve].updateCumulativeIndexes();

        //increasing reserve total borrows to account for the new borrow balance of the user
        //NOTE: Depending on the previous borrow mode, the borrows might need to be switched from variable to stable or vice versa

        updateReserveTotalBorrowsByRateModeInternal(
            _reserve,
            _user,
            _principalBorrowBalance,
            _balanceIncrease,
            _amountBorrowed,
            _rateMode
        );
    }

    /**
    * @dev updates the state of a user as a consequence of a borrow action.
    * @param _reserve the address of the reserve on which the user is borrowing
    * @param _user the address of the borrower
    * @param _amountBorrowed the amount borrowed
    * @param _balanceIncrease the accrued interest of the user on the previous borrowed amount
    * @param _rateMode the borrow rate mode (stable, variable)
    * @return the final borrow rate for the user. Emitted by the borrow() event
    **/

    function updateUserStateOnBorrowInternal(
        address _reserve,
        address _user,
        uint256 _amountBorrowed,
        uint256 _balanceIncrease,
        uint256 _fee,
        CoreLibrary.InterestRateMode _rateMode
    ) internal {
        CoreLibrary.ReserveData storage reserve = reserves[_reserve];
        CoreLibrary.UserReserveData storage user = usersReserveData[_user][_reserve];

        if (_rateMode == CoreLibrary.InterestRateMode.STABLE) {
            //stable
            //reset the user variable index, and update the stable rate
            user.stableBorrowRate = reserve.currentStableBorrowRate;
            user.lastVariableBorrowCumulativeIndex = 0;
        } else if (_rateMode == CoreLibrary.InterestRateMode.VARIABLE) {
            //variable
            //reset the user stable rate, and store the new borrow index
            user.stableBorrowRate = 0;
            user.lastVariableBorrowCumulativeIndex = reserve.lastVariableBorrowCumulativeIndex;
        } else {
            revert("Invalid borrow rate mode");
        }
        //increase the principal borrows and the origination fee
        user.principalBorrowBalance = user.principalBorrowBalance.add(_amountBorrowed).add(
            _balanceIncrease
        );
        user.originationFee = user.originationFee.add(_fee);

        //solium-disable-next-line
        user.lastUpdateTimestamp = uint40(block.timestamp);

    }

    /**
    * @dev updates the state of the reserve as a consequence of a repay action.
    * @param _reserve the address of the reserve on which the user is repaying
    * @param _user the address of the borrower
    * @param _paybackAmountMinusFees the amount being paid back minus fees
    * @param _balanceIncrease the accrued interest on the borrowed amount
    **/

    function updateReserveStateOnRepayInternal(
        address _reserve,
        address _user,
        uint256 _paybackAmountMinusFees,
        uint256 _balanceIncrease
    ) internal {
        CoreLibrary.ReserveData storage reserve = reserves[_reserve];
        CoreLibrary.UserReserveData storage user = usersReserveData[_reserve][_user];

        CoreLibrary.InterestRateMode borrowRateMode = getUserCurrentBorrowRateMode(_reserve, _user);

        //update the indexes
        reserves[_reserve].updateCumulativeIndexes();

        //compound the cumulated interest to the borrow balance and then subtracting the payback amount
        if (borrowRateMode == CoreLibrary.InterestRateMode.STABLE) {
            reserve.increaseTotalBorrowsStableAndUpdateAverageRate(
                _balanceIncrease,
                user.stableBorrowRate
            );
            reserve.decreaseTotalBorrowsStableAndUpdateAverageRate(
                _paybackAmountMinusFees,
                user.stableBorrowRate
            );
        } else {
            reserve.increaseTotalBorrowsVariable(_balanceIncrease);
            reserve.decreaseTotalBorrowsVariable(_paybackAmountMinusFees);
        }
    }

    /**
    * @dev updates the state of the user as a consequence of a repay action.
    * @param _reserve the address of the reserve on which the user is repaying
    * @param _user the address of the borrower
    * @param _paybackAmountMinusFees the amount being paid back minus fees
    * @param _originationFeeRepaid the fee on the amount that is being repaid
    * @param _balanceIncrease the accrued interest on the borrowed amount
    * @param _repaidWholeLoan true if the user is repaying the whole loan
    **/
    function updateUserStateOnRepayInternal(
        address _reserve,
        address _user,
        uint256 _paybackAmountMinusFees,
        uint256 _originationFeeRepaid,
        uint256 _balanceIncrease,
        bool _repaidWholeLoan
    ) internal {
        CoreLibrary.ReserveData storage reserve = reserves[_reserve];
        CoreLibrary.UserReserveData storage user = usersReserveData[_user][_reserve];

        //update the user principal borrow balance, adding the cumulated interest and then subtracting the payback amount
        user.principalBorrowBalance = user.principalBorrowBalance.add(_balanceIncrease).sub(
            _paybackAmountMinusFees
        );
        user.lastVariableBorrowCumulativeIndex = reserve.lastVariableBorrowCumulativeIndex;

        //if the balance decrease is equal to the previous principal (user is repaying the whole loan)
        //and the rate mode is stable, we reset the interest rate mode of the user
        if (_repaidWholeLoan) {
            user.stableBorrowRate = 0;
            user.lastVariableBorrowCumulativeIndex = 0;
        }
        user.originationFee = user.originationFee.sub(_originationFeeRepaid);

        //solium-disable-next-line
        user.lastUpdateTimestamp = uint40(block.timestamp);

    }

    /**
    * @dev updates the state of the user as a consequence of a swap rate action.
    * @param _reserve the address of the reserve on which the user is performing the rate swap
    * @param _user the address of the borrower
    * @param _principalBorrowBalance the the principal amount borrowed by the user
    * @param _compoundedBorrowBalance the principal amount plus the accrued interest
    * @param _currentRateMode the rate mode at which the user borrowed
    **/
    function updateReserveStateOnSwapRateInternal(
        address _reserve,
        address _user,
        uint256 _principalBorrowBalance,
        uint256 _compoundedBorrowBalance,
        CoreLibrary.InterestRateMode _currentRateMode
    ) internal {
        CoreLibrary.ReserveData storage reserve = reserves[_reserve];
        CoreLibrary.UserReserveData storage user = usersReserveData[_user][_reserve];

        //compounding reserve indexes
        reserve.updateCumulativeIndexes();

        if (_currentRateMode == CoreLibrary.InterestRateMode.STABLE) {
            uint256 userCurrentStableRate = user.stableBorrowRate;

            //swap to variable
            reserve.decreaseTotalBorrowsStableAndUpdateAverageRate(
                _principalBorrowBalance,
                userCurrentStableRate
            ); //decreasing stable from old principal balance
            reserve.increaseTotalBorrowsVariable(_compoundedBorrowBalance); //increase variable borrows
        } else if (_currentRateMode == CoreLibrary.InterestRateMode.VARIABLE) {
            //swap to stable
            uint256 currentStableRate = reserve.currentStableBorrowRate;
            reserve.decreaseTotalBorrowsVariable(_principalBorrowBalance);
            reserve.increaseTotalBorrowsStableAndUpdateAverageRate(
                _compoundedBorrowBalance,
                currentStableRate
            );

        } else {
            revert("Invalid rate mode received");
        }
    }

    /**
    * @dev updates the state of the user as a consequence of a swap rate action.
    * @param _reserve the address of the reserve on which the user is performing the swap
    * @param _user the address of the borrower
    * @param _balanceIncrease the accrued interest on the borrowed amount
    * @param _currentRateMode the current rate mode of the user
    **/

    function updateUserStateOnSwapRateInternal(
        address _reserve,
        address _user,
        uint256 _balanceIncrease,
        CoreLibrary.InterestRateMode _currentRateMode
    ) internal returns (CoreLibrary.InterestRateMode) {
        CoreLibrary.UserReserveData storage user = usersReserveData[_user][_reserve];
        CoreLibrary.ReserveData storage reserve = reserves[_reserve];

        CoreLibrary.InterestRateMode newMode = CoreLibrary.InterestRateMode.NONE;

        if (_currentRateMode == CoreLibrary.InterestRateMode.VARIABLE) {
            //switch to stable
            newMode = CoreLibrary.InterestRateMode.STABLE;
            user.stableBorrowRate = reserve.currentStableBorrowRate;
            user.lastVariableBorrowCumulativeIndex = 0;
        } else if (_currentRateMode == CoreLibrary.InterestRateMode.STABLE) {
            newMode = CoreLibrary.InterestRateMode.VARIABLE;
            user.stableBorrowRate = 0;
            user.lastVariableBorrowCumulativeIndex = reserve.lastVariableBorrowCumulativeIndex;
        } else {
            revert("Invalid interest rate mode received");
        }
        //compounding cumulated interest
        user.principalBorrowBalance = user.principalBorrowBalance.add(_balanceIncrease);
        //solium-disable-next-line
        user.lastUpdateTimestamp = uint40(block.timestamp);

        return newMode;
    }

    /**
    * @dev updates the state of the principal reserve as a consequence of a liquidation action.
    * @param _principalReserve the address of the principal reserve that is being repaid
    * @param _user the address of the borrower
    * @param _amountToLiquidate the amount being repaid by the liquidator
    * @param _balanceIncrease the accrued interest on the borrowed amount
    **/

    function updatePrincipalReserveStateOnLiquidationInternal(
        address _principalReserve,
        address _user,
        uint256 _amountToLiquidate,
        uint256 _balanceIncrease
    ) internal {
        CoreLibrary.ReserveData storage reserve = reserves[_principalReserve];
        CoreLibrary.UserReserveData storage user = usersReserveData[_user][_principalReserve];

        //update principal reserve data
        reserve.updateCumulativeIndexes();

        CoreLibrary.InterestRateMode borrowRateMode = getUserCurrentBorrowRateMode(
            _principalReserve,
            _user
        );

        if (borrowRateMode == CoreLibrary.InterestRateMode.STABLE) {
            //increase the total borrows by the compounded interest
            reserve.increaseTotalBorrowsStableAndUpdateAverageRate(
                _balanceIncrease,
                user.stableBorrowRate
            );

            //decrease by the actual amount to liquidate
            reserve.decreaseTotalBorrowsStableAndUpdateAverageRate(
                _amountToLiquidate,
                user.stableBorrowRate
            );

        } else {
            //increase the total borrows by the compounded interest
            reserve.increaseTotalBorrowsVariable(_balanceIncrease);

            //decrease by the actual amount to liquidate
            reserve.decreaseTotalBorrowsVariable(_amountToLiquidate);
        }

