// Copyright (C) 2015, 2016, 2017 Dapphub

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

pragma solidity ^0.4.18;

contract WETH9 {
    string public name     = "Wrapped Ether";
    string public symbol   = "WETH";
    uint8  public decimals = 18;

    event  Approval(address indexed src, address indexed guy, uint wad);
    event  Transfer(address indexed src, address indexed dst, uint wad);
    event  Deposit(address indexed dst, uint wad);
    event  Withdrawal(address indexed src, uint wad);

    mapping (address => uint)                       public  balanceOf;
    mapping (address => mapping (address => uint))  public  allowance;

    function() public payable {
        deposit();
    }
    function deposit() public payable {
        balanceOf[msg.sender] += msg.value;
        Deposit(msg.sender, msg.value);
    }
    function withdraw(uint wad) public {
        require(balanceOf[msg.sender] >= wad);
        balanceOf[msg.sender] -= wad;
        msg.sender.transfer(wad);
        Withdrawal(msg.sender, wad);
    }

    function totalSupply() public view returns (uint) {
        return this.balance;
    }

    function approve(address guy, uint wad) public returns (bool) {
        allowance[msg.sender][guy] = wad;
        Approval(msg.sender, guy, wad);
        return true;
    }

    function transfer(address dst, uint wad) public returns (bool) {
        return transferFrom(msg.sender, dst, wad);
    }

    function transferFrom(address src, address dst, uint wad)
        public
        returns (bool)
    {
        require(balanceOf[src] >= wad);

        if (src != msg.sender && allowance[src][msg.sender] != uint(-1)) {
            require(allowance[src][msg.sender] >= wad);
            allowance[src][msg.sender] -= wad;
        }

        balanceOf[src] -= wad;
        balanceOf[dst] += wad;

        Transfer(src, dst, wad);

        return true;
    }
}


/*
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DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD
PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS),
EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF
SUCH DAMAGES.

  17. Interpretation of Sections 15 and 16.

  If the disclaimer of warranty and limitation of liability provided
above cannot be given local legal effect according to their terms,
reviewing courts shall apply local law that most closely approximates
an absolute waiver of all civil liability in connection with the
Program, unless a warranty or assumption of liability accompanies a
copy of the Program in return for a fee.

                     END OF TERMS AND CONDITIONS

            How to Apply These Terms to Your New Programs

  If you develop a new program, and you want it to be of the greatest
possible use to the public, the best way to achieve this is to make it
free software which everyone can redistribute and change under these terms.

  To do so, attach the following notices to the program.  It is safest
to attach them to the start of each source file to most effectively
state the exclusion of warranty; and each file should have at least
the "copyright" line and a pointer to where the full notice is found.

    <one line to give the program's name and a brief idea of what it does.>
    Copyright (C) <year>  <name of author>

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.

Also add information on how to contact you by electronic and paper mail.

  If the program does terminal interaction, make it output a short
notice like this when it starts in an interactive mode:

    <program>  Copyright (C) <year>  <name of author>
    This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
    This is free software, and you are welcome to redistribute it
    under certain conditions; type `show c' for details.

The hypothetical commands `show w' and `show c' should show the appropriate
parts of the General Public License.  Of course, your program's commands
might be different; for a GUI interface, you would use an "about box".

  You should also get your employer (if you work as a programmer) or school,
if any, to sign a "copyright disclaimer" for the program, if necessary.
For more information on this, and how to apply and follow the GNU GPL, see
<http://www.gnu.org/licenses/>.

  The GNU General Public License does not permit incorporating your program
into proprietary programs.  If your program is a subroutine library, you
may consider it more useful to permit linking proprietary applications with
the library.  If this is what you want to do, use the GNU Lesser General
Public License instead of this License.  But first, please read
<http://www.gnu.org/philosophy/why-not-lgpl.html>.

*/

// File: contracts/interfaces/IUniswapV2Pair.sol

pragma solidity >=0.5.0;

interface IUniswapV2Pair {
    event Approval(address indexed owner, address indexed spender, uint value);
    event Transfer(address indexed from, address indexed to, uint value);

    function name() external pure returns (string memory);
    function symbol() external pure returns (string memory);
    function decimals() external pure returns (uint8);
    function totalSupply() external view returns (uint);
    function balanceOf(address owner) external view returns (uint);
    function allowance(address owner, address spender) external view returns (uint);

    function approve(address spender, uint value) external returns (bool);
    function transfer(address to, uint value) external returns (bool);
    function transferFrom(address from, address to, uint value) external returns (bool);

    function DOMAIN_SEPARATOR() external view returns (bytes32);
    function PERMIT_TYPEHASH() external pure returns (bytes32);
    function nonces(address owner) external view returns (uint);

    function permit(address owner, address spender, uint value, uint deadline, uint8 v, bytes32 r, bytes32 s) external;

    event Mint(address indexed sender, uint amount0, uint amount1);
    event Burn(address indexed sender, uint amount0, uint amount1, address indexed to);
    event Swap(
        address indexed sender,
        uint amount0In,
        uint amount1In,
        uint amount0Out,
        uint amount1Out,
        address indexed to
    );
    event Sync(uint112 reserve0, uint112 reserve1);

    function MINIMUM_LIQUIDITY() external pure returns (uint);
    function factory() external view returns (address);
    function token0() external view returns (address);
    function token1() external view returns (address);
    function getReserves() external view returns (uint112 reserve0, uint112 reserve1, uint32 blockTimestampLast);
    function price0CumulativeLast() external view returns (uint);
    function price1CumulativeLast() external view returns (uint);
    function kLast() external view returns (uint);

    function mint(address to) external returns (uint liquidity);
    function burn(address to) external returns (uint amount0, uint amount1);
    function swap(uint amount0Out, uint amount1Out, address to, bytes calldata data) external;
    function skim(address to) external;
    function sync() external;

    function initialize(address, address) external;
}

// File: contracts/interfaces/IUniswapV2ERC20.sol

pragma solidity >=0.5.0;

interface IUniswapV2ERC20 {
    event Approval(address indexed owner, address indexed spender, uint value);
    event Transfer(address indexed from, address indexed to, uint value);

    function name() external pure returns (string memory);
    function symbol() external pure returns (string memory);
    function decimals() external pure returns (uint8);
    function totalSupply() external view returns (uint);
    function balanceOf(address owner) external view returns (uint);
    function allowance(address owner, address spender) external view returns (uint);

    function approve(address spender, uint value) external returns (bool);
    function transfer(address to, uint value) external returns (bool);
    function transferFrom(address from, address to, uint value) external returns (bool);

    function DOMAIN_SEPARATOR() external view returns (bytes32);
    function PERMIT_TYPEHASH() external pure returns (bytes32);
    function nonces(address owner) external view returns (uint);

    function permit(address owner, address spender, uint value, uint deadline, uint8 v, bytes32 r, bytes32 s) external;
}

// File: contracts/libraries/SafeMath.sol

pragma solidity =0.5.16;

// a library for performing overflow-safe math, courtesy of DappHub (https://github.com/dapphub/ds-math)

library SafeMath {
    function add(uint x, uint y) internal pure returns (uint z) {
        require((z = x + y) >= x, 'ds-math-add-overflow');
    }

    function sub(uint x, uint y) internal pure returns (uint z) {
        require((z = x - y) <= x, 'ds-math-sub-underflow');
    }

    function mul(uint x, uint y) internal pure returns (uint z) {
        require(y == 0 || (z = x * y) / y == x, 'ds-math-mul-overflow');
    }
}

// File: contracts/UniswapV2ERC20.sol

pragma solidity =0.5.16;



contract UniswapV2ERC20 is IUniswapV2ERC20 {
    using SafeMath for uint;

    string public constant name = 'Uniswap V2';
    string public constant symbol = 'UNI-V2';
    uint8 public constant decimals = 18;
    uint  public totalSupply;
    mapping(address => uint) public balanceOf;
    mapping(address => mapping(address => uint)) public allowance;

    bytes32 public DOMAIN_SEPARATOR;
    // keccak256("Permit(address owner,address spender,uint256 value,uint256 nonce,uint256 deadline)");
    bytes32 public constant PERMIT_TYPEHASH = 0x6e71edae12b1b97f4d1f60370fef10105fa2faae0126114a169c64845d6126c9;
    mapping(address => uint) public nonces;

    event Approval(address indexed owner, address indexed spender, uint value);
    event Transfer(address indexed from, address indexed to, uint value);

    constructor() public {
        uint chainId;
        assembly {
            chainId := chainid
        }
        DOMAIN_SEPARATOR = keccak256(
            abi.encode(
                keccak256('EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)'),
                keccak256(bytes(name)),
                keccak256(bytes('1')),
                chainId,
                address(this)
            )
        );
    }

    function _mint(address to, uint value) internal {
        totalSupply = totalSupply.add(value);
        balanceOf[to] = balanceOf[to].add(value);
        emit Transfer(address(0), to, value);
    }

    function _burn(address from, uint value) internal {
        balanceOf[from] = balanceOf[from].sub(value);
        totalSupply = totalSupply.sub(value);
        emit Transfer(from, address(0), value);
    }

    function _approve(address owner, address spender, uint value) private {
        allowance[owner][spender] = value;
        emit Approval(owner, spender, value);
    }

    function _transfer(address from, address to, uint value) private {
        balanceOf[from] = balanceOf[from].sub(value);
        balanceOf[to] = balanceOf[to].add(value);
        emit Transfer(from, to, value);
    }

    function approve(address spender, uint value) external returns (bool) {
        _approve(msg.sender, spender, value);
        return true;
    }

    function transfer(address to, uint value) external returns (bool) {
        _transfer(msg.sender, to, value);
        return true;
    }

    function transferFrom(address from, address to, uint value) external returns (bool) {
        if (allowance[from][msg.sender] != uint(-1)) {
            allowance[from][msg.sender] = allowance[from][msg.sender].sub(value);
        }
        _transfer(from, to, value);
        return true;
    }

    function permit(address owner, address spender, uint value, uint deadline, uint8 v, bytes32 r, bytes32 s) external {
        require(deadline >= block.timestamp, 'UniswapV2: EXPIRED');
        bytes32 digest = keccak256(
            abi.encodePacked(
                '\x19\x01',
                DOMAIN_SEPARATOR,
                keccak256(abi.encode(PERMIT_TYPEHASH, owner, spender, value, nonces[owner]++, deadline))
            )
        );
        address recoveredAddress = ecrecover(digest, v, r, s);
        require(recoveredAddress != address(0) && recoveredAddress == owner, 'UniswapV2: INVALID_SIGNATURE');
        _approve(owner, spender, value);
    }
}

// File: contracts/libraries/Math.sol

pragma solidity =0.5.16;

// a library for performing various math operations

library Math {
    function min(uint x, uint y) internal pure returns (uint z) {
        z = x < y ? x : y;
    }

    // babylonian method (https://en.wikipedia.org/wiki/Methods_of_computing_square_roots#Babylonian_method)
    function sqrt(uint y) internal pure returns (uint z) {
        if (y > 3) {
            z = y;
            uint x = y / 2 + 1;
            while (x < z) {
                z = x;
                x = (y / x + x) / 2;
            }
        } else if (y != 0) {
            z = 1;
        }
    }
}

// File: contracts/libraries/UQ112x112.sol

pragma solidity =0.5.16;

// a library for handling binary fixed point numbers (https://en.wikipedia.org/wiki/Q_(number_format))

// range: [0, 2**112 - 1]
// resolution: 1 / 2**112

library UQ112x112 {
    uint224 constant Q112 = 2**112;

    // encode a uint112 as a UQ112x112
    function encode(uint112 y) internal pure returns (uint224 z) {
        z = uint224(y) * Q112; // never overflows
    }

    // divide a UQ112x112 by a uint112, returning a UQ112x112
    function uqdiv(uint224 x, uint112 y) internal pure returns (uint224 z) {
        z = x / uint224(y);
    }
}

// File: contracts/interfaces/IERC20.sol

pragma solidity >=0.5.0;

interface IERC20 {
    event Approval(address indexed owner, address indexed spender, uint value);
    event Transfer(address indexed from, address indexed to, uint value);

    function name() external view returns (string memory);
    function symbol() external view returns (string memory);
    function decimals() external view returns (uint8);
    function totalSupply() external view returns (uint);
    function balanceOf(address owner) external view returns (uint);
    function allowance(address owner, address spender) external view returns (uint);

    function approve(address spender, uint value) external returns (bool);
    function transfer(address to, uint value) external returns (bool);
    function transferFrom(address from, address to, uint value) external returns (bool);
}

// File: contracts/interfaces/IUniswapV2Factory.sol

pragma solidity >=0.5.0;

interface IUniswapV2Factory {
    event PairCreated(address indexed token0, address indexed token1, address pair, uint);

    function feeTo() external view returns (address);
    function feeToSetter() external view returns (address);

    function getPair(address tokenA, address tokenB) external view returns (address pair);
    function allPairs(uint) external view returns (address pair);
    function allPairsLength() external view returns (uint);

    function createPair(address tokenA, address tokenB) external returns (address pair);

    function setFeeTo(address) external;
    function setFeeToSetter(address) external;
}

// File: contracts/interfaces/IUniswapV2Callee.sol

pragma solidity >=0.5.0;

interface IUniswapV2Callee {
    function uniswapV2Call(address sender, uint amount0, uint amount1, bytes calldata data) external;
}

// File: contracts/UniswapV2Pair.sol

pragma solidity =0.5.16;








contract UniswapV2Pair is IUniswapV2Pair, UniswapV2ERC20 {
    using SafeMath  for uint;
    using UQ112x112 for uint224;

    uint public constant MINIMUM_LIQUIDITY = 10**3;
    bytes4 private constant SELECTOR = bytes4(keccak256(bytes('transfer(address,uint256)')));

    address public factory;
    address public token0;
    address public token1;

    uint112 private reserve0;           // uses single storage slot, accessible via getReserves
    uint112 private reserve1;           // uses single storage slot, accessible via getReserves
    uint32  private blockTimestampLast; // uses single storage slot, accessible via getReserves

    uint public price0CumulativeLast;
    uint public price1CumulativeLast;
    uint public kLast; // reserve0 * reserve1, as of immediately after the most recent liquidity event

    uint private unlocked = 1;
    modifier lock() {
        require(unlocked == 1, 'UniswapV2: LOCKED');
        unlocked = 0;
        _;
        unlocked = 1;
    }

    function getReserves() public view returns (uint112 _reserve0, uint112 _reserve1, uint32 _blockTimestampLast) {
        _reserve0 = reserve0;
        _reserve1 = reserve1;
        _blockTimestampLast = blockTimestampLast;
    }

    function _safeTransfer(address token, address to, uint value) private {
        (bool success, bytes memory data) = token.call(abi.encodeWithSelector(SELECTOR, to, value));
        require(success && (data.length == 0 || abi.decode(data, (bool))), 'UniswapV2: TRANSFER_FAILED');
    }

    event Mint(address indexed sender, uint amount0, uint amount1);
    event Burn(address indexed sender, uint amount0, uint amount1, address indexed to);
    event Swap(
        address indexed sender,
        uint amount0In,
        uint amount1In,
        uint amount0Out,
        uint amount1Out,
        address indexed to
    );
    event Sync(uint112 reserve0, uint112 reserve1);

    constructor() public {
        factory = msg.sender;
    }

    // called once by the factory at time of deployment
    function initialize(address _token0, address _token1) external {
        require(msg.sender == factory, 'UniswapV2: FORBIDDEN'); // sufficient check
        token0 = _token0;
        token1 = _token1;
    }

