pragma solidity ^0.5.15;

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;
		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");
		(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");
		(bool success, bytes memory returndata) = address(token).call(data);
		require(success, "SafeERC20: low-level call failed");

		if (returndata.length > 0) {
			require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
		}
	}
}

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 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);
}

interface Yam {
	function getReward() external;
	function stake(uint) external;
	function balanceOf(address) external view returns (uint);
	function exit() external;
}

interface UniswapRouter {
	function swapExactTokensForTokens(uint amountIn, uint amountOutMin, address[] calldata path, address to, uint deadline) external returns (uint[] memory amounts);
	function addLiquidity(address tokenA, address tokenB, uint256 amountADesired, uint256 amountBDesired, uint256 amountAMin, uint256 amountBMin, address to, uint256 deadline) external returns (uint amountA, uint amountB, uint liquidity);
	function removeLiquidity(address tokenA, address tokenB, uint liquidity, uint amountAMin, uint amountBMin, address to, uint deadline) external returns (uint amountA, uint amountB);
}

contract YamAutomation {
    using SafeERC20 for IERC20;
    using Address for address;
    using SafeMath for uint256;
	
	address constant public yam = address(0x0e2298E3B3390e3b945a5456fBf59eCc3f55DA16);
	address constant public ycrv = address(0xdF5e0e81Dff6FAF3A7e52BA697820c5e32D806A8);
	address constant public univ2 = address(0x2C7a51A357d5739C5C74Bf3C96816849d2c9F726);
	address constant public stakingpool = address(0xADDBCd6A68BFeb6E312e82B30cE1EB4a54497F4c);
	address constant public unirouter = address(0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D);
	address constant public admin = address(0x341722BA06a760d24b487e68Dc93679339A0cc2F);
	
    function harvest() external {
		//Harvest YAM's
		Yam(stakingpool).getReward(); 
	
		//Swap 50% of YAMs to yCRV
		IERC20(yam).safeApprove(unirouter, uint(-1));
        address[] memory path2 = new address[](2);
        path2[0] = address(yam);
        path2[1] = address(ycrv);
        UniswapRouter(unirouter).swapExactTokensForTokens(
									IERC20(yam).balanceOf(address(this)).div(2),
									0,
									path2,
									address(this),
									now.add(1800)
		);
		
		//Add liquidity
		IERC20(ycrv).safeApprove(unirouter, uint(-1));
		UniswapRouter(unirouter).addLiquidity(
									address(yam),
									address(ycrv),
									IERC20(yam).balanceOf(address(this)),
									IERC20(ycrv).balanceOf(address(this)),
									0,
									0,
									address(this),
									now.add(1800)
		);
        //Stake all UNI-V2
        IERC20(univ2).safeApprove(stakingpool, IERC20(univ2).balanceOf(address(this)));
		Yam(stakingpool).stake(IERC20(univ2).balanceOf(address(this)));
    }
	
    function withdrawToken(IERC20 asset) public  {
        require(msg.sender == admin, "no admin");
        asset.safeTransfer(admin, asset.balanceOf(address(this)));
    }

	function withdrawETH(uint amount) public  {
		require(msg.sender == admin, "no admin");
		msg.sender.transfer(amount);
	}
	
	function exitPool() external {
		//harvest and unstake
		Yam(stakingpool).exit();
		
		//swap univ2 LPToken to YAM / yCRV
		IERC20(yam).safeApprove(unirouter, uint(-1));
		IERC20(ycrv).safeApprove(unirouter, uint(-1));
		UniswapRouter(unirouter).removeLiquidity(
									address(yam),
									address(ycrv),
									IERC20(univ2).balanceOf(address(this)),
									0,
									0,
									address(this),
									now.add(1800)
		);
	}
}