pragma solidity ^0.4.11;

// ERC20 token protocol, see more details at
// https://theethereum.wiki/w/index.php/ERC20_Token_Standard
// And also https://github.com/ethereum/eips/issues/20

contract Token {
  function totalSupply() constant returns (uint256 supply);
  function balanceOf(address _owner) constant returns (uint256 balance);
  function transfer(address _to, uint256 _value) returns (bool success);
  function transferFrom(address _from, address _to, uint256 _value) returns (bool success);
  function approve(address _spender, uint256 _value) returns (bool success);
  function allowance(address _owner, address _spender) constant returns (uint256 remaining);

  event Transfer(address indexed _from, address indexed _to, uint256 _value);
  event Approval(address indexed _owner, address indexed _spender, uint256 _value);
}

// Safe mathematics to make the code more readable

contract SafeMath {
  function safeMul(uint a, uint b) internal returns (uint) {
    uint c = a * b;
    assert(a == 0 || c / a == b);
    return c;
  }

  function safeSub(uint a, uint b) internal returns (uint) {
    assert(b <= a);
    return a - b;
  }

  function safeAdd(uint a, uint b) internal returns (uint) {
    uint c = a + b;
    assert(c>=a && c>=b);
    return c;
  }
}

// Ownable interface to simplify owner checks

contract Ownable {
  address public owner;

  function Ownable() {
    owner = msg.sender;
  }

  modifier onlyOwner() {
    require(msg.sender == owner);
    _;
  }

  function transferOwnership(address _newOwner) onlyOwner {
    require(_newOwner != address(0));
    owner = _newOwner;
  }
}

// Interface for trading discounts and rebates for specific accounts

contract AccountModifiersInterface {
  function accountModifiers(address _user) constant returns(uint takeFeeDiscount, uint rebatePercentage);
  function tradeModifiers(address _maker, address _taker) constant returns(uint takeFeeDiscount, uint rebatePercentage);
}

// Interface for trade tacker

contract TradeTrackerInterface {
  function tradeComplete(address _tokenGet, uint _amountGet, address _tokenGive, uint _amountGive, address _get, address _give, uint _takerFee, uint _makerRebate);
}

// Exchange contract

contract TokenStore is SafeMath, Ownable {

  // The account that will receive fees
  address feeAccount;

  // The account that stores fee discounts/rebates
  address accountModifiers;
  
  // Trade tracker account
  address tradeTracker;

  // We charge only the takers and this is the fee, percentage times 1 ether
  uint public fee;

  // Mapping of token addresses to mapping of account balances (token 0 means Ether)
  mapping (address => mapping (address => uint)) public tokens;

  // Mapping of user accounts to mapping of order hashes to uints (amount of order that has been filled)
  mapping (address => mapping (bytes32 => uint)) public orderFills;
  
  // Address of a next and previous versions of the contract, also status of the contract
  // can be used for user-triggered fund migrations
  address public successor;
  address public predecessor;
  bool public deprecated;
  uint16 public version;

  // Logging events
  // Note: Order creation is handled off-chain, see explanation further below
  event Cancel(address tokenGet, uint amountGet, address tokenGive, uint amountGive, uint expires, uint nonce, address user, uint8 v, bytes32 r, bytes32 s);
  event Trade(address tokenGet, uint amountGet, address tokenGive, uint amountGive, address get, address give, uint nonce);
  event Deposit(address token, address user, uint amount, uint balance);
  event Withdraw(address token, address user, uint amount, uint balance);
  event FundsMigrated(address user);

  function TokenStore(uint _fee, address _predecessor) {
    feeAccount = owner;
    fee = _fee;
    predecessor = _predecessor;
    deprecated = false;
    if (predecessor != address(0)) {
      version = TokenStore(predecessor).version() + 1;
    } else {
      version = 1;
    }
  }

  // Throw on default handler to prevent direct transactions of Ether
  function() {
    revert();
  }
  
  modifier deprecable() {
    require(!deprecated);
    _;
  }

  function deprecate(bool _deprecated, address _successor) onlyOwner {
    deprecated = _deprecated;
    successor = _successor;
  }

  function changeFeeAccount(address _feeAccount) onlyOwner {
    require(_feeAccount != address(0));
    feeAccount = _feeAccount;
  }

  function changeAccountModifiers(address _accountModifiers) onlyOwner {
    accountModifiers = _accountModifiers;
  }
  
  function changeTradeTracker(address _tradeTracker) onlyOwner {
    tradeTracker = _tradeTracker;
  }