    }

    /**
    * @dev updates the state of the collateral reserve as a consequence of a liquidation action.
    * @param _collateralReserve the address of the collateral reserve that is being liquidated
    **/
    function updateCollateralReserveStateOnLiquidationInternal(
        address _collateralReserve
    ) internal {
        //update collateral reserve
        reserves[_collateralReserve].updateCumulativeIndexes();

    }

    /**
    * @dev updates the state of the user being liquidated as a consequence of a liquidation action.
    * @param _reserve the address of the principal reserve that is being repaid
    * @param _user the address of the borrower
    * @param _amountToLiquidate the amount being repaid by the liquidator
    * @param _feeLiquidated the amount of origination fee being liquidated
    * @param _balanceIncrease the accrued interest on the borrowed amount
    **/
    function updateUserStateOnLiquidationInternal(
        address _reserve,
        address _user,
        uint256 _amountToLiquidate,
        uint256 _feeLiquidated,
        uint256 _balanceIncrease
    ) internal {
        CoreLibrary.UserReserveData storage user = usersReserveData[_user][_reserve];
        CoreLibrary.ReserveData storage reserve = reserves[_reserve];
        //first increase by the compounded interest, then decrease by the liquidated amount
        user.principalBorrowBalance = user.principalBorrowBalance.add(_balanceIncrease).sub(
            _amountToLiquidate
        );

        if (
            getUserCurrentBorrowRateMode(_reserve, _user) == CoreLibrary.InterestRateMode.VARIABLE
        ) {
            user.lastVariableBorrowCumulativeIndex = reserve.lastVariableBorrowCumulativeIndex;
        }

        if(_feeLiquidated > 0){
            user.originationFee = user.originationFee.sub(_feeLiquidated);
        }

        //solium-disable-next-line
        user.lastUpdateTimestamp = uint40(block.timestamp);
    }

    /**
    * @dev updates the state of the reserve as a consequence of a stable rate rebalance
    * @param _reserve the address of the principal reserve where the user borrowed
    * @param _user the address of the borrower
    * @param _balanceIncrease the accrued interest on the borrowed amount
    **/

    function updateReserveStateOnRebalanceInternal(
        address _reserve,
        address _user,
        uint256 _balanceIncrease
    ) internal {
        CoreLibrary.ReserveData storage reserve = reserves[_reserve];
        CoreLibrary.UserReserveData storage user = usersReserveData[_user][_reserve];

        reserve.updateCumulativeIndexes();

        reserve.increaseTotalBorrowsStableAndUpdateAverageRate(
            _balanceIncrease,
            user.stableBorrowRate
        );

    }

    /**
    * @dev updates the state of the user as a consequence of a stable rate rebalance
    * @param _reserve the address of the principal reserve where the user borrowed
    * @param _user the address of the borrower
    * @param _balanceIncrease the accrued interest on the borrowed amount
    **/

    function updateUserStateOnRebalanceInternal(
        address _reserve,
        address _user,
        uint256 _balanceIncrease
    ) internal {
        CoreLibrary.UserReserveData storage user = usersReserveData[_user][_reserve];
        CoreLibrary.ReserveData storage reserve = reserves[_reserve];

        user.principalBorrowBalance = user.principalBorrowBalance.add(_balanceIncrease);
        user.stableBorrowRate = reserve.currentStableBorrowRate;

        //solium-disable-next-line
        user.lastUpdateTimestamp = uint40(block.timestamp);
    }

    /**
    * @dev updates the state of the user as a consequence of a stable rate rebalance
    * @param _reserve the address of the principal reserve where the user borrowed
    * @param _user the address of the borrower
    * @param _balanceIncrease the accrued interest on the borrowed amount
    * @param _amountBorrowed the accrued interest on the borrowed amount
    **/
    function updateReserveTotalBorrowsByRateModeInternal(
        address _reserve,
        address _user,
        uint256 _principalBalance,
        uint256 _balanceIncrease,
        uint256 _amountBorrowed,
        CoreLibrary.InterestRateMode _newBorrowRateMode
    ) internal {
        CoreLibrary.InterestRateMode previousRateMode = getUserCurrentBorrowRateMode(
            _reserve,
            _user
        );
        CoreLibrary.ReserveData storage reserve = reserves[_reserve];

        if (previousRateMode == CoreLibrary.InterestRateMode.STABLE) {
            CoreLibrary.UserReserveData storage user = usersReserveData[_user][_reserve];
            reserve.decreaseTotalBorrowsStableAndUpdateAverageRate(
                _principalBalance,
                user.stableBorrowRate
            );
        } else if (previousRateMode == CoreLibrary.InterestRateMode.VARIABLE) {
            reserve.decreaseTotalBorrowsVariable(_principalBalance);
        }

        uint256 newPrincipalAmount = _principalBalance.add(_balanceIncrease).add(_amountBorrowed);
        if (_newBorrowRateMode == CoreLibrary.InterestRateMode.STABLE) {
            reserve.increaseTotalBorrowsStableAndUpdateAverageRate(
                newPrincipalAmount,
                reserve.currentStableBorrowRate
            );
        } else if (_newBorrowRateMode == CoreLibrary.InterestRateMode.VARIABLE) {
            reserve.increaseTotalBorrowsVariable(newPrincipalAmount);
        } else {
            revert("Invalid new borrow rate mode");
        }
    }

    /**
    * @dev Updates the reserve current stable borrow rate Rf, the current variable borrow rate Rv and the current liquidity rate Rl.
    * Also updates the lastUpdateTimestamp value. Please refer to the whitepaper for further information.
    * @param _reserve the address of the reserve to be updated
    * @param _liquidityAdded the amount of liquidity added to the protocol (deposit or repay) in the previous action
    * @param _liquidityTaken the amount of liquidity taken from the protocol (redeem or borrow)
    **/

    function updateReserveInterestRatesAndTimestampInternal(
        address _reserve,
        uint256 _liquidityAdded,
        uint256 _liquidityTaken
    ) internal {
        CoreLibrary.ReserveData storage reserve = reserves[_reserve];
        (uint256 newLiquidityRate, uint256 newStableRate, uint256 newVariableRate) = IReserveInterestRateStrategy(
            reserve
                .interestRateStrategyAddress
        )
            .calculateInterestRates(
            _reserve,
            getReserveAvailableLiquidity(_reserve).add(_liquidityAdded).sub(_liquidityTaken),
            reserve.totalBorrowsStable,
            reserve.totalBorrowsVariable,
            reserve.currentAverageStableBorrowRate
        );

        reserve.currentLiquidityRate = newLiquidityRate;
        reserve.currentStableBorrowRate = newStableRate;
        reserve.currentVariableBorrowRate = newVariableRate;

        //solium-disable-next-line
        reserve.lastUpdateTimestamp = uint40(block.timestamp);

        emit ReserveUpdated(
            _reserve,
            newLiquidityRate,
            newStableRate,
            newVariableRate,
            reserve.lastLiquidityCumulativeIndex,
            reserve.lastVariableBorrowCumulativeIndex
        );
    }

    /**
    * @dev transfers to the protocol fees of a flashloan to the fees collection address
    * @param _token the address of the token being transferred
    * @param _amount the amount being transferred
    **/

    function transferFlashLoanProtocolFeeInternal(address _token, uint256 _amount) internal {
        address payable receiver = address(uint160(addressesProvider.getTokenDistributor()));

        if (_token != EthAddressLib.ethAddress()) {
            ERC20(_token).safeTransfer(receiver, _amount);
        } else {
            receiver.transfer(_amount);
        }
    }

    /**
    * @dev updates the internal configuration of the core
    **/
    function refreshConfigInternal() internal {
        lendingPoolAddress = addressesProvider.getLendingPool();
    }

    /**
    * @dev adds a reserve to the array of the reserves address
    **/
    function addReserveToListInternal(address _reserve) internal {
        bool reserveAlreadyAdded = false;
        for (uint256 i = 0; i < reservesList.length; i++)
            if (reservesList[i] == _reserve) {
                reserveAlreadyAdded = true;
            }
        if (!reserveAlreadyAdded) reservesList.push(_reserve);
    }

}

/**
* @title LendingPool contract
* @notice Implements the actions of the LendingPool, and exposes accessory methods to fetch the users and reserve data
* @author Aave
 **/

contract LendingPool is ReentrancyGuard, VersionedInitializable {
    using SafeMath for uint256;
    using WadRayMath for uint256;
    using Address for address;

    LendingPoolAddressesProvider public addressesProvider;
    LendingPoolCore public core;
    LendingPoolDataProvider public dataProvider;
    LendingPoolParametersProvider public parametersProvider;
    IFeeProvider feeProvider;

    /**
    * @dev emitted on deposit
    * @param _reserve the address of the reserve
    * @param _user the address of the user
    * @param _amount the amount to be deposited
    * @param _referral the referral number of the action
    * @param _timestamp the timestamp of the action
    **/
    event Deposit(
        address indexed _reserve,
        address indexed _user,
        uint256 _amount,
        uint16 indexed _referral,
        uint256 _timestamp
    );

    /**
    * @dev emitted during a redeem action.
    * @param _reserve the address of the reserve
    * @param _user the address of the user
    * @param _amount the amount to be deposited
    * @param _timestamp the timestamp of the action
    **/
    event RedeemUnderlying(
        address indexed _reserve,
        address indexed _user,
        uint256 _amount,
        uint256 _timestamp
    );

    /**
    * @dev emitted on borrow
    * @param _reserve the address of the reserve
    * @param _user the address of the user
    * @param _amount the amount to be deposited
    * @param _borrowRateMode the rate mode, can be either 1-stable or 2-variable
    * @param _borrowRate the rate at which the user has borrowed
    * @param _originationFee the origination fee to be paid by the user
    * @param _borrowBalanceIncrease the balance increase since the last borrow, 0 if it's the first time borrowing
    * @param _referral the referral number of the action
    * @param _timestamp the timestamp of the action
    **/
    event Borrow(
        address indexed _reserve,
        address indexed _user,
        uint256 _amount,
        uint256 _borrowRateMode,
        uint256 _borrowRate,
        uint256 _originationFee,
        uint256 _borrowBalanceIncrease,
        uint16 indexed _referral,
        uint256 _timestamp
    );

