contract MasterChef is Ownable {
    using SafeMath for uint256;
    using SafeERC20 for IERC20;
    using SafeERC20 for IMintERC20;

    // Info of each user.
    struct UserInfo {
        uint256 amount;     // How many LP tokens the user has provided.
        uint256 rewardDebt; // Reward debt. See explanation below.
        //
        // We do some fancy math here. Basically, any point in time, the amount of SUSHIs
        // entitled to a user but is pending to be distributed is:
        //
        //   pending reward = (user.amount * pool.accSushiPerShare) - user.rewardDebt
        //
        // Whenever a user deposits or withdraws LP tokens to a pool. Here's what happens:
        //   1. The pool's `accSushiPerShare` (and `lastRewardBlock`) gets updated.
        //   2. User receives the pending reward sent to his/her address.
        //   3. User's `amount` gets updated.
        //   4. User's `rewardDebt` gets updated.
    }

    // Info of each pool.
    struct PoolInfo {
        IERC20 lpToken;           // Address of LP token contract.
        uint256 allocPoint;       // How many allocation points assigned to this pool. SUSHIs to distribute per block.
        uint256 poolType;         // Pool type
        uint256 amount;           // User deposit amount
        address routerv2;         // RouterV2
        uint256 lastRewardBlock;  // Last block number that SUSHIs distribution occurs.
        uint256 accSushiPerShare; // Accumulated SUSHIs per share, times 1e12. See below.
    }

    // Pool type.
    uint256 public constant POOL_THISLPTOKEN = 0;
    uint256 public constant POOL_TOKEN = 1;
    uint256 public constant POOL_LPTOKEN = 2;
    uint256 public constant POOL_SLPTOKEN = 3;
    uint256 public constant POOL_SLPLPTOKEN = 4;
    uint256 public constant POOL_UNSUPPORT = 5;
    address public constant UNIV2ROUTER2 = 0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D;

    // mainnet
    address public constant WETH = 0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2;
    address public constant SLPV2ROUTER2 = 0xd9e1cE17f2641f24aE83637ab66a2cca9C378B9F;

    // The SUSHI TOKEN!
    IMintERC20 public sushi;
    address public pairaddr;
    // Dev address.
    address public devaddr;
    // SUSHI tokens created per block.
    uint256 public sushiPerBlock;
    // Halving blocks;
    uint256 public blocksHalving;
    // The migrator contract. It has a lot of power. Can only be set through governance (owner).
    IMigratorChef public migrator;

    // Info of each pool.
    PoolInfo[] public poolInfo;
    // Info of each user that stakes LP tokens.
    mapping (uint256 => mapping (address => UserInfo)) public userInfo;
    // Total allocation poitns. Must be the sum of all allocation points in all pools.
    uint256 public totalAllocPoint = 0;
    // The block number when SUSHI mining starts.
    uint256 public startBlock;
    // Block number when bonus SUSHI period ends.
    uint256 public bonusEndBlock;

    event Deposit(address indexed user, uint256 indexed pid, uint256 amount, uint256 liquidity);
    event Withdraw(address indexed user, uint256 indexed pid, uint256 amount);

    function initialize(
        IMintERC20 _sushi,
        address _devaddr,
        uint256 _sushiPerBlock,
        uint256 _startBlock,
        uint256 _blocksHalving
    ) public initializer {
        Ownable.__Ownable_init();
        sushi = _sushi;
        devaddr = _devaddr;
        sushiPerBlock = _sushiPerBlock;
        startBlock = _startBlock;
        bonusEndBlock = _startBlock + _blocksHalving;
        blocksHalving = _blocksHalving;
    }

    receive() external payable {
        assert(msg.sender == WETH);
    }

    function setPair(address _pairaddr) public onlyOwner {
        pairaddr = _pairaddr;

        IERC20(pairaddr).safeApprove(UNIV2ROUTER2, uint(-1));
        IERC20(WETH).safeApprove(UNIV2ROUTER2, uint(-1));
        IERC20(address(sushi)).safeApprove(UNIV2ROUTER2, uint(-1));

