// File: contracts/BrewlabsZapInSushi.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import "@openzeppelin/contracts/access/Ownable.sol";
import "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";

interface IWETH {
    function deposit() external payable;
}

interface IUniswapV2Factory {
    function getPair(address tokenA, address tokenB)
        external
        view
        returns (address pair);
}

interface IUniswapV2Router02 {
    function addLiquidity(
        address tokenA,
        address tokenB,
        uint amountADesired,
        uint amountBDesired,
        uint amountAMin,
        uint amountBMin,
        address to,
        uint 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);

    function removeLiquidityETH(
        address token,
        uint liquidity,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline
    ) external returns (uint amountToken, uint amountETH);

    function swapExactTokensForTokens(
        uint amountIn,
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external returns (uint[] memory amounts);

    function swapExactTokensForETH(
        uint amountIn,
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external returns (uint[] memory amounts);
}

interface IUniswapV2Pair {
    function token0() external view returns (address);

    function token1() external view returns (address);

    function getReserves()
        external
        view
        returns (
            uint112 reserve0,
            uint112 reserve1,
            uint32 blockTimestampLast
        );
}

interface IMasterChefV2 {
    function deposit(
        uint256 pid,
        uint256 amount,
        address to
    ) external;

    function withdrawAndHarvest(
        uint256 pid,
        uint256 amount,
        address to
    ) external;

    function harvest(uint256 pid, address to) external;

    function harvestFromMasterChef() external;

    function pendingSushi(uint256 _pid, address _user)
        external
        view
        returns (uint256);
}

library Babylonian {
    function sqrt(uint256 y) internal pure returns (uint256 z) {
        if (y > 3) {
            z = y;
            uint256 x = y / 2 + 1;
            while (x < z) {
                z = x;
                x = (y / x + x) / 2;
            }
        } else if (y != 0) {
            z = 1;
        }
        // else z = 0
    }
}

contract BrewlabsZapInSushi is Ownable {
    using SafeERC20 for IERC20;

    IUniswapV2Factory private constant sushiswapFactory =
        IUniswapV2Factory(0xC0AEe478e3658e2610c5F7A4A2E1777cE9e4f2Ac);

    IUniswapV2Router02 private constant sushiswapRouter =
        IUniswapV2Router02(0xd9e1cE17f2641f24aE83637ab66a2cca9C378B9F);

    IUniswapV2Router02 private constant uniswapRouter =
        IUniswapV2Router02(0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D);

    IMasterChefV2 private constant masterChefV2 =
        IMasterChefV2(0xEF0881eC094552b2e128Cf945EF17a6752B4Ec5d);

    IERC20 private constant sushi =
        IERC20(0x6B3595068778DD592e39A122f4f5a5cF09C90fE2);

    address private constant wethTokenAddress =
        0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2;

    address private constant brewlabsAddress =
        0xe745d88A390e89E6562B29F6aC17ec03804050Ad;

    address internal constant ETHAddress =
        0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE;

    uint256 private constant deadline =
        0xf000000000000000000000000000000000000000000000000000000000000000;

    uint256 public feeAmount;
    address payable public feeAddress;

    struct UserInfo {
        uint256 amount;
        uint256 rewardDebt;
        uint256 totalRewards;
    }

    struct PoolInfo {
        uint256 accCakePerShare;
        uint256 lastRewardBlock;
        uint256 totalBoostedShare;
        uint256 totalRewards;
    }

    mapping(uint256 => PoolInfo) public poolInfo;
    mapping(uint256 => address) public lpToken;
    mapping(uint256 => mapping(address => UserInfo)) public userInfo;

    uint256 public constant ACC_CAKE_PRECISION = 1e18;

    event Deposit(address indexed user, uint256 indexed pid, uint256 amount);
    event Withdraw(address indexed user, uint256 indexed pid, uint256 amount);
    event UpdateFeeAmount(uint256 indexed oldAmount, uint256 indexed newAmount);
    event UpdateFeeAddress(
        address indexed oldAddress,
        address indexed newAddress
    );

    constructor(uint256 _feeAmount, address payable _feeAddress) {
        feeAmount = _feeAmount;
        feeAddress = _feeAddress;
    }

    receive() external payable {
        require(msg.sender != tx.origin, "Do not send ETH directly");
    }

    function updateFeeAmount(uint256 _newAmount) external onlyOwner {
        require(
            _newAmount != feeAmount,
            "Brewlabs: Cannot update to same value"
        );
        uint256 _oldAmount = feeAmount;
        feeAmount = _newAmount;
        emit UpdateFeeAmount(_oldAmount, _newAmount);
    }