    // update reserves and, on the first call per block, price accumulators
    function _update(uint balance0, uint balance1, uint112 _reserve0, uint112 _reserve1) private {
        require(balance0 <= uint112(-1) && balance1 <= uint112(-1), 'UniswapV2: OVERFLOW');
        uint32 blockTimestamp = uint32(block.timestamp % 2**32);
        uint32 timeElapsed = blockTimestamp - blockTimestampLast; // overflow is desired
        if (timeElapsed > 0 && _reserve0 != 0 && _reserve1 != 0) {
            // * never overflows, and + overflow is desired
            price0CumulativeLast += uint(UQ112x112.encode(_reserve1).uqdiv(_reserve0)) * timeElapsed;
            price1CumulativeLast += uint(UQ112x112.encode(_reserve0).uqdiv(_reserve1)) * timeElapsed;
        }
        reserve0 = uint112(balance0);
        reserve1 = uint112(balance1);
        blockTimestampLast = blockTimestamp;
        emit Sync(reserve0, reserve1);
    }

    // if fee is on, mint liquidity equivalent to 1/6th of the growth in sqrt(k)
    function _mintFee(uint112 _reserve0, uint112 _reserve1) private returns (bool feeOn) {
        address feeTo = IUniswapV2Factory(factory).feeTo();
        feeOn = feeTo != address(0);
        uint _kLast = kLast; // gas savings
        if (feeOn) {
            if (_kLast != 0) {
                uint rootK = Math.sqrt(uint(_reserve0).mul(_reserve1));
                uint rootKLast = Math.sqrt(_kLast);
                if (rootK > rootKLast) {
                    uint numerator = totalSupply.mul(rootK.sub(rootKLast));
                    uint denominator = rootK.mul(5).add(rootKLast);
                    uint liquidity = numerator / denominator;
                    if (liquidity > 0) _mint(feeTo, liquidity);
                }
            }
        } else if (_kLast != 0) {
            kLast = 0;
        }
    }

    // this low-level function should be called from a contract which performs important safety checks
    function mint(address to) external lock returns (uint liquidity) {
        (uint112 _reserve0, uint112 _reserve1,) = getReserves(); // gas savings
        uint balance0 = IERC20(token0).balanceOf(address(this));
        uint balance1 = IERC20(token1).balanceOf(address(this));
        uint amount0 = balance0.sub(_reserve0);
        uint amount1 = balance1.sub(_reserve1);

        bool feeOn = _mintFee(_reserve0, _reserve1);
        uint _totalSupply = totalSupply; // gas savings, must be defined here since totalSupply can update in _mintFee
        if (_totalSupply == 0) {
            liquidity = Math.sqrt(amount0.mul(amount1)).sub(MINIMUM_LIQUIDITY);
           _mint(address(0), MINIMUM_LIQUIDITY); // permanently lock the first MINIMUM_LIQUIDITY tokens
        } else {
            liquidity = Math.min(amount0.mul(_totalSupply) / _reserve0, amount1.mul(_totalSupply) / _reserve1);
        }
        require(liquidity > 0, 'UniswapV2: INSUFFICIENT_LIQUIDITY_MINTED');
        _mint(to, liquidity);

        _update(balance0, balance1, _reserve0, _reserve1);
        if (feeOn) kLast = uint(reserve0).mul(reserve1); // reserve0 and reserve1 are up-to-date
        emit Mint(msg.sender, amount0, amount1);
    }

    // this low-level function should be called from a contract which performs important safety checks
    function burn(address to) external lock returns (uint amount0, uint amount1) {
        (uint112 _reserve0, uint112 _reserve1,) = getReserves(); // gas savings
        address _token0 = token0;                                // gas savings
        address _token1 = token1;                                // gas savings
        uint balance0 = IERC20(_token0).balanceOf(address(this));
        uint balance1 = IERC20(_token1).balanceOf(address(this));
        uint liquidity = balanceOf[address(this)];

        bool feeOn = _mintFee(_reserve0, _reserve1);
        uint _totalSupply = totalSupply; // gas savings, must be defined here since totalSupply can update in _mintFee
        amount0 = liquidity.mul(balance0) / _totalSupply; // using balances ensures pro-rata distribution
        amount1 = liquidity.mul(balance1) / _totalSupply; // using balances ensures pro-rata distribution
        require(amount0 > 0 && amount1 > 0, 'UniswapV2: INSUFFICIENT_LIQUIDITY_BURNED');
        _burn(address(this), liquidity);
        _safeTransfer(_token0, to, amount0);
        _safeTransfer(_token1, to, amount1);
        balance0 = IERC20(_token0).balanceOf(address(this));
        balance1 = IERC20(_token1).balanceOf(address(this));

        _update(balance0, balance1, _reserve0, _reserve1);
        if (feeOn) kLast = uint(reserve0).mul(reserve1); // reserve0 and reserve1 are up-to-date
        emit Burn(msg.sender, amount0, amount1, to);
    }

    // this low-level function should be called from a contract which performs important safety checks
    function swap(uint amount0Out, uint amount1Out, address to, bytes calldata data) external lock {
        require(amount0Out > 0 || amount1Out > 0, 'UniswapV2: INSUFFICIENT_OUTPUT_AMOUNT');
        (uint112 _reserve0, uint112 _reserve1,) = getReserves(); // gas savings
        require(amount0Out < _reserve0 && amount1Out < _reserve1, 'UniswapV2: INSUFFICIENT_LIQUIDITY');

        uint balance0;
        uint balance1;
        { // scope for _token{0,1}, avoids stack too deep errors
        address _token0 = token0;
        address _token1 = token1;
        require(to != _token0 && to != _token1, 'UniswapV2: INVALID_TO');
        if (amount0Out > 0) _safeTransfer(_token0, to, amount0Out); // optimistically transfer tokens
        if (amount1Out > 0) _safeTransfer(_token1, to, amount1Out); // optimistically transfer tokens
        if (data.length > 0) IUniswapV2Callee(to).uniswapV2Call(msg.sender, amount0Out, amount1Out, data);
        balance0 = IERC20(_token0).balanceOf(address(this));
        balance1 = IERC20(_token1).balanceOf(address(this));
        }
        uint amount0In = balance0 > _reserve0 - amount0Out ? balance0 - (_reserve0 - amount0Out) : 0;
        uint amount1In = balance1 > _reserve1 - amount1Out ? balance1 - (_reserve1 - amount1Out) : 0;
        require(amount0In > 0 || amount1In > 0, 'UniswapV2: INSUFFICIENT_INPUT_AMOUNT');
        { // scope for reserve{0,1}Adjusted, avoids stack too deep errors
        uint balance0Adjusted = balance0.mul(1000).sub(amount0In.mul(3));
        uint balance1Adjusted = balance1.mul(1000).sub(amount1In.mul(3));
        require(balance0Adjusted.mul(balance1Adjusted) >= uint(_reserve0).mul(_reserve1).mul(1000**2), 'UniswapV2: K');
        }

        _update(balance0, balance1, _reserve0, _reserve1);
        emit Swap(msg.sender, amount0In, amount1In, amount0Out, amount1Out, to);
    }

    // force balances to match reserves
    function skim(address to) external lock {
        address _token0 = token0; // gas savings
        address _token1 = token1; // gas savings
        _safeTransfer(_token0, to, IERC20(_token0).balanceOf(address(this)).sub(reserve0));
        _safeTransfer(_token1, to, IERC20(_token1).balanceOf(address(this)).sub(reserve1));
    }

    // force reserves to match balances
    function sync() external lock {
        _update(IERC20(token0).balanceOf(address(this)), IERC20(token1).balanceOf(address(this)), reserve0, reserve1);
    }
}

// This software is a subject to Ambisafe License Agreement.
// No use or distribution is allowed without written permission from Ambisafe.
// https://ambisafe.com/terms.pdf

contract Ambi {
    function getNodeAddress(bytes32 _nodeName) constant returns(address);
    function hasRelation(bytes32 _nodeName, bytes32 _relation, address _to) constant returns(bool);
    function addNode(bytes32 _nodeName, address _nodeAddress) constant returns(bool);
}

contract AmbiEnabled {
    Ambi public ambiC;
    bool public isImmortal;
    bytes32 public name;

    modifier checkAccess(bytes32 _role) {
        if(address(ambiC) != 0x0 && ambiC.hasRelation(name, _role, msg.sender)){
            _
        }
    }
    
    function getAddress(bytes32 _name) constant returns (address) {
        return ambiC.getNodeAddress(_name);
    }

    function setAmbiAddress(address _ambi, bytes32 _name) returns (bool){
        if(address(ambiC) != 0x0){
            return false;
        }
        Ambi ambiContract = Ambi(_ambi);
        if(ambiContract.getNodeAddress(_name)!=address(this)) {
            if (!ambiContract.addNode(_name, address(this))){
                return false;
            }
        }
        name = _name;
        ambiC = ambiContract;
        return true;
    }

    function immortality() checkAccess("owner") returns(bool) {
        isImmortal = true;
        return true;
    }

    function remove() checkAccess("owner") returns(bool) {
        if (isImmortal) {
            return false;
        }
        selfdestruct(msg.sender);
        return true;
    }
}

library StackDepthLib {
    // This will probably work with a value of 390 but no need to cut it
    // that close in the case that the optimizer changes slightly or
    // something causing that number to rise slightly.
    uint constant GAS_PER_DEPTH = 400;

    function checkDepth(address self, uint n) constant returns(bool) {
        if (n == 0) return true;
        return self.call.gas(GAS_PER_DEPTH * n)(0x21835af6, n - 1);
    }

    function __dig(uint n) constant {
        if (n == 0) return;
        if (!address(this).delegatecall(0x21835af6, n - 1)) throw;
    }
}

contract Safe {
    // Should always be placed as first modifier!
    modifier noValue {
        if (msg.value > 0) {
            // Internal Out Of Gas/Throw: revert this transaction too;
            // Call Stack Depth Limit reached: revert this transaction too;
            // Recursive Call: safe, no any changes applied yet, we are inside of modifier.
            _safeSend(msg.sender, msg.value);
        }
        _
    }

    modifier onlyHuman {
        if (_isHuman()) {
            _
        }
    }

    modifier noCallback {
        if (!isCall) {
            _
        }
    }

    modifier immutable(address _address) {
        if (_address == 0) {
            _
        }
    }

    address stackDepthLib;
    function setupStackDepthLib(address _stackDepthLib) immutable(address(stackDepthLib)) returns(bool) {
        stackDepthLib = _stackDepthLib;
        return true;
    }

    modifier requireStackDepth(uint16 _depth) {
        if (stackDepthLib == 0x0) {
            throw;
        }
        if (_depth > 1023) {
            throw;
        }
        if (!stackDepthLib.delegatecall(0x32921690, stackDepthLib, _depth)) {
            throw;
        }
        _
    }

    // Must not be used inside the functions that have noValue() modifier!
    function _safeFalse() internal noValue() returns(bool) {
        return false;
    }

    function _safeSend(address _to, uint _value) internal {
        if (!_unsafeSend(_to, _value)) {
            throw;
        }
    }

    function _unsafeSend(address _to, uint _value) internal returns(bool) {
        return _to.call.value(_value)();
    }

    function _isContract() constant internal returns(bool) {
        return msg.sender != tx.origin;
    }

    function _isHuman() constant internal returns(bool) {
        return !_isContract();
    }

    bool private isCall = false;
    function _setupNoCallback() internal {
        isCall = true;
    }

    function _finishNoCallback() internal {
        isCall = false;
    }
}

/**
 * @title Events History universal contract.
 *
 * Contract serves as an Events storage and version history for a particular contract type.
 * Events appear on this contract address but their definitions provided by other contracts/libraries.
 * Version info is provided for historical and informational purposes.
 *
 * Note: all the non constant functions return false instead of throwing in case if state change
 * didn't happen yet.
 */
contract EventsHistory is AmbiEnabled, Safe {
    // Event emitter signature to address with Event definiton mapping.
    mapping(bytes4 => address) public emitters;

    // Calling contract address to version mapping.
    mapping(address => uint) public versions;

    // Version to info mapping.
    mapping(uint => VersionInfo) public versionInfo;

    // Latest verion number.
    uint public latestVersion;

    struct VersionInfo {
        uint block;        // Block number in which version has been introduced.
        address by;        // Contract owner address who added version.
        address caller;    // Address of this version calling contract.
        string name;       // Version name, informative.
        string changelog;  // Version changelog, informative.
    }

    /**
     * Assign emitter address to a specified emit function signature.
     *
     * Can be set only once for each signature, and only by contract owner.
     * Caller contract should be sure that emitter for a particular signature will never change.
     *
     * @param _eventSignature signature of the event emitting function.
     * @param _emitter address with Event definition.
     *
     * @return success.
     */
    function addEmitter(bytes4 _eventSignature, address _emitter) noValue() checkAccess("admin") returns(bool) {
        if (emitters[_eventSignature] != 0x0) {
            return false;
        }
        emitters[_eventSignature] = _emitter;
        return true;
    }

    /**
     * Introduce new caller contract version specifing version information.
     *
     * Can be set only once for each caller, and only by contract owner.
     * Name and changelog should not be empty.
     *
     * @param _caller address of the new caller.
     * @param _name version name.
     * @param _changelog version changelog.
     *
     * @return success.
     */
    function addVersion(address _caller, string _name, string _changelog) noValue() checkAccess("admin") returns(bool) {
        if (versions[_caller] != 0) {
            return false;
        }
        if (bytes(_name).length == 0) {
            return false;
        }
        if (bytes(_changelog).length == 0) {
            return false;
        }
        uint version = ++latestVersion;
        versions[_caller] = version;
        versionInfo[version] = VersionInfo(block.number, msg.sender, _caller, _name, _changelog);
        return true;
    }

    /**
     * Event emitting fallback.
     *
     * Can be and only called caller with assigned version.
     * Resolves msg.sig to an emitter address, and calls it to emit an event.
     *
     * Throws if emit function signature is not registered, or call failed.
     */
    function () noValue() {
        if (versions[msg.sender] == 0) {
            return;
        }
        // Internal Out Of Gas/Throw: revert this transaction too;
        // Call Stack Depth Limit reached: revert this transaction too;
        // Recursive Call: safe, all changes already made.
        if (!emitters[msg.sig].delegatecall(msg.data)) {
            throw;
        }
    }
}

/**
 *Submitted for verification at Etherscan.io on 2019-05-28
*/

// File: contracts/EToken2Interface.sol

pragma solidity 0.5.8;


contract RegistryICAPInterface {
    function parse(bytes32 _icap) public view returns(address, bytes32, bool);
    function institutions(bytes32 _institution) public view returns(address);
}


contract EToken2Interface {
    function registryICAP() public view returns(RegistryICAPInterface);
    function baseUnit(bytes32 _symbol) public view returns(uint8);
    function description(bytes32 _symbol) public view returns(string memory);
    function owner(bytes32 _symbol) public view returns(address);
    function isOwner(address _owner, bytes32 _symbol) public view returns(bool);
    function totalSupply(bytes32 _symbol) public view returns(uint);
    function balanceOf(address _holder, bytes32 _symbol) public view returns(uint);
    function isLocked(bytes32 _symbol) public view returns(bool);

    function issueAsset(
        bytes32 _symbol,
        uint _value,
        string memory _name,
        string memory _description,
        uint8 _baseUnit,
        bool _isReissuable)
    public returns(bool);

    function reissueAsset(bytes32 _symbol, uint _value) public returns(bool);
    function revokeAsset(bytes32 _symbol, uint _value) public returns(bool);
    function setProxy(address _address, bytes32 _symbol) public returns(bool);
    function lockAsset(bytes32 _symbol) public returns(bool);

    function proxyTransferFromToICAPWithReference(
        address _from,
        bytes32 _icap,
        uint _value,
        string memory _reference,
        address _sender)
    public returns(bool);

    function proxyApprove(address _spender, uint _value, bytes32 _symbol, address _sender)
    public returns(bool);
    
    function allowance(address _from, address _spender, bytes32 _symbol) public view returns(uint);

    function proxyTransferFromWithReference(
        address _from,
        address _to,
        uint _value,
        bytes32 _symbol,
        string memory _reference,
        address _sender)
    public returns(bool);

    function changeOwnership(bytes32 _symbol, address _newOwner) public returns(bool);
}

