// 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 decimals() external view returns (uint);
    function name() external view returns (string memory);
    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);
}

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");
        }
    }
}

interface Controller {
    function vaults(address) external view returns (address);
    function rewards() external view returns (address);
}

/*

 A strategy must implement the following calls;
 
 - deposit()
 - withdraw(address) must exclude any tokens used in the yield - Controller role - withdraw should return to Controller
 - withdraw(uint) - Controller | Vault role - withdraw should always return to vault
 - withdrawAll() - Controller | Vault role - withdraw should always return to vault
 - balanceOf()
 
 Where possible, strategies must remain as immutable as possible, instead of updating variables, we update the contract by linking it in the controller
 
*/

interface Gauge {
    function deposit(uint) external;
    function balanceOf(address) external view returns (uint);
    function withdraw(uint) external;
}

interface Mintr {
    function mint(address) external;
}

interface UniswapRouter {
    function swapExactTokensForTokens(uint, uint, address[] calldata, address, uint) external;
}


interface ICurveFi {

  function add_liquidity(
    uint256[4] calldata amounts,
    uint256 min_mint_amount
  ) external;
  function exchange_underlying(
    int128 from, int128 to, uint256 _from_amount, uint256 _min_to_amount
  ) external;
}

contract StrategyCurveHUSD {
    using SafeERC20 for IERC20;
    using Address for address;
    using SafeMath for uint256;
    
    address constant public want = address(0x5B5CFE992AdAC0C9D48E05854B2d91C73a003858); //husd3crv
    
    address constant public pool = address(0x2db0E83599a91b508Ac268a6197b8B14F5e72840);

    address constant public mintr = address(0xd061D61a4d941c39E5453435B6345Dc261C2fcE0);

    address constant public crv = address(0xD533a949740bb3306d119CC777fa900bA034cd52);
    address constant public output = address(0xD533a949740bb3306d119CC777fa900bA034cd52);

    address constant public unirouter = address(0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D);
    address constant public weth = address(0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2); // used for crv <> weth <> dai route
    address constant public dai = address(0x6B175474E89094C44Da98b954EedeAC495271d0F); // used for crv <> weth <> dai route


    address constant public curve = address(0x0a53FaDa2d943057C47A301D25a4D9b3B8e01e8E); //husd -> husd3crv


    address constant public yfii = address(0xa1d0E215a23d7030842FC67cE582a6aFa3CCaB83);

    
    uint public strategyfee = 100;
    uint public fee = 300;
    uint public burnfee = 500;
    uint public callfee = 100;
    uint constant public max = 1000;

    uint public withdrawalFee = 0;
    uint constant public withdrawalMax = 10000;

    
    address public governance;
    address public controller;
    address public strategyDev;
    address public burnAddress = 0xB6af2DabCEBC7d30E440714A33E5BD45CEEd103a;

    string public getName;

    address[] public swap2YFIIRouting;
    address[] public swap2TokenRouting;

    
    constructor() public {
        governance = tx.origin;
        controller = 0xcDCf1f9Ac816Fed665B09a00f60c885dd8848b02;
        getName = string(
            abi.encodePacked("yfii:Strategy:", 
                abi.encodePacked(IERC20(want).name(),
                    abi.encodePacked(":",IERC20(output).name())
                )
            ));
        swap2YFIIRouting = [output,weth,yfii];
        swap2TokenRouting = [output,weth,dai];
        doApprove();
        strategyDev = tx.origin;
        
    }

    function doApprove () public{
        IERC20(output).safeApprove(unirouter, 0);
        IERC20(output).safeApprove(unirouter, uint(-1));
        
        //husd3crv -> pool
        IERC20(want).safeApprove(pool, 0);
        IERC20(want).safeApprove(pool, uint(-1));

        //dai ->husd3crv
        IERC20(dai).safeApprove(curve, 0);
        IERC20(dai).safeApprove(curve, uint(-1));
        
    }
    
    
    function deposit() public {
        uint _want = IERC20(want).balanceOf(address(this));
        if (_want > 0) {
            Gauge(pool).deposit(_want);
        }
    }
    
    // Controller only function for creating additional rewards from dust
    function withdraw(IERC20 _asset) external returns (uint balance) {
        require(msg.sender == controller, "!controller");
        require(want != address(_asset), "want");
        require(crv != address(_asset), "crv");
        require(dai != address(_asset), "dai");
        balance = _asset.balanceOf(address(this));
        _asset.safeTransfer(controller, balance);
    }
    
