// File: ./contracts/uniswap/IUniswapV2Router02.sol



pragma solidity >=0.5.0;

interface IUniswapV2Router02 {
    function factory() external pure returns (address);

    function WETH() external pure returns (address);

    function addLiquidity(
        address tokenA,
        address tokenB,
        uint256 amountADesired,
        uint256 amountBDesired,
        uint256 amountAMin,
        uint256 amountBMin,
        address to,
        uint256 deadline
    )
        external
        returns (
            uint256 amountA,
            uint256 amountB,
            uint256 liquidity
        );

    function addLiquidityETH(
        address token,
        uint256 amountTokenDesired,
        uint256 amountTokenMin,
        uint256 amountETHMin,
        address to,
        uint256 deadline
    )
        external
        payable
        returns (
            uint256 amountToken,
            uint256 amountETH,
            uint256 liquidity
        );

    function removeLiquidity(
        address tokenA,
        address tokenB,
        uint256 liquidity,
        uint256 amountAMin,
        uint256 amountBMin,
        address to,
        uint256 deadline
    ) external returns (uint256 amountA, uint256 amountB);

    function removeLiquidityETH(
        address token,
        uint256 liquidity,
        uint256 amountTokenMin,
        uint256 amountETHMin,
        address to,
        uint256 deadline
    ) external returns (uint256 amountToken, uint256 amountETH);

    function removeLiquidityWithPermit(
        address tokenA,
        address tokenB,
        uint256 liquidity,
        uint256 amountAMin,
        uint256 amountBMin,
        address to,
        uint256 deadline,
        bool approveMax,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external returns (uint256 amountA, uint256 amountB);

    function removeLiquidityETHWithPermit(
        address token,
        uint256 liquidity,
        uint256 amountTokenMin,
        uint256 amountETHMin,
        address to,
        uint256 deadline,
        bool approveMax,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external returns (uint256 amountToken, uint256 amountETH);

    function swapExactTokensForTokens(
        uint256 amountIn,
        uint256 amountOutMin,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external returns (uint256[] memory amounts);

    function swapTokensForExactTokens(
        uint256 amountOut,
        uint256 amountInMax,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external returns (uint256[] memory amounts);

    function swapExactETHForTokens(
        uint256 amountOutMin,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external payable returns (uint256[] memory amounts);

    function swapTokensForExactETH(
        uint256 amountOut,
        uint256 amountInMax,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external returns (uint256[] memory amounts);

    function swapExactTokensForETH(
        uint256 amountIn,
        uint256 amountOutMin,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external returns (uint256[] memory amounts);

    function swapETHForExactTokens(
        uint256 amountOut,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external payable returns (uint256[] memory amounts);

    function quote(
        uint256 amountA,
        uint256 reserveA,
        uint256 reserveB
    ) external pure returns (uint256 amountB);

    function getAmountOut(
        uint256 amountIn,
        uint256 reserveIn,
        uint256 reserveOut
    ) external pure returns (uint256 amountOut);

    function getAmountIn(
        uint256 amountOut,
        uint256 reserveIn,
        uint256 reserveOut
    ) external pure returns (uint256 amountIn);

    function getAmountsOut(uint256 amountIn, address[] calldata path)
        external
        view
        returns (uint256[] memory amounts);

    function getAmountsIn(uint256 amountOut, address[] calldata path)
        external
        view
        returns (uint256[] memory amounts);

    function removeLiquidityETHSupportingFeeOnTransferTokens(
        address token,
        uint256 liquidity,
        uint256 amountTokenMin,
        uint256 amountETHMin,
        address to,
        uint256 deadline
    ) external returns (uint256 amountETH);

    function removeLiquidityETHWithPermitSupportingFeeOnTransferTokens(
        address token,
        uint256 liquidity,
        uint256 amountTokenMin,
        uint256 amountETHMin,
        address to,
        uint256 deadline,
        bool approveMax,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external returns (uint256 amountETH);

    function swapExactTokensForTokensSupportingFeeOnTransferTokens(
        uint256 amountIn,
        uint256 amountOutMin,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external;

    function swapExactETHForTokensSupportingFeeOnTransferTokens(
        uint256 amountOutMin,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external payable;

    function swapExactTokensForETHSupportingFeeOnTransferTokens(
        uint256 amountIn,
        uint256 amountOutMin,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external;
}

// File: ./contracts/uniswap/UniswapV2Library.sol



pragma solidity >=0.5.0;

import 'Uniswap/uniswap-v2-core@1.0.1/contracts/interfaces/IUniswapV2Pair.sol';
import 'Uniswap/uniswap-v2-core@1.0.1/contracts/interfaces/IUniswapV2Factory.sol';
import 'OpenZeppelin/openzeppelin-contracts@2.3.0/contracts/math/SafeMath.sol';

library UniswapV2Library {
  using SafeMath for uint256;

  // returns sorted token addresses, used to handle return values from pairs sorted in this order
  function sortTokens(address tokenA, address tokenB) internal pure returns (address token0, address token1) {
    require(tokenA != tokenB, 'UniswapV2Library: IDENTICAL_ADDRESSES');
    (token0, token1) = tokenA < tokenB ? (tokenA, tokenB) : (tokenB, tokenA);
    require(token0 != address(0), 'UniswapV2Library: ZERO_ADDRESS');
  }

  // calculates the CREATE2 address for a pair without making any external calls
  function pairFor(
    address factory,
    address tokenA,
    address tokenB
  ) internal view returns (address pair) {
    return IUniswapV2Factory(factory).getPair(tokenA, tokenB); // For easy testing
    // (address token0, address token1) = sortTokens(tokenA, tokenB);        
    // pair = address(
    //   uint256(
    //     keccak256(
    //       abi.encodePacked(
    //         hex'ff',
    //         factory,
    //         keccak256(abi.encodePacked(token0, token1)),
    //         hex'fc4928e335b531bb85a6d9454f46863f9d6101351e3e8b84620b1806d4a3fcb3' // init code hash
    //       )
    //     )
    //   )
    // );
  }

  // fetches and sorts the reserves for a pair
  function getReserves(
    address factory,
    address tokenA,
    address tokenB
  ) internal view returns (uint256 reserveA, uint256 reserveB) {
    (address token0, ) = sortTokens(tokenA, tokenB);
    (uint256 reserve0, uint256 reserve1, ) = IUniswapV2Pair(pairFor(factory, tokenA, tokenB)).getReserves();
    (reserveA, reserveB) = tokenA == token0 ? (reserve0, reserve1) : (reserve1, reserve0);
  }

  // given some amount of an asset and pair reserves, returns an equivalent amount of the other asset
  function quote(
    uint256 amountA,
    uint256 reserveA,
    uint256 reserveB
  ) internal pure returns (uint256 amountB) {
    require(amountA > 0, 'UniswapV2Library: INSUFFICIENT_AMOUNT');
    require(reserveA > 0 && reserveB > 0, 'UniswapV2Library: INSUFFICIENT_LIQUIDITY');
    amountB = amountA.mul(reserveB) / reserveA;
  }