    /**
    * @dev emitted on repay
    * @param _reserve the address of the reserve
    * @param _user the address of the user for which the repay has been executed
    * @param _repayer the address of the user that has performed the repay action
    * @param _amountMinusFees the amount repaid minus fees
    * @param _fees the fees repaid
    * @param _borrowBalanceIncrease the balance increase since the last action
    * @param _timestamp the timestamp of the action
    **/
    event Repay(
        address indexed _reserve,
        address indexed _user,
        address indexed _repayer,
        uint256 _amountMinusFees,
        uint256 _fees,
        uint256 _borrowBalanceIncrease,
        uint256 _timestamp
    );

    /**
    * @dev emitted when a user performs a rate swap
    * @param _reserve the address of the reserve
    * @param _user the address of the user executing the swap
    * @param _newRateMode the new interest rate mode
    * @param _newRate the new borrow rate
    * @param _borrowBalanceIncrease the balance increase since the last action
    * @param _timestamp the timestamp of the action
    **/
    event Swap(
        address indexed _reserve,
        address indexed _user,
        uint256 _newRateMode,
        uint256 _newRate,
        uint256 _borrowBalanceIncrease,
        uint256 _timestamp
    );

    /**
    * @dev emitted when a user enables a reserve as collateral
    * @param _reserve the address of the reserve
    * @param _user the address of the user
    **/
    event ReserveUsedAsCollateralEnabled(address indexed _reserve, address indexed _user);

    /**
    * @dev emitted when a user disables a reserve as collateral
    * @param _reserve the address of the reserve
    * @param _user the address of the user
    **/
    event ReserveUsedAsCollateralDisabled(address indexed _reserve, address indexed _user);

    /**
    * @dev emitted when the stable rate of a user gets rebalanced
    * @param _reserve the address of the reserve
    * @param _user the address of the user for which the rebalance has been executed
    * @param _newStableRate the new stable borrow rate after the rebalance
    * @param _borrowBalanceIncrease the balance increase since the last action
    * @param _timestamp the timestamp of the action
    **/
    event RebalanceStableBorrowRate(
        address indexed _reserve,
        address indexed _user,
        uint256 _newStableRate,
        uint256 _borrowBalanceIncrease,
        uint256 _timestamp
    );

    /**
    * @dev emitted when a flashloan is executed
    * @param _target the address of the flashLoanReceiver
    * @param _reserve the address of the reserve
    * @param _amount the amount requested
    * @param _totalFee the total fee on the amount
    * @param _protocolFee the part of the fee for the protocol
    * @param _timestamp the timestamp of the action
    **/
    event FlashLoan(
        address indexed _target,
        address indexed _reserve,
        uint256 _amount,
        uint256 _totalFee,
        uint256 _protocolFee,
        uint256 _timestamp
    );

    /**
    * @dev these events are not emitted directly by the LendingPool
    * but they are declared here as the LendingPoolLiquidationManager
    * is executed using a delegateCall().
    * This allows to have the events in the generated ABI for LendingPool.
    **/

    /**
    * @dev emitted when a borrow fee is liquidated
    * @param _collateral the address of the collateral being liquidated
    * @param _reserve the address of the reserve
    * @param _user the address of the user being liquidated
    * @param _feeLiquidated the total fee liquidated
    * @param _liquidatedCollateralForFee the amount of collateral received by the protocol in exchange for the fee
    * @param _timestamp the timestamp of the action
    **/
    event OriginationFeeLiquidated(
        address indexed _collateral,
        address indexed _reserve,
        address indexed _user,
        uint256 _feeLiquidated,
        uint256 _liquidatedCollateralForFee,
        uint256 _timestamp
    );

    /**
    * @dev emitted when a borrower is liquidated
    * @param _collateral the address of the collateral being liquidated
    * @param _reserve the address of the reserve
    * @param _user the address of the user being liquidated
    * @param _purchaseAmount the total amount liquidated
    * @param _liquidatedCollateralAmount the amount of collateral being liquidated
    * @param _accruedBorrowInterest the amount of interest accrued by the borrower since the last action
    * @param _liquidator the address of the liquidator
    * @param _receiveAToken true if the liquidator wants to receive aTokens, false otherwise
    * @param _timestamp the timestamp of the action
    **/
    event LiquidationCall(
        address indexed _collateral,
        address indexed _reserve,
        address indexed _user,
        uint256 _purchaseAmount,
        uint256 _liquidatedCollateralAmount,
        uint256 _accruedBorrowInterest,
        address _liquidator,
        bool _receiveAToken,
        uint256 _timestamp
    );

    /**
    * @dev functions affected by this modifier can only be invoked by the
    * aToken.sol contract
    * @param _reserve the address of the reserve
    **/
    modifier onlyOverlyingAToken(address _reserve) {
        require(
            msg.sender == core.getReserveATokenAddress(_reserve),
            "The caller of this function can only be the aToken contract of this reserve"
        );
        _;
    }

    /**
    * @dev functions affected by this modifier can only be invoked if the reserve is active
    * @param _reserve the address of the reserve
    **/
    modifier onlyActiveReserve(address _reserve) {
        requireReserveActiveInternal(_reserve);
        _;
    }

    /**
    * @dev functions affected by this modifier can only be invoked if the reserve is not freezed.
    * A freezed reserve only allows redeems, repays, rebalances and liquidations.
    * @param _reserve the address of the reserve
    **/
    modifier onlyUnfreezedReserve(address _reserve) {
        requireReserveNotFreezedInternal(_reserve);
        _;
    }

    /**
    * @dev functions affected by this modifier can only be invoked if the provided _amount input parameter
    * is not zero.
    * @param _amount the amount provided
    **/
    modifier onlyAmountGreaterThanZero(uint256 _amount) {
        requireAmountGreaterThanZeroInternal(_amount);
        _;
    }

    uint256 public constant UINT_MAX_VALUE = uint256(-1);

    uint256 public constant LENDINGPOOL_REVISION = 0x2;

    function getRevision() internal pure returns (uint256) {
        return LENDINGPOOL_REVISION;
    }

    /**
    * @dev this function is invoked by the proxy contract when the LendingPool contract is added to the
    * AddressesProvider.
    * @param _addressesProvider the address of the LendingPoolAddressesProvider registry
    **/
    function initialize(LendingPoolAddressesProvider _addressesProvider) public initializer {
        addressesProvider = _addressesProvider;
        core = LendingPoolCore(addressesProvider.getLendingPoolCore());
        dataProvider = LendingPoolDataProvider(addressesProvider.getLendingPoolDataProvider());
        parametersProvider = LendingPoolParametersProvider(
            addressesProvider.getLendingPoolParametersProvider()
        );
        feeProvider = IFeeProvider(addressesProvider.getFeeProvider());
    }

    /**
    * @dev deposits The underlying asset into the reserve. A corresponding amount of the overlying asset (aTokens)
    * is minted.
    * @param _reserve the address of the reserve
    * @param _amount the amount to be deposited
    * @param _referralCode integrators are assigned a referral code and can potentially receive rewards.
    **/
    function deposit(address _reserve, uint256 _amount, uint16 _referralCode)
        external
        payable
        nonReentrant
        onlyActiveReserve(_reserve)
        onlyUnfreezedReserve(_reserve)
        onlyAmountGreaterThanZero(_amount)
    {
        AToken aToken = AToken(core.getReserveATokenAddress(_reserve));

        bool isFirstDeposit = aToken.balanceOf(msg.sender) == 0;

        core.updateStateOnDeposit(_reserve, msg.sender, _amount, isFirstDeposit);

        //minting AToken to user 1:1 with the specific exchange rate
        aToken.mintOnDeposit(msg.sender, _amount);

        //transfer to the core contract
        core.transferToReserve.value(msg.value)(_reserve, msg.sender, _amount);

        //solium-disable-next-line
        emit Deposit(_reserve, msg.sender, _amount, _referralCode, block.timestamp);

    }

    /**
    * @dev Redeems the underlying amount of assets requested by _user.
    * This function is executed by the overlying aToken contract in response to a redeem action.
    * @param _reserve the address of the reserve
    * @param _user the address of the user performing the action
    * @param _amount the underlying amount to be redeemed
    **/
    function redeemUnderlying(
        address _reserve,
        address payable _user,
        uint256 _amount,
        uint256 _aTokenBalanceAfterRedeem
    )
        external
        nonReentrant
        onlyOverlyingAToken(_reserve)
        onlyActiveReserve(_reserve)
        onlyAmountGreaterThanZero(_amount)
    {
        uint256 currentAvailableLiquidity = core.getReserveAvailableLiquidity(_reserve);
        require(
            currentAvailableLiquidity >= _amount,
            "There is not enough liquidity available to redeem"
        );

        core.updateStateOnRedeem(_reserve, _user, _amount, _aTokenBalanceAfterRedeem == 0);

        core.transferToUser(_reserve, _user, _amount);

        //solium-disable-next-line
        emit RedeemUnderlying(_reserve, _user, _amount, block.timestamp);

    }

    /**
    * @dev data structures for local computations in the borrow() method.
    */

    struct BorrowLocalVars {
        uint256 principalBorrowBalance;
        uint256 currentLtv;
        uint256 currentLiquidationThreshold;
        uint256 borrowFee;
        uint256 requestedBorrowAmountETH;
        uint256 amountOfCollateralNeededETH;
        uint256 userCollateralBalanceETH;
        uint256 userBorrowBalanceETH;
        uint256 userTotalFeesETH;
        uint256 borrowBalanceIncrease;
        uint256 currentReserveStableRate;
        uint256 availableLiquidity;
        uint256 reserveDecimals;
        uint256 finalUserBorrowRate;
        CoreLibrary.InterestRateMode rateMode;
        bool healthFactorBelowThreshold;
    }

    /**
    * @dev Allows users to borrow a specific amount of the reserve currency, provided that the borrower
    * already deposited enough collateral.
    * @param _reserve the address of the reserve
    * @param _amount the amount to be borrowed
    * @param _interestRateMode the interest rate mode at which the user wants to borrow. Can be 0 (STABLE) or 1 (VARIABLE)
    **/
    function borrow(
        address _reserve,
        uint256 _amount,
        uint256 _interestRateMode,
        uint16 _referralCode
    )
        external
        nonReentrant
        onlyActiveReserve(_reserve)
        onlyUnfreezedReserve(_reserve)
        onlyAmountGreaterThanZero(_amount)
    {
        // Usage of a memory struct of vars to avoid "Stack too deep" errors due to local variables
        BorrowLocalVars memory vars;