  // Fee can only be decreased!
  function changeFee(uint _fee) onlyOwner {
    require(_fee <= fee);
    fee = _fee;
  }
  
  // Allows a user to get her current discount/rebate
  function getAccountModifiers() constant returns(uint takeFeeDiscount, uint rebatePercentage) {
    if (accountModifiers != address(0)) {
      return AccountModifiersInterface(accountModifiers).accountModifiers(msg.sender);
    } else {
      return (0, 0);
    }
  }
  
  ////////////////////////////////////////////////////////////////////////////////
  // Deposits, withdrawals, balances
  ////////////////////////////////////////////////////////////////////////////////

  function deposit() payable deprecable {
    tokens[0][msg.sender] = safeAdd(tokens[0][msg.sender], msg.value);
    Deposit(0, msg.sender, msg.value, tokens[0][msg.sender]);
  }

  function withdraw(uint _amount) {
    require(tokens[0][msg.sender] >= _amount);
    tokens[0][msg.sender] = safeSub(tokens[0][msg.sender], _amount);
    if (!msg.sender.call.value(_amount)()) {
      revert();
    }
    Withdraw(0, msg.sender, _amount, tokens[0][msg.sender]);
  }

  function depositToken(address _token, uint _amount) deprecable {
    // Note that Token(_token).approve(this, _amount) needs to be called
    // first or this contract will not be able to do the transfer.
    require(_token != 0);
    if (!Token(_token).transferFrom(msg.sender, this, _amount)) {
      revert();
    }
    tokens[_token][msg.sender] = safeAdd(tokens[_token][msg.sender], _amount);
    Deposit(_token, msg.sender, _amount, tokens[_token][msg.sender]);
  }

  function withdrawToken(address _token, uint _amount) {
    require(_token != 0);
    require(tokens[_token][msg.sender] >= _amount);
    tokens[_token][msg.sender] = safeSub(tokens[_token][msg.sender], _amount);
    if (!Token(_token).transfer(msg.sender, _amount)) {
      revert();
    }
    Withdraw(_token, msg.sender, _amount, tokens[_token][msg.sender]);
  }

  function balanceOf(address _token, address _user) constant returns (uint) {
    return tokens[_token][_user];
  }
  
  ////////////////////////////////////////////////////////////////////////////////
  // Trading
  ////////////////////////////////////////////////////////////////////////////////

  // Note: Order creation happens off-chain but the orders are signed by creators,
  // we validate the contents and the creator address in the logic below

  function trade(address _tokenGet, uint _amountGet, address _tokenGive, uint _amountGive,
      uint _expires, uint _nonce, address _user, uint8 _v, bytes32 _r, bytes32 _s, uint _amount) {
    bytes32 hash = sha256(this, _tokenGet, _amountGet, _tokenGive, _amountGive, _expires, _nonce);
    // Check order signatures and expiration, also check if not fulfilled yet
		if (ecrecover(sha3("\x19Ethereum Signed Message:\n32", hash), _v, _r, _s) != _user ||
      block.number > _expires ||
      safeAdd(orderFills[_user][hash], _amount) > _amountGet) {
      revert();
    }
    tradeBalances(_tokenGet, _amountGet, _tokenGive, _amountGive, _user, msg.sender, _amount);
    orderFills[_user][hash] = safeAdd(orderFills[_user][hash], _amount);
    Trade(_tokenGet, _amount, _tokenGive, _amountGive * _amount / _amountGet, _user, msg.sender, _nonce);
  }
  
  function tradeBalances(address _tokenGet, uint _amountGet, address _tokenGive, uint _amountGive,
      address _user, address _caller, uint _amount) private {

    uint feeTakeValue = safeMul(_amount, fee) / (1 ether);
    uint rebateValue = 0;
    uint tokenGiveValue = safeMul(_amountGive, _amount) / _amountGet; // Proportionate to request ratio