  // given an input amount of an asset and pair reserves, returns the maximum output amount of the other asset
  function getAmountOut(
    uint256 amountIn,
    uint256 reserveIn,
    uint256 reserveOut
  ) internal pure returns (uint256 amountOut) {
    require(amountIn > 0, 'UniswapV2Library: INSUFFICIENT_INPUT_AMOUNT');
    require(reserveIn > 0 && reserveOut > 0, 'UniswapV2Library: INSUFFICIENT_LIQUIDITY');
    uint256 amountInWithFee = amountIn.mul(997);
    uint256 numerator = amountInWithFee.mul(reserveOut);
    uint256 denominator = reserveIn.mul(1000).add(amountInWithFee);
    amountOut = numerator / denominator;
  }

  // given an output amount of an asset and pair reserves, returns a required input amount of the other asset
  function getAmountIn(
    uint256 amountOut,
    uint256 reserveIn,
    uint256 reserveOut
  ) internal pure returns (uint256 amountIn) {
    require(amountOut > 0, 'UniswapV2Library: INSUFFICIENT_OUTPUT_AMOUNT');
    require(reserveIn > 0 && reserveOut > 0, 'UniswapV2Library: INSUFFICIENT_LIQUIDITY');
    uint256 numerator = reserveIn.mul(amountOut).mul(1000);
    uint256 denominator = reserveOut.sub(amountOut).mul(997);
    amountIn = (numerator / denominator).add(1);
  }

  // performs chained getAmountOut calculations on any number of pairs
  function getAmountsOut(
    address factory,
    uint256 amountIn,
    address[] memory path
  ) internal view returns (uint256[] memory amounts) {
    require(path.length >= 2, 'UniswapV2Library: INVALID_PATH');
    amounts = new uint256[](path.length);
    amounts[0] = amountIn;
    for (uint256 i; i < path.length - 1; i++) {
      (uint256 reserveIn, uint256 reserveOut) = getReserves(factory, path[i], path[i + 1]);
      amounts[i + 1] = getAmountOut(amounts[i], reserveIn, reserveOut);
    }
  }

  // performs chained getAmountIn calculations on any number of pairs
  function getAmountsIn(
    address factory,
    uint256 amountOut,
    address[] memory path
  ) internal view returns (uint256[] memory amounts) {
    require(path.length >= 2, 'UniswapV2Library: INVALID_PATH');
    amounts = new uint256[](path.length);
    amounts[amounts.length - 1] = amountOut;
    for (uint256 i = path.length - 1; i > 0; i--) {
      (uint256 reserveIn, uint256 reserveOut) = getReserves(factory, path[i - 1], path[i]);
      amounts[i - 1] = getAmountIn(amounts[i], reserveIn, reserveOut);
    }
  }
}

// File: ./contracts/uniswap/UniswapV2Router02.sol



pragma solidity =0.5.16;

import 'Uniswap/uniswap-v2-core@1.0.1/contracts/interfaces/IUniswapV2Factory.sol';
import "OpenZeppelin/openzeppelin-contracts@2.3.0/contracts/token/ERC20/IERC20.sol";
import 'OpenZeppelin/openzeppelin-contracts@2.3.0/contracts/math/SafeMath.sol';

import "../weth/IWETH.sol";
import "./UniswapV2Library.sol";
import "./IUniswapV2Router02.sol";

// helper methods for interacting with ERC20 tokens and sending ETH that do not consistently return true/false
library TransferHelper {
    function safeApprove(
        address token,
        address to,
        uint256 value
    ) internal {
        // bytes4(keccak256(bytes('approve(address,uint256)')));
        (bool success, bytes memory data) = token.call(
            abi.encodeWithSelector(0x095ea7b3, to, value)
        );
        require(
            success && (data.length == 0 || abi.decode(data, (bool))),
            "TransferHelper: APPROVE_FAILED"
        );
    }

    function safeTransfer(
        address token,
        address to,
        uint256 value
    ) internal {
        // bytes4(keccak256(bytes('transfer(address,uint256)')));
        (bool success, bytes memory data) = token.call(
            abi.encodeWithSelector(0xa9059cbb, to, value)
        );
        require(
            success && (data.length == 0 || abi.decode(data, (bool))),
            "TransferHelper: TRANSFER_FAILED"
        );
    }

    function safeTransferFrom(
        address token,
        address from,
        address to,
        uint256 value
    ) internal {
        // bytes4(keccak256(bytes('transferFrom(address,address,uint256)')));
        (bool success, bytes memory data) = token.call(
            abi.encodeWithSelector(0x23b872dd, from, to, value)
        );
        require(
            success && (data.length == 0 || abi.decode(data, (bool))),
            "TransferHelper: TRANSFER_FROM_FAILED"
        );
    }

    function safeTransferETH(address to, uint256 value) internal {
        (bool success, ) = to.call.value(value)(new bytes(0));
        require(success, "TransferHelper: ETH_TRANSFER_FAILED");
    }
}

contract UniswapV2Router02 is IUniswapV2Router02 {
    using SafeMath for uint256;

    address public factory;
    address public WETH;

    modifier ensure(uint256 deadline) {
        require(deadline >= block.timestamp, "UniswapV2Router: EXPIRED");
        _;
    }

    constructor(address _factory, address _WETH) public {
        factory = _factory;
        WETH = _WETH;
    }

    function() external payable {
        assert(msg.sender == WETH); // only accept ETH via fallback from the WETH contract
    }

    // **** ADD LIQUIDITY ****
    function _addLiquidity(
        address tokenA,
        address tokenB,
        uint256 amountADesired,
        uint256 amountBDesired,
        uint256 amountAMin,
        uint256 amountBMin
    ) internal returns (uint256 amountA, uint256 amountB) {
        // create the pair if it doesn't exist yet
        if (IUniswapV2Factory(factory).getPair(tokenA, tokenB) == address(0)) {
            IUniswapV2Factory(factory).createPair(tokenA, tokenB);
        }
        (uint256 reserveA, uint256 reserveB) = UniswapV2Library.getReserves(
            factory,
            tokenA,
            tokenB
        );
        if (reserveA == 0 && reserveB == 0) {
            (amountA, amountB) = (amountADesired, amountBDesired);
        } else {
            uint256 amountBOptimal = UniswapV2Library.quote(
                amountADesired,
                reserveA,
                reserveB
            );
            if (amountBOptimal <= amountBDesired) {
                require(
                    amountBOptimal >= amountBMin,
                    "UniswapV2Router: INSUFFICIENT_B_AMOUNT"
                );
                (amountA, amountB) = (amountADesired, amountBOptimal);
            } else {
                uint256 amountAOptimal = UniswapV2Library.quote(
                    amountBDesired,
                    reserveB,
                    reserveA
                );
                assert(amountAOptimal <= amountADesired);
                require(
                    amountAOptimal >= amountAMin,
                    "UniswapV2Router: INSUFFICIENT_A_AMOUNT"
                );
                (amountA, amountB) = (amountAOptimal, amountBDesired);
            }
        }
    }