        //check that the reserve is enabled for borrowing
        require(core.isReserveBorrowingEnabled(_reserve), "Reserve is not enabled for borrowing");
        //validate interest rate mode
        require(
            uint256(CoreLibrary.InterestRateMode.VARIABLE) == _interestRateMode ||
                uint256(CoreLibrary.InterestRateMode.STABLE) == _interestRateMode,
            "Invalid interest rate mode selected"
        );

        //cast the rateMode to coreLibrary.interestRateMode
        vars.rateMode = CoreLibrary.InterestRateMode(_interestRateMode);

        //check that the amount is available in the reserve
        vars.availableLiquidity = core.getReserveAvailableLiquidity(_reserve);

        require(
            vars.availableLiquidity >= _amount,
            "There is not enough liquidity available in the reserve"
        );

        (
            ,
            vars.userCollateralBalanceETH,
            vars.userBorrowBalanceETH,
            vars.userTotalFeesETH,
            vars.currentLtv,
            vars.currentLiquidationThreshold,
            ,
            vars.healthFactorBelowThreshold
        ) = dataProvider.calculateUserGlobalData(msg.sender);

        require(vars.userCollateralBalanceETH > 0, "The collateral balance is 0");

        require(
            !vars.healthFactorBelowThreshold,
            "The borrower can already be liquidated so he cannot borrow more"
        );

        //calculating fees
        vars.borrowFee = feeProvider.calculateLoanOriginationFee(msg.sender, _amount);

        require(vars.borrowFee > 0, "The amount to borrow is too small");

        vars.amountOfCollateralNeededETH = dataProvider.calculateCollateralNeededInETH(
            _reserve,
            _amount,
            vars.borrowFee,
            vars.userBorrowBalanceETH,
            vars.userTotalFeesETH,
            vars.currentLtv
        );

        require(
            vars.amountOfCollateralNeededETH <= vars.userCollateralBalanceETH,
            "There is not enough collateral to cover a new borrow"
        );

        /**
        * Following conditions need to be met if the user is borrowing at a stable rate:
        * 1. Reserve must be enabled for stable rate borrowing
        * 2. Users cannot borrow from the reserve if their collateral is (mostly) the same currency
        *    they are borrowing, to prevent abuses.
        * 3. Users will be able to borrow only a relatively small, configurable amount of the total
        *    liquidity
        **/

        if (vars.rateMode == CoreLibrary.InterestRateMode.STABLE) {
            //check if the borrow mode is stable and if stable rate borrowing is enabled on this reserve
            require(
                core.isUserAllowedToBorrowAtStable(_reserve, msg.sender, _amount),
                "User cannot borrow the selected amount with a stable rate"
            );

            //calculate the max available loan size in stable rate mode as a percentage of the
            //available liquidity
            uint256 maxLoanPercent = parametersProvider.getMaxStableRateBorrowSizePercent();
            uint256 maxLoanSizeStable = vars.availableLiquidity.mul(maxLoanPercent).div(100);

            require(
                _amount <= maxLoanSizeStable,
                "User is trying to borrow too much liquidity at a stable rate"
            );
        }

        //all conditions passed - borrow is accepted
        (vars.finalUserBorrowRate, vars.borrowBalanceIncrease) = core.updateStateOnBorrow(
            _reserve,
            msg.sender,
            _amount,
            vars.borrowFee,
            vars.rateMode
        );

        //if we reached this point, we can transfer
        core.transferToUser(_reserve, msg.sender, _amount);

        emit Borrow(
            _reserve,
            msg.sender,
            _amount,
            _interestRateMode,
            vars.finalUserBorrowRate,
            vars.borrowFee,
            vars.borrowBalanceIncrease,
            _referralCode,
            //solium-disable-next-line
            block.timestamp
        );
    }

    /**
    * @notice repays a borrow on the specific reserve, for the specified amount (or for the whole amount, if uint256(-1) is specified).
    * @dev the target user is defined by _onBehalfOf. If there is no repayment on behalf of another account,
    * _onBehalfOf must be equal to msg.sender.
    * @param _reserve the address of the reserve on which the user borrowed
    * @param _amount the amount to repay, or uint256(-1) if the user wants to repay everything
    * @param _onBehalfOf the address for which msg.sender is repaying.
    **/

    struct RepayLocalVars {
        uint256 principalBorrowBalance;
        uint256 compoundedBorrowBalance;
        uint256 borrowBalanceIncrease;
        bool isETH;
        uint256 paybackAmount;
        uint256 paybackAmountMinusFees;
        uint256 currentStableRate;
        uint256 originationFee;
    }

    function repay(address _reserve, uint256 _amount, address payable _onBehalfOf)
        external
        payable
        nonReentrant
        onlyActiveReserve(_reserve)
        onlyAmountGreaterThanZero(_amount)
    {
        // Usage of a memory struct of vars to avoid "Stack too deep" errors due to local variables
        RepayLocalVars memory vars;

        (
            vars.principalBorrowBalance,
            vars.compoundedBorrowBalance,
            vars.borrowBalanceIncrease
        ) = core.getUserBorrowBalances(_reserve, _onBehalfOf);

        vars.originationFee = core.getUserOriginationFee(_reserve, _onBehalfOf);
        vars.isETH = EthAddressLib.ethAddress() == _reserve;

        require(vars.compoundedBorrowBalance > 0, "The user does not have any borrow pending");

        require(
            _amount != UINT_MAX_VALUE || msg.sender == _onBehalfOf,
            "To repay on behalf of an user an explicit amount to repay is needed."
        );

        //default to max amount
        vars.paybackAmount = vars.compoundedBorrowBalance.add(vars.originationFee);

        if (_amount != UINT_MAX_VALUE && _amount < vars.paybackAmount) {
            vars.paybackAmount = _amount;
        }

        require(
            !vars.isETH || msg.value >= vars.paybackAmount,
            "Invalid msg.value sent for the repayment"
        );

        //if the amount is smaller than the origination fee, just transfer the amount to the fee destination address
        if (vars.paybackAmount <= vars.originationFee) {
            core.updateStateOnRepay(
                _reserve,
                _onBehalfOf,
                0,
                vars.paybackAmount,
                vars.borrowBalanceIncrease,
                false
            );

            core.transferToFeeCollectionAddress.value(vars.isETH ? vars.paybackAmount : 0)(
                _reserve,
                _onBehalfOf,
                vars.paybackAmount,
                addressesProvider.getTokenDistributor()
            );

            emit Repay(
                _reserve,
                _onBehalfOf,
                msg.sender,
                0,
                vars.paybackAmount,
                vars.borrowBalanceIncrease,
                //solium-disable-next-line
                block.timestamp
            );
            return;
        }

        vars.paybackAmountMinusFees = vars.paybackAmount.sub(vars.originationFee);

        core.updateStateOnRepay(
            _reserve,
            _onBehalfOf,
            vars.paybackAmountMinusFees,
            vars.originationFee,
            vars.borrowBalanceIncrease,
            vars.compoundedBorrowBalance == vars.paybackAmountMinusFees
        );

        //if the user didn't repay the origination fee, transfer the fee to the fee collection address
        if(vars.originationFee > 0) {
            core.transferToFeeCollectionAddress.value(vars.isETH ? vars.originationFee : 0)(
                _reserve,
                _onBehalfOf,
                vars.originationFee,
                addressesProvider.getTokenDistributor()
            );
        }

        //sending the total msg.value if the transfer is ETH.
        //the transferToReserve() function will take care of sending the
        //excess ETH back to the caller
        core.transferToReserve.value(vars.isETH ? msg.value.sub(vars.originationFee) : 0)(
            _reserve,
            msg.sender,
            vars.paybackAmountMinusFees
        );

        emit Repay(
            _reserve,
            _onBehalfOf,
            msg.sender,
            vars.paybackAmountMinusFees,
            vars.originationFee,
            vars.borrowBalanceIncrease,
            //solium-disable-next-line
            block.timestamp
        );
    }

    /**
    * @dev borrowers can user this function to swap between stable and variable borrow rate modes.
    * @param _reserve the address of the reserve on which the user borrowed
    **/
    function swapBorrowRateMode(address _reserve)
        external
        nonReentrant
        onlyActiveReserve(_reserve)
        onlyUnfreezedReserve(_reserve)
    {
        (uint256 principalBorrowBalance, uint256 compoundedBorrowBalance, uint256 borrowBalanceIncrease) = core
            .getUserBorrowBalances(_reserve, msg.sender);

        require(
            compoundedBorrowBalance > 0,
            "User does not have a borrow in progress on this reserve"
        );

        CoreLibrary.InterestRateMode currentRateMode = core.getUserCurrentBorrowRateMode(
            _reserve,
            msg.sender
        );

        if (currentRateMode == CoreLibrary.InterestRateMode.VARIABLE) {
            /**
            * user wants to swap to stable, before swapping we need to ensure that
            * 1. stable borrow rate is enabled on the reserve
            * 2. user is not trying to abuse the reserve by depositing
            * more collateral than he is borrowing, artificially lowering
            * the interest rate, borrowing at variable, and switching to stable
            **/
            require(
                core.isUserAllowedToBorrowAtStable(_reserve, msg.sender, compoundedBorrowBalance),
                "User cannot borrow the selected amount at stable"
            );
        }

        (CoreLibrary.InterestRateMode newRateMode, uint256 newBorrowRate) = core
            .updateStateOnSwapRate(
            _reserve,
            msg.sender,
            principalBorrowBalance,
            compoundedBorrowBalance,
            borrowBalanceIncrease,
            currentRateMode
        );

        emit Swap(
            _reserve,
            msg.sender,
            uint256(newRateMode),
            newBorrowRate,
            borrowBalanceIncrease,
            //solium-disable-next-line
            block.timestamp
        );
    }

    /**
    * @dev rebalances the stable interest rate of a user if current liquidity rate > user stable rate.
    * this is regulated by Aave to ensure that the protocol is not abused, and the user is paying a fair
    * rate. Anyone can call this function though.
    * @param _reserve the address of the reserve
    * @param _user the address of the user to be rebalanced
    **/
    function rebalanceStableBorrowRate(address _reserve, address _user)
        external
        nonReentrant
        onlyActiveReserve(_reserve)
    {
        (, uint256 compoundedBalance, uint256 borrowBalanceIncrease) = core.getUserBorrowBalances(
            _reserve,
            _user
        );