    // Apply modifiers
    if (accountModifiers != address(0)) {
      var (feeTakeDiscount, rebatePercentage) = AccountModifiersInterface(accountModifiers).tradeModifiers(_user, _caller);
      // Check that the discounts/rebates are never higher then 100%
      if (feeTakeDiscount > 100) {
        feeTakeDiscount = 0;
      }
      if (rebatePercentage > 100) {
        rebatePercentage = 0;
      }
      feeTakeValue = safeMul(feeTakeValue, 100 - feeTakeDiscount) / 100;  // discounted fee
      rebateValue = safeMul(rebatePercentage, feeTakeValue) / 100;        // % of actual taker fee
    }
    
    tokens[_tokenGet][_user] = safeAdd(tokens[_tokenGet][_user], safeAdd(_amount, rebateValue));
    tokens[_tokenGet][_caller] = safeSub(tokens[_tokenGet][_caller], safeAdd(_amount, feeTakeValue));
    tokens[_tokenGive][_user] = safeSub(tokens[_tokenGive][_user], tokenGiveValue);
    tokens[_tokenGive][_caller] = safeAdd(tokens[_tokenGive][_caller], tokenGiveValue);
    tokens[_tokenGet][feeAccount] = safeAdd(tokens[_tokenGet][feeAccount], safeSub(feeTakeValue, rebateValue));
    
    if (tradeTracker != address(0)) {
      TradeTrackerInterface(tradeTracker).tradeComplete(_tokenGet, _amount, _tokenGive, tokenGiveValue, _user, _caller, feeTakeValue, rebateValue);
    }
  }

  function testTrade(address _tokenGet, uint _amountGet, address _tokenGive, uint _amountGive, uint _expires,
      uint _nonce, address _user, uint8 _v, bytes32 _r, bytes32 _s, uint _amount, address _sender) constant returns(bool) {
    if (tokens[_tokenGet][_sender] < _amount ||
      availableVolume(_tokenGet, _amountGet, _tokenGive, _amountGive, _expires, _nonce, _user, _v, _r, _s) < _amount) {
      return false;
    }
    return true;
  }

  function availableVolume(address _tokenGet, uint _amountGet, address _tokenGive, uint _amountGive, uint _expires,
      uint _nonce, address _user, uint8 _v, bytes32 _r, bytes32 _s) constant returns(uint) {
    bytes32 hash = sha256(this, _tokenGet, _amountGet, _tokenGive, _amountGive, _expires, _nonce);
    if (ecrecover(sha3("\x19Ethereum Signed Message:\n32", hash), _v, _r, _s) != _user ||
      block.number > _expires) {
      return 0;
    }
    uint available1 = safeSub(_amountGet, orderFills[_user][hash]);
    uint available2 = safeMul(tokens[_tokenGive][_user], _amountGet) / _amountGive;
    if (available1 < available2) return available1;
    return available2;
  }

  function amountFilled(address _tokenGet, uint _amountGet, address _tokenGive, uint _amountGive, uint _expires,
      uint _nonce, address _user) constant returns(uint) {
    bytes32 hash = sha256(this, _tokenGet, _amountGet, _tokenGive, _amountGive, _expires, _nonce);
    return orderFills[_user][hash];
  }

  function cancelOrder(address _tokenGet, uint _amountGet, address _tokenGive, uint _amountGive, uint _expires,
      uint _nonce, uint8 _v, bytes32 _r, bytes32 _s) {
    bytes32 hash = sha256(this, _tokenGet, _amountGet, _tokenGive, _amountGive, _expires, _nonce);
    if (!(ecrecover(sha3("\x19Ethereum Signed Message:\n32", hash), _v, _r, _s) == msg.sender)) {
      revert();
    }
    orderFills[msg.sender][hash] = _amountGet;
    Cancel(_tokenGet, _amountGet, _tokenGive, _amountGive, _expires, _nonce, msg.sender, _v, _r, _s);
  }
  
  ////////////////////////////////////////////////////////////////////////////////
  // Migrations
  ////////////////////////////////////////////////////////////////////////////////

  // User-triggered (!) fund migrations in case contract got updated
  // Similar to withdraw but we use a successor account instead
  // As we don't store user tokens list on chain, it has to be passed from the outside
  function migrateFunds(address[] _tokens) {
  