    function addLiquidity(
        address tokenA,
        address tokenB,
        uint256 amountADesired,
        uint256 amountBDesired,
        uint256 amountAMin,
        uint256 amountBMin,
        address to,
        uint256 deadline
    )
        external
        ensure(deadline)
        returns (
            uint256 amountA,
            uint256 amountB,
            uint256 liquidity
        )
    {
        (amountA, amountB) = _addLiquidity(
            tokenA,
            tokenB,
            amountADesired,
            amountBDesired,
            amountAMin,
            amountBMin
        );
        address pair = UniswapV2Library.pairFor(factory, tokenA, tokenB);
        TransferHelper.safeTransferFrom(tokenA, msg.sender, pair, amountA);
        TransferHelper.safeTransferFrom(tokenB, msg.sender, pair, amountB);
        liquidity = IUniswapV2Pair(pair).mint(to);
    }

    function addLiquidityETH(
        address token,
        uint256 amountTokenDesired,
        uint256 amountTokenMin,
        uint256 amountETHMin,
        address to,
        uint256 deadline
    )
        external
        payable
        ensure(deadline)
        returns (
            uint256 amountToken,
            uint256 amountETH,
            uint256 liquidity
        )
    {
        (amountToken, amountETH) = _addLiquidity(
            token,
            WETH,
            amountTokenDesired,
            msg.value,
            amountTokenMin,
            amountETHMin
        );
        address pair = UniswapV2Library.pairFor(factory, token, WETH);
        TransferHelper.safeTransferFrom(token, msg.sender, pair, amountToken);
        IWETH(WETH).deposit.value(amountETH)();
        assert(IWETH(WETH).transfer(pair, amountETH));
        liquidity = IUniswapV2Pair(pair).mint(to);
        // refund dust eth, if any
        if (msg.value > amountETH)
            TransferHelper.safeTransferETH(msg.sender, msg.value - amountETH);
    }

    // **** REMOVE LIQUIDITY ****
    function removeLiquidity(
        address tokenA,
        address tokenB,
        uint256 liquidity,
        uint256 amountAMin,
        uint256 amountBMin,
        address to,
        uint256 deadline
    ) public ensure(deadline) returns (uint256 amountA, uint256 amountB) {
        address pair = UniswapV2Library.pairFor(factory, tokenA, tokenB);        
        IUniswapV2Pair(pair).transferFrom(msg.sender, pair, liquidity); // send liquidity to pair
        (uint256 amount0, uint256 amount1) = IUniswapV2Pair(pair).burn(to);
        (address token0, ) = UniswapV2Library.sortTokens(tokenA, tokenB);
        (amountA, amountB) = tokenA == token0
            ? (amount0, amount1)
            : (amount1, amount0);
        require(
            amountA >= amountAMin,
            "UniswapV2Router: INSUFFICIENT_A_AMOUNT"
        );
        require(
            amountB >= amountBMin,
            "UniswapV2Router: INSUFFICIENT_B_AMOUNT"
        );
    }

    function removeLiquidityETH(
        address token,
        uint256 liquidity,
        uint256 amountTokenMin,
        uint256 amountETHMin,
        address to,
        uint256 deadline
    ) public ensure(deadline) returns (uint256 amountToken, uint256 amountETH) {
        (amountToken, amountETH) = removeLiquidity(
            token,
            WETH,
            liquidity,
            amountTokenMin,
            amountETHMin,
            address(this),
            deadline
        );
        TransferHelper.safeTransfer(token, to, amountToken);
        IWETH(WETH).withdraw(amountETH);
        TransferHelper.safeTransferETH(to, amountETH);
    }

    function removeLiquidityWithPermit(
        address tokenA,
        address tokenB,
        uint256 liquidity,
        uint256 amountAMin,
        uint256 amountBMin,
        address to,
        uint256 deadline,
        bool approveMax,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external returns (uint256 amountA, uint256 amountB) {
        address pair = UniswapV2Library.pairFor(factory, tokenA, tokenB);
        uint256 value = approveMax ? uint256(-1) : liquidity;
        IUniswapV2Pair(pair).permit(
            msg.sender,
            address(this),
            value,
            deadline,
            v,
            r,
            s
        );
        (amountA, amountB) = removeLiquidity(
            tokenA,
            tokenB,
            liquidity,
            amountAMin,
            amountBMin,
            to,
            deadline
        );
    }

    function removeLiquidityETHWithPermit(
        address token,
        uint256 liquidity,
        uint256 amountTokenMin,
        uint256 amountETHMin,
        address to,
        uint256 deadline,
        bool approveMax,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external returns (uint256 amountToken, uint256 amountETH) {
        address pair = UniswapV2Library.pairFor(factory, token, WETH);
        uint256 value = approveMax ? uint256(-1) : liquidity;
        IUniswapV2Pair(pair).permit(
            msg.sender,
            address(this),
            value,
            deadline,
            v,
            r,
            s
        );
        (amountToken, amountETH) = removeLiquidityETH(
            token,
            liquidity,
            amountTokenMin,
            amountETHMin,
            to,
            deadline
        );
    }

    // **** REMOVE LIQUIDITY (supporting fee-on-transfer tokens) ****
    function removeLiquidityETHSupportingFeeOnTransferTokens(
        address token,
        uint256 liquidity,
        uint256 amountTokenMin,
        uint256 amountETHMin,
        address to,
        uint256 deadline
    ) public ensure(deadline) returns (uint256 amountETH) {
        (, amountETH) = removeLiquidity(
            token,
            WETH,
            liquidity,
            amountTokenMin,
            amountETHMin,
            address(this),
            deadline
        );
        TransferHelper.safeTransfer(
            token,
            to,
            IERC20(token).balanceOf(address(this))
        );
        IWETH(WETH).withdraw(amountETH);
        TransferHelper.safeTransferETH(to, amountETH);
    }

    function removeLiquidityETHWithPermitSupportingFeeOnTransferTokens(
        address token,
        uint256 liquidity,
        uint256 amountTokenMin,
        uint256 amountETHMin,
        address to,
        uint256 deadline,
        bool approveMax,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external returns (uint256 amountETH) {
        address pair = UniswapV2Library.pairFor(factory, token, WETH);
        uint256 value = approveMax ? uint256(-1) : liquidity;
        IUniswapV2Pair(pair).permit(
            msg.sender,
            address(this),
            value,
            deadline,
            v,
            r,
            s
        );
        amountETH = removeLiquidityETHSupportingFeeOnTransferTokens(
            token,
            liquidity,
            amountTokenMin,
            amountETHMin,
            to,
            deadline
        );
    }