// File: contracts/AssetInterface.sol

pragma solidity 0.5.8;


contract AssetInterface {
    function _performTransferWithReference(
        address _to,
        uint _value,
        string memory _reference,
        address _sender)
    public returns(bool);

    function _performTransferToICAPWithReference(
        bytes32 _icap,
        uint _value,
        string memory _reference,
        address _sender)
    public returns(bool);

    function _performApprove(address _spender, uint _value, address _sender)
    public returns(bool);

    function _performTransferFromWithReference(
        address _from,
        address _to,
        uint _value,
        string memory _reference,
        address _sender)
    public returns(bool);

    function _performTransferFromToICAPWithReference(
        address _from,
        bytes32 _icap,
        uint _value,
        string memory _reference,
        address _sender)
    public returns(bool);

    function _performGeneric(bytes memory, address) public payable {
        revert();
    }
}

// File: contracts/ERC20Interface.sol

pragma solidity 0.5.8;


contract ERC20Interface {
    event Transfer(address indexed from, address indexed to, uint256 value);
    event Approval(address indexed from, address indexed spender, uint256 value);

    function totalSupply() public view returns(uint256 supply);
    function balanceOf(address _owner) public view returns(uint256 balance);
    // solhint-disable-next-line no-simple-event-func-name
    function transfer(address _to, uint256 _value) public returns(bool success);
    function transferFrom(address _from, address _to, uint256 _value) public returns(bool success);
    function approve(address _spender, uint256 _value) public returns(bool success);
    function allowance(address _owner, address _spender) public view returns(uint256 remaining);

    // function symbol() constant returns(string);
    function decimals() public view returns(uint8);
    // function name() constant returns(string);
}

// File: contracts/AssetProxyInterface.sol

pragma solidity 0.5.8;



contract AssetProxyInterface is ERC20Interface {
    function _forwardApprove(address _spender, uint _value, address _sender)
    public returns(bool);

    function _forwardTransferFromWithReference(
        address _from,
        address _to,
        uint _value,
        string memory _reference,
        address _sender)
    public returns(bool);

    function _forwardTransferFromToICAPWithReference(
        address _from,
        bytes32 _icap,
        uint _value,
        string memory _reference,
        address _sender)
    public returns(bool);

    function recoverTokens(ERC20Interface _asset, address _receiver, uint _value)
    public returns(bool);

    function etoken2() external view returns(address); // To be replaced by the implicit getter;

    // To be replaced by the implicit getter;
    function etoken2Symbol() external view returns(bytes32);
}

// File: smart-contracts-common/contracts/Bytes32.sol

pragma solidity 0.5.8;


contract Bytes32 {
    function _bytes32(string memory _input) internal pure returns(bytes32 result) {
        assembly {
            result := mload(add(_input, 32))
        }
    }
}

// File: smart-contracts-common/contracts/ReturnData.sol

pragma solidity 0.5.8;


contract ReturnData {
    function _returnReturnData(bool _success) internal pure {
        assembly {
            let returndatastart := 0
            returndatacopy(returndatastart, 0, returndatasize)
            switch _success case 0 { revert(returndatastart, returndatasize) }
                default { return(returndatastart, returndatasize) }
        }
    }

    function _assemblyCall(address _destination, uint _value, bytes memory _data)
    internal returns(bool success) {
        assembly {
            success := call(gas, _destination, _value, add(_data, 32), mload(_data), 0, 0)
        }
    }
}

// File: contracts/AssetProxy.sol

pragma solidity 0.5.8;








/**
 * @title EToken2 Asset Proxy.
 *
 * Proxy implements ERC20 interface and acts as a gateway to a single EToken2 asset.
 * Proxy adds etoken2Symbol and caller(sender) when forwarding requests to EToken2.
 * Every request that is made by caller first sent to the specific asset implementation
 * contract, which then calls back to be forwarded onto EToken2.
 *
 * Calls flow: Caller ->
 *             Proxy.func(...) ->
 *             Asset._performFunc(..., Caller.address) ->
 *             Proxy._forwardFunc(..., Caller.address) ->
 *             Platform.proxyFunc(..., symbol, Caller.address)
 *
 * Generic call flow: Caller ->
 *             Proxy.unknownFunc(...) ->
 *             Asset._performGeneric(..., Caller.address) ->
 *             Asset.unknownFunc(...)
 *
 * Asset implementation contract is mutable, but each user have an option to stick with
 * old implementation, through explicit decision made in timely manner, if he doesn't agree
 * with new rules.
 * Each user have a possibility to upgrade to latest asset contract implementation, without the
 * possibility to rollback.
 *
 * Note: all the non constant functions return false instead of throwing in case if state change
 * didn't happen yet.
 */
contract AssetProxy is ERC20Interface, AssetProxyInterface, Bytes32, ReturnData {
    // Assigned EToken2, immutable.
    EToken2Interface public etoken2;

    // Assigned symbol, immutable.
    bytes32 public etoken2Symbol;

    // Assigned name, immutable. For UI.
    string public name;
    string public symbol;

    /**
     * Sets EToken2 address, assigns symbol and name.
     *
     * Can be set only once.
     *
     * @param _etoken2 EToken2 contract address.
     * @param _symbol assigned symbol.
     * @param _name assigned name.
     *
     * @return success.
     */
    function init(EToken2Interface _etoken2, string memory _symbol, string memory _name)
        public returns(bool)
    {
        if (address(etoken2) != address(0)) {
            return false;
        }
        etoken2 = _etoken2;
        etoken2Symbol = _bytes32(_symbol);
        name = _name;
        symbol = _symbol;
        return true;
    }

    /**
     * Only EToken2 is allowed to call.
     */
    modifier onlyEToken2() {
        if (msg.sender == address(etoken2)) {
            _;
        }
    }

    /**
     * Only current asset owner is allowed to call.
     */
    modifier onlyAssetOwner() {
        if (etoken2.isOwner(msg.sender, etoken2Symbol)) {
            _;
        }
    }

    /**
     * Returns asset implementation contract for current caller.
     *
     * @return asset implementation contract.
     */
    function _getAsset() internal view returns(AssetInterface) {
        return AssetInterface(getVersionFor(msg.sender));
    }

    /**
     * Recovers tokens on proxy contract
     *
     * @param _asset type of tokens to recover.
     * @param _value tokens that will be recovered.
     * @param _receiver address where to send recovered tokens.
     *
     * @return success.
     */
    function recoverTokens(ERC20Interface _asset, address _receiver, uint _value)
    public onlyAssetOwner() returns(bool) {
        return _asset.transfer(_receiver, _value);
    }

    /**
     * Returns asset total supply.
     *
     * @return asset total supply.
     */
    function totalSupply() public view returns(uint) {
        return etoken2.totalSupply(etoken2Symbol);
    }

    /**
     * Returns asset balance for a particular holder.
     *
     * @param _owner holder address.
     *
     * @return holder balance.
     */
    function balanceOf(address _owner) public view returns(uint) {
        return etoken2.balanceOf(_owner, etoken2Symbol);
    }

    /**
     * Returns asset allowance from one holder to another.
     *
     * @param _from holder that allowed spending.
     * @param _spender holder that is allowed to spend.
     *
     * @return holder to spender allowance.
     */
    function allowance(address _from, address _spender) public view returns(uint) {
        return etoken2.allowance(_from, _spender, etoken2Symbol);
    }

    /**
     * Returns asset decimals.
     *
     * @return asset decimals.
     */
    function decimals() public view returns(uint8) {
        return etoken2.baseUnit(etoken2Symbol);
    }

    /**
     * Transfers asset balance from the caller to specified receiver.
     *
     * @param _to holder address to give to.
     * @param _value amount to transfer.
     *
     * @return success.
     */
    function transfer(address _to, uint _value) public returns(bool) {
        return transferWithReference(_to, _value, '');
    }

    /**
     * Transfers asset balance from the caller to specified receiver adding specified comment.
     * Resolves asset implementation contract for the caller and forwards there arguments along with
     * the caller address.
     *
     * @param _to holder address to give to.
     * @param _value amount to transfer.
     * @param _reference transfer comment to be included in a EToken2's Transfer event.
     *
     * @return success.
     */
    function transferWithReference(address _to, uint _value, string memory _reference)
    public returns(bool) {
        return _getAsset()._performTransferWithReference(
            _to, _value, _reference, msg.sender);
    }

    /**
     * Transfers asset balance from the caller to specified ICAP.
     *
     * @param _icap recipient ICAP to give to.
     * @param _value amount to transfer.
     *
     * @return success.
     */
    function transferToICAP(bytes32 _icap, uint _value) public returns(bool) {
        return transferToICAPWithReference(_icap, _value, '');
    }

    /**
     * Transfers asset balance from the caller to specified ICAP adding specified comment.
     * Resolves asset implementation contract for the caller and forwards there arguments along with
     * the caller address.
     *
     * @param _icap recipient ICAP to give to.
     * @param _value amount to transfer.
     * @param _reference transfer comment to be included in a EToken2's Transfer event.
     *
     * @return success.
     */
    function transferToICAPWithReference(
        bytes32 _icap,
        uint _value,
        string memory _reference)
    public returns(bool) {
        return _getAsset()._performTransferToICAPWithReference(
            _icap, _value, _reference, msg.sender);
    }

    /**
     * Prforms allowance transfer of asset balance between holders.
     *
     * @param _from holder address to take from.
     * @param _to holder address to give to.
     * @param _value amount to transfer.
     *
     * @return success.
     */
    function transferFrom(address _from, address _to, uint _value) public returns(bool) {
        return transferFromWithReference(_from, _to, _value, '');
    }

    /**
     * Prforms allowance transfer of asset balance between holders adding specified comment.
     * Resolves asset implementation contract for the caller and forwards there arguments along with
     * the caller address.
     *
     * @param _from holder address to take from.
     * @param _to holder address to give to.
     * @param _value amount to transfer.
     * @param _reference transfer comment to be included in a EToken2's Transfer event.
     *
     * @return success.
     */
    function transferFromWithReference(
        address _from,
        address _to,
        uint _value,
        string memory _reference)
    public returns(bool) {
        return _getAsset()._performTransferFromWithReference(
            _from,
            _to,
            _value,
            _reference,
            msg.sender
        );
    }

    /**
     * Performs transfer call on the EToken2 by the name of specified sender.
     *
     * Can only be called by asset implementation contract assigned to sender.
     *
     * @param _from holder address to take from.
     * @param _to holder address to give to.
     * @param _value amount to transfer.
     * @param _reference transfer comment to be included in a EToken2's Transfer event.
     * @param _sender initial caller.
     *
     * @return success.
     */
    function _forwardTransferFromWithReference(
        address _from,
        address _to,
        uint _value,
        string memory _reference,
        address _sender)
    public onlyImplementationFor(_sender) returns(bool) {
        return etoken2.proxyTransferFromWithReference(
            _from,
            _to,
            _value,
            etoken2Symbol,
            _reference,
            _sender
        );
    }

    /**
     * Prforms allowance transfer of asset balance between holders.
     *
     * @param _from holder address to take from.
     * @param _icap recipient ICAP address to give to.
     * @param _value amount to transfer.
     *
     * @return success.
     */
    function transferFromToICAP(address _from, bytes32 _icap, uint _value)
    public returns(bool) {
        return transferFromToICAPWithReference(_from, _icap, _value, '');
    }

    /**
     * Prforms allowance transfer of asset balance between holders adding specified comment.
     * Resolves asset implementation contract for the caller and forwards there arguments along with
     * the caller address.
     *
     * @param _from holder address to take from.
     * @param _icap recipient ICAP address to give to.
     * @param _value amount to transfer.
     * @param _reference transfer comment to be included in a EToken2's Transfer event.
     *
     * @return success.
     */
    function transferFromToICAPWithReference(
        address _from,
        bytes32 _icap,
        uint _value,
        string memory _reference)
    public returns(bool) {
        return _getAsset()._performTransferFromToICAPWithReference(
            _from,
            _icap,
            _value,
            _reference,
            msg.sender
        );
    }

    /**
     * Performs allowance transfer to ICAP call on the EToken2 by the name of specified sender.
     *
     * Can only be called by asset implementation contract assigned to sender.
     *
     * @param _from holder address to take from.
     * @param _icap recipient ICAP address to give to.
     * @param _value amount to transfer.
     * @param _reference transfer comment to be included in a EToken2's Transfer event.
     * @param _sender initial caller.
     *
     * @return success.
     */
    function _forwardTransferFromToICAPWithReference(
        address _from,
        bytes32 _icap,
        uint _value,
        string memory _reference,
        address _sender)
    public onlyImplementationFor(_sender) returns(bool) {
        return etoken2.proxyTransferFromToICAPWithReference(
            _from,
            _icap,
            _value,
            _reference,
            _sender
        );
    }

    /**
     * Sets asset spending allowance for a specified spender.
     * Resolves asset implementation contract for the caller and forwards there arguments along with
     * the caller address.
     *
     * @param _spender holder address to set allowance to.
     * @param _value amount to allow.
     *
     * @return success.
     */
    function approve(address _spender, uint _value) public returns(bool) {
        return _getAsset()._performApprove(_spender, _value, msg.sender);
    }

    /**
     * Performs allowance setting call on the EToken2 by the name of specified sender.
     *
     * Can only be called by asset implementation contract assigned to sender.
     *
     * @param _spender holder address to set allowance to.
     * @param _value amount to allow.
     * @param _sender initial caller.
     *
     * @return success.
     */
    function _forwardApprove(address _spender, uint _value, address _sender)
    public onlyImplementationFor(_sender) returns(bool) {
        return etoken2.proxyApprove(_spender, _value, etoken2Symbol, _sender);
    }

    /**
     * Emits ERC20 Transfer event on this contract.
     *
     * Can only be, and, called by assigned EToken2 when asset transfer happens.
     */
    function emitTransfer(address _from, address _to, uint _value) public onlyEToken2() {
        emit Transfer(_from, _to, _value);
    }

    /**
     * Emits ERC20 Approval event on this contract.
     *
     * Can only be, and, called by assigned EToken2 when asset allowance set happens.
     */
    function emitApprove(address _from, address _spender, uint _value) public onlyEToken2() {
        emit Approval(_from, _spender, _value);
    }

    /**
     * Resolves asset implementation contract for the caller and forwards there transaction data,
     * along with the value. This allows for proxy interface growth.
     */
    function () external payable {
        _getAsset()._performGeneric.value(msg.value)(msg.data, msg.sender);
        _returnReturnData(true);
    }

    // Interface functions to allow specifying ICAP addresses as strings.
    function transferToICAP(string memory _icap, uint _value) public returns(bool) {
        return transferToICAPWithReference(_icap, _value, '');
    }

    function transferToICAPWithReference(string memory _icap, uint _value, string memory _reference)
    public returns(bool) {
        return transferToICAPWithReference(_bytes32(_icap), _value, _reference);
    }

    function transferFromToICAP(address _from, string memory _icap, uint _value)
        public returns(bool)
    {
        return transferFromToICAPWithReference(_from, _icap, _value, '');
    }

    function transferFromToICAPWithReference(
        address _from,
        string memory _icap,
        uint _value,
        string memory _reference)
    public returns(bool) {
        return transferFromToICAPWithReference(_from, _bytes32(_icap), _value, _reference);
    }