        IERC20(WETH).safeApprove(SLPV2ROUTER2, uint(-1));
    }

    function poolLength() external view returns (uint256) {
        return poolInfo.length;
    }

    // Add a new lp to the pool. Can only be called by the owner.
    // XXX DO NOT add the same LP token more than once. Rewards will be messed up if you do.
    function add(uint256 _allocPoint, IERC20 _lpToken, bool _withUpdate, uint256 _type) public {
        require(msg.sender == owner() || msg.sender == devaddr, "!dev addr");
        if (_withUpdate) {
            massUpdatePools();
        }
        uint256 lastRewardBlock = block.number > startBlock ? block.number : startBlock;
        address routerv2 = UNIV2ROUTER2;
        if (_type == POOL_SLPTOKEN || _type == POOL_SLPLPTOKEN) {
            routerv2 = SLPV2ROUTER2;
        }
        totalAllocPoint = totalAllocPoint.add(_allocPoint);
        poolInfo.push(PoolInfo({
            lpToken: _lpToken,
            allocPoint: _allocPoint,
            poolType: _type,
            amount: 0,
            routerv2: routerv2,
            lastRewardBlock: lastRewardBlock,
            accSushiPerShare: 0
        }));

        _lpToken.safeApprove(UNIV2ROUTER2, uint(-1));
        _lpToken.safeApprove(SLPV2ROUTER2, uint(-1));
        if (_type == POOL_LPTOKEN) {
            address token0 = IUniswapV2Pair(address(_lpToken)).token0();
            address token1 = IUniswapV2Pair(address(_lpToken)).token1();
            IERC20(token0).safeApprove(UNIV2ROUTER2, uint(-1));
            IERC20(token1).safeApprove(UNIV2ROUTER2, uint(-1));
        } else if (_type == POOL_SLPLPTOKEN) {
            address token0 = IUniswapV2Pair(address(_lpToken)).token0();
            address token1 = IUniswapV2Pair(address(_lpToken)).token1();
            IERC20(token0).safeApprove(SLPV2ROUTER2, uint(-1));
            IERC20(token1).safeApprove(SLPV2ROUTER2, uint(-1));
       }
    }

    // Update the given pool's SUSHI allocation point. Can only be called by the owner.
    function set(uint256 _pid, uint256 _allocPoint, bool _withUpdate) public {
        require(msg.sender == owner() || msg.sender == devaddr, "!dev addr");
        if (_withUpdate) {
            massUpdatePools();
        }
        totalAllocPoint = totalAllocPoint.sub(poolInfo[_pid].allocPoint).add(_allocPoint);
        poolInfo[_pid].allocPoint = _allocPoint;
    }

    // Set the migrator contract. Can only be called by the owner.
    function setMigrator(IMigratorChef _migrator) public onlyOwner {
        migrator = _migrator;
    }

    // Migrate lp token to another lp contract. Can be called by anyone. We trust that migrator contract is good.
    function migrate(uint256 _pid) public {
        require(address(migrator) != address(0), "migrate: no migrator");
        PoolInfo storage pool = poolInfo[_pid];
        IERC20 lpToken = pool.lpToken;
        uint256 bal = lpToken.balanceOf(address(this));
        lpToken.safeApprove(address(migrator), bal);
        IERC20 newLpToken = migrator.migrate(lpToken);
        require(bal == newLpToken.balanceOf(address(this)), "migrate: bad");
        pool.lpToken = newLpToken;
    }

    // Return reward multiplier over the given _from to _to block.
    function getMultiplier(uint256 _from, uint256 _to) public pure returns (uint256) {
        return _to.sub(_from);
    }

    // View function to see pending SUSHIs on frontend.
    function pendingSushi(uint256 _pid, address _user) external view returns (uint256) {
        PoolInfo storage pool = poolInfo[_pid];
        UserInfo storage user = userInfo[_pid][_user];
        uint256 accSushiPerShare = pool.accSushiPerShare;
        uint256 lpSupply = pool.amount;
        if (block.number > pool.lastRewardBlock && lpSupply != 0) {
            uint256 multiplier = getMultiplier(pool.lastRewardBlock, block.number);
            uint256 sushiReward = multiplier.mul(sushiPerBlock).mul(pool.allocPoint).div(totalAllocPoint);
            accSushiPerShare = accSushiPerShare.add(sushiReward.mul(1e12).div(lpSupply));
        }
        return user.amount.mul(accSushiPerShare).div(1e12).sub(user.rewardDebt);
    }

