// SPDX-License-Identifier: MIT

pragma solidity ^0.5.17;

interface IERC20 {
    function totalSupply() external view returns (uint256);
    function balanceOf(address account) external view returns (uint256);
    function transfer(address recipient, uint256 amount) external returns (bool);
    function allowance(address owner, address spender) external view returns (uint256);
    function approve(address spender, uint256 amount) external returns (bool);
    function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);
    event Transfer(address indexed from, address indexed to, uint256 value);
    event Approval(address indexed owner, address indexed spender, uint256 value);
}

contract Context {
    constructor () internal { }
    // solhint-disable-previous-line no-empty-blocks

    function _msgSender() internal view returns (address payable) {
        return msg.sender;
    }

    function _msgData() internal view returns (bytes memory) {
        this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
        return msg.data;
    }
}

library SafeMath {
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        require(c >= a, "SafeMath: addition overflow");

        return c;
    }
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        return sub(a, b, "SafeMath: subtraction overflow");
    }
    function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b <= a, errorMessage);
        uint256 c = a - b;

        return c;
    }
    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        if (a == 0) {
            return 0;
        }

        uint256 c = a * b;
        require(c / a == b, "SafeMath: multiplication overflow");

        return c;
    }
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        return div(a, b, "SafeMath: division by zero");
    }
    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;

        return c;
    }
    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        return mod(a, b, "SafeMath: modulo by zero");
    }
    function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b != 0, errorMessage);
        return a % b;
    }
}

library Address {
    function isContract(address account) internal view returns (bool) {
        bytes32 codehash;
        bytes32 accountHash = 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470;
        // solhint-disable-next-line no-inline-assembly
        assembly { codehash := extcodehash(account) }
        return (codehash != 0x0 && codehash != accountHash);
    }
    function toPayable(address account) internal pure returns (address payable) {
        return address(uint160(account));
    }
    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");

        // solhint-disable-next-line avoid-call-value
        (bool success, ) = recipient.call.value(amount)("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }
}

library SafeERC20 {
    using SafeMath for uint256;
    using Address for address;

    function safeTransfer(IERC20 token, address to, uint256 value) internal {
        callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
    }

    function safeTransferFrom(IERC20 token, address from, address to, uint256 value) internal {
        callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
    }

    function safeApprove(IERC20 token, address spender, uint256 value) internal {
        require((value == 0) || (token.allowance(address(this), spender) == 0),
            "SafeERC20: approve from non-zero to non-zero allowance"
        );
        callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
    }
    function callOptionalReturn(IERC20 token, bytes memory data) private {
        require(address(token).isContract(), "SafeERC20: call to non-contract");

        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = address(token).call(data);
        require(success, "SafeERC20: low-level call failed");

        if (returndata.length > 0) { // Return data is optional
            // solhint-disable-next-line max-line-length
            require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
        }
    }
}

/* 

 Very low risk COMP farming strategy

*/

interface yERC20 {
    function deposit(uint256) external;
    function balanceOf(address) external view returns (uint);
}

interface ICurveFi {
    function add_liquidity(
        uint256[4] calldata amounts,
        uint256 min_mint_amount
    ) external;
}

contract ConverterDAItoYCRV {
    using SafeERC20 for IERC20;
    using Address for address;
    using SafeMath for uint256;
    
    address public governance;
    address public controller;
    IERC20 constant public dai = IERC20(0x6B175474E89094C44Da98b954EedeAC495271d0F);
    yERC20 constant public ydai = yERC20(0x16de59092dAE5CcF4A1E6439D611fd0653f0Bd01);
    IERC20 constant public ycrv = IERC20(0xdF5e0e81Dff6FAF3A7e52BA697820c5e32D806A8);
    ICurveFi constant public swap = ICurveFi(0x45F783CCE6B7FF23B2ab2D70e416cdb7D6055f51);
    
    constructor() public {
        governance = msg.sender;
        controller = msg.sender;
    }
    
    function convert(address _strategy) external {
        require(msg.sender == controller, "!controller");
        uint _dai = dai.balanceOf(address(this));
        dai.safeApprove(address(ydai), 0);
        dai.safeApprove(address(ydai), _dai);
        ydai.deposit(_dai);
        uint _ydai = ydai.balanceOf(address(this));
        IERC20(address(ydai)).safeApprove(address(swap), 0);
        IERC20(address(ydai)).safeApprove(address(swap), _ydai);
        swap.add_liquidity([_ydai,0,0,0],0);
        ycrv.safeTransfer(_strategy, ycrv.balanceOf(address(this)));
    }
    
    function seize(IERC20 _token) external {
        require(msg.sender == governance, "!governance");
        _token.safeTransfer(governance, _token.balanceOf(address(this)));
    }
    
    function setGovernance(address _governance) external {
        require(msg.sender == governance, "!governance");
        governance = _governance;
    }
        
    function setController(address _controller) external {
        require(msg.sender == governance, "!governance");
        controller = _controller;
    }
}