    /**
     * Indicates an upgrade freeze-time start, and the next asset implementation contract.
     */
    event UpgradeProposed(address newVersion);
    event UpgradePurged(address newVersion);
    event UpgradeCommited(address newVersion);
    event OptedOut(address sender, address version);
    event OptedIn(address sender, address version);

    // Current asset implementation contract address.
    address internal latestVersion;

    // Proposed next asset implementation contract address.
    address internal pendingVersion;

    // Upgrade freeze-time start.
    uint internal pendingVersionTimestamp;

    // Timespan for users to review the new implementation and make decision.
    uint internal constant UPGRADE_FREEZE_TIME = 3 days;

    // Asset implementation contract address that user decided to stick with.
    // 0x0 means that user uses latest version.
    mapping(address => address) internal userOptOutVersion;

    /**
     * Only asset implementation contract assigned to sender is allowed to call.
     */
    modifier onlyImplementationFor(address _sender) {
        if (getVersionFor(_sender) == msg.sender) {
            _;
        }
    }

    /**
     * Returns asset implementation contract address assigned to sender.
     *
     * @param _sender sender address.
     *
     * @return asset implementation contract address.
     */
    function getVersionFor(address _sender) public view returns(address) {
        return userOptOutVersion[_sender] == address(0) ?
            latestVersion : userOptOutVersion[_sender];
    }

    /**
     * Returns current asset implementation contract address.
     *
     * @return asset implementation contract address.
     */
    function getLatestVersion() public view returns(address) {
        return latestVersion;
    }

    /**
     * Returns proposed next asset implementation contract address.
     *
     * @return asset implementation contract address.
     */
    function getPendingVersion() public view returns(address) {
        return pendingVersion;
    }

    /**
     * Returns upgrade freeze-time start.
     *
     * @return freeze-time start.
     */
    function getPendingVersionTimestamp() public view returns(uint) {
        return pendingVersionTimestamp;
    }

    /**
     * Propose next asset implementation contract address.
     *
     * Can only be called by current asset owner.
     *
     * Note: freeze-time should not be applied for the initial setup.
     *
     * @param _newVersion asset implementation contract address.
     *
     * @return success.
     */
    function proposeUpgrade(address _newVersion) public onlyAssetOwner() returns(bool) {
        // Should not already be in the upgrading process.
        if (pendingVersion != address(0)) {
            return false;
        }
        // New version address should be other than 0x0.
        if (_newVersion == address(0)) {
            return false;
        }
        // Don't apply freeze-time for the initial setup.
        if (latestVersion == address(0)) {
            latestVersion = _newVersion;
            return true;
        }
        pendingVersion = _newVersion;
        // solhint-disable-next-line not-rely-on-time
        pendingVersionTimestamp = now;
        emit UpgradeProposed(_newVersion);
        return true;
    }

    /**
     * Cancel the pending upgrade process.
     *
     * Can only be called by current asset owner.
     *
     * @return success.
     */
    function purgeUpgrade() public onlyAssetOwner() returns(bool) {
        if (pendingVersion == address(0)) {
            return false;
        }
        emit UpgradePurged(pendingVersion);
        delete pendingVersion;
        delete pendingVersionTimestamp;
        return true;
    }

    /**
     * Finalize an upgrade process setting new asset implementation contract address.
     *
     * Can only be called after an upgrade freeze-time.
     *
     * @return success.
     */
    function commitUpgrade() public returns(bool) {
        if (pendingVersion == address(0)) {
            return false;
        }
        // solhint-disable-next-line not-rely-on-time
        if (pendingVersionTimestamp + UPGRADE_FREEZE_TIME > now) {
            return false;
        }
        latestVersion = pendingVersion;
        delete pendingVersion;
        delete pendingVersionTimestamp;
        emit UpgradeCommited(latestVersion);
        return true;
    }

    /**
     * Disagree with proposed upgrade, and stick with current asset implementation
     * until further explicit agreement to upgrade.
     *
     * @return success.
     */
    function optOut() public returns(bool) {
        if (userOptOutVersion[msg.sender] != address(0)) {
            return false;
        }
        userOptOutVersion[msg.sender] = latestVersion;
        emit OptedOut(msg.sender, latestVersion);
        return true;
    }

    /**
     * Implicitly agree to upgrade to current and future asset implementation upgrades,
     * until further explicit disagreement.
     *
     * @return success.
     */
    function optIn() public returns(bool) {
        delete userOptOutVersion[msg.sender];
        emit OptedIn(msg.sender, latestVersion);
        return true;
    }

    // Backwards compatibility.
    function multiAsset() public view returns(EToken2Interface) {
        return etoken2;
    }
}

/**
 *Submitted for verification at Etherscan.io on 2019-05-28
*/

// File: contracts/EToken2Interface.sol

pragma solidity 0.5.8;


contract RegistryICAPInterface {
    function parse(bytes32 _icap) public view returns(address, bytes32, bool);
    function institutions(bytes32 _institution) public view returns(address);
}


contract EToken2Interface {
    function registryICAP() public view returns(RegistryICAPInterface);
    function baseUnit(bytes32 _symbol) public view returns(uint8);
    function description(bytes32 _symbol) public view returns(string memory);
    function owner(bytes32 _symbol) public view returns(address);
    function isOwner(address _owner, bytes32 _symbol) public view returns(bool);
    function totalSupply(bytes32 _symbol) public view returns(uint);
    function balanceOf(address _holder, bytes32 _symbol) public view returns(uint);
    function isLocked(bytes32 _symbol) public view returns(bool);

    function issueAsset(
        bytes32 _symbol,
        uint _value,
        string memory _name,
        string memory _description,
        uint8 _baseUnit,
        bool _isReissuable)
    public returns(bool);

    function reissueAsset(bytes32 _symbol, uint _value) public returns(bool);
    function revokeAsset(bytes32 _symbol, uint _value) public returns(bool);
    function setProxy(address _address, bytes32 _symbol) public returns(bool);
    function lockAsset(bytes32 _symbol) public returns(bool);

    function proxyTransferFromToICAPWithReference(
        address _from,
        bytes32 _icap,
        uint _value,
        string memory _reference,
        address _sender)
    public returns(bool);

    function proxyApprove(address _spender, uint _value, bytes32 _symbol, address _sender)
    public returns(bool);
    
    function allowance(address _from, address _spender, bytes32 _symbol) public view returns(uint);

    function proxyTransferFromWithReference(
        address _from,
        address _to,
        uint _value,
        bytes32 _symbol,
        string memory _reference,
        address _sender)
    public returns(bool);

    function changeOwnership(bytes32 _symbol, address _newOwner) public returns(bool);
}

// File: contracts/AssetInterface.sol

pragma solidity 0.5.8;


contract AssetInterface {
    function _performTransferWithReference(
        address _to,
        uint _value,
        string memory _reference,
        address _sender)
    public returns(bool);

    function _performTransferToICAPWithReference(
        bytes32 _icap,
        uint _value,
        string memory _reference,
        address _sender)
    public returns(bool);

    function _performApprove(address _spender, uint _value, address _sender)
    public returns(bool);

    function _performTransferFromWithReference(
        address _from,
        address _to,
        uint _value,
        string memory _reference,
        address _sender)
    public returns(bool);

    function _performTransferFromToICAPWithReference(
        address _from,
        bytes32 _icap,
        uint _value,
        string memory _reference,
        address _sender)
    public returns(bool);

    function _performGeneric(bytes memory, address) public payable {
        revert();
    }
}

// File: contracts/ERC20Interface.sol

pragma solidity 0.5.8;


contract ERC20Interface {
    event Transfer(address indexed from, address indexed to, uint256 value);
    event Approval(address indexed from, address indexed spender, uint256 value);

    function totalSupply() public view returns(uint256 supply);
    function balanceOf(address _owner) public view returns(uint256 balance);
    // solhint-disable-next-line no-simple-event-func-name
    function transfer(address _to, uint256 _value) public returns(bool success);
    function transferFrom(address _from, address _to, uint256 _value) public returns(bool success);
    function approve(address _spender, uint256 _value) public returns(bool success);
    function allowance(address _owner, address _spender) public view returns(uint256 remaining);

    // function symbol() constant returns(string);
    function decimals() public view returns(uint8);
    // function name() constant returns(string);
}

// File: contracts/AssetProxyInterface.sol

pragma solidity 0.5.8;



contract AssetProxyInterface is ERC20Interface {
    function _forwardApprove(address _spender, uint _value, address _sender)
    public returns(bool);

    function _forwardTransferFromWithReference(
        address _from,
        address _to,
        uint _value,
        string memory _reference,
        address _sender)
    public returns(bool);

    function _forwardTransferFromToICAPWithReference(
        address _from,
        bytes32 _icap,
        uint _value,
        string memory _reference,
        address _sender)
    public returns(bool);

    function recoverTokens(ERC20Interface _asset, address _receiver, uint _value)
    public returns(bool);

    function etoken2() external view returns(address); // To be replaced by the implicit getter;

    // To be replaced by the implicit getter;
    function etoken2Symbol() external view returns(bytes32);
}

// File: smart-contracts-common/contracts/Bytes32.sol

pragma solidity 0.5.8;


contract Bytes32 {
    function _bytes32(string memory _input) internal pure returns(bytes32 result) {
        assembly {
            result := mload(add(_input, 32))
        }
    }
}

// File: smart-contracts-common/contracts/ReturnData.sol

pragma solidity 0.5.8;


contract ReturnData {
    function _returnReturnData(bool _success) internal pure {
        assembly {
            let returndatastart := 0
            returndatacopy(returndatastart, 0, returndatasize)
            switch _success case 0 { revert(returndatastart, returndatasize) }
                default { return(returndatastart, returndatasize) }
        }
    }

    function _assemblyCall(address _destination, uint _value, bytes memory _data)
    internal returns(bool success) {
        assembly {
            success := call(gas, _destination, _value, add(_data, 32), mload(_data), 0, 0)
        }
    }
}

// File: contracts/AssetProxy.sol

pragma solidity 0.5.8;








/**
 * @title EToken2 Asset Proxy.
 *
 * Proxy implements ERC20 interface and acts as a gateway to a single EToken2 asset.
 * Proxy adds etoken2Symbol and caller(sender) when forwarding requests to EToken2.
 * Every request that is made by caller first sent to the specific asset implementation
 * contract, which then calls back to be forwarded onto EToken2.
 *
 * Calls flow: Caller ->
 *             Proxy.func(...) ->
 *             Asset._performFunc(..., Caller.address) ->
 *             Proxy._forwardFunc(..., Caller.address) ->
 *             Platform.proxyFunc(..., symbol, Caller.address)
 *
 * Generic call flow: Caller ->
 *             Proxy.unknownFunc(...) ->
 *             Asset._performGeneric(..., Caller.address) ->
 *             Asset.unknownFunc(...)
 *
 * Asset implementation contract is mutable, but each user have an option to stick with
 * old implementation, through explicit decision made in timely manner, if he doesn't agree
 * with new rules.
 * Each user have a possibility to upgrade to latest asset contract implementation, without the
 * possibility to rollback.
 *
 * Note: all the non constant functions return false instead of throwing in case if state change
 * didn't happen yet.
 */
contract AssetProxy is ERC20Interface, AssetProxyInterface, Bytes32, ReturnData {
    // Assigned EToken2, immutable.
    EToken2Interface public etoken2;

    // Assigned symbol, immutable.
    bytes32 public etoken2Symbol;

    // Assigned name, immutable. For UI.
    string public name;
    string public symbol;

    /**
     * Sets EToken2 address, assigns symbol and name.
     *
     * Can be set only once.
     *
     * @param _etoken2 EToken2 contract address.
     * @param _symbol assigned symbol.
     * @param _name assigned name.
     *
     * @return success.
     */
    function init(EToken2Interface _etoken2, string memory _symbol, string memory _name)
        public returns(bool)
    {
        if (address(etoken2) != address(0)) {
            return false;
        }
        etoken2 = _etoken2;
        etoken2Symbol = _bytes32(_symbol);
        name = _name;
        symbol = _symbol;
        return true;
    }

    /**
     * Only EToken2 is allowed to call.
     */
    modifier onlyEToken2() {
        if (msg.sender == address(etoken2)) {
            _;
        }
    }

    /**
     * Only current asset owner is allowed to call.
     */
    modifier onlyAssetOwner() {
        if (etoken2.isOwner(msg.sender, etoken2Symbol)) {
            _;
        }
    }

    /**
     * Returns asset implementation contract for current caller.
     *
     * @return asset implementation contract.
     */
    function _getAsset() internal view returns(AssetInterface) {
        return AssetInterface(getVersionFor(msg.sender));
    }

    /**
     * Recovers tokens on proxy contract
     *
     * @param _asset type of tokens to recover.
     * @param _value tokens that will be recovered.
     * @param _receiver address where to send recovered tokens.
     *
     * @return success.
     */
    function recoverTokens(ERC20Interface _asset, address _receiver, uint _value)
    public onlyAssetOwner() returns(bool) {
        return _asset.transfer(_receiver, _value);
    }

    /**
     * Returns asset total supply.
     *
     * @return asset total supply.
     */
    function totalSupply() public view returns(uint) {
        return etoken2.totalSupply(etoken2Symbol);
    }

    /**
     * Returns asset balance for a particular holder.
     *
     * @param _owner holder address.
     *
     * @return holder balance.
     */
    function balanceOf(address _owner) public view returns(uint) {
        return etoken2.balanceOf(_owner, etoken2Symbol);
    }

    /**
     * Returns asset allowance from one holder to another.
     *
     * @param _from holder that allowed spending.
     * @param _spender holder that is allowed to spend.
     *
     * @return holder to spender allowance.
     */
    function allowance(address _from, address _spender) public view returns(uint) {
        return etoken2.allowance(_from, _spender, etoken2Symbol);
    }

    /**
     * Returns asset decimals.
     *
     * @return asset decimals.
     */
    function decimals() public view returns(uint8) {
        return etoken2.baseUnit(etoken2Symbol);
    }

    /**
     * Transfers asset balance from the caller to specified receiver.
     *
     * @param _to holder address to give to.
     * @param _value amount to transfer.
     *
     * @return success.
     */
    function transfer(address _to, uint _value) public returns(bool) {
        return transferWithReference(_to, _value, '');
    }

    /**
     * Transfers asset balance from the caller to specified receiver adding specified comment.
     * Resolves asset implementation contract for the caller and forwards there arguments along with
     * the caller address.
     *
     * @param _to holder address to give to.
     * @param _value amount to transfer.
     * @param _reference transfer comment to be included in a EToken2's Transfer event.
     *
     * @return success.
     */
    function transferWithReference(address _to, uint _value, string memory _reference)
    public returns(bool) {
        return _getAsset()._performTransferWithReference(
            _to, _value, _reference, msg.sender);
    }

    /**
     * Transfers asset balance from the caller to specified ICAP.
     *
     * @param _icap recipient ICAP to give to.
     * @param _value amount to transfer.
     *
     * @return success.
     */
    function transferToICAP(bytes32 _icap, uint _value) public returns(bool) {
        return transferToICAPWithReference(_icap, _value, '');
    }