    // Get the latest successor in the chain
    require(successor != address(0));
    TokenStore newExchange = TokenStore(successor);
    for (uint16 n = 0; n < 20; n++) {  // We will look past 20 contracts in the future
      address nextSuccessor = newExchange.successor();
      if (nextSuccessor == address(this)) {  // Circular succession
        revert();
      }
      if (nextSuccessor == address(0)) { // We reached the newest, stop
        break;
      }
      newExchange = TokenStore(nextSuccessor);
    }

    // Ether
    uint etherAmount = tokens[0][msg.sender];
    if (etherAmount > 0) {
      tokens[0][msg.sender] = 0;
      newExchange.depositForUser.value(etherAmount)(msg.sender);
    }

    // Tokens
    for (n = 0; n < _tokens.length; n++) {
      address token = _tokens[n];
      require(token != address(0)); // 0 = Ether, we handle it above
      uint tokenAmount = tokens[token][msg.sender];
      if (tokenAmount == 0) {
        continue;
      }
      if (!Token(token).approve(newExchange, tokenAmount)) {
        revert();
      }
      tokens[token][msg.sender] = 0;
      newExchange.depositTokenForUser(token, tokenAmount, msg.sender);
    }

    FundsMigrated(msg.sender);
  }

  // This is used for migrations only. To be called by previous exchange only,
  // user-triggered, on behalf of the user called the migrateFunds method.
  // Note that it does exactly the same as depositToken, but as this is called
  // by a previous generation of exchange itself, we credit internally not the
  // previous exchange, but the user it was called for.
  function depositForUser(address _user) payable deprecable {
    require(_user != address(0));
    require(msg.value > 0);
    TokenStore caller = TokenStore(msg.sender);
    require(caller.version() > 0); // Make sure it's an exchange account
    tokens[0][_user] = safeAdd(tokens[0][_user], msg.value);
  }

  function depositTokenForUser(address _token, uint _amount, address _user) deprecable {
    require(_token != address(0));
    require(_user != address(0));
    require(_amount > 0);
    TokenStore caller = TokenStore(msg.sender);
    require(caller.version() > 0); // Make sure it's an exchange account
    if (!Token(_token).transferFrom(msg.sender, this, _amount)) {
      revert();
    }
    tokens[_token][_user] = safeAdd(tokens[_token][_user], _amount);
  }
}

pragma solidity ^0.4.24;
// produced by the Solididy File Flattener (c) David Appleton 2018
// contact : [email protected]
// released under Apache 2.0 licence
contract ERC20Basic {
  function totalSupply() public view returns (uint256);
  function balanceOf(address who) public view returns (uint256);
  function transfer(address to, uint256 value) public returns (bool);
  event Transfer(address indexed from, address indexed to, uint256 value);
}

contract Ownable {
  address public owner;


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


  /**
   * @dev The Ownable constructor sets the original `owner` of the contract to the sender
   * account.
   */
  constructor() 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 relinquish control of the contract.
   */
  function renounceOwnership() public onlyOwner {
    emit OwnershipRenounced(owner);
    owner = address(0);
  }

  /**
   * @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 {
    _transferOwnership(_newOwner);
  }

  /**
   * @dev Transfers control of the contract to a newOwner.
   * @param _newOwner The address to transfer ownership to.
   */
  function _transferOwnership(address _newOwner) internal {
    require(_newOwner != address(0));
    emit OwnershipTransferred(owner, _newOwner);
    owner = _newOwner;
  }
}

library SafeMath {

  /**
  * @dev Multiplies two numbers, throws on overflow.
  */
  function mul(uint256 a, uint256 b) internal pure returns (uint256 c) {
    // Gas optimization: this is cheaper than asserting '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;
    }

    c = a * b;
    assert(c / a == b);
    return c;
  }

  /**
  * @dev Integer division of two numbers, truncating the quotient.
  */
  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 a / b;
  }

  /**
  * @dev Subtracts two numbers, throws on overflow (i.e. if subtrahend is greater than minuend).
  */
  function sub(uint256 a, uint256 b) internal pure returns (uint256) {
    assert(b <= a);
    return a - b;
  }

  /**
  * @dev Adds two numbers, throws on overflow.
  */
  function add(uint256 a, uint256 b) internal pure returns (uint256 c) {
    c = a + b;
    assert(c >= a);
    return c;
  }
}

contract ERC20 is ERC20Basic {
  function allowance(address owner, address spender)
    public view returns (uint256);

  function transferFrom(address from, address to, uint256 value)
    public returns (bool);

  function approve(address spender, uint256 value) public returns (bool);
  event Approval(
    address indexed owner,
    address indexed spender,
    uint256 value
  );
}