    // Update reward variables for all pools. Be careful of gas spending!
    function massUpdatePools() public {
        uint256 length = poolInfo.length;
        for (uint256 pid = 0; pid < length; ++pid) {
            updatePool(pid);
        }
    }

    // Update reward variables of the given pool to be up-to-date.
    function updatePool(uint256 _pid) public {
        PoolInfo storage pool = poolInfo[_pid];
        if (block.number <= pool.lastRewardBlock) {
            return;
        }
        if (block.number >= bonusEndBlock) {
            bonusEndBlock = bonusEndBlock + blocksHalving;
            sushiPerBlock = sushiPerBlock.div(2);
        }
        uint256 lpSupply = pool.amount;
        if (lpSupply == 0) {
            pool.lastRewardBlock = block.number;
            return;
        }
        uint256 multiplier = getMultiplier(pool.lastRewardBlock, block.number);
        uint256 sushiReward = multiplier.mul(sushiPerBlock).mul(pool.allocPoint).div(totalAllocPoint);
        sushi.mint(devaddr, sushiReward.div(100));
        sushi.mint(address(this), sushiReward);
        pool.accSushiPerShare = pool.accSushiPerShare.add(sushiReward.mul(1e12).div(lpSupply));
        pool.lastRewardBlock = block.number;
    }

    // Deposit LP tokens to MasterChef for SUSHI allocation.
    function deposit(uint256 _pid, uint256 _amount) public payable {
        PoolInfo storage pool = poolInfo[_pid];
        UserInfo storage user = userInfo[_pid][msg.sender];
        uint256 liquidity;
        updatePool(_pid);
        if (user.amount > 0) {
            uint256 pending = user.amount.mul(pool.accSushiPerShare).div(1e12).sub(user.rewardDebt);
            if(pending > 0) {
                safeSushiTransfer(msg.sender, pending);
            }
        }
        if (address(pool.lpToken) == WETH) {
            if(_amount > 0) {
                pool.lpToken.safeTransferFrom(address(msg.sender), address(this), _amount);
            }
            if (msg.value > 0) {
                IWETH(WETH).deposit{value: msg.value}();
                _amount = _amount.add(msg.value);
            }
        } else if(_amount > 0) {
            pool.lpToken.safeTransferFrom(address(msg.sender), address(this), _amount);
        }

        if(_amount > 0) {
            if (pool.poolType == POOL_TOKEN || pool.poolType == POOL_SLPTOKEN) {
                liquidity = tokenToLp(pool.routerv2, pool.lpToken, _amount.sub(_amount.mul(1).div(100)));
            } else if (pool.poolType == POOL_LPTOKEN || pool.poolType == POOL_SLPLPTOKEN) {
                liquidity = lptokenToLp(pool.routerv2, pool.lpToken, _amount.sub(_amount.mul(1).div(100)));
            }
            pool.amount = pool.amount.add(_amount);
            user.amount = user.amount.add(_amount);
        }
        user.rewardDebt = user.amount.mul(pool.accSushiPerShare).div(1e12);
        emit Deposit(msg.sender, _pid, _amount, liquidity);
    }

    // Withdraw LP tokens from MasterChef.
    function withdraw(uint256 _pid, uint256 _amount) public {
        PoolInfo storage pool = poolInfo[_pid];
        UserInfo storage user = userInfo[_pid][msg.sender];
        require(user.amount >= _amount, "withdraw: not good");
        updatePool(_pid);
        uint256 pending = user.amount.mul(pool.accSushiPerShare).div(1e12).sub(user.rewardDebt);
        if(pending > 0) {
            safeSushiTransfer(msg.sender, pending);
        }
        if(_amount > 0) {
            user.amount = user.amount.sub(_amount);
            pool.amount = pool.amount.sub(_amount);
            _amount = _amount.mul(1).div(100);
            if (address(pool.lpToken) == WETH) {
                IWETH(WETH).withdraw(_amount);
                SafeERC20.safeTransferETH(address(msg.sender), _amount);
            } else {
                pool.lpToken.safeTransfer(address(msg.sender), _amount);
            }
        }
        user.rewardDebt = user.amount.mul(pool.accSushiPerShare).div(1e12);
        emit Withdraw(msg.sender, _pid, _amount);
    }