        //step 1: user must be borrowing on _reserve at a stable rate
        require(compoundedBalance > 0, "User does not have any borrow for this reserve");

        require(
            core.getUserCurrentBorrowRateMode(_reserve, _user) ==
                CoreLibrary.InterestRateMode.STABLE,
            "The user borrow is variable and cannot be rebalanced"
        );

        uint256 userCurrentStableRate = core.getUserCurrentStableBorrowRate(_reserve, _user);
        uint256 liquidityRate = core.getReserveCurrentLiquidityRate(_reserve);
        uint256 reserveCurrentStableRate = core.getReserveCurrentStableBorrowRate(_reserve);
        uint256 rebalanceDownRateThreshold = reserveCurrentStableRate.rayMul(
            WadRayMath.ray().add(parametersProvider.getRebalanceDownRateDelta())
        );

        //step 2: we have two possible situations to rebalance:

        //1. user stable borrow rate is below the current liquidity rate. The loan needs to be rebalanced,
        //as this situation can be abused (user putting back the borrowed liquidity in the same reserve to earn on it)
        //2. user stable rate is above the market avg borrow rate of a certain delta, and utilization rate is low.
        //In this case, the user is paying an interest that is too high, and needs to be rescaled down.
        if (
            userCurrentStableRate < liquidityRate ||
            userCurrentStableRate > rebalanceDownRateThreshold
        ) {
            uint256 newStableRate = core.updateStateOnRebalance(
                _reserve,
                _user,
                borrowBalanceIncrease
            );

            emit RebalanceStableBorrowRate(
                _reserve,
                _user,
                newStableRate,
                borrowBalanceIncrease,
                //solium-disable-next-line
                block.timestamp
            );

            return;

        }

        revert("Interest rate rebalance conditions were not met");
    }

    /**
    * @dev allows depositors to enable or disable a specific deposit as collateral.
    * @param _reserve the address of the reserve
    * @param _useAsCollateral true if the user wants to user the deposit as collateral, false otherwise.
    **/
    function setUserUseReserveAsCollateral(address _reserve, bool _useAsCollateral)
        external
        nonReentrant
        onlyActiveReserve(_reserve)
        onlyUnfreezedReserve(_reserve)
    {
        uint256 underlyingBalance = core.getUserUnderlyingAssetBalance(_reserve, msg.sender);

        require(underlyingBalance > 0, "User does not have any liquidity deposited");

        require(
            dataProvider.balanceDecreaseAllowed(_reserve, msg.sender, underlyingBalance),
            "User deposit is already being used as collateral"
        );

        core.setUserUseReserveAsCollateral(_reserve, msg.sender, _useAsCollateral);

        if (_useAsCollateral) {
            emit ReserveUsedAsCollateralEnabled(_reserve, msg.sender);
        } else {
            emit ReserveUsedAsCollateralDisabled(_reserve, msg.sender);
        }
    }

    /**
    * @dev users can invoke this function to liquidate an undercollateralized position.
    * @param _reserve the address of the collateral to liquidated
    * @param _reserve the address of the principal reserve
    * @param _user the address of the borrower
    * @param _purchaseAmount the amount of principal that the liquidator wants to repay
    * @param _receiveAToken true if the liquidators wants to receive the aTokens, false if
    * he wants to receive the underlying asset directly
    **/
    function liquidationCall(
        address _collateral,
        address _reserve,
        address _user,
        uint256 _purchaseAmount,
        bool _receiveAToken
    ) external payable nonReentrant onlyActiveReserve(_reserve) onlyActiveReserve(_collateral) {
        address liquidationManager = addressesProvider.getLendingPoolLiquidationManager();

        //solium-disable-next-line
        (bool success, bytes memory result) = liquidationManager.delegatecall(
            abi.encodeWithSignature(
                "liquidationCall(address,address,address,uint256,bool)",
                _collateral,
                _reserve,
                _user,
                _purchaseAmount,
                _receiveAToken
            )
        );
        require(success, "Liquidation call failed");

        (uint256 returnCode, string memory returnMessage) = abi.decode(result, (uint256, string));

        if (returnCode != 0) {
            //error found
            revert(string(abi.encodePacked("Liquidation failed: ", returnMessage)));
        }
    }

    /**
    * @dev allows smartcontracts to access the liquidity of the pool within one transaction,
    * as long as the amount taken plus a fee is returned. NOTE There are security concerns for developers of flashloan receiver contracts
    * that must be kept into consideration. For further details please visit https://developers.aave.com
    * @param _receiver The address of the contract receiving the funds. The receiver should implement the IFlashLoanReceiver interface.
    * @param _reserve the address of the principal reserve
    * @param _amount the amount requested for this flashloan
    **/
    function flashLoan(address _receiver, address _reserve, uint256 _amount, bytes memory _params)
        public
        nonReentrant
        onlyActiveReserve(_reserve)
        onlyAmountGreaterThanZero(_amount)
    {
        //check that the reserve has enough available liquidity
        //we avoid using the getAvailableLiquidity() function in LendingPoolCore to save gas
        uint256 availableLiquidityBefore = _reserve == EthAddressLib.ethAddress()
            ? address(core).balance
            : IERC20(_reserve).balanceOf(address(core));

        require(
            availableLiquidityBefore >= _amount,
            "There is not enough liquidity available to borrow"
        );

        (uint256 totalFeeBips, uint256 protocolFeeBips) = parametersProvider
            .getFlashLoanFeesInBips();
        //calculate amount fee
        uint256 amountFee = _amount.mul(totalFeeBips).div(10000);

        //protocol fee is the part of the amountFee reserved for the protocol - the rest goes to depositors
        uint256 protocolFee = amountFee.mul(protocolFeeBips).div(10000);
        require(
            amountFee > 0 && protocolFee > 0,
            "The requested amount is too small for a flashLoan."
        );

        //get the FlashLoanReceiver instance
        IFlashLoanReceiver receiver = IFlashLoanReceiver(_receiver);

        address payable userPayable = address(uint160(_receiver));

        //transfer funds to the receiver
        core.transferToUser(_reserve, userPayable, _amount);

        //execute action of the receiver
        receiver.executeOperation(_reserve, _amount, amountFee, _params);

        //check that the actual balance of the core contract includes the returned amount
        uint256 availableLiquidityAfter = _reserve == EthAddressLib.ethAddress()
            ? address(core).balance
            : IERC20(_reserve).balanceOf(address(core));

        require(
            availableLiquidityAfter == availableLiquidityBefore.add(amountFee),
            "The actual balance of the protocol is inconsistent"
        );

        core.updateStateOnFlashLoan(
            _reserve,
            availableLiquidityBefore,
            amountFee.sub(protocolFee),
            protocolFee
        );

        //solium-disable-next-line
        emit FlashLoan(_receiver, _reserve, _amount, amountFee, protocolFee, block.timestamp);
    }

    /**
    * @dev accessory functions to fetch data from the core contract
    **/

    function getReserveConfigurationData(address _reserve)
        external
        view
        returns (
            uint256 ltv,
            uint256 liquidationThreshold,
            uint256 liquidationBonus,
            address interestRateStrategyAddress,
            bool usageAsCollateralEnabled,
            bool borrowingEnabled,
            bool stableBorrowRateEnabled,
            bool isActive
        )
    {
        return dataProvider.getReserveConfigurationData(_reserve);
    }

    function getReserveData(address _reserve)
        external
        view
        returns (
            uint256 totalLiquidity,
            uint256 availableLiquidity,
            uint256 totalBorrowsStable,
            uint256 totalBorrowsVariable,
            uint256 liquidityRate,
            uint256 variableBorrowRate,
            uint256 stableBorrowRate,
            uint256 averageStableBorrowRate,
            uint256 utilizationRate,
            uint256 liquidityIndex,
            uint256 variableBorrowIndex,
            address aTokenAddress,
            uint40 lastUpdateTimestamp
        )
    {
        return dataProvider.getReserveData(_reserve);
    }

    function getUserAccountData(address _user)
        external
        view
        returns (
            uint256 totalLiquidityETH,
            uint256 totalCollateralETH,
            uint256 totalBorrowsETH,
            uint256 totalFeesETH,
            uint256 availableBorrowsETH,
            uint256 currentLiquidationThreshold,
            uint256 ltv,
            uint256 healthFactor
        )
    {
        return dataProvider.getUserAccountData(_user);
    }

    function getUserReserveData(address _reserve, address _user)
        external
        view
        returns (
            uint256 currentATokenBalance,
            uint256 currentBorrowBalance,
            uint256 principalBorrowBalance,
            uint256 borrowRateMode,
            uint256 borrowRate,
            uint256 liquidityRate,
            uint256 originationFee,
            uint256 variableBorrowIndex,
            uint256 lastUpdateTimestamp,
            bool usageAsCollateralEnabled
        )
    {
        return dataProvider.getUserReserveData(_reserve, _user);
    }

    function getReserves() external view returns (address[] memory) {
        return core.getReserves();
    }

    /**
    * @dev internal function to save on code size for the onlyActiveReserve modifier
    **/
    function requireReserveActiveInternal(address _reserve) internal view {
        require(core.getReserveIsActive(_reserve), "Action requires an active reserve");
    }

    /**
    * @notice internal function to save on code size for the onlyUnfreezedReserve modifier
    **/
    function requireReserveNotFreezedInternal(address _reserve) internal view {
        require(!core.getReserveIsFreezed(_reserve), "Action requires an unfreezed reserve");
    }

    /**
    * @notice internal function to save on code size for the onlyAmountGreaterThanZero modifier
    **/
    function requireAmountGreaterThanZeroInternal(uint256 _amount) internal pure {
        require(_amount > 0, "Amount must be greater than 0");
    }
}

/**
* @title LendingPoolLiquidationManager contract
* @author Aave
* @notice Implements the liquidation function.
**/
contract LendingPoolLiquidationManager is ReentrancyGuard, VersionedInitializable {
    using SafeMath for uint256;
    using WadRayMath for uint256;
    using Address for address;

    LendingPoolAddressesProvider public addressesProvider;
    LendingPoolCore core;
    LendingPoolDataProvider dataProvider;
    LendingPoolParametersProvider parametersProvider;
    IFeeProvider feeProvider;
    address ethereumAddress;

    uint256 constant LIQUIDATION_CLOSE_FACTOR_PERCENT = 50;

    /**
    * @dev emitted when a borrow fee is liquidated
    * @param _collateral the address of the collateral being liquidated
    * @param _reserve the address of the reserve
    * @param _user the address of the user being liquidated
    * @param _feeLiquidated the total fee liquidated
    * @param _liquidatedCollateralForFee the amount of collateral received by the protocol in exchange for the fee
    * @param _timestamp the timestamp of the action
    **/
    event OriginationFeeLiquidated(
        address indexed _collateral,
        address indexed _reserve,
        address indexed _user,
        uint256 _feeLiquidated,
        uint256 _liquidatedCollateralForFee,
        uint256 _timestamp
    );