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;
    emit Pause();
  }

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

contract DetailedERC20 is ERC20 {
  string public name;
  string public symbol;
  uint8 public decimals;

  constructor(string _name, string _symbol, uint8 _decimals) public {
    name = _name;
    symbol = _symbol;
    decimals = _decimals;
  }
}

contract BasicToken is ERC20Basic {
  using SafeMath for uint256;

  mapping(address => uint256) balances;

  uint256 totalSupply_;

  /**
  * @dev total number of tokens in existence
  */
  function totalSupply() public view returns (uint256) {
    return totalSupply_;
  }

  /**
  * @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, uint256 _value) public returns (bool) {
    require(_to != address(0));
    require(_value <= balances[msg.sender]);

    balances[msg.sender] = balances[msg.sender].sub(_value);
    balances[_to] = balances[_to].add(_value);
    emit Transfer(msg.sender, _to, _value);
    return true;
  }

  /**
  * @dev Gets the balance of the specified address.
  * @param _owner The address to query the the balance of.
  * @return An uint256 representing the amount owned by the passed address.
  */
  function balanceOf(address _owner) public view returns (uint256) {
    return balances[_owner];
  }

}

contract BurnableToken is BasicToken {

  event Burn(address indexed burner, uint256 value);

  /**
   * @dev Burns a specific amount of tokens.
   * @param _value The amount of token to be burned.
   */
  function burn(uint256 _value) public {
    _burn(msg.sender, _value);
  }

  function _burn(address _who, uint256 _value) internal {
    require(_value <= balances[_who]);
    // no need to require value <= totalSupply, since that would imply the
    // sender's balance is greater than the totalSupply, which *should* be an assertion failure

    balances[_who] = balances[_who].sub(_value);
    totalSupply_ = totalSupply_.sub(_value);
    emit Burn(_who, _value);
    emit Transfer(_who, address(0), _value);
  }
}

contract StandardToken is ERC20, BasicToken {

  mapping (address => mapping (address => uint256)) internal allowed;


  /**
   * @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 uint256 the amount of tokens to be transferred
   */
  function transferFrom(
    address _from,
    address _to,
    uint256 _value
  )
    public
    returns (bool)
  {
    require(_to != address(0));
    require(_value <= balances[_from]);
    require(_value <= allowed[_from][msg.sender]);

    balances[_from] = balances[_from].sub(_value);
    balances[_to] = balances[_to].add(_value);
    allowed[_from][msg.sender] = allowed[_from][msg.sender].sub(_value);
    emit Transfer(_from, _to, _value);
    return true;
  }

  /**
   * @dev Approve the passed address to spend the specified amount of tokens on behalf of msg.sender.
   *
   * 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
   * @param _spender The address which will spend the funds.
   * @param _value The amount of tokens to be spent.
   */
  function approve(address _spender, uint256 _value) public returns (bool) {
    allowed[msg.sender][_spender] = _value;
    emit Approval(msg.sender, _spender, _value);
    return true;
  }

  /**
   * @dev Function to check the amount of tokens that 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 uint256 specifying the amount of tokens still available for the spender.
   */
  function allowance(
    address _owner,
    address _spender
   )
    public
    view
    returns (uint256)
  {
    return allowed[_owner][_spender];
  }

  /**
   * @dev Increase the amount of tokens that an owner allowed to a spender.
   *
   * approve should be called when allowed[_spender] == 0. To increment
   * allowed value is better to use this function to avoid 2 calls (and wait until
   * the first transaction is mined)
   * From MonolithDAO Token.sol
   * @param _spender The address which will spend the funds.
   * @param _addedValue The amount of tokens to increase the allowance by.
   */
  function increaseApproval(
    address _spender,
    uint _addedValue
  )
    public
    returns (bool)
  {
    allowed[msg.sender][_spender] = (
      allowed[msg.sender][_spender].add(_addedValue));
    emit Approval(msg.sender, _spender, allowed[msg.sender][_spender]);
    return true;
  }