    function updateFeeAddress(address payable _newAddress) external onlyOwner {
        require(
            _newAddress != feeAddress,
            "Brewlabs: Cannot update to same value"
        );
        address _oldAddress = feeAddress;
        feeAddress = _newAddress;
        emit UpdateFeeAddress(_oldAddress, _newAddress);
    }

    function withdrawTokens(address[] calldata tokens) external onlyOwner {
        for (uint256 i = 0; i < tokens.length; i++) {
            if (tokens[i] == ETHAddress) {
                Address.sendValue(payable(owner()), address(this).balance);
            } else {
                IERC20(tokens[i]).safeTransfer(
                    owner(),
                    IERC20(tokens[i]).balanceOf(address(this))
                );
            }
        }
    }

    function zapIn(
        address _FromTokenContractAddress,
        address _pairAddress,
        uint256 _pid,
        uint256 _amount,
        uint256 _minPoolTokens,
        address _rewardAddress
    ) external payable {
        if (isETH(_FromTokenContractAddress)) {
            require(
                msg.value >= _amount + feeAmount,
                "Brewlabs: Eth is not enough"
            );
        } else {
            require(msg.value >= feeAmount, "Brewlabs: Eth is not enough");
        }
        feeAddress.transfer(feeAmount);

        uint256 LPBought = _performZapIn(
            _FromTokenContractAddress,
            _pairAddress,
            _amount
        );
        require(LPBought >= _minPoolTokens, "Brewlabs: High Slippage");

        if (lpToken[_pid] == address(0)) lpToken[_pid] = _pairAddress;
        deposit(_pid, LPBought, _rewardAddress);

        emit Deposit(msg.sender, _pid, LPBought);
    }

    function zapOut(
        uint256 _pid,
        uint256 _amount,
        address _reward
    ) external payable {
        require(msg.value >= feeAmount, "Brewlabs: Eth is not enough");
        feeAddress.transfer(feeAmount);

        PoolInfo memory pool = updatePool(_pid);
        UserInfo storage user = userInfo[_pid][msg.sender];

        require(user.amount >= _amount, "Brewlabs: Insufficient for withdraw");

        uint256 pendingSushi = masterChefV2.pendingSushi(_pid, address(this));
        uint256 balanceOf = sushi.balanceOf(address(masterChefV2));

        if (pendingSushi > balanceOf) {
            masterChefV2.harvestFromMasterChef();
        }
        masterChefV2.withdrawAndHarvest(_pid, _amount, address(this));

        settlePendingCake(msg.sender, _pid, _reward);

        if (_amount > 0) {
            user.amount = user.amount - _amount;
            withdraw(_pid, _amount);
        }

        user.rewardDebt =
            (user.amount * pool.accCakePerShare) /
            ACC_CAKE_PRECISION;
        poolInfo[_pid].totalBoostedShare =
            poolInfo[_pid].totalBoostedShare -
            _amount;

        emit Withdraw(msg.sender, _pid, _amount);
    }

    function pendingCake(uint256 _pid, address _user)
        external
        view
        returns (uint256)
    {
        PoolInfo memory pool = poolInfo[_pid];
        UserInfo memory user = userInfo[_pid][_user];
        uint256 accCakePerShare = pool.accCakePerShare;
        uint256 lpSupply = pool.totalBoostedShare;

        if (block.number > pool.lastRewardBlock && lpSupply != 0) {
            uint256 cakeReward = masterChefV2.pendingSushi(_pid, address(this));
            accCakePerShare =
                accCakePerShare +
                (cakeReward * ACC_CAKE_PRECISION) /
                lpSupply;
        }
        return
            (user.amount * accCakePerShare) /
            ACC_CAKE_PRECISION -
            user.rewardDebt;
    }

    function deposit(
        uint256 _pid,
        uint256 _amount,
        address _reward
    ) internal {
        PoolInfo memory pool = updatePool(_pid);
        UserInfo storage user = userInfo[_pid][msg.sender];

        if (_amount > 0)
            _approveToken(lpToken[_pid], address(masterChefV2), _amount);

        uint256 pendingSushi = masterChefV2.pendingSushi(_pid, address(this));
        uint256 balanceOf = sushi.balanceOf(address(masterChefV2));

        if (pendingSushi > balanceOf) {
            masterChefV2.harvestFromMasterChef();
        }

        masterChefV2.harvest(_pid, address(this));
        masterChefV2.deposit(_pid, _amount, address(this));

        if (_amount > 0) {
            user.amount = user.amount + _amount;
            poolInfo[_pid].totalBoostedShare =
                poolInfo[_pid].totalBoostedShare +
                _amount;
        }

        user.rewardDebt =
            user.rewardDebt +
            (_amount * pool.accCakePerShare) /
            ACC_CAKE_PRECISION;
    }

    function withdraw(uint256 _pid, uint256 _amount) internal {
        IUniswapV2Pair pair = IUniswapV2Pair(lpToken[_pid]);

        address token0 = pair.token0();
        address token1 = pair.token1();