    /**
    * @dev emitted when a borrower is liquidated
    * @param _collateral the address of the collateral being liquidated
    * @param _reserve the address of the reserve
    * @param _user the address of the user being liquidated
    * @param _purchaseAmount the total amount liquidated
    * @param _liquidatedCollateralAmount the amount of collateral being liquidated
    * @param _accruedBorrowInterest the amount of interest accrued by the borrower since the last action
    * @param _liquidator the address of the liquidator
    * @param _receiveAToken true if the liquidator wants to receive aTokens, false otherwise
    * @param _timestamp the timestamp of the action
    **/
    event LiquidationCall(
        address indexed _collateral,
        address indexed _reserve,
        address indexed _user,
        uint256 _purchaseAmount,
        uint256 _liquidatedCollateralAmount,
        uint256 _accruedBorrowInterest,
        address _liquidator,
        bool _receiveAToken,
        uint256 _timestamp
    );

    enum LiquidationErrors {
        NO_ERROR,
        NO_COLLATERAL_AVAILABLE,
        COLLATERAL_CANNOT_BE_LIQUIDATED,
        CURRRENCY_NOT_BORROWED,
        HEALTH_FACTOR_ABOVE_THRESHOLD,
        NOT_ENOUGH_LIQUIDITY
    }

    struct LiquidationCallLocalVars {
        uint256 userCollateralBalance;
        uint256 userCompoundedBorrowBalance;
        uint256 borrowBalanceIncrease;
        uint256 maxPrincipalAmountToLiquidate;
        uint256 actualAmountToLiquidate;
        uint256 liquidationRatio;
        uint256 collateralPrice;
        uint256 principalCurrencyPrice;
        uint256 maxAmountCollateralToLiquidate;
        uint256 originationFee;
        uint256 feeLiquidated;
        uint256 liquidatedCollateralForFee;
        CoreLibrary.InterestRateMode borrowRateMode;
        uint256 userStableRate;
        bool isCollateralEnabled;
        bool healthFactorBelowThreshold;
    }

    /**
    * @dev as the contract extends the VersionedInitializable contract to match the state
    * of the LendingPool contract, the getRevision() function is needed.
    */
    function getRevision() internal pure returns (uint256) {
        return 0;
    }

    /**
    * @dev users can invoke this function to liquidate an undercollateralized position.
    * @param _reserve the address of the collateral to liquidated
    * @param _reserve the address of the principal reserve
    * @param _user the address of the borrower
    * @param _purchaseAmount the amount of principal that the liquidator wants to repay
    * @param _receiveAToken true if the liquidators wants to receive the aTokens, false if
    * he wants to receive the underlying asset directly
    **/
    function liquidationCall(
        address _collateral,
        address _reserve,
        address _user,
        uint256 _purchaseAmount,
        bool _receiveAToken
    ) external payable returns (uint256, string memory) {
        // Usage of a memory struct of vars to avoid "Stack too deep" errors due to local variables
        LiquidationCallLocalVars memory vars;

        (, , , , , , , vars.healthFactorBelowThreshold) = dataProvider.calculateUserGlobalData(
            _user
        );

        if (!vars.healthFactorBelowThreshold) {
            return (
                uint256(LiquidationErrors.HEALTH_FACTOR_ABOVE_THRESHOLD),
                "Health factor is not below the threshold"
            );
        }

        vars.userCollateralBalance = core.getUserUnderlyingAssetBalance(_collateral, _user);

        //if _user hasn't deposited this specific collateral, nothing can be liquidated
        if (vars.userCollateralBalance == 0) {
            return (
                uint256(LiquidationErrors.NO_COLLATERAL_AVAILABLE),
                "Invalid collateral to liquidate"
            );
        }

        vars.isCollateralEnabled =
            core.isReserveUsageAsCollateralEnabled(_collateral) &&
            core.isUserUseReserveAsCollateralEnabled(_collateral, _user);

        //if _collateral isn't enabled as collateral by _user, it cannot be liquidated
        if (!vars.isCollateralEnabled) {
            return (
                uint256(LiquidationErrors.COLLATERAL_CANNOT_BE_LIQUIDATED),
                "The collateral chosen cannot be liquidated"
            );
        }

        //if the user hasn't borrowed the specific currency defined by _reserve, it cannot be liquidated
        (, vars.userCompoundedBorrowBalance, vars.borrowBalanceIncrease) = core
            .getUserBorrowBalances(_reserve, _user);

        if (vars.userCompoundedBorrowBalance == 0) {
            return (
                uint256(LiquidationErrors.CURRRENCY_NOT_BORROWED),
                "User did not borrow the specified currency"
            );
        }

        //all clear - calculate the max principal amount that can be liquidated
        vars.maxPrincipalAmountToLiquidate = vars
            .userCompoundedBorrowBalance
            .mul(LIQUIDATION_CLOSE_FACTOR_PERCENT)
            .div(100);

        vars.actualAmountToLiquidate = _purchaseAmount > vars.maxPrincipalAmountToLiquidate
            ? vars.maxPrincipalAmountToLiquidate
            : _purchaseAmount;

        (uint256 maxCollateralToLiquidate, uint256 principalAmountNeeded) = calculateAvailableCollateralToLiquidate(
            _collateral,
            _reserve,
            vars.actualAmountToLiquidate,
            vars.userCollateralBalance
        );

        vars.originationFee = core.getUserOriginationFee(_reserve, _user);

        //if there is a fee to liquidate, calculate the maximum amount of fee that can be liquidated
        if (vars.originationFee > 0) {
            (
                vars.liquidatedCollateralForFee,
                vars.feeLiquidated
            ) = calculateAvailableCollateralToLiquidate(
                _collateral,
                _reserve,
                vars.originationFee,
                vars.userCollateralBalance.sub(maxCollateralToLiquidate)
            );
        }

        //if principalAmountNeeded < vars.ActualAmountToLiquidate, there isn't enough
        //of _collateral to cover the actual amount that is being liquidated, hence we liquidate
        //a smaller amount

        if (principalAmountNeeded < vars.actualAmountToLiquidate) {
            vars.actualAmountToLiquidate = principalAmountNeeded;
        }

        //if liquidator reclaims the underlying asset, we make sure there is enough available collateral in the reserve
        if (!_receiveAToken) {
            uint256 currentAvailableCollateral = core.getReserveAvailableLiquidity(_collateral);
            if (currentAvailableCollateral < maxCollateralToLiquidate) {
                return (
                    uint256(LiquidationErrors.NOT_ENOUGH_LIQUIDITY),
                    "There isn't enough liquidity available to liquidate"
                );
            }
        }

        core.updateStateOnLiquidation(
            _reserve,
            _collateral,
            _user,
            vars.actualAmountToLiquidate,
            maxCollateralToLiquidate,
            vars.feeLiquidated,
            vars.liquidatedCollateralForFee,
            vars.borrowBalanceIncrease,
            _receiveAToken
        );

        AToken collateralAtoken = AToken(core.getReserveATokenAddress(_collateral));

        //if liquidator reclaims the aToken, he receives the equivalent atoken amount
        if (_receiveAToken) {
            collateralAtoken.transferOnLiquidation(_user, msg.sender, maxCollateralToLiquidate);
        } else {
            //otherwise receives the underlying asset
            //burn the equivalent amount of atoken
            collateralAtoken.burnOnLiquidation(_user, maxCollateralToLiquidate);
            core.transferToUser(_collateral, msg.sender, maxCollateralToLiquidate);
        }

        //transfers the principal currency to the pool
        core.transferToReserve.value(msg.value)(_reserve, msg.sender, vars.actualAmountToLiquidate);

        if (vars.feeLiquidated > 0) {
            //if there is enough collateral to liquidate the fee, first transfer burn an equivalent amount of
            //aTokens of the user
            collateralAtoken.burnOnLiquidation(_user, vars.liquidatedCollateralForFee);

            //then liquidate the fee by transferring it to the fee collection address
            core.liquidateFee(
                _collateral,
                vars.liquidatedCollateralForFee,
                addressesProvider.getTokenDistributor()
            );

            emit OriginationFeeLiquidated(
                _collateral,
                _reserve,
                _user,
                vars.feeLiquidated,
                vars.liquidatedCollateralForFee,
                //solium-disable-next-line
                block.timestamp
            );

        }
        emit LiquidationCall(
            _collateral,
            _reserve,
            _user,
            vars.actualAmountToLiquidate,
            maxCollateralToLiquidate,
            vars.borrowBalanceIncrease,
            msg.sender,
            _receiveAToken,
            //solium-disable-next-line
            block.timestamp
        );

        return (uint256(LiquidationErrors.NO_ERROR), "No errors");
    }

    struct AvailableCollateralToLiquidateLocalVars {
        uint256 userCompoundedBorrowBalance;
        uint256 liquidationBonus;
        uint256 collateralPrice;
        uint256 principalCurrencyPrice;
        uint256 maxAmountCollateralToLiquidate;
    }

    /**
    * @dev calculates how much of a specific collateral can be liquidated, given
    * a certain amount of principal currency. This function needs to be called after
    * all the checks to validate the liquidation have been performed, otherwise it might fail.
    * @param _collateral the collateral to be liquidated
    * @param _principal the principal currency to be liquidated
    * @param _purchaseAmount the amount of principal being liquidated
    * @param _userCollateralBalance the collatera balance for the specific _collateral asset of the user being liquidated
    * @return the maximum amount that is possible to liquidated given all the liquidation constraints (user balance, close factor) and
    * the purchase amount
    **/
    function calculateAvailableCollateralToLiquidate(
        address _collateral,
        address _principal,
        uint256 _purchaseAmount,
        uint256 _userCollateralBalance
    ) internal view returns (uint256 collateralAmount, uint256 principalAmountNeeded) {
        collateralAmount = 0;
        principalAmountNeeded = 0;
        IPriceOracleGetter oracle = IPriceOracleGetter(addressesProvider.getPriceOracle());

        // Usage of a memory struct of vars to avoid "Stack too deep" errors due to local variables
        AvailableCollateralToLiquidateLocalVars memory vars;

        vars.collateralPrice = oracle.getAssetPrice(_collateral);
        vars.principalCurrencyPrice = oracle.getAssetPrice(_principal);
        vars.liquidationBonus = core.getReserveLiquidationBonus(_collateral);