  /**
   * @dev Decrease the amount of tokens that an owner allowed to a spender.
   *
   * approve should be called when allowed[_spender] == 0. To decrement
   * allowed value is better to use this function to avoid 2 calls (and wait until
   * the first transaction is mined)
   * From MonolithDAO Token.sol
   * @param _spender The address which will spend the funds.
   * @param _subtractedValue The amount of tokens to decrease the allowance by.
   */
  function decreaseApproval(
    address _spender,
    uint _subtractedValue
  )
    public
    returns (bool)
  {
    uint oldValue = allowed[msg.sender][_spender];
    if (_subtractedValue > oldValue) {
      allowed[msg.sender][_spender] = 0;
    } else {
      allowed[msg.sender][_spender] = oldValue.sub(_subtractedValue);
    }
    emit Approval(msg.sender, _spender, allowed[msg.sender][_spender]);
    return true;
  }

}

contract PausableToken is StandardToken, Pausable {

  function transfer(
    address _to,
    uint256 _value
  )
    public
    whenNotPaused
    returns (bool)
  {
    return super.transfer(_to, _value);
  }

  function transferFrom(
    address _from,
    address _to,
    uint256 _value
  )
    public
    whenNotPaused
    returns (bool)
  {
    return super.transferFrom(_from, _to, _value);
  }

  function approve(
    address _spender,
    uint256 _value
  )
    public
    whenNotPaused
    returns (bool)
  {
    return super.approve(_spender, _value);
  }

  function increaseApproval(
    address _spender,
    uint _addedValue
  )
    public
    whenNotPaused
    returns (bool success)
  {
    return super.increaseApproval(_spender, _addedValue);
  }

  function decreaseApproval(
    address _spender,
    uint _subtractedValue
  )
    public
    whenNotPaused
    returns (bool success)
  {
    return super.decreaseApproval(_spender, _subtractedValue);
  }
}

contract MintableToken is StandardToken, Ownable {
  event Mint(address indexed to, uint256 amount);
  event MintFinished();

  bool public mintingFinished = false;


  modifier canMint() {
    require(!mintingFinished);
    _;
  }

  modifier hasMintPermission() {
    require(msg.sender == owner);
    _;
  }

  /**
   * @dev Function to mint tokens
   * @param _to The address that will receive the minted tokens.
   * @param _amount The amount of tokens to mint.
   * @return A boolean that indicates if the operation was successful.
   */
  function mint(
    address _to,
    uint256 _amount
  )
    hasMintPermission
    canMint
    public
    returns (bool)
  {
    totalSupply_ = totalSupply_.add(_amount);
    balances[_to] = balances[_to].add(_amount);
    emit Mint(_to, _amount);
    emit Transfer(address(0), _to, _amount);
    return true;
  }

  /**
   * @dev Function to stop minting new tokens.
   * @return True if the operation was successful.
   */
  function finishMinting() onlyOwner canMint public returns (bool) {
    mintingFinished = true;
    emit MintFinished();
    return true;
  }
}

contract WhitelistedPausableToken is PausableToken {
    // UNIX timestamp (in seconds) after which this whitelist no longer applies
    uint256 public whitelistExpiration;
    // While the whitelist is active, either the sender or recipient must be
    // in allowedTransactors.
    mapping (address => bool) public allowedTransactors;

    event SetWhitelistExpiration(uint256 expiration);
    event AllowedTransactorAdded(address sender);
    event AllowedTransactorRemoved(address sender);

    //
    // Functions for maintaining whitelist
    //

    modifier allowedTransfer(address _from, address _to) {
        require(
            // solium-disable-next-line operator-whitespace
            !whitelistActive() ||
            allowedTransactors[_from] ||
            allowedTransactors[_to],
            "neither sender nor recipient are allowed"
        );
        _;
    }

    function whitelistActive() public view returns (bool) {
        return block.timestamp < whitelistExpiration;
    }

    function addAllowedTransactor(address _transactor) public onlyOwner {
        emit AllowedTransactorAdded(_transactor);
        allowedTransactors[_transactor] = true;
    }

    function removeAllowedTransactor(address _transactor) public onlyOwner {
        emit AllowedTransactorRemoved(_transactor);
        delete allowedTransactors[_transactor];
    }