        _approveToken(lpToken[_pid], address(sushiswapRouter), _amount);

        if (token0 == wethTokenAddress || token1 == wethTokenAddress) {
            address _token = token0 == wethTokenAddress ? token1 : token0;

            (uint256 amountToken, uint256 amountETH) = sushiswapRouter
                .removeLiquidityETH(
                    _token,
                    _amount,
                    0,
                    0,
                    address(this),
                    block.timestamp + 600
                );

            uint256 amountTrade = _token2ETH(_token, amountToken);

            payable(msg.sender).transfer(amountETH + amountTrade);
        } else {
            (uint256 amountA, uint256 amountB) = sushiswapRouter
                .removeLiquidity(
                    token0,
                    token1,
                    _amount,
                    0,
                    0,
                    address(this),
                    block.timestamp + 600
                );

            uint256 amountETH0 = _token2ETH(token0, amountA);
            uint256 amountETH1 = _token2ETH(token1, amountB);

            payable(msg.sender).transfer(amountETH0 + amountETH1);
        }
    }

    function updatePool(uint256 _pid) internal returns (PoolInfo memory pool) {
        pool = poolInfo[_pid];
        if (block.number > pool.lastRewardBlock) {
            uint256 lpSupply = pool.totalBoostedShare;

            if (lpSupply > 0) {
                uint256 cakeReward = masterChefV2.pendingSushi(
                    _pid,
                    address(this)
                );
                pool.accCakePerShare =
                    pool.accCakePerShare +
                    ((cakeReward * ACC_CAKE_PRECISION) / lpSupply);
            }
            pool.lastRewardBlock = block.number;
            poolInfo[_pid] = pool;
        }
    }

    function settlePendingCake(
        address _user,
        uint256 _pid,
        address _reward
    ) internal {
        PoolInfo storage pool = poolInfo[_pid];
        UserInfo storage user = userInfo[_pid][_user];

        uint256 accCake = (user.amount * (pool.accCakePerShare)) /
            ACC_CAKE_PRECISION;
        uint256 pending = accCake - user.rewardDebt;

        user.totalRewards = user.totalRewards + pending;
        pool.totalRewards = pool.totalRewards + pending;

        if (_reward == address(sushi)) {
            sushi.safeTransfer(_user, pending);
        } else if (_reward == lpToken[_pid]) {
            // swap cake rewards to eth
            uint amountETH = _token2ETH(address(sushi), pending);

            // invest the eth to buy LP
            uint256 _amount = _performZapIn(
                ETHAddress,
                lpToken[_pid],
                amountETH
            );

            // deposit to masterChef manually
            _approveToken(lpToken[_pid], address(masterChefV2), _amount);
            masterChefV2.deposit(_pid, _amount, address(this));

            // update user and pool info
            user.amount = user.amount + _amount;
            pool.totalBoostedShare = pool.totalBoostedShare + _amount;
        } else {
            // swap cake to reward token
            uint256 beforeAmt = IERC20(_reward).balanceOf(address(this));
            _token2Token(address(sushi), _reward, pending);
            uint256 afterAmt = IERC20(_reward).balanceOf(address(this));

            IERC20(_reward).safeTransfer(_user, afterAmt - beforeAmt);
        }
    }

    function _performZapIn(
        address _FromTokenContractAddress,
        address _pairAddress,
        uint256 _amount
    ) internal returns (uint256) {
        uint256 intermediateAmt;
        address intermediateToken;
        (address _ToUniswapToken0, address _ToUniswapToken1) = _getPairTokens(
            _pairAddress
        );

        if (isETH(_FromTokenContractAddress)) {
            IWETH(wethTokenAddress).deposit{value: _amount}();
            intermediateToken = wethTokenAddress;
            intermediateAmt = _amount;
        } else {
            IERC20(_FromTokenContractAddress).safeTransferFrom(
                msg.sender,
                address(this),
                _amount
            );
            if (
                _ToUniswapToken0 == _FromTokenContractAddress ||
                _ToUniswapToken1 == _FromTokenContractAddress
            ) {
                intermediateToken = _FromTokenContractAddress;
                intermediateAmt = _amount;
            } else {
                intermediateToken = wethTokenAddress;
                intermediateAmt = _token2Token(
                    _FromTokenContractAddress,
                    wethTokenAddress,
                    _amount
                );
            }
        }