    // **** SWAP ****
    // requires the initial amount to have already been sent to the first pair
    function _swap(
        uint256[] memory amounts,
        address[] memory path,
        address _to
    ) internal {
        for (uint256 i; i < path.length - 1; i++) {
            (address input, address output) = (path[i], path[i + 1]);
            (address token0, ) = UniswapV2Library.sortTokens(input, output);
            uint256 amountOut = amounts[i + 1];
            (uint256 amount0Out, uint256 amount1Out) = input == token0
                ? (uint256(0), amountOut)
                : (amountOut, uint256(0));
            address to = i < path.length - 2
                ? UniswapV2Library.pairFor(factory, output, path[i + 2])
                : _to;
            IUniswapV2Pair(UniswapV2Library.pairFor(factory, input, output))
                .swap(amount0Out, amount1Out, to, new bytes(0));
        }
    }

    function swapExactTokensForTokens(
        uint256 amountIn,
        uint256 amountOutMin,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external ensure(deadline) returns (uint256[] memory amounts) {
        amounts = UniswapV2Library.getAmountsOut(factory, amountIn, path);        
        require(
            amounts[amounts.length - 1] >= amountOutMin,
            "UniswapV2Router: INSUFFICIENT_OUTPUT_AMOUNT"
        );
        TransferHelper.safeTransferFrom(
            path[0],
            msg.sender,
            UniswapV2Library.pairFor(factory, path[0], path[1]),
            amounts[0]
        );
        _swap(amounts, path, to);
    }

    function swapTokensForExactTokens(
        uint256 amountOut,
        uint256 amountInMax,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external ensure(deadline) returns (uint256[] memory amounts) {
        amounts = UniswapV2Library.getAmountsIn(factory, amountOut, path);
        require(
            amounts[0] <= amountInMax,
            "UniswapV2Router: EXCESSIVE_INPUT_AMOUNT"
        );
        TransferHelper.safeTransferFrom(
            path[0],
            msg.sender,
            UniswapV2Library.pairFor(factory, path[0], path[1]),
            amounts[0]
        );
        _swap(amounts, path, to);
    }

    function swapExactETHForTokens(
        uint256 amountOutMin,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external payable ensure(deadline) returns (uint256[] memory amounts) {
        require(path[0] == WETH, "UniswapV2Router: INVALID_PATH");
        amounts = UniswapV2Library.getAmountsOut(factory, msg.value, path);
        require(
            amounts[amounts.length - 1] >= amountOutMin,
            "UniswapV2Router: INSUFFICIENT_OUTPUT_AMOUNT"
        );
        IWETH(WETH).deposit.value(amounts[0])();
        assert(
            IWETH(WETH).transfer(
                UniswapV2Library.pairFor(factory, path[0], path[1]),
                amounts[0]
            )
        );
        _swap(amounts, path, to);
    }

    function swapTokensForExactETH(
        uint256 amountOut,
        uint256 amountInMax,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external ensure(deadline) returns (uint256[] memory amounts) {
        require(path[path.length - 1] == WETH, "UniswapV2Router: INVALID_PATH");
        amounts = UniswapV2Library.getAmountsIn(factory, amountOut, path);
        require(
            amounts[0] <= amountInMax,
            "UniswapV2Router: EXCESSIVE_INPUT_AMOUNT"
        );
        TransferHelper.safeTransferFrom(
            path[0],
            msg.sender,
            UniswapV2Library.pairFor(factory, path[0], path[1]),
            amounts[0]
        );
        _swap(amounts, path, address(this));
        IWETH(WETH).withdraw(amounts[amounts.length - 1]);
        TransferHelper.safeTransferETH(to, amounts[amounts.length - 1]);
    }

    function swapExactTokensForETH(
        uint256 amountIn,
        uint256 amountOutMin,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external ensure(deadline) returns (uint256[] memory amounts) {
        require(path[path.length - 1] == WETH, "UniswapV2Router: INVALID_PATH");
        amounts = UniswapV2Library.getAmountsOut(factory, amountIn, path);
        require(
            amounts[amounts.length - 1] >= amountOutMin,
            "UniswapV2Router: INSUFFICIENT_OUTPUT_AMOUNT"
        );
        TransferHelper.safeTransferFrom(
            path[0],
            msg.sender,
            UniswapV2Library.pairFor(factory, path[0], path[1]),
            amounts[0]
        );
        _swap(amounts, path, address(this));
        IWETH(WETH).withdraw(amounts[amounts.length - 1]);
        TransferHelper.safeTransferETH(to, amounts[amounts.length - 1]);
    }

    function swapETHForExactTokens(
        uint256 amountOut,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external payable ensure(deadline) returns (uint256[] memory amounts) {
        require(path[0] == WETH, "UniswapV2Router: INVALID_PATH");
        amounts = UniswapV2Library.getAmountsIn(factory, amountOut, path);
        require(
            amounts[0] <= msg.value,
            "UniswapV2Router: EXCESSIVE_INPUT_AMOUNT"
        );
        IWETH(WETH).deposit.value(amounts[0])();
        assert(
            IWETH(WETH).transfer(
                UniswapV2Library.pairFor(factory, path[0], path[1]),
                amounts[0]
            )
        );
        _swap(amounts, path, to);
        // refund dust eth, if any
        if (msg.value > amounts[0])
            TransferHelper.safeTransferETH(msg.sender, msg.value - amounts[0]);
    }

    // **** SWAP (supporting fee-on-transfer tokens) ****
    // requires the initial amount to have already been sent to the first pair
    function _swapSupportingFeeOnTransferTokens(
        address[] memory path,
        address _to
    ) internal {
        for (uint256 i; i < path.length - 1; i++) {
            (address input, address output) = (path[i], path[i + 1]);
            (address token0, ) = UniswapV2Library.sortTokens(input, output);
            IUniswapV2Pair pair = IUniswapV2Pair(
                UniswapV2Library.pairFor(factory, input, output)
            );
            uint256 amountInput;
            uint256 amountOutput;
            {
                // scope to avoid stack too deep errors
                (uint256 reserve0, uint256 reserve1, ) = pair.getReserves();
                (uint256 reserveInput, uint256 reserveOutput) = input == token0
                    ? (reserve0, reserve1)
                    : (reserve1, reserve0);
                amountInput = IERC20(input).balanceOf(address(pair)).sub(
                    reserveInput
                );
                amountOutput = UniswapV2Library.getAmountOut(
                    amountInput,
                    reserveInput,
                    reserveOutput
                );
            }
            (uint256 amount0Out, uint256 amount1Out) = input == token0
                ? (uint256(0), amountOutput)
                : (amountOutput, uint256(0));
            address to = i < path.length - 2
                ? UniswapV2Library.pairFor(factory, output, path[i + 2])
                : _to;
            pair.swap(amount0Out, amount1Out, to, new bytes(0));
        }
    }

    function swapExactTokensForTokensSupportingFeeOnTransferTokens(
        uint256 amountIn,
        uint256 amountOutMin,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external ensure(deadline) {
        TransferHelper.safeTransferFrom(
            path[0],
            msg.sender,
            UniswapV2Library.pairFor(factory, path[0], path[1]),
            amountIn
        );
        uint256 balanceBefore = IERC20(path[path.length - 1]).balanceOf(to);
        _swapSupportingFeeOnTransferTokens(path, to);
        require(
            IERC20(path[path.length - 1]).balanceOf(to).sub(balanceBefore) >=
                amountOutMin,
            "UniswapV2Router: INSUFFICIENT_OUTPUT_AMOUNT"
        );
    }

    function swapExactETHForTokensSupportingFeeOnTransferTokens(
        uint256 amountOutMin,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external payable ensure(deadline) {
        require(path[0] == WETH, "UniswapV2Router: INVALID_PATH");
        uint256 amountIn = msg.value;
        IWETH(WETH).deposit.value(amountIn)();
        assert(
            IWETH(WETH).transfer(
                UniswapV2Library.pairFor(factory, path[0], path[1]),
                amountIn
            )
        );
        uint256 balanceBefore = IERC20(path[path.length - 1]).balanceOf(to);
        _swapSupportingFeeOnTransferTokens(path, to);
        require(
            IERC20(path[path.length - 1]).balanceOf(to).sub(balanceBefore) >=
                amountOutMin,
            "UniswapV2Router: INSUFFICIENT_OUTPUT_AMOUNT"
        );
    }