    /**
     * Transfers asset balance from the caller to specified ICAP adding specified comment.
     * Resolves asset implementation contract for the caller and forwards there arguments along with
     * the caller address.
     *
     * @param _icap recipient ICAP to give to.
     * @param _value amount to transfer.
     * @param _reference transfer comment to be included in a EToken2's Transfer event.
     *
     * @return success.
     */
    function transferToICAPWithReference(
        bytes32 _icap,
        uint _value,
        string memory _reference)
    public returns(bool) {
        return _getAsset()._performTransferToICAPWithReference(
            _icap, _value, _reference, msg.sender);
    }

    /**
     * Prforms allowance transfer of asset balance between holders.
     *
     * @param _from holder address to take from.
     * @param _to holder address to give to.
     * @param _value amount to transfer.
     *
     * @return success.
     */
    function transferFrom(address _from, address _to, uint _value) public returns(bool) {
        return transferFromWithReference(_from, _to, _value, '');
    }

    /**
     * Prforms allowance transfer of asset balance between holders adding specified comment.
     * Resolves asset implementation contract for the caller and forwards there arguments along with
     * the caller address.
     *
     * @param _from holder address to take from.
     * @param _to holder address to give to.
     * @param _value amount to transfer.
     * @param _reference transfer comment to be included in a EToken2's Transfer event.
     *
     * @return success.
     */
    function transferFromWithReference(
        address _from,
        address _to,
        uint _value,
        string memory _reference)
    public returns(bool) {
        return _getAsset()._performTransferFromWithReference(
            _from,
            _to,
            _value,
            _reference,
            msg.sender
        );
    }

    /**
     * Performs transfer call on the EToken2 by the name of specified sender.
     *
     * Can only be called by asset implementation contract assigned to sender.
     *
     * @param _from holder address to take from.
     * @param _to holder address to give to.
     * @param _value amount to transfer.
     * @param _reference transfer comment to be included in a EToken2's Transfer event.
     * @param _sender initial caller.
     *
     * @return success.
     */
    function _forwardTransferFromWithReference(
        address _from,
        address _to,
        uint _value,
        string memory _reference,
        address _sender)
    public onlyImplementationFor(_sender) returns(bool) {
        return etoken2.proxyTransferFromWithReference(
            _from,
            _to,
            _value,
            etoken2Symbol,
            _reference,
            _sender
        );
    }

    /**
     * Prforms allowance transfer of asset balance between holders.
     *
     * @param _from holder address to take from.
     * @param _icap recipient ICAP address to give to.
     * @param _value amount to transfer.
     *
     * @return success.
     */
    function transferFromToICAP(address _from, bytes32 _icap, uint _value)
    public returns(bool) {
        return transferFromToICAPWithReference(_from, _icap, _value, '');
    }

    /**
     * Prforms allowance transfer of asset balance between holders adding specified comment.
     * Resolves asset implementation contract for the caller and forwards there arguments along with
     * the caller address.
     *
     * @param _from holder address to take from.
     * @param _icap recipient ICAP address to give to.
     * @param _value amount to transfer.
     * @param _reference transfer comment to be included in a EToken2's Transfer event.
     *
     * @return success.
     */
    function transferFromToICAPWithReference(
        address _from,
        bytes32 _icap,
        uint _value,
        string memory _reference)
    public returns(bool) {
        return _getAsset()._performTransferFromToICAPWithReference(
            _from,
            _icap,
            _value,
            _reference,
            msg.sender
        );
    }

    /**
     * Performs allowance transfer to ICAP call on the EToken2 by the name of specified sender.
     *
     * Can only be called by asset implementation contract assigned to sender.
     *
     * @param _from holder address to take from.
     * @param _icap recipient ICAP address to give to.
     * @param _value amount to transfer.
     * @param _reference transfer comment to be included in a EToken2's Transfer event.
     * @param _sender initial caller.
     *
     * @return success.
     */
    function _forwardTransferFromToICAPWithReference(
        address _from,
        bytes32 _icap,
        uint _value,
        string memory _reference,
        address _sender)
    public onlyImplementationFor(_sender) returns(bool) {
        return etoken2.proxyTransferFromToICAPWithReference(
            _from,
            _icap,
            _value,
            _reference,
            _sender
        );
    }

    /**
     * Sets asset spending allowance for a specified spender.
     * Resolves asset implementation contract for the caller and forwards there arguments along with
     * the caller address.
     *
     * @param _spender holder address to set allowance to.
     * @param _value amount to allow.
     *
     * @return success.
     */
    function approve(address _spender, uint _value) public returns(bool) {
        return _getAsset()._performApprove(_spender, _value, msg.sender);
    }

    /**
     * Performs allowance setting call on the EToken2 by the name of specified sender.
     *
     * Can only be called by asset implementation contract assigned to sender.
     *
     * @param _spender holder address to set allowance to.
     * @param _value amount to allow.
     * @param _sender initial caller.
     *
     * @return success.
     */
    function _forwardApprove(address _spender, uint _value, address _sender)
    public onlyImplementationFor(_sender) returns(bool) {
        return etoken2.proxyApprove(_spender, _value, etoken2Symbol, _sender);
    }

    /**
     * Emits ERC20 Transfer event on this contract.
     *
     * Can only be, and, called by assigned EToken2 when asset transfer happens.
     */
    function emitTransfer(address _from, address _to, uint _value) public onlyEToken2() {
        emit Transfer(_from, _to, _value);
    }

    /**
     * Emits ERC20 Approval event on this contract.
     *
     * Can only be, and, called by assigned EToken2 when asset allowance set happens.
     */
    function emitApprove(address _from, address _spender, uint _value) public onlyEToken2() {
        emit Approval(_from, _spender, _value);
    }

    /**
     * Resolves asset implementation contract for the caller and forwards there transaction data,
     * along with the value. This allows for proxy interface growth.
     */
    function () external payable {
        _getAsset()._performGeneric.value(msg.value)(msg.data, msg.sender);
        _returnReturnData(true);
    }

    // Interface functions to allow specifying ICAP addresses as strings.
    function transferToICAP(string memory _icap, uint _value) public returns(bool) {
        return transferToICAPWithReference(_icap, _value, '');
    }

    function transferToICAPWithReference(string memory _icap, uint _value, string memory _reference)
    public returns(bool) {
        return transferToICAPWithReference(_bytes32(_icap), _value, _reference);
    }

    function transferFromToICAP(address _from, string memory _icap, uint _value)
        public returns(bool)
    {
        return transferFromToICAPWithReference(_from, _icap, _value, '');
    }

    function transferFromToICAPWithReference(
        address _from,
        string memory _icap,
        uint _value,
        string memory _reference)
    public returns(bool) {
        return transferFromToICAPWithReference(_from, _bytes32(_icap), _value, _reference);
    }

    /**
     * Indicates an upgrade freeze-time start, and the next asset implementation contract.
     */
    event UpgradeProposed(address newVersion);
    event UpgradePurged(address newVersion);
    event UpgradeCommited(address newVersion);
    event OptedOut(address sender, address version);
    event OptedIn(address sender, address version);

    // Current asset implementation contract address.
    address internal latestVersion;

    // Proposed next asset implementation contract address.
    address internal pendingVersion;

    // Upgrade freeze-time start.
    uint internal pendingVersionTimestamp;

    // Timespan for users to review the new implementation and make decision.
    uint internal constant UPGRADE_FREEZE_TIME = 3 days;

    // Asset implementation contract address that user decided to stick with.
    // 0x0 means that user uses latest version.
    mapping(address => address) internal userOptOutVersion;

    /**
     * Only asset implementation contract assigned to sender is allowed to call.
     */
    modifier onlyImplementationFor(address _sender) {
        if (getVersionFor(_sender) == msg.sender) {
            _;
        }
    }

    /**
     * Returns asset implementation contract address assigned to sender.
     *
     * @param _sender sender address.
     *
     * @return asset implementation contract address.
     */
    function getVersionFor(address _sender) public view returns(address) {
        return userOptOutVersion[_sender] == address(0) ?
            latestVersion : userOptOutVersion[_sender];
    }

    /**
     * Returns current asset implementation contract address.
     *
     * @return asset implementation contract address.
     */
    function getLatestVersion() public view returns(address) {
        return latestVersion;
    }

    /**
     * Returns proposed next asset implementation contract address.
     *
     * @return asset implementation contract address.
     */
    function getPendingVersion() public view returns(address) {
        return pendingVersion;
    }

    /**
     * Returns upgrade freeze-time start.
     *
     * @return freeze-time start.
     */
    function getPendingVersionTimestamp() public view returns(uint) {
        return pendingVersionTimestamp;
    }

    /**
     * Propose next asset implementation contract address.
     *
     * Can only be called by current asset owner.
     *
     * Note: freeze-time should not be applied for the initial setup.
     *
     * @param _newVersion asset implementation contract address.
     *
     * @return success.
     */
    function proposeUpgrade(address _newVersion) public onlyAssetOwner() returns(bool) {
        // Should not already be in the upgrading process.
        if (pendingVersion != address(0)) {
            return false;
        }
        // New version address should be other than 0x0.
        if (_newVersion == address(0)) {
            return false;
        }
        // Don't apply freeze-time for the initial setup.
        if (latestVersion == address(0)) {
            latestVersion = _newVersion;
            return true;
        }
        pendingVersion = _newVersion;
        // solhint-disable-next-line not-rely-on-time
        pendingVersionTimestamp = now;
        emit UpgradeProposed(_newVersion);
        return true;
    }

    /**
     * Cancel the pending upgrade process.
     *
     * Can only be called by current asset owner.
     *
     * @return success.
     */
    function purgeUpgrade() public onlyAssetOwner() returns(bool) {
        if (pendingVersion == address(0)) {
            return false;
        }
        emit UpgradePurged(pendingVersion);
        delete pendingVersion;
        delete pendingVersionTimestamp;
        return true;
    }

    /**
     * Finalize an upgrade process setting new asset implementation contract address.
     *
     * Can only be called after an upgrade freeze-time.
     *
     * @return success.
     */
    function commitUpgrade() public returns(bool) {
        if (pendingVersion == address(0)) {
            return false;
        }
        // solhint-disable-next-line not-rely-on-time
        if (pendingVersionTimestamp + UPGRADE_FREEZE_TIME > now) {
            return false;
        }
        latestVersion = pendingVersion;
        delete pendingVersion;
        delete pendingVersionTimestamp;
        emit UpgradeCommited(latestVersion);
        return true;
    }

    /**
     * Disagree with proposed upgrade, and stick with current asset implementation
     * until further explicit agreement to upgrade.
     *
     * @return success.
     */
    function optOut() public returns(bool) {
        if (userOptOutVersion[msg.sender] != address(0)) {
            return false;
        }
        userOptOutVersion[msg.sender] = latestVersion;
        emit OptedOut(msg.sender, latestVersion);
        return true;
    }

    /**
     * Implicitly agree to upgrade to current and future asset implementation upgrades,
     * until further explicit disagreement.
     *
     * @return success.
     */
    function optIn() public returns(bool) {
        delete userOptOutVersion[msg.sender];
        emit OptedIn(msg.sender, latestVersion);
        return true;
    }

    // Backwards compatibility.
    function multiAsset() public view returns(EToken2Interface) {
        return etoken2;
    }
}

// This software is a subject to Ambisafe License Agreement.
// No use or distribution is allowed without written permission from Ambisafe.
// https://ambisafe.com/terms.pdf

pragma solidity 0.4.8;

contract Ambi2 {
    function claimFor(address _address, address _owner) returns(bool);
    function hasRole(address _from, bytes32 _role, address _to) constant returns(bool);
    function isOwner(address _node, address _owner) constant returns(bool);
}

contract Ambi2Enabled {
    Ambi2 ambi2;

    modifier onlyRole(bytes32 _role) {
        if (address(ambi2) != 0x0 && ambi2.hasRole(this, _role, msg.sender)) {
            _;
        }
    }

    // Perform only after claiming the node, or claim in the same tx.
    function setupAmbi2(Ambi2 _ambi2) returns(bool) {
        if (address(ambi2) != 0x0) {
            return false;
        }

        ambi2 = _ambi2;
        return true;
    }
}

contract Ambi2EnabledFull is Ambi2Enabled {
    // Setup and claim atomically.
    function setupAmbi2(Ambi2 _ambi2) returns(bool) {
        if (address(ambi2) != 0x0) {
            return false;
        }
        if (!_ambi2.claimFor(this, msg.sender) && !_ambi2.isOwner(this, msg.sender)) {
            return false;
        }

        ambi2 = _ambi2;
        return true;
    }
}

contract RegistryICAPInterface {
    function parse(bytes32 _icap) constant returns(address, bytes32, bool);
    function institutions(bytes32 _institution) constant returns(address);
}

contract Cosigner {
    function consumeOperation(bytes32 _opHash, uint _required) returns(bool);
}

contract Emitter {
    function emitTransfer(address _from, address _to, bytes32 _symbol, uint _value, string _reference);
    function emitTransferToICAP(address _from, address _to, bytes32 _icap, uint _value, string _reference);
    function emitIssue(bytes32 _symbol, uint _value, address _by);
    function emitRevoke(bytes32 _symbol, uint _value, address _by);
    function emitOwnershipChange(address _from, address _to, bytes32 _symbol);
    function emitApprove(address _from, address _spender, bytes32 _symbol, uint _value);
    function emitRecovery(address _from, address _to, address _by);
    function emitError(bytes32 _message);
    function emitChange(bytes32 _symbol);
}

contract Proxy {
    function emitTransfer(address _from, address _to, uint _value);
    function emitApprove(address _from, address _spender, uint _value);
}

/**
 * @title EToken2.
 *
 * The official Ambisafe assets platform powering all kinds of tokens.
 * EToken2 uses EventsHistory contract to keep events, so that in case it needs to be redeployed
 * at some point, all the events keep appearing at the same place.
 *
 * Every asset is meant to be used through a proxy contract. Only one proxy contract have access
 * rights for a particular asset.
 *
 * Features: assets issuance, transfers, allowances, supply adjustments, lost wallet access recovery.
 *           cosignature check, ICAP.
 *
 * Note: all the non constant functions return false instead of throwing in case if state change
 * didn't happen yet.
 */
contract EToken2 is Ambi2EnabledFull {
    mapping(bytes32 => bool) switches;

    function isEnabled(bytes32 _switch) constant returns(bool) {
        return switches[_switch];
    }

    function enableSwitch(bytes32 _switch) onlyRole('issuance') returns(bool) {
        switches[_switch] = true;
        return true;
    }

    modifier checkEnabledSwitch(bytes32 _switch) {
        if (!isEnabled(_switch)) {
            _error('Feature is disabled');
        } else {
            _;
        }
    }

    enum Features { Issue, TransferWithReference, Revoke, ChangeOwnership, Allowances, ICAP }

    // Structure of a particular asset.
    struct Asset {
        uint owner;                       // Asset's owner id.
        uint totalSupply;                 // Asset's total supply.
        string name;                      // Asset's name, for information purposes.
        string description;               // Asset's description, for information purposes.
        bool isReissuable;                // Indicates if asset have dynamic of fixed supply.
        uint8 baseUnit;                   // Proposed number of decimals.
        bool isLocked;                    // Are changes still allowed.
        mapping(uint => Wallet) wallets;  // Holders wallets.
    }

    // Structure of an asset holder wallet for particular asset.
    struct Wallet {
        uint balance;
        mapping(uint => uint) allowance;
    }

    // Structure of an asset holder.
    struct Holder {
        address addr;                    // Current address of the holder.
        Cosigner cosigner;               // Cosigner contract for 2FA and recovery.
        mapping(address => bool) trust;  // Addresses that are trusted with recovery proocedure.
    }

    // Iterable mapping pattern is used for holders.
    uint public holdersCount;
    mapping(uint => Holder) public holders;