        //this is the maximum possible amount of the selected collateral that can be liquidated, given the
        //max amount of principal currency that is available for liquidation.
        vars.maxAmountCollateralToLiquidate = vars
            .principalCurrencyPrice
            .mul(_purchaseAmount)
            .div(vars.collateralPrice)
            .mul(vars.liquidationBonus)
            .div(100);

        if (vars.maxAmountCollateralToLiquidate > _userCollateralBalance) {
            collateralAmount = _userCollateralBalance;
            principalAmountNeeded = vars
                .collateralPrice
                .mul(collateralAmount)
                .div(vars.principalCurrencyPrice)
                .mul(100)
                .div(vars.liquidationBonus);
        } else {
            collateralAmount = vars.maxAmountCollateralToLiquidate;
            principalAmountNeeded = _purchaseAmount;
        }

        return (collateralAmount, principalAmountNeeded);
    }
}

// File: @openzeppelin/contracts/token/ERC20/IERC20.sol

pragma solidity ^0.5.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP. Does not include
 * the optional functions; to access them see {ERC20Detailed}.
 */
interface IERC20 {
    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns the amount of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);

    /**
     * @dev Moves `amount` tokens from the caller's account to `recipient`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address recipient, uint256 amount) external returns (bool);

    /**
     * @dev Returns the remaining number of tokens that `spender` will be
     * allowed to spend on behalf of `owner` through {transferFrom}. This is
     * zero by default.
     *
     * This value changes when {approve} or {transferFrom} are called.
     */
    function allowance(address owner, address spender) external view returns (uint256);

    /**
     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * IMPORTANT: Beware that changing an allowance with this method brings the risk
     * that someone may use both the old and the new allowance by unfortunate
     * transaction ordering. One possible solution to mitigate this race
     * condition is to first reduce the spender's allowance to 0 and set the
     * desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     *
     * Emits an {Approval} event.
     */
    function approve(address spender, uint256 amount) external returns (bool);

    /**
     * @dev Moves `amount` tokens from `sender` to `recipient` using the
     * allowance mechanism. `amount` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);

    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);

    /**
     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
     * a call to {approve}. `value` is the new allowance.
     */
    event Approval(address indexed owner, address indexed spender, uint256 value);
}

// File: @openzeppelin/contracts/token/ERC20/ERC20Detailed.sol

pragma solidity ^0.5.0;


/**
 * @dev Optional functions from the ERC20 standard.
 */
contract ERC20Detailed is IERC20 {
    string private _name;
    string private _symbol;
    uint8 private _decimals;

    /**
     * @dev Sets the values for `name`, `symbol`, and `decimals`. All three of
     * these values are immutable: they can only be set once during
     * construction.
     */
    constructor (string memory name, string memory symbol, uint8 decimals) public {
        _name = name;
        _symbol = symbol;
        _decimals = decimals;
    }

    /**
     * @dev Returns the name of the token.
     */
    function name() public view returns (string memory) {
        return _name;
    }

    /**
     * @dev Returns the symbol of the token, usually a shorter version of the
     * name.
     */
    function symbol() public view returns (string memory) {
        return _symbol;
    }

    /**
     * @dev Returns the number of decimals used to get its user representation.
     * For example, if `decimals` equals `2`, a balance of `505` tokens should
     * be displayed to a user as `5,05` (`505 / 10 ** 2`).
     *
     * Tokens usually opt for a value of 18, imitating the relationship between
     * Ether and Wei.
     *
     * NOTE: This information is only used for _display_ purposes: it in
     * no way affects any of the arithmetic of the contract, including
     * {IERC20-balanceOf} and {IERC20-transfer}.
     */
    function decimals() public view returns (uint8) {
        return _decimals;
    }
}

// File: @openzeppelin/contracts/math/SafeMath.sol

pragma solidity ^0.5.0;

/**
 * @dev Wrappers over Solidity's arithmetic operations with added overflow
 * checks.
 *
 * Arithmetic operations in Solidity wrap on overflow. This can easily result
 * in bugs, because programmers usually assume that an overflow raises an
 * error, which is the standard behavior in high level programming languages.
 * `SafeMath` restores this intuition by reverting the transaction when an
 * operation overflows.
 *
 * Using this library instead of the unchecked operations eliminates an entire
 * class of bugs, so it's recommended to use it always.
 */
library SafeMath {
    /**
     * @dev Returns the addition of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `+` operator.
     *
     * Requirements:
     * - Addition cannot overflow.
     */
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        require(c >= a, "SafeMath: addition overflow");

        return c;
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        return sub(a, b, "SafeMath: subtraction overflow");
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     * - Subtraction cannot overflow.
     *
     * _Available since v2.4.0._
     */
    function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b <= a, errorMessage);
        uint256 c = a - b;

        return c;
    }

    /**
     * @dev Returns the multiplication of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `*` operator.
     *
     * Requirements:
     * - Multiplication cannot overflow.
     */
    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
        // benefit is lost if 'b' is also tested.
        // See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
        if (a == 0) {
            return 0;
        }

        uint256 c = a * b;
        require(c / a == b, "SafeMath: multiplication overflow");

        return c;
    }

    /**
     * @dev Returns the integer division of two unsigned integers. Reverts on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        return div(a, b, "SafeMath: division by zero");
    }

    /**
     * @dev Returns the integer division of two unsigned integers. Reverts with custom message on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     * - The divisor cannot be zero.
     *
     * _Available since v2.4.0._
     */
    function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        // Solidity only automatically asserts when dividing by 0
        require(b > 0, errorMessage);
        uint256 c = a / b;
        // assert(a == b * c + a % b); // There is no case in which this doesn't hold

        return c;
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * Reverts when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     * - The divisor cannot be zero.
     */
    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        return mod(a, b, "SafeMath: modulo by zero");
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * Reverts with custom message when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     * - The divisor cannot be zero.
     *
     * _Available since v2.4.0._
     */
    function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b != 0, errorMessage);
        return a % b;
    }
}

// File: @openzeppelin/contracts/utils/Address.sol

pragma solidity ^0.5.5;

/**
 * @dev Collection of functions related to the address type
 */
library Address {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * This test is non-exhaustive, and there may be false-negatives: during the
     * execution of a contract's constructor, its address will be reported as
     * not containing a contract.
     *
     * IMPORTANT: It is unsafe to assume that an address for which this
     * function returns false is an externally-owned account (EOA) and not a
     * contract.
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies in extcodesize, which returns 0 for contracts in
        // construction, since the code is only stored at the end of the
        // constructor execution.

        // According to EIP-1052, 0x0 is the value returned for not-yet created accounts
        // and 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470 is returned
        // for accounts without code, i.e. `keccak256('')`
        bytes32 codehash;
        bytes32 accountHash = 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470;
        // solhint-disable-next-line no-inline-assembly
        assembly { codehash := extcodehash(account) }
        return (codehash != 0x0 && codehash != accountHash);
    }

    /**
     * @dev Converts an `address` into `address payable`. Note that this is
     * simply a type cast: the actual underlying value is not changed.
     *
     * _Available since v2.4.0._
     */
    function toPayable(address account) internal pure returns (address payable) {
        return address(uint160(account));
    }

    /**
     * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
     * `recipient`, forwarding all available gas and reverting on errors.
     *
     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
     * of certain opcodes, possibly making contracts go over the 2300 gas limit
     * imposed by `transfer`, making them unable to receive funds via
     * `transfer`. {sendValue} removes this limitation.
     *
     * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
     *
     * IMPORTANT: because control is transferred to `recipient`, care must be
     * taken to not create reentrancy vulnerabilities. Consider using
     * {ReentrancyGuard} or the
     * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     *
     * _Available since v2.4.0._
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");

        // solhint-disable-next-line avoid-call-value
        (bool success, ) = recipient.call.value(amount)("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }
}

// File: @openzeppelin/contracts/token/ERC20/SafeERC20.sol

pragma solidity ^0.5.0;




/**
 * @title SafeERC20
 * @dev Wrappers around ERC20 operations that throw on failure (when the token
 * contract returns false). Tokens that return no value (and instead revert or
 * throw on failure) are also supported, non-reverting calls are assumed to be
 * successful.
 * To use this library you can add a `using SafeERC20 for ERC20;` statement to your contract,
 * which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
 */
library SafeERC20 {
    using SafeMath for uint256;
    using Address for address;

    function safeTransfer(IERC20 token, address to, uint256 value) internal {
        callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
    }

    function safeTransferFrom(IERC20 token, address from, address to, uint256 value) internal {
        callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
    }

    function safeApprove(IERC20 token, address spender, uint256 value) internal {
        // safeApprove should only be called when setting an initial allowance,
        // or when resetting it to zero. To increase and decrease it, use
        // 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
        // solhint-disable-next-line max-line-length
        require((value == 0) || (token.allowance(address(this), spender) == 0),
            "SafeERC20: approve from non-zero to non-zero allowance"
        );
        callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
    }

    function safeIncreaseAllowance(IERC20 token, address spender, uint256 value) internal {
        uint256 newAllowance = token.allowance(address(this), spender).add(value);
        callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
    }

    function safeDecreaseAllowance(IERC20 token, address spender, uint256 value) internal {
        uint256 newAllowance = token.allowance(address(this), spender).sub(value, "SafeERC20: decreased allowance below zero");
        callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
    }

    /**
     * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
     * on the return value: the return value is optional (but if data is returned, it must not be false).
     * @param token The token targeted by the call.
     * @param data The call data (encoded using abi.encode or one of its variants).
     */
    function callOptionalReturn(IERC20 token, bytes memory data) private {
        // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
        // we're implementing it ourselves.