    function swapExactTokensForETHSupportingFeeOnTransferTokens(
        uint256 amountIn,
        uint256 amountOutMin,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external ensure(deadline) {
        require(path[path.length - 1] == WETH, "UniswapV2Router: INVALID_PATH");
        TransferHelper.safeTransferFrom(
            path[0],
            msg.sender,
            UniswapV2Library.pairFor(factory, path[0], path[1]),
            amountIn
        );
        _swapSupportingFeeOnTransferTokens(path, address(this));
        uint256 amountOut = IERC20(WETH).balanceOf(address(this));
        require(
            amountOut >= amountOutMin,
            "UniswapV2Router: INSUFFICIENT_OUTPUT_AMOUNT"
        );
        IWETH(WETH).withdraw(amountOut);
        TransferHelper.safeTransferETH(to, amountOut);
    }

    // **** LIBRARY FUNCTIONS ****
    function quote(
        uint256 amountA,
        uint256 reserveA,
        uint256 reserveB
    ) public pure returns (uint256 amountB) {
        return UniswapV2Library.quote(amountA, reserveA, reserveB);
    }

    function getAmountOut(
        uint256 amountIn,
        uint256 reserveIn,
        uint256 reserveOut
    ) public pure returns (uint256 amountOut) {
        return UniswapV2Library.getAmountOut(amountIn, reserveIn, reserveOut);
    }

    function getAmountIn(
        uint256 amountOut,
        uint256 reserveIn,
        uint256 reserveOut
    ) public pure returns (uint256 amountIn) {
        return UniswapV2Library.getAmountIn(amountOut, reserveIn, reserveOut);
    }

    function getAmountsOut(uint256 amountIn, address[] memory path)
        public
        view
        returns (uint256[] memory amounts)
    {
        return UniswapV2Library.getAmountsOut(factory, amountIn, path);
    }

    function getAmountsIn(uint256 amountOut, address[] memory path)
        public
        view
        returns (uint256[] memory amounts)
    {
        return UniswapV2Library.getAmountsIn(factory, amountOut, path);
    }
}

// File: ./contracts/weth/IWETH.sol



pragma solidity >=0.5.0;

interface IWETH {
    function deposit() external payable;
    function transfer(address to, uint256 value) external returns (bool);
    function withdraw(uint256) external;
}

// File: ./contracts/StrategyAddTwoSidesOptimal.sol



pragma solidity 0.5.16;
import 'OpenZeppelin/openzeppelin-contracts@2.3.0/contracts/ownership/Ownable.sol';
import 'OpenZeppelin/openzeppelin-contracts@2.3.0/contracts/math/SafeMath.sol';
import 'OpenZeppelin/openzeppelin-contracts@2.3.0/contracts/utils/ReentrancyGuard.sol';
import 'Uniswap/uniswap-v2-core@1.0.1/contracts/interfaces/IUniswapV2Factory.sol';
import 'Uniswap/uniswap-v2-core@1.0.1/contracts/interfaces/IUniswapV2Pair.sol';
import 'Uniswap/uniswap-v2-core@1.0.1/contracts/libraries/Math.sol';
import "./uniswap/IUniswapV2Router02.sol";
import "./SafeToken.sol";
import "./Strategy.sol";

contract StrategyAddTwoSidesOptimal is Ownable, ReentrancyGuard, Strategy {
    using SafeToken for address;
    using SafeMath for uint256;

    IUniswapV2Factory public factory;
    IUniswapV2Router02 public router;
    address public weth;
    address public goblin;
    address public fToken_;

    /// @dev Create a new add two-side optimal strategy instance.
    /// @param _router The Uniswap router smart contract.
    constructor(IUniswapV2Router02 _router, address _goblin, address _fToken) public {
        factory = IUniswapV2Factory(_router.factory());
        router = _router;
        weth = _router.WETH();
        goblin = _goblin;
        fToken_ = _fToken;
    }
    
    /// @dev Throws if called by any account other than the goblin.
    modifier onlyGoblin() {
        require(isGoblin(), "caller is not the goblin");
        _;
    }

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

    /// @dev Compute optimal deposit amount
    /// @param amtA amount of token A desired to deposit
    /// @param amtB amonut of token B desired to deposit
    /// @param resA amount of token A in reserve
    /// @param resB amount of token B in reserve
    function optimalDeposit(
        uint256 amtA,
        uint256 amtB,
        uint256 resA,
        uint256 resB
    ) internal pure returns (uint256 swapAmt, bool isReversed) {
        if (amtA.mul(resB) >= amtB.mul(resA)) {
            swapAmt = _optimalDepositA(amtA, amtB, resA, resB);
            isReversed = false;
        } else {
            swapAmt = _optimalDepositA(amtB, amtA, resB, resA);
            isReversed = true;
        }
    }

    /// @dev Compute optimal deposit amount helper
    /// @param amtA amount of token A desired to deposit
    /// @param amtB amonut of token B desired to deposit
    /// @param resA amount of token A in reserve
    /// @param resB amount of token B in reserve
    function _optimalDepositA(
        uint256 amtA,
        uint256 amtB,
        uint256 resA,
        uint256 resB
    ) internal pure returns (uint256) {
        require(amtA.mul(resB) >= amtB.mul(resA), "Reversed");

        uint256 a = 997;
        uint256 b = uint256(1997).mul(resA);
        uint256 _c = (amtA.mul(resB)).sub(amtB.mul(resA));
        uint256 c = _c.mul(1000).div(amtB.add(resB)).mul(resA);

        uint256 d = a.mul(c).mul(4);
        uint256 e = Math.sqrt(b.mul(b).add(d));

        uint256 numerator = e.sub(b);
        uint256 denominator = a.mul(2);

        return numerator.div(denominator);
    }

    /// @dev Execute worker strategy. Take LP tokens + ETH. Return LP tokens + ETH.
    /// @param user User address
    /// @param data Extra calldata information passed along to this strategy.
    function execute(address user, uint256, /* debt */ bytes calldata data) 
        external         
        payable  
        onlyGoblin       
        nonReentrant 
    {
        // 1. Find out what farming token we are dealing with.
        (address fToken, uint256 fAmount, uint256 minLPAmount) = abi.decode(data, (address, uint256, uint256));
        require(fToken == fToken_, 'token mismatched');
        IUniswapV2Pair lpToken = IUniswapV2Pair(factory.getPair(fToken, weth));        
        // 2. Compute the optimal amount of ETH and fToken to be converted.  
        if (fAmount > 0) {  
            fToken.safeTransferFrom(user, address(this), fAmount);            
        }
        uint256 ethBalance = address(this).balance;
        uint256 swapAmt;
        bool isReversed;
        {
            (uint256 r0, uint256 r1, ) = lpToken.getReserves();
            (uint256 ethReserve, uint256 fReserve) = lpToken.token0() == weth ? (r0, r1) : (r1, r0);
            (swapAmt, isReversed) = optimalDeposit(ethBalance, fToken.myBalance(), ethReserve, fReserve);
        }
        // 3. Convert between ETH and farming tokens
        fToken.safeApprove(address(router), 0);
        fToken.safeApprove(address(router), uint256(-1));
        address[] memory path = new address[](2);
        (path[0], path[1]) = isReversed ? (fToken, weth) : (weth, fToken);
        if (isReversed) {
            router.swapExactTokensForETH(swapAmt, 0, path, address(this), now); // farming tokens to ETH
        } else {
            router.swapExactETHForTokens.value(swapAmt)(0, path, address(this), now); // ETH to farming tokens
        }
        // 4. Mint more LP tokens and return all LP tokens to the sender.
        (,, uint256 moreLPAmount) = router.addLiquidityETH.value(address(this).balance)(
            fToken, fToken.myBalance(), 0, 0, address(this), now
        );
        require(moreLPAmount >= minLPAmount, "insufficient LP tokens received");
        lpToken.transfer(msg.sender, lpToken.balanceOf(address(this)));
    }