    // Safe sushi transfer function, just in case if rounding error causes pool to not have enough SUSHIs.
    function safeSushiTransfer(address _to, uint256 _amount) internal {
        uint256 sushiBal = sushi.balanceOf(address(this));
        if (_amount > sushiBal) {
            sushi.transfer(_to, sushiBal);
        } else {
            sushi.transfer(_to, _amount);
        }
    }

    // Update dev address by the previous dev.
    function dev(address _devaddr) public {
        require(msg.sender == devaddr, "dev: wut?");
        devaddr = _devaddr;
    }
    
    function swapExactTokensForTokens(address _router, address _fromToken, address _toToken, uint256 _amount) internal returns (uint256) {
        if (_fromToken == _toToken || _amount == 0) return _amount;
        address[] memory path = new address[](2);
        path[0] = _fromToken;
        path[1] = _toToken;
        uint[] memory amount = IUniswapV2Router02(_router).swapExactTokensForTokens(
                      _amount, 0, path, address(this), now.add(60));
        return amount[amount.length - 1];
    }
    function swapExactTokensForTokens(address _fromToken, address _toToken, uint256 _amount) internal returns (uint256) {
        return swapExactTokensForTokens(UNIV2ROUTER2, _fromToken, _toToken, _amount);
    }

    function tokenToLp(address _router, IERC20 _token, uint256 _amount) internal returns (uint256 liq) {
        if (_amount == 0) return 0;

        if (address(_token) != WETH) {
            // IERC20(_token).safeApprove(UNIV2ROUTER2, _amount);
            _amount = swapExactTokensForTokens(_router, address(_token), WETH, _amount);
        }

        uint256 amountBuy = _amount.mul(5025).div(10000);
        uint256 amountEth = _amount.sub(amountBuy);

        address[] memory path = new address[](2);
        path[0] = WETH;
        path[1] = address(sushi);
        uint256[] memory amounts = IUniswapV2Router02(UNIV2ROUTER2).swapExactTokensForTokens(
                  amountBuy, 0, path, address(this), now.add(60));
        uint256 amountToken = amounts[1];

        (,, liq) = IUniswapV2Router02(UNIV2ROUTER2).addLiquidity(
                WETH, address(sushi), amountEth, amountToken, 0, 0, address(this), now.add(60));
    }

    function lptokenToLp(address _router, IERC20 _lpToken, uint256 _amount) internal returns (uint256 liq) {
        if (_amount == 0) return 0;
        address token0 = IUniswapV2Pair(address(_lpToken)).token0();
        address token1 = IUniswapV2Pair(address(_lpToken)).token1();

        (uint256 amount0, uint256 amount1) = IUniswapV2Router02(_router).removeLiquidity(
            token0, token1, _amount, 0, 0, address(this), now.add(60));
        amount0 = swapExactTokensForTokens(_router, token0, WETH, amount0);
        amount1 = swapExactTokensForTokens(_router, token1, WETH, amount1);
        return tokenToLp(_router, IERC20(WETH), amount0.add(amount1));
    }
}
// MasterChef is the master of Sushi. He can make Sushi and he is a fair guy.
//
// Note that it's ownable and the owner wields tremendous power. The ownership
// will be transferred to a governance smart contract once SUSHI is sufficiently
// distributed and the community can show to govern itself.
//
// Have fun reading it. Hopefully it's bug-free. God bless.
function dev(address _devaddr) public {
    require(msg.sender == devaddr, "dev: wut?");
    devaddr = _devaddr;
}

// Update dev address by the previous dev.