    // This is an access address mapping. Many addresses may have access to a single holder.
    mapping(address => uint) holderIndex;

    // Asset symbol to asset mapping.
    mapping(bytes32 => Asset) public assets;

    // Asset symbol to asset proxy mapping.
    mapping(bytes32 => address) public proxies;

    // ICAP registry contract.
    RegistryICAPInterface public registryICAP;

    // Should use interface of the emitter, but address of events history.
    Emitter public eventsHistory;

    /**
     * Emits Error event with specified error message.
     *
     * Should only be used if no state changes happened.
     *
     * @param _message error message.
     */
    function _error(bytes32 _message) internal {
        eventsHistory.emitError(_message);
    }

    /**
     * Sets EventsHstory contract address.
     *
     * Can be set only once, and only by contract owner.
     *
     * @param _eventsHistory EventsHistory contract address.
     *
     * @return success.
     */
    function setupEventsHistory(Emitter _eventsHistory) onlyRole('setup') returns(bool) {
        if (address(eventsHistory) != 0) {
            return false;
        }
        eventsHistory = _eventsHistory;
        return true;
    }

    /**
     * Sets RegistryICAP contract address.
     *
     * Can be set only once, and only by contract owner.
     *
     * @param _registryICAP RegistryICAP contract address.
     *
     * @return success.
     */
    function setupRegistryICAP(RegistryICAPInterface _registryICAP) onlyRole('setup') returns(bool) {
        if (address(registryICAP) != 0) {
            return false;
        }
        registryICAP = _registryICAP;
        return true;
    }

    /**
     * Emits Error if called not by asset owner.
     */
    modifier onlyOwner(bytes32 _symbol) {
        if (_isSignedOwner(_symbol)) {
            _;
        } else {
            _error('Only owner: access denied');
        }
    }

    /**
     * Emits Error if called not by asset proxy.
     */
    modifier onlyProxy(bytes32 _symbol) {
        if (_isProxy(_symbol)) {
            _;
        } else {
            _error('Only proxy: access denied');
        }
    }

    /**
     * Emits Error if _from doesn't trust _to.
     */
    modifier checkTrust(address _from, address _to) {
        if (isTrusted(_from, _to)) {
            _;
        } else {
            _error('Only trusted: access denied');
        }
    }

    function _isSignedOwner(bytes32 _symbol) internal checkSigned(getHolderId(msg.sender), 1) returns(bool) {
        return isOwner(msg.sender, _symbol);
    }

    /**
     * Check asset existance.
     *
     * @param _symbol asset symbol.
     *
     * @return asset existance.
     */
    function isCreated(bytes32 _symbol) constant returns(bool) {
        return assets[_symbol].owner != 0;
    }

    function isLocked(bytes32 _symbol) constant returns(bool) {
        return assets[_symbol].isLocked;
    }

    /**
     * Returns asset decimals.
     *
     * @param _symbol asset symbol.
     *
     * @return asset decimals.
     */
    function baseUnit(bytes32 _symbol) constant returns(uint8) {
        return assets[_symbol].baseUnit;
    }

    /**
     * Returns asset name.
     *
     * @param _symbol asset symbol.
     *
     * @return asset name.
     */
    function name(bytes32 _symbol) constant returns(string) {
        return assets[_symbol].name;
    }

    /**
     * Returns asset description.
     *
     * @param _symbol asset symbol.
     *
     * @return asset description.
     */
    function description(bytes32 _symbol) constant returns(string) {
        return assets[_symbol].description;
    }

    /**
     * Returns asset reissuability.
     *
     * @param _symbol asset symbol.
     *
     * @return asset reissuability.
     */
    function isReissuable(bytes32 _symbol) constant returns(bool) {
        return assets[_symbol].isReissuable;
    }

    /**
     * Returns asset owner address.
     *
     * @param _symbol asset symbol.
     *
     * @return asset owner address.
     */
    function owner(bytes32 _symbol) constant returns(address) {
        return holders[assets[_symbol].owner].addr;
    }

    /**
     * Check if specified address has asset owner rights.
     *
     * @param _owner address to check.
     * @param _symbol asset symbol.
     *
     * @return owner rights availability.
     */
    function isOwner(address _owner, bytes32 _symbol) constant returns(bool) {
        return isCreated(_symbol) && (assets[_symbol].owner == getHolderId(_owner));
    }

    /**
     * Returns asset total supply.
     *
     * @param _symbol asset symbol.
     *
     * @return asset total supply.
     */
    function totalSupply(bytes32 _symbol) constant returns(uint) {
        return assets[_symbol].totalSupply;
    }

    /**
     * Returns asset balance for current address of a particular holder.
     *
     * @param _holder holder address.
     * @param _symbol asset symbol.
     *
     * @return holder balance.
     */
    function balanceOf(address _holder, bytes32 _symbol) constant returns(uint) {
        uint holderId = getHolderId(_holder);
        return holders[holderId].addr == _holder ? _balanceOf(holderId, _symbol) : 0;
    }

    /**
     * Returns asset balance for a particular holder id.
     *
     * @param _holderId holder id.
     * @param _symbol asset symbol.
     *
     * @return holder balance.
     */
    function _balanceOf(uint _holderId, bytes32 _symbol) constant internal returns(uint) {
        return assets[_symbol].wallets[_holderId].balance;
    }

    /**
     * Returns current address for a particular holder id.
     *
     * @param _holderId holder id.
     *
     * @return holder address.
     */
    function _address(uint _holderId) constant internal returns(address) {
        return holders[_holderId].addr;
    }

    function _isProxy(bytes32 _symbol) constant internal returns(bool) {
        return proxies[_symbol] == msg.sender;
    }

    /**
     * Sets Proxy contract address for a particular asset.
     *
     * Can be set only once for each asset, and only by contract owner.
     *
     * @param _address Proxy contract address.
     * @param _symbol asset symbol.
     *
     * @return success.
     */
    function setProxy(address _address, bytes32 _symbol) onlyOwner(_symbol) returns(bool) {
        if (proxies[_symbol] != 0x0 && assets[_symbol].isLocked) {
            return false;
        }
        proxies[_symbol] = _address;
        return true;
    }

    /**
     * Transfers asset balance between holders wallets.
     *
     * @param _fromId holder id to take from.
     * @param _toId holder id to give to.
     * @param _value amount to transfer.
     * @param _symbol asset symbol.
     */
    function _transferDirect(uint _fromId, uint _toId, uint _value, bytes32 _symbol) internal {
        assets[_symbol].wallets[_fromId].balance -= _value;
        assets[_symbol].wallets[_toId].balance += _value;
    }

    /**
     * Transfers asset balance between holders wallets.
     *
     * Performs sanity checks and takes care of allowances adjustment.
     *
     * @param _fromId holder id to take from.
     * @param _toId holder id to give to.
     * @param _value amount to transfer.
     * @param _symbol asset symbol.
     * @param _reference transfer comment to be included in a Transfer event.
     * @param _senderId transfer initiator holder id.
     *
     * @return success.
     */
    function _transfer(uint _fromId, uint _toId, uint _value, bytes32 _symbol, string _reference, uint _senderId) internal checkSigned(_senderId, 1) returns(bool) {
        // Should not allow to send to oneself.
        if (_fromId == _toId) {
            _error('Cannot send to oneself');
            return false;
        }
        // Should have positive value.
        if (_value == 0) {
            _error('Cannot send 0 value');
            return false;
        }
        // Should have enough balance.
        if (_balanceOf(_fromId, _symbol) < _value) {
            _error('Insufficient balance');
            return false;
        }
        // Should allow references.
        if (bytes(_reference).length > 0 && !isEnabled(sha3(_symbol, Features.TransferWithReference))) {
            _error('References feature is disabled');
            return false;
        }
        // Should have enough allowance.
        if (_fromId != _senderId && _allowance(_fromId, _senderId, _symbol) < _value) {
            _error('Not enough allowance');
            return false;
        }
        // Adjust allowance.
        if (_fromId != _senderId) {
            assets[_symbol].wallets[_fromId].allowance[_senderId] -= _value;
        }
        _transferDirect(_fromId, _toId, _value, _symbol);
        // Internal Out Of Gas/Throw: revert this transaction too;
        // Recursive Call: safe, all changes already made.
        eventsHistory.emitTransfer(_address(_fromId), _address(_toId), _symbol, _value, _reference);
        _proxyTransferEvent(_fromId, _toId, _value, _symbol);
        return true;
    }

    // Feature and proxy checks done internally due to unknown symbol when the function is called.
    function _transferToICAP(uint _fromId, bytes32 _icap, uint _value, string _reference, uint _senderId) internal returns(bool) {
        var (to, symbol, success) = registryICAP.parse(_icap);
        if (!success) {
            _error('ICAP is not registered');
            return false;
        }
        if (!isEnabled(sha3(symbol, Features.ICAP))) {
            _error('ICAP feature is disabled');
            return false;
        }
        if (!_isProxy(symbol)) {
            _error('Only proxy: access denied');
            return false;
        }
        uint toId = _createHolderId(to);
        if (!_transfer(_fromId, toId, _value, symbol, _reference, _senderId)) {
            return false;
        }
        // Internal Out Of Gas/Throw: revert this transaction too;
        // Recursive Call: safe, all changes already made.
        eventsHistory.emitTransferToICAP(_address(_fromId), _address(toId), _icap, _value, _reference);
        return true;
    }

    function proxyTransferFromToICAPWithReference(address _from, bytes32 _icap, uint _value, string _reference, address _sender) returns(bool) {
        return _transferToICAP(getHolderId(_from), _icap, _value, _reference, getHolderId(_sender));
    }

    /**
     * Ask asset Proxy contract to emit ERC20 compliant Transfer event.
     *
     * @param _fromId holder id to take from.
     * @param _toId holder id to give to.
     * @param _value amount to transfer.
     * @param _symbol asset symbol.
     */
    function _proxyTransferEvent(uint _fromId, uint _toId, uint _value, bytes32 _symbol) internal {
        if (proxies[_symbol] != 0x0) {
            // Internal Out Of Gas/Throw: revert this transaction too;
            // Recursive Call: safe, all changes already made.
            Proxy(proxies[_symbol]).emitTransfer(_address(_fromId), _address(_toId), _value);
        }
    }

    /**
     * Returns holder id for the specified address.
     *
     * @param _holder holder address.
     *
     * @return holder id.
     */
    function getHolderId(address _holder) constant returns(uint) {
        return holderIndex[_holder];
    }

    /**
     * Returns holder id for the specified address, creates it if needed.
     *
     * @param _holder holder address.
     *
     * @return holder id.
     */
    function _createHolderId(address _holder) internal returns(uint) {
        uint holderId = holderIndex[_holder];
        if (holderId == 0) {
            holderId = ++holdersCount;
            holders[holderId].addr = _holder;
            holderIndex[_holder] = holderId;
        }
        return holderId;
    }

    /**
     * Issues new asset token on the platform.
     *
     * Tokens issued with this call go straight to contract owner.
     * Each symbol can be issued only once, and only by contract owner.
     *
     * _isReissuable is included in checkEnabledSwitch because it should be
     * explicitly allowed before issuing new asset.
     *
     * @param _symbol asset symbol.
     * @param _value amount of tokens to issue immediately.
     * @param _name name of the asset.
     * @param _description description for the asset.
     * @param _baseUnit number of decimals.
     * @param _isReissuable dynamic or fixed supply.
     *
     * @return success.
     */
    function issueAsset(bytes32 _symbol, uint _value, string _name, string _description, uint8 _baseUnit, bool _isReissuable) checkEnabledSwitch(sha3(_symbol, _isReissuable, Features.Issue)) returns(bool) {
        // Should have positive value if supply is going to be fixed.
        if (_value == 0 && !_isReissuable) {
            _error('Cannot issue 0 value fixed asset');
            return false;
        }
        // Should not be issued yet.
        if (isCreated(_symbol)) {
            _error('Asset already issued');
            return false;
        }
        uint holderId = _createHolderId(msg.sender);

        assets[_symbol] = Asset(holderId, _value, _name, _description, _isReissuable, _baseUnit, false);
        assets[_symbol].wallets[holderId].balance = _value;
        // Internal Out Of Gas/Throw: revert this transaction too;
        // Recursive Call: safe, all changes already made.
        eventsHistory.emitIssue(_symbol, _value, _address(holderId));
        return true;
    }

    function changeAsset(bytes32 _symbol, string _name, string _description, uint8 _baseUnit) onlyOwner(_symbol) returns(bool) {
        if (isLocked(_symbol)) {
            _error('Asset is locked');
            return false;
        }
        assets[_symbol].name = _name;
        assets[_symbol].description = _description;
        assets[_symbol].baseUnit = _baseUnit;
        eventsHistory.emitChange(_symbol);
        return true;
    }

    function lockAsset(bytes32 _symbol) onlyOwner(_symbol) returns(bool) {
        if (isLocked(_symbol)) {
            _error('Asset is locked');
            return false;
        }
        assets[_symbol].isLocked = true;
        return true;
    }

    /**
     * Issues additional asset tokens if the asset have dynamic supply.
     *
     * Tokens issued with this call go straight to asset owner.
     * Can only be called by asset owner.
     *
     * @param _symbol asset symbol.
     * @param _value amount of additional tokens to issue.
     *
     * @return success.
     */
    function reissueAsset(bytes32 _symbol, uint _value) onlyOwner(_symbol) returns(bool) {
        // Should have positive value.
        if (_value == 0) {
            _error('Cannot reissue 0 value');
            return false;
        }
        Asset asset = assets[_symbol];
        // Should have dynamic supply.
        if (!asset.isReissuable) {
            _error('Cannot reissue fixed asset');
            return false;
        }
        // Resulting total supply should not overflow.
        if (asset.totalSupply + _value < asset.totalSupply) {
            _error('Total supply overflow');
            return false;
        }
        uint holderId = getHolderId(msg.sender);
        asset.wallets[holderId].balance += _value;
        asset.totalSupply += _value;
        // Internal Out Of Gas/Throw: revert this transaction too;
        // Recursive Call: safe, all changes already made.
        eventsHistory.emitIssue(_symbol, _value, _address(holderId));
        _proxyTransferEvent(0, holderId, _value, _symbol);
        return true;
    }

    /**
     * Destroys specified amount of senders asset tokens.
     *
     * @param _symbol asset symbol.
     * @param _value amount of tokens to destroy.
     *
     * @return success.
     */
    function revokeAsset(bytes32 _symbol, uint _value) checkEnabledSwitch(sha3(_symbol, Features.Revoke)) checkSigned(getHolderId(msg.sender), 1) returns(bool) {
        // Should have positive value.
        if (_value == 0) {
            _error('Cannot revoke 0 value');
            return false;
        }
        Asset asset = assets[_symbol];
        uint holderId = getHolderId(msg.sender);
        // Should have enough tokens.
        if (asset.wallets[holderId].balance < _value) {
            _error('Not enough tokens to revoke');
            return false;
        }
        asset.wallets[holderId].balance -= _value;
        asset.totalSupply -= _value;
        // Internal Out Of Gas/Throw: revert this transaction too;
        // Recursive Call: safe, all changes already made.
        eventsHistory.emitRevoke(_symbol, _value, _address(holderId));
        _proxyTransferEvent(holderId, 0, _value, _symbol);
        return true;
    }