        // A Solidity high level call has three parts:
        //  1. The target address is checked to verify it contains contract code
        //  2. The call itself is made, and success asserted
        //  3. The return value is decoded, which in turn checks the size of the returned data.
        // solhint-disable-next-line max-line-length
        require(address(token).isContract(), "SafeERC20: call to non-contract");

        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = address(token).call(data);
        require(success, "SafeERC20: low-level call failed");

        if (returndata.length > 0) { // Return data is optional
            // solhint-disable-next-line max-line-length
            require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
        }
    }
}

// File: @openzeppelin/contracts/GSN/Context.sol

pragma solidity ^0.5.0;

/*
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with GSN meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
contract Context {
    // Empty internal constructor, to prevent people from mistakenly deploying
    // an instance of this contract, which should be used via inheritance.
    constructor () internal { }
    // solhint-disable-previous-line no-empty-blocks

    function _msgSender() internal view returns (address payable) {
        return msg.sender;
    }

    function _msgData() internal view returns (bytes memory) {
        this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
        return msg.data;
    }
}

// File: @openzeppelin/contracts/ownership/Ownable.sol

pragma solidity ^0.5.0;

/**
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an owner) that can be granted exclusive access to
 * specific functions.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be applied to your functions to restrict their use to
 * the owner.
 */
contract Ownable is Context {
    address private _owner;

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    constructor () internal {
        _owner = _msgSender();
        emit OwnershipTransferred(address(0), _owner);
    }

    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view returns (address) {
        return _owner;
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        require(isOwner(), "Ownable: caller is not the owner");
        _;
    }

    /**
     * @dev Returns true if the caller is the current owner.
     */
    function isOwner() public view returns (bool) {
        return _msgSender() == _owner;
    }

    /**
     * @dev Leaves the contract without owner. It will not be possible to call
     * `onlyOwner` functions anymore. Can only be called by the current owner.
     *
     * NOTE: Renouncing ownership will leave the contract without an owner,
     * thereby removing any functionality that is only available to the owner.
     */
    function renounceOwnership() public onlyOwner {
        emit OwnershipTransferred(_owner, address(0));
        _owner = address(0);
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Can only be called by the current owner.
     */
    function transferOwnership(address newOwner) public onlyOwner {
        _transferOwnership(newOwner);
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     */
    function _transferOwnership(address newOwner) internal {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        emit OwnershipTransferred(_owner, newOwner);
        _owner = newOwner;
    }
}

// File: contracts/interfaces/ILendingProtocol.sol

pragma solidity 0.5.16;

interface ILendingProtocol {
  function mint() external returns (uint256);
  function redeem(address account) external returns (uint256);
  function nextSupplyRate(uint256 amount) external view returns (uint256);
  function nextSupplyRateWithParams(uint256[] calldata params) external view returns (uint256);
  function getAPR() external view returns (uint256);
  function getPriceInToken() external view returns (uint256);
  function token() external view returns (address);
  function underlying() external view returns (address);
  function availableLiquidity() external view returns (uint256);
}

// File: contracts/interfaces/AaveLendingPoolProvider.sol

pragma solidity 0.5.16;

interface AaveLendingPoolProvider {
  function getLendingPool() external view returns (address);
  function getLendingPoolCore() external view returns (address);
}

// File: contracts/interfaces/AaveLendingPool.sol

pragma solidity 0.5.16;

interface AaveLendingPool {
  function deposit(address _reserve, uint256 _amount, uint16 _referralCode) external;
  function getReserveData(address _reserve)
    external view returns (
      uint256 totalLiquidity,
      uint256 availableLiquidity,
      uint256 totalBorrowsStable,
      uint256 totalBorrowsVariable,
      uint256 liquidityRate,
      uint256 variableBorrowRate,
      uint256 stableBorrowRate,
      uint256 averageStableBorrowRate,
      uint256 utilizationRate,
      uint256 liquidityIndex,
      uint256 variableBorrowIndex,
      address aTokenAddress,
      uint40 lastUpdateTimestamp
    );
}

// File: contracts/interfaces/AaveLendingPoolCore.sol

pragma solidity 0.5.16;

interface AaveLendingPoolCore {
  function getReserveCurrentLiquidityRate(address _reserve) external view returns (uint256);
  function getReserveInterestRateStrategyAddress(address _reserve) external view returns (address);
  function getReserveTotalBorrowsStable(address _reserve) external view returns (uint256);
  function getReserveTotalBorrowsVariable(address _reserve) external view returns (uint256);
  function getReserveCurrentAverageStableBorrowRate(address _reserve) external view returns (uint256);
  function getReserveAvailableLiquidity(address _reserve) external view returns (uint256);
}

// File: contracts/interfaces/AToken.sol

pragma solidity 0.5.16;

interface AToken {
  function redeem(uint256 amount) external;
}

// File: contracts/interfaces/AaveInterestRateStrategy.sol

pragma solidity 0.5.16;

interface AaveInterestRateStrategy {
  function getBaseVariableBorrowRate() external view returns (uint256);
  function calculateInterestRates(
    address _reserve,
    uint256 _utilizationRate,
    uint256 _totalBorrowsStable,
    uint256 _totalBorrowsVariable,
    uint256 _averageStableBorrowRate) external view
  returns (uint256 liquidityRate, uint256 stableBorrowRate, uint256 variableBorrowRate);
}

// File: contracts/wrappers/IdleAave.sol

/**
 * @title: Aave wrapper
 * @summary: Used for interacting with Aave. Has
 *           a common interface with all other protocol wrappers.
 *           This contract holds assets only during a tx, after tx it should be empty
 * @author: Idle Labs Inc., idle.finance
 */
pragma solidity 0.5.16;












contract IdleAave is ILendingProtocol, Ownable {
  using SafeERC20 for IERC20;
  using SafeMath for uint256;

  // protocol token (aToken) address
  address public token;
  // underlying token (token eg DAI) address
  address public underlying;
  address public idleToken;

  address public constant aaveAddressesProvider = address(0x24a42fD28C976A61Df5D00D0599C34c4f90748c8);
  AaveLendingPoolProvider provider = AaveLendingPoolProvider(aaveAddressesProvider);

  /**
   * @param _token : aToken address
   * @param _underlying : underlying token (eg DAI) address
   */
  constructor(address _token, address _underlying) public {
    require(_token != address(0) && _underlying != address(0), 'AAVE: some addr is 0');

    token = _token;
    underlying = _underlying;
    IERC20(_underlying).safeApprove(
      provider.getLendingPoolCore(),
      uint256(-1)
    );
  }

  /**
   * Throws if called by any account other than IdleToken contract.
   */
  modifier onlyIdle() {
    require(msg.sender == idleToken, "Ownable: caller is not IdleToken");
    _;
  }

  // onlyOwner
  /**
   * sets idleToken address
   * NOTE: can be called only once. It's not on the constructor because we are deploying this contract
   *       after the IdleToken contract
   * @param _idleToken : idleToken address
   */
  function setIdleToken(address _idleToken)
    external onlyOwner {
      require(idleToken == address(0), "idleToken addr already set");
      require(_idleToken != address(0), "_idleToken addr is 0");
      idleToken = _idleToken;
  }
  // end onlyOwner

  /**
   * Calculate next supply rate for Aave, given an `_amount` supplied (last array param)
   * and all other params supplied.
   * on calculations.
   *
   * @param params : array with all params needed for calculation (see below)
   * @return : yearly net rate
   */
  function nextSupplyRateWithParams(uint256[] calldata params)
    external view
    returns (uint256) {
      AaveLendingPoolCore core = AaveLendingPoolCore(provider.getLendingPoolCore());
      AaveInterestRateStrategy apr = AaveInterestRateStrategy(core.getReserveInterestRateStrategyAddress(underlying));
      /*
        params[0] = core.getReserveAvailableLiquidity(underlying);
        params[1] = core.getReserveTotalBorrowsStable(underlying);
        params[2] = core.getReserveTotalBorrowsVariable(underlying);
        params[3] = core.getReserveCurrentAverageStableBorrowRate(underlying);
        params[4] = _amount;
      */

      (uint256 newLiquidityRate,,) = apr.calculateInterestRates(
        underlying,
        params[0].add(params[4]),
        params[1],
        params[2],
        params[3]
      );

      // newLiquidityRate is in RAY (ie 1e27)
      // also newLiquidityRate is in the form 0.03 * 1e27
      // while we need the result in the form 3 * 1e18
      return newLiquidityRate.mul(100).div(10**9);
  }

  /**
   * Calculate next supply rate for Aave, given an `_amount` supplied
   *
   * @param _amount : new underlying amount supplied (eg DAI)
   * @return : yearly net rate
   */
  function nextSupplyRate(uint256 _amount)
    external view
    returns (uint256) {
      AaveLendingPoolCore core = AaveLendingPoolCore(provider.getLendingPoolCore());
      AaveInterestRateStrategy apr = AaveInterestRateStrategy(core.getReserveInterestRateStrategyAddress(underlying));

      (uint256 newLiquidityRate,,) = apr.calculateInterestRates(
        underlying,
        core.getReserveAvailableLiquidity(underlying).add(_amount),
        core.getReserveTotalBorrowsStable(underlying),
        core.getReserveTotalBorrowsVariable(underlying),
        core.getReserveCurrentAverageStableBorrowRate(underlying)
      );
      return newLiquidityRate.mul(100).div(10**9);
  }

  /**
   * @return current price of aToken in underlying, Aave price is always 1
   */
  function getPriceInToken()
    external view
    returns (uint256) {
      return 10**18;
  }

  /**
   * @return apr : current yearly net rate
   */
  function getAPR()
    external view
    returns (uint256) {
      AaveLendingPoolCore core = AaveLendingPoolCore(provider.getLendingPoolCore());
      return core.getReserveCurrentLiquidityRate(underlying).mul(100).div(10**9);
  }

  /**
   * Gets all underlying tokens in this contract and mints aTokens
   * tokens are then transferred to msg.sender
   * NOTE: underlying tokens needs to be sent here before calling this
   *
   * @return aTokens minted
   */
  function mint()
    external onlyIdle
    returns (uint256 aTokens) {
      uint256 balance = IERC20(underlying).balanceOf(address(this));
      if (balance == 0) {
        return aTokens;
      }
      AaveLendingPool lendingPool = AaveLendingPool(provider.getLendingPool());
      lendingPool.deposit(underlying, balance, 29); // 29 -> referral
      aTokens = IERC20(token).balanceOf(address(this));
      // transfer them to the caller
      IERC20(token).safeTransfer(msg.sender, aTokens);
  }

  /**
   * Gets all aTokens in this contract and redeems underlying tokens.
   * underlying tokens are then transferred to `_account`
   * NOTE: aTokens needs to be sent here before calling this
   *
   * @return underlying tokens redeemd
   */
  function redeem(address _account)
    external onlyIdle
    returns (uint256 tokens) {
      AToken(token).redeem(IERC20(token).balanceOf(address(this)));
      IERC20 _underlying = IERC20(underlying);

      tokens = _underlying.balanceOf(address(this));
      _underlying.safeTransfer(_account, tokens);
  }

  function availableLiquidity() external view returns (uint256) {
    AaveLendingPoolCore core = AaveLendingPoolCore(provider.getLendingPoolCore());
    return IERC20(underlying).balanceOf(address(core));
  }
}