    /**
    * @dev Set the whitelist expiration, after which the whitelist no longer
    * applies.
    */
    function setWhitelistExpiration(uint256 _expiration) public onlyOwner {
        // allow only if whitelist expiration hasn't yet been set, or if the
        // whitelist expiration hasn't passed yet
        require(
            whitelistExpiration == 0 || whitelistActive(),
            "an expired whitelist cannot be extended"
        );
        // prevent possible mistakes in calling this function
        require(
            _expiration >= block.timestamp + 1 days,
            "whitelist expiration not far enough into the future"
        );
        emit SetWhitelistExpiration(_expiration);
        whitelistExpiration = _expiration;
    }

    //
    // ERC20 transfer functions that have been overridden to enforce the
    // whitelist.
    //

    function transfer(
        address _to,
        uint256 _value
    )
        public
        allowedTransfer(msg.sender, _to)
        returns (bool)
    {
        return super.transfer(_to, _value);
    }

    function transferFrom(
        address _from,
        address _to,
        uint256 _value
    )
    public
        allowedTransfer(_from, _to)
    returns (bool)
    {
        return super.transferFrom(_from, _to, _value);
    }
}

contract OriginToken is BurnableToken, MintableToken, WhitelistedPausableToken, DetailedERC20 {
    event AddCallSpenderWhitelist(address enabler, address spender);
    event RemoveCallSpenderWhitelist(address disabler, address spender);

    mapping (address => bool) public callSpenderWhitelist;

    // @dev Constructor that gives msg.sender all initial tokens.
    constructor(uint256 _initialSupply) DetailedERC20("OriginToken", "OGN", 18) public {
        owner = msg.sender;
        mint(owner, _initialSupply);
    }

    //
    // Burn methods
    //

    // @dev Burns tokens belonging to the sender
    // @param _value Amount of token to be burned
    function burn(uint256 _value) public onlyOwner {
        // TODO: add a function & modifier to enable for all accounts without doing
        // a contract migration?
        super.burn(_value);
    }

    // @dev Burns tokens belonging to the specified address
    // @param _who The account whose tokens we're burning
    // @param _value Amount of token to be burned
    function burn(address _who, uint256 _value) public onlyOwner {
        _burn(_who, _value);
    }

    //
    // approveAndCall methods
    //

    // @dev Add spender to whitelist of spenders for approveAndCall
    // @param _spender Address to add
    function addCallSpenderWhitelist(address _spender) public onlyOwner {
        callSpenderWhitelist[_spender] = true;
        emit AddCallSpenderWhitelist(msg.sender, _spender);
    }

    // @dev Remove spender from whitelist of spenders for approveAndCall
    // @param _spender Address to remove
    function removeCallSpenderWhitelist(address _spender) public onlyOwner {
        delete callSpenderWhitelist[_spender];
        emit RemoveCallSpenderWhitelist(msg.sender, _spender);
    }

    // @dev Approve transfer of tokens and make a contract call in a single
    // @dev transaction. This allows a DApp to avoid requiring two MetaMask
    // @dev approvals for a single logical action, such as creating a listing,
    // @dev which requires the seller to approve a token transfer and the
    // @dev marketplace contract to transfer tokens from the seller.
    //
    // @dev This is based on the ERC827 function approveAndCall and avoids
    // @dev security issues by only working with a whitelisted set of _spender
    // @dev addresses. The other difference is that the combination of this
    // @dev function ensures that the proxied function call receives the
    // @dev msg.sender for this function as its first parameter.
    //
    // @param _spender The address that will spend the funds.
    // @param _value The amount of tokens to be spent.
    // @param _selector Function selector for function to be called.
    // @param _callParams Packed, encoded parameters, omitting the first parameter which is always msg.sender
    function approveAndCallWithSender(
        address _spender,
        uint256 _value,
        bytes4 _selector,
        bytes _callParams
    )
        public
        payable
        returns (bool)
    {
        require(_spender != address(this), "token contract can't be approved");
        require(callSpenderWhitelist[_spender], "spender not in whitelist");

        require(super.approve(_spender, _value), "approve failed");

        bytes memory callData = abi.encodePacked(_selector, uint256(msg.sender), _callParams);
        // solium-disable-next-line security/no-call-value
        require(_spender.call.value(msg.value)(callData), "proxied call failed");
        return true;
    }
}