    // Withdraw partial funds, normally used with a vault withdrawal
    function withdraw(uint _amount) external {
        require(msg.sender == controller, "!controller");
        uint _balance = IERC20(want).balanceOf(address(this));
        if (_balance < _amount) {
            _amount = _withdrawSome(_amount.sub(_balance));
            _amount = _amount.add(_balance);
        }
        
        uint _fee = 0;
        if (withdrawalFee>0){
            _fee = _amount.mul(withdrawalFee).div(withdrawalMax);        
            IERC20(want).safeTransfer(Controller(controller).rewards(), _fee);
        }
        
        address _vault = Controller(controller).vaults(address(want));
        require(_vault != address(0), "!vault"); // additional protection so we don't burn the funds
        
        IERC20(want).safeTransfer(_vault, _amount.sub(_fee));
    }
    
    // Withdraw all funds, normally used when migrating strategies
    function withdrawAll() external returns (uint balance) {
        require(msg.sender == controller, "!controller");
        _withdrawAll();
        
        
        balance = IERC20(want).balanceOf(address(this));
        
        address _vault = Controller(controller).vaults(address(want));
        require(_vault != address(0), "!vault"); // additional protection so we don't burn the funds
        IERC20(want).safeTransfer(_vault, balance);
    }
    
    function _withdrawAll() internal {
        Gauge(pool).withdraw(Gauge(pool).balanceOf(address(this)));
    }
    
    function harvest() public {
        require(!Address.isContract(msg.sender),"!contract");
        Mintr(mintr).mint(pool);
        
        doswap();
        dosplit();
        deposit();
        
    }
    function doswap() internal {
        uint256 _2token = IERC20(output).balanceOf(address(this)).mul(90).div(100); //90%
        uint256 _2yfii = IERC20(output).balanceOf(address(this)).mul(10).div(100);  //10%
        UniswapRouter(unirouter).swapExactTokensForTokens(_2token, 0, swap2TokenRouting, address(this), now.add(1800));
        UniswapRouter(unirouter).swapExactTokensForTokens(_2yfii, 0, swap2YFIIRouting, address(this), now.add(1800));

        //dai -> husd3crv
        uint _dai = IERC20(dai).balanceOf(address(this));
        if (_dai > 0) {
            ICurveFi(curve).add_liquidity([0,_dai,0,0],0);
        }
        

    }
    function dosplit() internal{
        uint b = IERC20(yfii).balanceOf(address(this));
        uint _fee = b.mul(fee).div(max);
        uint _callfee = b.mul(callfee).div(max);
        uint _burnfee = b.mul(burnfee).div(max);
        IERC20(yfii).safeTransfer(Controller(controller).rewards(), _fee); //4%  3% team +1% insurance
        IERC20(yfii).safeTransfer(msg.sender, _callfee); //call fee 1%
        IERC20(yfii).safeTransfer(burnAddress, _burnfee); //burn fee 5%

        if (strategyfee >0){
            uint _strategyfee = b.mul(strategyfee).div(max);
            IERC20(yfii).safeTransfer(strategyDev, _strategyfee);
        }
    }
    
    function _withdrawSome(uint256 _amount) internal returns (uint) {
        Gauge(pool).withdraw(_amount);
        return _amount;
    }
    
    function balanceOfWant() public view returns (uint) {
        return IERC20(want).balanceOf(address(this));
    }
    
    function balanceOfPool() public view returns (uint) {
        return Gauge(pool).balanceOf(address(this));
    }
    
    function balanceOf() public view returns (uint) {
        return balanceOfWant()
               .add(balanceOfPool());
    }
    
    function setGovernance(address _governance) external {
        require(msg.sender == governance, "!governance");
        governance = _governance;
    }
    
    function setController(address _controller) external {
        require(msg.sender == governance, "!governance");
        controller = _controller;
    }
    function setFee(uint256 _fee) external{
        require(msg.sender == governance, "!governance");
        fee = _fee;
    }
    function setStrategyFee(uint256 _fee) external{
        require(msg.sender == governance, "!governance");
        strategyfee = _fee;
    }
    function setCallFee(uint256 _fee) external{
        require(msg.sender == governance, "!governance");
        callfee = _fee;
    }
    function setBurnFee(uint256 _fee) external{
        require(msg.sender == governance, "!governance");
        burnfee = _fee;
    }
    function setBurnAddress(address _burnAddress) public{
        require(msg.sender == governance, "!governance");
        burnAddress = _burnAddress;
    }

    function setWithdrawalFee(uint _withdrawalFee) external {
        require(msg.sender == governance, "!governance");
        require(_withdrawalFee <=100,"fee >= 1%"); //max:1%
        withdrawalFee = _withdrawalFee;
    }
    
    
    function setSwap2YFII(address[] memory _path) public{
        require(msg.sender == governance, "!governance");
        swap2YFIIRouting = _path;
    }
    
    function setSwap2Token(address[] memory _path) public{
        require(msg.sender == governance, "!governance");
        swap2TokenRouting = _path;
    }

}