    /// @dev Recover ERC20 tokens that were accidentally sent to this smart contract.
    /// @param token The token contract. Can be anything. This contract should not hold ERC20 tokens.
    /// @param to The address to send the tokens to.
    /// @param value The number of tokens to transfer to `to`.
    function recover(address token, address to, uint256 value) external onlyOwner nonReentrant {
        token.safeTransfer(to, value);
    }

    function() external payable {}
}

// File: ./contracts/SafeToken.sol



pragma solidity 0.5.16;

interface ERC20Interface {
    function balanceOf(address user) external view returns (uint256);
}

library SafeToken {
    function myBalance(address token) internal view returns (uint256) {
        return ERC20Interface(token).balanceOf(address(this));
    }

    function balanceOf(address token, address user) internal view returns (uint256) {
        return ERC20Interface(token).balanceOf(user);
    }

    function safeApprove(address token, address to, uint256 value) internal {
        // bytes4(keccak256(bytes('approve(address,uint256)')));
        (bool success, bytes memory data) = token.call(abi.encodeWithSelector(0x095ea7b3, to, value));
        require(success && (data.length == 0 || abi.decode(data, (bool))), "!safeApprove");
    }

    function safeTransfer(address token, address to, uint256 value) internal {
        // bytes4(keccak256(bytes('transfer(address,uint256)')));
        (bool success, bytes memory data) = token.call(abi.encodeWithSelector(0xa9059cbb, to, value));
        require(success && (data.length == 0 || abi.decode(data, (bool))), "!safeTransfer");
    }

    function safeTransferFrom(address token, address from, address to, uint256 value) internal {
        // bytes4(keccak256(bytes('transferFrom(address,address,uint256)')));
        (bool success, bytes memory data) = token.call(abi.encodeWithSelector(0x23b872dd, from, to, value));
        require(success && (data.length == 0 || abi.decode(data, (bool))), "!safeTransferFrom");
    }

    function safeTransferETH(address to, uint256 value) internal {
        (bool success, ) = to.call.value(value)(new bytes(0));
        require(success, "!safeTransferETH");
    }
}

// File: ./contracts/Strategy.sol



pragma solidity 0.5.16;

interface Strategy {
  /// @dev Execute worker strategy. Take LP tokens + BNB. Return LP tokens + BNB.
  /// @param user The original user that is interacting with the operator.
  /// @param debt The user's total debt, for better decision making context.
  /// @param data Extra calldata information passed along to this strategy.
  function execute(
    address user,
    uint debt,
    bytes calldata data
  ) external payable;
}

// File: ./contracts/StrategyAllETHOnly.sol



pragma solidity 0.5.16;
import 'OpenZeppelin/openzeppelin-contracts@2.3.0/contracts/ownership/Ownable.sol';
import 'OpenZeppelin/openzeppelin-contracts@2.3.0/contracts/math/SafeMath.sol';
import 'OpenZeppelin/openzeppelin-contracts@2.3.0/contracts/utils/ReentrancyGuard.sol';
import 'Uniswap/uniswap-v2-core@1.0.1/contracts/interfaces/IUniswapV2Factory.sol';
import 'Uniswap/uniswap-v2-core@1.0.1/contracts/interfaces/IUniswapV2Pair.sol';
import 'Uniswap/uniswap-v2-core@1.0.1/contracts/libraries/Math.sol';
import "./uniswap/IUniswapV2Router02.sol";
import "./SafeToken.sol";
import "./Strategy.sol";


contract StrategyAllETHOnly is Ownable, ReentrancyGuard, Strategy {
    using SafeToken for address;
    using SafeMath for uint256;

    IUniswapV2Factory public factory;
    IUniswapV2Router02 public router;
    address public weth;

    mapping(address => bool) public whitelistedTokens;

    /// @dev Create a new add ETH only strategy instance.
    /// @param _router The Uniswap router smart contract.
    constructor(IUniswapV2Router02 _router) public {
        factory = IUniswapV2Factory(_router.factory());
        router = _router;
        weth = _router.WETH();
    }

    /// @dev Set whitelist tokens
    /// @param tokens Token list to set statuses
    /// @param statuses Status list to set tokens to
    function setWhitelistTokens(address[] calldata tokens, bool[] calldata statuses)
        external
        onlyOwner
    {
        require(tokens.length == statuses.length, 'tokens & statuses length mismatched');
        for (uint256 idx = 0; idx < tokens.length; idx++) {
            whitelistedTokens[tokens[idx]] = statuses[idx];
        }
    }

    /// @dev Execute worker strategy. Take LP tokens + ETH. Return LP tokens + ETH.
    /// @param data Extra calldata information passed along to this strategy.
    function execute(address /* user */, uint256 /* debt */, bytes calldata data)
        external
        payable
        nonReentrant
    {
        // 1. Find out what farming token we are dealing with and min additional LP tokens.
        (address fToken, uint256 minLPAmount) = abi.decode(data, (address, uint256));
        require(whitelistedTokens[fToken], 'token not whitelisted');
        IUniswapV2Pair lpToken = IUniswapV2Pair(factory.getPair(fToken, weth));
        // 2. Compute the optimal amount of ETH to be converted to farming tokens.
        uint256 balance = address(this).balance;
        (uint256 r0, uint256 r1, ) = lpToken.getReserves();
        uint256 rIn = lpToken.token0() == weth ? r0 : r1;
        uint256 aIn = Math.sqrt(rIn.mul(balance.mul(3988000).add(rIn.mul(3988009)))).sub(rIn.mul(1997)) / 1994;
        // 3. Convert that portion of ETH to farming tokens.
        address[] memory path = new address[](2);
        path[0] = weth;
        path[1] = fToken;
        router.swapExactETHForTokens.value(aIn)(0, path, address(this), now);
        // 4. Mint more LP tokens and return all LP tokens to the sender.
        fToken.safeApprove(address(router), 0);
        fToken.safeApprove(address(router), uint(-1));
        (,, uint256 moreLPAmount) = router.addLiquidityETH.value(address(this).balance)(
            fToken, fToken.myBalance(), 0, 0, address(this), now
        );
        require(moreLPAmount >= minLPAmount, "insufficient LP tokens received");
        lpToken.transfer(msg.sender, lpToken.balanceOf(address(this)));
    }