    /**
     * Passes asset ownership to specified address.
     *
     * Only ownership is changed, balances are not touched.
     * Can only be called by asset owner.
     *
     * @param _symbol asset symbol.
     * @param _newOwner address to become a new owner.
     *
     * @return success.
     */
    function changeOwnership(bytes32 _symbol, address _newOwner) checkEnabledSwitch(sha3(_symbol, Features.ChangeOwnership)) onlyOwner(_symbol) returns(bool) {
        Asset asset = assets[_symbol];
        uint newOwnerId = _createHolderId(_newOwner);
        // Should pass ownership to another holder.
        if (asset.owner == newOwnerId) {
            _error('Cannot pass ownership to oneself');
            return false;
        }
        address oldOwner = _address(asset.owner);
        asset.owner = newOwnerId;
        // Internal Out Of Gas/Throw: revert this transaction too;
        // Recursive Call: safe, all changes already made.
        eventsHistory.emitOwnershipChange(oldOwner, _address(newOwnerId), _symbol);
        return true;
    }

    function setCosignerAddress(Cosigner _cosigner) checkSigned(_createHolderId(msg.sender), 1) returns(bool) {
        if (!_checkSigned(_cosigner, getHolderId(msg.sender), 1)) {
            _error('Invalid cosigner');
            return false;
        }
        holders[_createHolderId(msg.sender)].cosigner = _cosigner;
        return true;
    }

    function isCosignerSet(uint _holderId) constant returns(bool) {
        return address(holders[_holderId].cosigner) != 0x0;
    }

    function _checkSigned(Cosigner _cosigner, uint _holderId, uint _required) internal returns(bool) {
        return _cosigner.consumeOperation(sha3(msg.data, _holderId), _required);
    }

    modifier checkSigned(uint _holderId, uint _required) {
        if (!isCosignerSet(_holderId) || _checkSigned(holders[_holderId].cosigner, _holderId, _required)) {
            _;
        } else {
            _error('Cosigner: access denied');
        }
    }

    /**
     * Check if specified holder trusts an address with recovery procedure.
     *
     * @param _from truster.
     * @param _to trustee.
     *
     * @return trust existance.
     */
    function isTrusted(address _from, address _to) constant returns(bool) {
        return holders[getHolderId(_from)].trust[_to];
    }

    /**
     * Trust an address to perform recovery procedure for the caller.
     *
     * @param _to trustee.
     *
     * @return success.
     */
    function trust(address _to) returns(bool) {
        uint fromId = _createHolderId(msg.sender);
        // Should trust to another address.
        if (fromId == getHolderId(_to)) {
            _error('Cannot trust to oneself');
            return false;
        }
        // Should trust to yet untrusted.
        if (isTrusted(msg.sender, _to)) {
            _error('Already trusted');
            return false;
        }
        holders[fromId].trust[_to] = true;
        return true;
    }

    /**
     * Revoke trust to perform recovery procedure from an address.
     *
     * @param _to trustee.
     *
     * @return success.
     */
    function distrust(address _to) checkTrust(msg.sender, _to) returns(bool) {
        holders[getHolderId(msg.sender)].trust[_to] = false;
        return true;
    }

    /**
     * Perform recovery procedure.
     *
     * This function logic is actually more of an grantAccess(uint _holderId, address _to).
     * It grants another address access to recovery subject wallets.
     * Can only be called by trustee of recovery subject.
     * If cosigning is enabled, should have atleast 2 confirmations.
     *
     * @dev Deprecated. Backward compatibility.
     *
     * @param _from holder address to recover from.
     * @param _to address to grant access to.
     *
     * @return success.
     */
    function recover(address _from, address _to) checkTrust(_from, msg.sender) returns(bool) {
        return _grantAccess(getHolderId(_from), _to);
    }

    /**
     * Perform recovery procedure.
     *
     * This function logic is actually more of an grantAccess(uint _holderId, address _to).
     * It grants another address access to subject holder wallets.
     * Can only be called if pre-confirmed by atleast 2 cosign oracles.
     *
     * @param _from holder address to recover from.
     * @param _to address to grant access to.
     *
     * @return success.
     */
    function grantAccess(address _from, address _to) returns(bool) {
        if (!isCosignerSet(getHolderId(_from))) {
            _error('Cosigner not set');
            return false;
        }
        return _grantAccess(getHolderId(_from), _to);
    }

    function _grantAccess(uint _fromId, address _to) internal checkSigned(_fromId, 2) returns(bool) {
        // Should recover to previously unused address.
        if (getHolderId(_to) != 0) {
            _error('Should recover to new address');
            return false;
        }
        // We take current holder address because it might not equal _from.
        // It is possible to recover from any old holder address, but event should have the current one.
        address from = holders[_fromId].addr;
        holders[_fromId].addr = _to;
        holderIndex[_to] = _fromId;
        // Internal Out Of Gas/Throw: revert this transaction too;
        // Recursive Call: safe, all changes already made.
        eventsHistory.emitRecovery(from, _to, msg.sender);
        return true;
    }

    /**
     * Sets asset spending allowance for a specified spender.
     *
     * Note: to revoke allowance, one needs to set allowance to 0.
     *
     * @param _spenderId holder id to set allowance for.
     * @param _value amount to allow.
     * @param _symbol asset symbol.
     * @param _senderId approve initiator holder id.
     *
     * @return success.
     */
    function _approve(uint _spenderId, uint _value, bytes32 _symbol, uint _senderId) internal checkEnabledSwitch(sha3(_symbol, Features.Allowances)) checkSigned(_senderId, 1) returns(bool) {
        // Asset should exist.
        if (!isCreated(_symbol)) {
            _error('Asset is not issued');
            return false;
        }
        // Should allow to another holder.
        if (_senderId == _spenderId) {
            _error('Cannot approve to oneself');
            return false;
        }
        assets[_symbol].wallets[_senderId].allowance[_spenderId] = _value;
        // Internal Out Of Gas/Throw: revert this transaction too;
        // Recursive Call: safe, all changes already made.
        eventsHistory.emitApprove(_address(_senderId), _address(_spenderId), _symbol, _value);
        if (proxies[_symbol] != 0x0) {
            // Internal Out Of Gas/Throw: revert this transaction too;
            // Recursive Call: safe, all changes already made.
            Proxy(proxies[_symbol]).emitApprove(_address(_senderId), _address(_spenderId), _value);
        }
        return true;
    }

    /**
     * Sets asset spending allowance for a specified spender.
     *
     * Can only be called by asset proxy.
     *
     * @param _spender holder address to set allowance to.
     * @param _value amount to allow.
     * @param _symbol asset symbol.
     * @param _sender approve initiator address.
     *
     * @return success.
     */
    function proxyApprove(address _spender, uint _value, bytes32 _symbol, address _sender) onlyProxy(_symbol) returns(bool) {
        return _approve(_createHolderId(_spender), _value, _symbol, _createHolderId(_sender));
    }

    /**
     * Returns asset allowance from one holder to another.
     *
     * @param _from holder that allowed spending.
     * @param _spender holder that is allowed to spend.
     * @param _symbol asset symbol.
     *
     * @return holder to spender allowance.
     */
    function allowance(address _from, address _spender, bytes32 _symbol) constant returns(uint) {
        return _allowance(getHolderId(_from), getHolderId(_spender), _symbol);
    }

    /**
     * Returns asset allowance from one holder to another.
     *
     * @param _fromId holder id that allowed spending.
     * @param _toId holder id that is allowed to spend.
     * @param _symbol asset symbol.
     *
     * @return holder to spender allowance.
     */
    function _allowance(uint _fromId, uint _toId, bytes32 _symbol) constant internal returns(uint) {
        return assets[_symbol].wallets[_fromId].allowance[_toId];
    }

    /**
     * Prforms allowance transfer of asset balance between holders wallets.
     *
     * Can only be called by asset proxy.
     *
     * @param _from holder address to take from.
     * @param _to holder address to give to.
     * @param _value amount to transfer.
     * @param _symbol asset symbol.
     * @param _reference transfer comment to be included in a Transfer event.
     * @param _sender allowance transfer initiator address.
     *
     * @return success.
     */
    function proxyTransferFromWithReference(address _from, address _to, uint _value, bytes32 _symbol, string _reference, address _sender) onlyProxy(_symbol) returns(bool) {
        return _transfer(getHolderId(_from), _createHolderId(_to), _value, _symbol, _reference, getHolderId(_sender));
    }
}

/**
 * @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: contracts\AssetInterface.sol

pragma solidity 0.5.8;


contract AssetInterface {
    function _performTransferWithReference(
        address _to,
        uint _value,
        string memory _reference,
        address _sender)
    public returns(bool);

    function _performTransferToICAPWithReference(
        bytes32 _icap,
        uint _value,
        string memory _reference,
        address _sender)
    public returns(bool);

    function _performApprove(address _spender, uint _value, address _sender)
    public returns(bool);

    function _performTransferFromWithReference(
        address _from,
        address _to,
        uint _value,
        string memory _reference,
        address _sender)
    public returns(bool);

    function _performTransferFromToICAPWithReference(
        address _from,
        bytes32 _icap,
        uint _value,
        string memory _reference,
        address _sender)
    public returns(bool);

    function _performGeneric(bytes memory, address) public payable {
        revert();
    }
}

// File: contracts\ERC20Interface.sol

pragma solidity 0.5.8;


contract ERC20Interface {
    event Transfer(address indexed from, address indexed to, uint256 value);
    event Approval(address indexed from, address indexed spender, uint256 value);

    function totalSupply() public view returns(uint256 supply);
    function balanceOf(address _owner) public view returns(uint256 balance);
    // solhint-disable-next-line no-simple-event-func-name
    function transfer(address _to, uint256 _value) public returns(bool success);
    function transferFrom(address _from, address _to, uint256 _value) public returns(bool success);
    function approve(address _spender, uint256 _value) public returns(bool success);
    function allowance(address _owner, address _spender) public view returns(uint256 remaining);

    // function symbol() constant returns(string);
    function decimals() public view returns(uint8);
    // function name() constant returns(string);
}

// File: contracts\AssetProxyInterface.sol

pragma solidity 0.5.8;



contract AssetProxyInterface is ERC20Interface {
    function _forwardApprove(address _spender, uint _value, address _sender)
    public returns(bool);

    function _forwardTransferFromWithReference(
        address _from,
        address _to,
        uint _value,
        string memory _reference,
        address _sender)
    public returns(bool);

    function _forwardTransferFromToICAPWithReference(
        address _from,
        bytes32 _icap,
        uint _value,
        string memory _reference,
        address _sender)
    public returns(bool);

    function recoverTokens(ERC20Interface _asset, address _receiver, uint _value)
    public returns(bool);

    function etoken2() external view returns(address); // To be replaced by the implicit getter;

    // To be replaced by the implicit getter;
    function etoken2Symbol() external view returns(bytes32);
}

// File: @orderbook\smart-contracts-common\contracts\Bytes32.sol

pragma solidity 0.5.8;


contract Bytes32 {
    function _bytes32(string memory _input) internal pure returns(bytes32 result) {
        assembly {
            result := mload(add(_input, 32))
        }
    }
}

// File: @orderbook\smart-contracts-common\contracts\ReturnData.sol

pragma solidity 0.5.8;


contract ReturnData {
    function _returnReturnData(bool _success) internal pure {
        assembly {
            let returndatastart := 0
            returndatacopy(returndatastart, 0, returndatasize)
            switch _success case 0 { revert(returndatastart, returndatasize) }
                default { return(returndatastart, returndatasize) }
        }
    }

    function _assemblyCall(address _destination, uint _value, bytes memory _data)
    internal returns(bool success) {
        assembly {
            success := call(gas, _destination, _value, add(_data, 32), mload(_data), 0, 0)
        }
    }
}

// File: contracts\Asset.sol

pragma solidity 0.5.8;






/**
 * @title EToken2 Asset implementation contract.
 *
 * Basic asset implementation contract, without any additional logic.
 * Every other asset implementation contracts should derive from this one.
 * Receives calls from the proxy, and calls back immediately without arguments modification.
 *
 * Note: all the non constant functions return false instead of throwing in case if state change
 * didn't happen yet.
 */
contract Asset is AssetInterface, Bytes32, ReturnData {
    // Assigned asset proxy contract, immutable.
    AssetProxyInterface public proxy;

    /**
     * Only assigned proxy is allowed to call.
     */
    modifier onlyProxy() {
        if (address(proxy) == msg.sender) {
            _;
        }
    }

    /**
     * Sets asset proxy address.
     *
     * Can be set only once.
     *
     * @param _proxy asset proxy contract address.
     *
     * @return success.
     * @dev function is final, and must not be overridden.
     */
    function init(AssetProxyInterface _proxy) public returns(bool) {
        if (address(proxy) != address(0)) {
            return false;
        }
        proxy = _proxy;
        return true;
    }

    /**
     * Passes execution into virtual function.
     *
     * Can only be called by assigned asset proxy.
     *
     * @return success.
     * @dev function is final, and must not be overridden.
     */
    function _performTransferWithReference(
        address _to,
        uint _value,
        string memory _reference,
        address _sender)
    public onlyProxy() returns(bool) {
        if (isICAP(_to)) {
            return _transferToICAPWithReference(
                bytes20(_to), _value, _reference, _sender);
        }
        return _transferWithReference(_to, _value, _reference, _sender);
    }

    /**
     * Calls back without modifications.
     *
     * @return success.
     * @dev function is virtual, and meant to be overridden.
     */
    function _transferWithReference(
        address _to,
        uint _value,
        string memory _reference,
        address _sender)
    internal returns(bool) {
        return proxy._forwardTransferFromWithReference(
            _sender, _to, _value, _reference, _sender);
    }

    /**
     * Passes execution into virtual function.
     *
     * Can only be called by assigned asset proxy.
     *
     * @return success.
     * @dev function is final, and must not be overridden.
     */
    function _performTransferToICAPWithReference(
        bytes32 _icap,
        uint _value,
        string memory _reference,
        address _sender)
    public onlyProxy() returns(bool) {
        return _transferToICAPWithReference(_icap, _value, _reference, _sender);
    }

    /**
     * Calls back without modifications.
     *
     * @return success.
     * @dev function is virtual, and meant to be overridden.
     */
    function _transferToICAPWithReference(
        bytes32 _icap,
        uint _value,
        string memory _reference,
        address _sender)
    internal returns(bool) {
        return proxy._forwardTransferFromToICAPWithReference(
            _sender, _icap, _value, _reference, _sender);
    }

    /**
     * Passes execution into virtual function.
     *
     * Can only be called by assigned asset proxy.
     *
     * @return success.
     * @dev function is final, and must not be overridden.
     */
    function _performTransferFromWithReference(
        address _from,
        address _to,
        uint _value,
        string memory _reference,
        address _sender)
    public onlyProxy() returns(bool) {
        if (isICAP(_to)) {
            return _transferFromToICAPWithReference(
                _from, bytes20(_to), _value, _reference, _sender);
        }
        return _transferFromWithReference(_from, _to, _value, _reference, _sender);
    }

    /**
     * Calls back without modifications.
     *
     * @return success.
     * @dev function is virtual, and meant to be overridden.
     */
    function _transferFromWithReference(
        address _from,
        address _to,
        uint _value,
        string memory _reference,
        address _sender)
    internal returns(bool) {
        return proxy._forwardTransferFromWithReference(
            _from, _to, _value, _reference, _sender);
    }

    /**
     * Passes execution into virtual function.
     *
     * Can only be called by assigned asset proxy.
     *
     * @return success.
     * @dev function is final, and must not be overridden.
     */
    function _performTransferFromToICAPWithReference(
        address _from,
        bytes32 _icap,
        uint _value,
        string memory _reference,
        address _sender)
    public onlyProxy() returns(bool) {
        return _transferFromToICAPWithReference(
            _from, _icap, _value, _reference, _sender);
    }