    /// @dev Recover ERC20 tokens that were accidentally sent to this smart contract.
    /// @param token The token contract. Can be anything. This contract should not hold ERC20 tokens.
    /// @param to The address to send the tokens to.
    /// @param value The number of tokens to transfer to `to`.
    function recover(address token, address to, uint256 value) external onlyOwner nonReentrant {
        token.safeTransfer(to, value);
    }

    function() external payable {}
}

// File: ./contracts/StrategyWithdrawMinimizeTrading.sol



pragma solidity 0.5.16;
import 'OpenZeppelin/openzeppelin-contracts@2.3.0/contracts/ownership/Ownable.sol';
import 'OpenZeppelin/openzeppelin-contracts@2.3.0/contracts/utils/ReentrancyGuard.sol';
import 'OpenZeppelin/openzeppelin-contracts@2.3.0/contracts/math/SafeMath.sol';
import 'Uniswap/uniswap-v2-core@1.0.1/contracts/interfaces/IUniswapV2Factory.sol';
import 'Uniswap/uniswap-v2-core@1.0.1/contracts/interfaces/IUniswapV2Pair.sol';
import './uniswap/IUniswapV2Router02.sol';
import './SafeToken.sol';
import './Strategy.sol';

contract StrategyWithdrawMinimizeTrading is Ownable, ReentrancyGuard, Strategy {
    using SafeToken for address;
    using SafeMath for uint256;

    IUniswapV2Factory public factory;
    IUniswapV2Router02 public router;
    address public weth;

    mapping(address => bool) public whitelistedTokens;

    /// @dev Create a new withdraw minimize trading strategy instance.
    /// @param _router The Uniswap router smart contract.
    constructor(IUniswapV2Router02 _router) public {
        factory = IUniswapV2Factory(_router.factory());
        router = _router;
        weth = _router.WETH();
    }

    /// @dev Set whitelisted tokens
    /// @param tokens Token list to set whitelist status
    /// @param statuses Status list to set tokens to
    function setWhitelistTokens(address[] calldata tokens, bool[] calldata statuses)
        external
        onlyOwner
    {
        require(tokens.length == statuses.length, 'tokens & statuses length mismatched');
        for (uint256 idx = 0; idx < tokens.length; idx++) {
            whitelistedTokens[tokens[idx]] = statuses[idx];
        }
    }

    /// @dev Execute worker strategy. Take LP tokens + ETH. Return LP tokens + ETH.
    /// @param user User address to withdraw liquidity.
    /// @param debt Debt amount in WAD of the user.
    /// @param data Extra calldata information passed along to this strategy.
    function execute(address user, uint256 debt, bytes calldata data) external payable nonReentrant {
        // 1. Find out what farming token we are dealing with.
        (address fToken, uint256 minFToken) = abi.decode(data, (address, uint256));
        require(whitelistedTokens[fToken], 'token not whitelisted');
        IUniswapV2Pair lpToken = IUniswapV2Pair(factory.getPair(fToken, weth));
        // 2. Remove all liquidity back to ETH and farming tokens.
        lpToken.approve(address(router), uint256(-1));
        router.removeLiquidityETH(fToken, lpToken.balanceOf(address(this)), 0, 0, address(this), now);
        // 3. Convert farming tokens to ETH.
        address[] memory path = new address[](2);
        path[0] = fToken;
        path[1] = weth;
        fToken.safeApprove(address(router), 0);
        fToken.safeApprove(address(router), uint256(-1));
        uint256 balance = address(this).balance;
        if (debt > balance) {
            // Convert some farming tokens to ETH.
            uint256 remainingDebt = debt.sub(balance);
            router.swapTokensForExactETH(remainingDebt, fToken.myBalance(), path, address(this), now);
        }
        // 4. Return ETH back to the original caller.
        uint256 remainingBalance = address(this).balance;
        SafeToken.safeTransferETH(msg.sender, remainingBalance);
        // 5. Return remaining farming tokens to user.
        uint256 remainingFToken = fToken.myBalance();
        require(remainingFToken >= minFToken, 'insufficient farming tokens received');
        if (remainingFToken > 0) {
            fToken.safeTransfer(user, remainingFToken);
        }
    }

    /// @dev Recover ERC20 tokens that were accidentally sent to this smart contract.
    /// @param token The token contract. Can be anything. This contract should not hold ERC20 tokens.
    /// @param to The address to send the tokens to.
    /// @param value The number of tokens to transfer to `to`.
    function recover(address token, address to, uint256 value) external onlyOwner nonReentrant {
        token.safeTransfer(to, value);
    }

    function() external payable {}
}

// File: ./contracts/weth/WETH.sol



pragma solidity 0.5.16;
import "./IWETH.sol";

// 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 WETH is IWETH {
    string public name = "Wrapped Ether";
    string public symbol = "WETH";
    uint8 public decimals = 18;

    event Approval(address indexed src, address indexed guy, uint256 wad);
    event Transfer(address indexed src, address indexed dst, uint256 wad);
    event Deposit(address indexed dst, uint256 wad);
    event Withdrawal(address indexed src, uint256 wad);

    mapping(address => uint256) public balanceOf;
    mapping(address => mapping(address => uint256)) public allowance;

    function() external payable {
        deposit();
    }

    function deposit() public payable {
        balanceOf[msg.sender] += msg.value;
        emit Deposit(msg.sender, msg.value);
    }

    function withdraw(uint256 wad) public {
        require(balanceOf[msg.sender] >= wad);
        balanceOf[msg.sender] -= wad;
        msg.sender.transfer(wad);
        emit Withdrawal(msg.sender, wad);
    }

    function totalSupply() public view returns (uint256) {
        return address(this).balance;
    }

    function approve(address guy, uint256 wad) public returns (bool) {
        allowance[msg.sender][guy] = wad;
        emit Approval(msg.sender, guy, wad);
        return true;
    }

    function transfer(address dst, uint256 wad) public returns (bool) {
        return transferFrom(msg.sender, dst, wad);
    }

    function transferFrom(
        address src,
        address dst,
        uint256 wad
    ) public returns (bool) {
        require(balanceOf[src] >= wad);

        if (src != msg.sender && allowance[src][msg.sender] != uint256(-1)) {
            require(allowance[src][msg.sender] >= wad);
            allowance[src][msg.sender] -= wad;
        }

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

        emit Transfer(src, dst, wad);

        return true;
    }
}

/*
                    GNU GENERAL PUBLIC LICENSE
                       Version 3, 29 June 2007

 Copyright (C) 2007 Free Software Foundation, Inc. <http://fsf.org/>
 Everyone is permitted to copy and distribute verbatim copies
 of this license document, but changing it is not allowed.

                            Preamble

  The GNU General Public License is a free, copyleft license for
software and other kinds of works.

  The licenses for most software and other practical works are designed
to take away your freedom to share and change the works.  By contrast,
the GNU General Public License is intended to guarantee your freedom to
share and change all versions of a program--to make sure it remains free
software for all its users.  We, the Free Software Foundation, use the
GNU General Public License for most of our software; it applies also to
any other work released this way by its authors.  You can apply it to
your programs, too.