    /**
     * Calls back without modifications.
     *
     * @return success.
     * @dev function is virtual, and meant to be overridden.
     */
    function _transferFromToICAPWithReference(
        address _from,
        bytes32 _icap,
        uint _value,
        string memory _reference,
        address _sender)
    internal returns(bool) {
        return proxy._forwardTransferFromToICAPWithReference(
            _from, _icap, _value, _reference, _sender);
    }

    /**
     * Passes execution into virtual function.
     *
     * Can only be called by assigned asset proxy.
     *
     * @return success.
     * @dev function is final, and must not be overridden.
     */
    function _performApprove(address _spender, uint _value, address _sender)
    public onlyProxy() returns(bool) {
        return _approve(_spender, _value, _sender);
    }

    /**
     * Calls back without modifications.
     *
     * @return success.
     * @dev function is virtual, and meant to be overridden.
     */
    function _approve(address _spender, uint _value, address _sender)
    internal returns(bool) {
        return proxy._forwardApprove(_spender, _value, _sender);
    }

    /**
     * Passes execution into virtual function.
     *
     * Can only be called by assigned asset proxy.
     *
     * @return bytes32 result.
     * @dev function is final, and must not be overridden.
     */
    function _performGeneric(bytes memory _data, address _sender)
    public payable onlyProxy() {
        _generic(_data, msg.value, _sender);
    }

    modifier onlyMe() {
        if (address(this) == msg.sender) {
            _;
        }
    }

    // Most probably the following should never be redefined in child contracts.
    address public genericSender;

    function _generic(bytes memory _data, uint _value, address _msgSender) internal {
        // Restrict reentrancy.
        require(genericSender == address(0));
        genericSender = _msgSender;
        bool success = _assemblyCall(address(this), _value, _data);
        delete genericSender;
        _returnReturnData(success);
    }

    // Decsendants should use _sender() instead of msg.sender to properly process proxied calls.
    function _sender() internal view returns(address) {
        return address(this) == msg.sender ? genericSender : msg.sender;
    }

    // Interface functions to allow specifying ICAP addresses as strings.
    function transferToICAP(string memory _icap, uint _value) public returns(bool) {
        return transferToICAPWithReference(_icap, _value, '');
    }

    function transferToICAPWithReference(string memory _icap, uint _value, string memory _reference)
    public returns(bool) {
        return _transferToICAPWithReference(
            _bytes32(_icap), _value, _reference, _sender());
    }

    function transferFromToICAP(address _from, string memory _icap, uint _value)
    public returns(bool) {
        return transferFromToICAPWithReference(_from, _icap, _value, '');
    }

    function transferFromToICAPWithReference(
        address _from,
        string memory _icap,
        uint _value,
        string memory _reference)
    public returns(bool) {
        return _transferFromToICAPWithReference(
            _from, _bytes32(_icap), _value, _reference, _sender());
    }

    function isICAP(address _address) public pure returns(bool) {
        bytes20 a = bytes20(_address);
        if (a[0] != 'X' || a[1] != 'E') {
            return false;
        }
        if (uint8(a[2]) < 48 || uint8(a[2]) > 57 || uint8(a[3]) < 48 || uint8(a[3]) > 57) {
            return false;
        }
        for (uint i = 4; i < 20; i++) {
            uint char = uint8(a[i]);
            if (char < 48 || char > 90 || (char > 57 && char < 65)) {
                return false;
            }
        }
        return true;
    }
}

// File: contracts\Ambi2Enabled.sol

pragma solidity 0.5.8;


contract Ambi2 {
    function claimFor(address _address, address _owner) public returns(bool);
    function hasRole(address _from, bytes32 _role, address _to) public view returns(bool);
    function isOwner(address _node, address _owner) public view returns(bool);
}


contract Ambi2Enabled {
    Ambi2 public ambi2;

    modifier onlyRole(bytes32 _role) {
        if (address(ambi2) != address(0) && ambi2.hasRole(address(this), _role, msg.sender)) {
            _;
        }
    }

    // Perform only after claiming the node, or claim in the same tx.
    function setupAmbi2(Ambi2 _ambi2) public returns(bool) {
        if (address(ambi2) != address(0)) {
            return false;
        }

        ambi2 = _ambi2;
        return true;
    }
}

// File: contracts\Ambi2EnabledFull.sol

pragma solidity 0.5.8;



contract Ambi2EnabledFull is Ambi2Enabled {
    // Setup and claim atomically.
    function setupAmbi2(Ambi2 _ambi2) public returns(bool) {
        if (address(ambi2) != address(0)) {
            return false;
        }
        if (!_ambi2.claimFor(address(this), msg.sender) &&
            !_ambi2.isOwner(address(this), msg.sender)) {
            return false;
        }

        ambi2 = _ambi2;
        return true;
    }
}

// File: contracts\AssetWithAmbi.sol

pragma solidity 0.5.8;




contract AssetWithAmbi is Asset, Ambi2EnabledFull {
    modifier onlyRole(bytes32 _role) {
        if (address(ambi2) != address(0) && (ambi2.hasRole(address(this), _role, _sender()))) {
            _;
        }
    }
}

// File: contracts\AssetWithWhitelist.sol

pragma solidity 0.5.8;



interface INUXAsset {
    function availableBalanceOf(address _holder) external view returns(uint);
    function scheduleReleaseStart() external;
    function transferLock(address _to, uint _value) external;
}

contract NUXConstants {
    uint constant NUX = 10**18;
}

contract Readable {
    function since(uint _timestamp) internal view returns(uint) {
        if (not(passed(_timestamp))) {
            return 0;
        }
        return block.timestamp - _timestamp;
    }

    function passed(uint _timestamp) internal view returns(bool) {
        return _timestamp < block.timestamp;
    }

    function not(bool _condition) internal pure returns(bool) {
        return !_condition;
    }
}

library ExtraMath {
    function toUInt64(uint _a) internal pure returns(uint64) {
        require(_a <= uint64(-1), 'uint64 overflow');
        return uint64(_a);
    }

    function toUInt128(uint _a) internal pure returns(uint128) {
        require(_a <= uint128(-1), 'uint128 overflow');
        return uint128(_a);
    }
}

contract EToken2Interface {
    function revokeAsset(bytes32 _symbol, uint _value) public returns(bool);
}

contract NUXAsset is AssetWithAmbi, NUXConstants, Readable {
    using SafeMath for uint;
    using ExtraMath for uint;

    uint public constant PRESALE_RELEASE_PERIOD = 760 days; // ~25 months
    uint64 constant UNSET = uint64(-1);

    struct ReleaseConfig {
        uint64 preSale;
        uint64 publicSale;
        uint64 publicSaleReleasePeriod;
    }

    ReleaseConfig private _releaseConfig = ReleaseConfig(UNSET, UNSET, UNSET);
    
    struct Lock {
        uint128 preSale;
        uint128 publicSale;
    }

    mapping(address => Lock) private _locked;

    event PreSaleLockTransfer(address _from, address _to, uint _value);
    event PublicSaleLockTransfer(address _from, address _to, uint _value);
    event PreSaleReleaseScheduled(uint _releaseStart);
    event PublicSaleReleaseScheduled(uint _releaseStart, uint _releasePeriod);
    event Unlocked(address _holder);

    modifier onlyRole(bytes32 _role) {
        require(address(ambi2) != address(0) && (ambi2.hasRole(address(this), _role, _sender())),
            'Access denied');
        _;
    }

    modifier validateAvailableBalance(address _sender, uint _value) {
        require(availableBalanceOf(_sender) >= _value, 'Insufficient available balance');
        _;
    }

    modifier validateAllowance(address _from, address _spender, uint _value) {
        require(proxy.allowance(_from, _spender) >= _value, 'Insufficient allowance');
        _;
    }

    function _migrate(address _holder, uint _lock) private {
        uint128 preSale = uint128(_lock >> 128);
        uint128 publicSale = uint128(_lock);
        _locked[_holder] = Lock(preSale, publicSale);
        if (preSale > 0) {
            emit PreSaleLockTransfer(address(0), _holder, preSale);
        }
        if (publicSale > 0) {
            emit PublicSaleLockTransfer(address(0), _holder, publicSale);
        }
    }

    function migrate(address[] calldata _holders, uint[] calldata _locks) external onlyRole('admin') {
        require(not(passed(_releaseConfig.preSale)), 'Migration finished');
        uint len = _holders.length;
        require(len == _locks.length, 'Length mismatch');
        for (uint i = 0; i < len; i++) {
            _migrate(_holders[i], _locks[i]);
        }
    }

    function releaseConfig() public view returns(uint, uint, uint) {
        ReleaseConfig memory config = _releaseConfig;
        return (config.preSale, config.publicSale, config.publicSaleReleasePeriod);
    }

    function locked(address _holder) public view returns(uint, uint) {
        Lock memory lock = _locked[_holder];
        return (lock.preSale, lock.publicSale);
    }

    function _calcualteLocked(uint _lock, uint _releaseStart, uint _releasePeriod) private view returns(uint) {
        uint released = (_lock.mul(since(_releaseStart))) / _releasePeriod;
        if (_lock <= released) {
            return 0;
        }
        return _lock - released;
    }

    function availableBalanceOf(address _holder) public view returns(uint) {
        uint totalBalance = proxy.balanceOf(_holder);
        uint preSaleLock;
        uint publicSaleLock;
        (preSaleLock, publicSaleLock) = locked(_holder);
        uint preSaleReleaseStart;
        uint publicSaleReleaseStart;
        uint publicSaleReleasePeriod;
        (preSaleReleaseStart, publicSaleReleaseStart, publicSaleReleasePeriod) = releaseConfig();
        preSaleLock = _calcualteLocked(preSaleLock, preSaleReleaseStart, PRESALE_RELEASE_PERIOD);
        publicSaleLock = _calcualteLocked(publicSaleLock, publicSaleReleaseStart, publicSaleReleasePeriod);
        uint stillLocked = preSaleLock.add(publicSaleLock);
        if (totalBalance <= stillLocked) {
            return 0;
        }
        return totalBalance - stillLocked;
    }

    function preSaleScheduleReleaseStart(uint _releaseStart) public onlyRole('admin') {
        require(_releaseConfig.preSale == UNSET, 'Already scheduled');
        uint64 releaseStart = _releaseStart.toUInt64();
        _releaseConfig.preSale = releaseStart;
        emit PreSaleReleaseScheduled(releaseStart);
    }

    function publicSaleScheduleReleaseStart(uint _releaseStart, uint _releasePeriod) public onlyRole('admin') {
        require(_releaseConfig.publicSale == UNSET, 'Already scheduled');
        require(_releaseConfig.publicSaleReleasePeriod == UNSET, 'Already scheduled');
        _releaseConfig.publicSale = _releaseStart.toUInt64();
        _releaseConfig.publicSaleReleasePeriod = _releasePeriod.toUInt64();
        emit PublicSaleReleaseScheduled(_releaseStart, _releasePeriod);
    }

    function preSaleTransferLock(address _to, uint _value) public onlyRole('distributor') {
        address _from = _sender();
        uint preSaleLock;
        uint publicSaleLock;
        (preSaleLock, publicSaleLock) = locked(_from);
        require(preSaleLock >= _value, 'Not enough locked');
        require(proxy.balanceOf(_from) >= publicSaleLock.add(preSaleLock), 'Cannot transfer released');
        _locked[_from].preSale = (preSaleLock - _value).toUInt128();
        if (_to == address(0)) {
            _burn(_from, _value);
        } else {
            _locked[_to].preSale = uint(_locked[_to].preSale).add(_value).toUInt128();
            require(super._transferWithReference(_to, _value, '', _from), 'Transfer failed');
        }
        emit PreSaleLockTransfer(_from, _to, _value);
    }

    function publicSaleTransferLock(address _to, uint _value) public onlyRole('distributor') {
        address _from = _sender();
        uint preSaleLock;
        uint publicSaleLock;
        (preSaleLock, publicSaleLock) = locked(_from);
        require(publicSaleLock >= _value, 'Not enough locked');
        require(proxy.balanceOf(_from) >= publicSaleLock.add(preSaleLock), 'Cannot transfer released');
        _locked[_from].publicSale = (publicSaleLock - _value).toUInt128();
        if (_to == address(0)) {
            _burn(_from, _value);
        } else {
            _locked[_to].publicSale = uint(_locked[_to].publicSale).add(_value).toUInt128();
            require(super._transferWithReference(_to, _value, '', _from), 'Transfer failed');
        }
        emit PublicSaleLockTransfer(_from, _to, _value);
    }

    function unlock(address _holder) public onlyRole('unlocker') {
        delete _locked[_holder];
        emit Unlocked(_holder);
    }

    function preSaleTransferLockFrom(address _from, address _to, uint _value)
    public
    onlyRole('distributor')
    validateAllowance(_from, _sender(), _value) {
        uint preSaleLock;
        uint publicSaleLock;
        (preSaleLock, publicSaleLock) = locked(_from);
        require(preSaleLock >= _value, 'Not enough locked');
        require(proxy.balanceOf(_from) >= publicSaleLock.add(preSaleLock), 'Cannot transfer released');
        _locked[_from].preSale = (preSaleLock - _value).toUInt128();
        _locked[_to].preSale = uint(_locked[_to].preSale).add(_value).toUInt128();
        require(super._transferFromWithReference(_from, _to, _value, '', _sender()), 'Transfer failed');
        emit PreSaleLockTransfer(_from, _to, _value);
    }

    function publicSaleTransferLockFrom(address _from, address _to, uint _value)
    public
    onlyRole('distributor')
    validateAllowance(_from, _sender(), _value) {
        uint preSaleLock;
        uint publicSaleLock;
        (preSaleLock, publicSaleLock) = locked(_from);
        require(publicSaleLock >= _value, 'Not enough locked');
        require(proxy.balanceOf(_from) >= publicSaleLock.add(preSaleLock), 'Cannot transfer released');
        _locked[_from].publicSale = (publicSaleLock - _value).toUInt128();
        _locked[_to].publicSale = uint(_locked[_to].publicSale).add(_value).toUInt128();
        require(super._transferFromWithReference(_from, _to, _value, '', _sender()), 'Transfer failed');
        emit PublicSaleLockTransfer(_from, _to, _value);
    }

    function _burn(address _from, uint _value) private {
        require(super._transferWithReference(address(this), _value, '', _from), 'Burn transfer failed');
        require(EToken2Interface(proxy.etoken2()).revokeAsset(proxy.etoken2Symbol(), _value), 'Burn failed');
    }

    function _transferWithReference(
        address _to,
        uint _value,
        string memory _reference,
        address _sender)
    internal validateAvailableBalance(_sender, _value) returns(bool) {
        return super._transferWithReference(_to, _value, _reference, _sender);
    }

    function _transferFromWithReference(
        address _from,
        address _to,
        uint _value,
        string memory _reference,
        address _sender)
    internal
    validateAvailableBalance(_from, _value)
    validateAllowance(_from, _sender, _value)
    returns(bool) {
        return super._transferFromWithReference(_from, _to, _value, _reference, _sender);
    }

    function _transferToICAPWithReference(
        bytes32 _icap,
        uint _value,
        string memory _reference,
        address _sender)
    internal validateAvailableBalance(_sender, _value) returns(bool) {
        return super._transferToICAPWithReference(_icap, _value, _reference, _sender);
    }

    function _transferFromToICAPWithReference(
        address _from,
        bytes32 _icap,
        uint _value,
        string memory _reference,
        address _sender)
    internal
    validateAvailableBalance(_from, _value)
    validateAllowance(_from, _sender, _value)
    returns(bool) {
        return super._transferFromToICAPWithReference(_from, _icap, _value, _reference, _sender);
    }
}