  When we speak of free software, we are referring to freedom, not
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  To protect your rights, we need to prevent others from denying you
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know their rights.

  Developers that use the GNU GPL protect your rights with two steps:
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                       TERMS AND CONDITIONS

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  The Corresponding Source for a work in source code form is that
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  All rights granted under this License are granted for the term of
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  You may convey verbatim copies of the Program's source code as you
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  You may convey a work based on the Program, or the modifications to
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  7. Additional Terms.

  "Additional permissions" are terms that supplement the terms of this
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  10. Automatic Licensing of Downstream Recipients.

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  11. Patents.

  A "contributor" is a copyright holder who authorizes use under this
License of the Program or a work on which the Program is based.  The
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  If you convey a covered work, knowingly relying on a patent license,
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  If, pursuant to or in connection with a single transaction or
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or that patent license was granted, prior to 28 March 2007.

  Nothing in this License shall be construed as excluding or limiting
any implied license or other defenses to infringement that may
otherwise be available to you under applicable patent law.

  12. No Surrender of Others' Freedom.

  If conditions are imposed on you (whether by court order, agreement or
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covered work so as to satisfy simultaneously your obligations under this
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to collect a royalty for further conveying from those to whom you convey
the Program, the only way you could satisfy both those terms and this
License would be to refrain entirely from conveying the Program.

  13. Use with the GNU Affero General Public License.

  Notwithstanding any other provision of this License, you have
permission to link or combine any covered work with a work licensed
under version 3 of the GNU Affero General Public License into a single
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but the special requirements of the GNU Affero General Public License,
section 13, concerning interaction through a network will apply to the
combination as such.

  14. Revised Versions of this License.

  The Free Software Foundation may publish revised and/or new versions of
the GNU General Public License from time to time.  Such new versions will
be similar in spirit to the present version, but may differ in detail to
address new problems or concerns.

  Each version is given a distinguishing version number.  If the
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Public License "or any later version" applies to it, you have the
option of following the terms and conditions either of that numbered
version or of any later version published by the Free Software
Foundation.  If the Program does not specify a version number of the
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by the Free Software Foundation.

  If the Program specifies that a proxy can decide which future
versions of the GNU General Public License can be used, that proxy's
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to choose that version for the Program.

  Later license versions may give you additional or different
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author or copyright holder as a result of your choosing to follow a
later version.

  15. Disclaimer of Warranty.

  THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY
APPLICABLE LAW.  EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT
HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY
OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO,
THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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IS WITH YOU.  SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF
ALL NECESSARY SERVICING, REPAIR OR CORRECTION.

  16. Limitation of Liability.

  IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS
THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY
GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE
USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF
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/StrategyLiquidate.sol



pragma solidity 0.5.16;
import 'OpenZeppelin/openzeppelin-contracts@2.3.0/contracts/ownership/Ownable.sol';
import 'OpenZeppelin/openzeppelin-contracts@2.3.0/contracts/utils/ReentrancyGuard.sol';
import 'Uniswap/uniswap-v2-core@1.0.1/contracts/interfaces/IUniswapV2Factory.sol';
import 'Uniswap/uniswap-v2-core@1.0.1/contracts/interfaces/IUniswapV2Pair.sol';
import "./uniswap/IUniswapV2Router02.sol";
import "./SafeToken.sol";
import "./Strategy.sol";

contract StrategyLiquidate is Ownable, ReentrancyGuard, Strategy {
    using SafeToken for address;

    IUniswapV2Factory public factory;
    IUniswapV2Router02 public router;
    address public weth;

    mapping(address => bool) public whitelistedTokens;

    /// @dev Create a new liquidate strategy instance.
    /// @param _router The Uniswap router smart contract.
    constructor(IUniswapV2Router02 _router) public {
        factory = IUniswapV2Factory(_router.factory());
        router = _router;
        weth = _router.WETH();
    }

    /// @dev Set whitelisted tokens
    /// @param tokens Token list to set whitelist status
    /// @param statuses Status list to set tokens to
    function setWhitelistTokens(address[] calldata tokens, bool[] calldata statuses)
        external
        onlyOwner
    {
        require(tokens.length == statuses.length, 'tokens & statuses length mismatched');
        for (uint256 idx = 0; idx < tokens.length; idx++) {
            whitelistedTokens[tokens[idx]] = statuses[idx];
        }
    }

    /// @dev Execute worker strategy. Take LP tokens + ETH. Return LP tokens + ETH.
    /// @param data Extra calldata information passed along to this strategy.
    function execute(address /* user */, uint256 /* debt */, bytes calldata data)
        external
        payable
        nonReentrant
    {
        // 1. Find out what farming token we are dealing with.
        (address fToken, uint256 minETH) = abi.decode(data, (address, uint256));
        require(whitelistedTokens[fToken], 'token not whitelisted');
        IUniswapV2Pair lpToken = IUniswapV2Pair(factory.getPair(fToken, weth));
        // 2. Remove all liquidity back to ETH and farming tokens.
        lpToken.approve(address(router), uint256(-1));
        router.removeLiquidityETH(fToken, lpToken.balanceOf(address(this)), 0, 0, address(this), now);
        // 3. Convert farming tokens to ETH.
        address[] memory path = new address[](2);
        path[0] = fToken;
        path[1] = weth;
        fToken.safeApprove(address(router), 0);
        fToken.safeApprove(address(router), uint256(-1));
        router.swapExactTokensForETH(fToken.myBalance(), 0, path, address(this), now);
        // 4. Return all ETH back to the original caller.
        uint256 balance = address(this).balance;
        require(balance >= minETH, "insufficient ETH received");
        SafeToken.safeTransferETH(msg.sender, balance);
    }

    /// @dev Recover ERC20 tokens that were accidentally sent to this smart contract.
    /// @param token The token contract. Can be anything. This contract should not hold ERC20 tokens.
    /// @param to The address to send the tokens to.
    /// @param value The number of tokens to transfer to `to`.
    function recover(address token, address to, uint256 value) external onlyOwner nonReentrant {
        token.safeTransfer(to, value);
    }

    function() external payable {}
}

// File: Uniswap/uniswap-v2-core@1.0.1/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: Uniswap/uniswap-v2-core@1.0.1/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: OpenZeppelin/openzeppelin-contracts@2.3.0/contracts/math/SafeMath.sol



pragma solidity ^0.5.0;

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

        return c;
    }

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

        return c;
    }

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

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

        return c;
    }

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

        return c;
    }

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

// File: OpenZeppelin/openzeppelin-contracts@2.3.0/contracts/token/ERC20/IERC20.sol



pragma solidity ^0.5.0;

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

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

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

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

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

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

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

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

// File: OpenZeppelin/openzeppelin-contracts@2.3.0/contracts/ownership/Ownable.sol



pragma solidity ^0.5.0;

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

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

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

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

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

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

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

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

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

// File: OpenZeppelin/openzeppelin-contracts@2.3.0/contracts/utils/ReentrancyGuard.sol



pragma solidity ^0.5.0;

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

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

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

// File: Uniswap/uniswap-v2-core@1.0.1/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;
        }
    }
}