        (uint256 token0Bought, uint256 token1Bought) = _swapIntermediate(
            intermediateToken,
            _ToUniswapToken0,
            _ToUniswapToken1,
            intermediateAmt
        );

        return
            _uniDeposit(
                _ToUniswapToken0,
                _ToUniswapToken1,
                token0Bought,
                token1Bought
            );
    }

    function _uniDeposit(
        address _ToUnipoolToken0,
        address _ToUnipoolToken1,
        uint256 token0Bought,
        uint256 token1Bought
    ) internal returns (uint256) {
        _approveToken(_ToUnipoolToken0, address(sushiswapRouter), token0Bought);
        _approveToken(_ToUnipoolToken1, address(sushiswapRouter), token1Bought);

        (uint256 amountA, uint256 amountB, uint256 LP) = sushiswapRouter
            .addLiquidity(
                _ToUnipoolToken0,
                _ToUnipoolToken1,
                token0Bought,
                token1Bought,
                1,
                1,
                address(this),
                deadline
            );
        if (token0Bought > amountA) {
            IERC20(_ToUnipoolToken0).safeTransfer(
                msg.sender,
                token0Bought - amountA
            );
        }
        if (token1Bought > amountB) {
            IERC20(_ToUnipoolToken1).safeTransfer(
                msg.sender,
                token1Bought - amountB
            );
        }
        return LP;
    }

    function _swapIntermediate(
        address _toContractAddress,
        address _ToUnipoolToken0,
        address _ToUnipoolToken1,
        uint256 _amount
    ) internal returns (uint256 token0Bought, uint256 token1Bought) {
        IUniswapV2Pair pair = IUniswapV2Pair(
            sushiswapFactory.getPair(_ToUnipoolToken0, _ToUnipoolToken1)
        );
        (uint256 res0, uint256 res1, ) = pair.getReserves();
        if (_toContractAddress == _ToUnipoolToken0) {
            uint256 amountToSwap = calculateSwapInAmount(res0, _amount);
            if (amountToSwap <= 0) amountToSwap = _amount / 2;
            token1Bought = _token2Token(
                _toContractAddress,
                _ToUnipoolToken1,
                amountToSwap
            );
            token0Bought = _amount - amountToSwap;
        } else if (_toContractAddress == _ToUnipoolToken1) {
            uint256 amountToSwap = calculateSwapInAmount(res1, _amount);
            if (amountToSwap <= 0) amountToSwap = _amount / 2;
            token0Bought = _token2Token(
                _toContractAddress,
                _ToUnipoolToken0,
                amountToSwap
            );
            token1Bought = _amount - amountToSwap;
        } else {
            uint256 amountToSwap = _amount / 2;
            token0Bought = _token2Token(
                _toContractAddress,
                _ToUnipoolToken0,
                amountToSwap
            );
            token1Bought = _token2Token(
                _toContractAddress,
                _ToUnipoolToken1,
                _amount - amountToSwap
            );
        }
    }

    function _token2Token(
        address _FromTokenContractAddress,
        address _ToTokenContractAddress,
        uint256 tokens2Trade
    ) internal returns (uint256 tokenBought) {
        if (_FromTokenContractAddress == _ToTokenContractAddress) {
            return tokens2Trade;
        }

        if (_ToTokenContractAddress == brewlabsAddress) {
            _approveToken(
                _FromTokenContractAddress,
                address(uniswapRouter),
                tokens2Trade
            );

            address[] memory path = new address[](3);
            path[0] = _FromTokenContractAddress;
            path[1] = wethTokenAddress;
            path[2] = _ToTokenContractAddress;

            tokenBought = uniswapRouter.swapExactTokensForTokens(
                tokens2Trade,
                1,
                path,
                address(this),
                deadline
            )[path.length - 1];
        } else {
            _approveToken(
                _FromTokenContractAddress,
                address(sushiswapRouter),
                tokens2Trade
            );

            address[] memory path = new address[](2);
            path[0] = _FromTokenContractAddress;
            path[1] = _ToTokenContractAddress;

            tokenBought = sushiswapRouter.swapExactTokensForTokens(
                tokens2Trade,
                1,
                path,
                address(this),
                deadline
            )[path.length - 1];
        }
    }

    function _token2ETH(address _FromTokenContractAddress, uint256 tokens2Trade)
        internal
        returns (uint256 amountETH)
    {
        _approveToken(
            _FromTokenContractAddress,
            address(sushiswapRouter),
            tokens2Trade
        );

        address[] memory path = new address[](2);
        path[0] = _FromTokenContractAddress;
        path[1] = wethTokenAddress;

        amountETH = sushiswapRouter.swapExactTokensForETH(
            tokens2Trade,
            1,
            path,
            address(this),
            deadline
        )[path.length - 1];
    }

    function _approveToken(address token, address spender) internal {
        IERC20 _token = IERC20(token);
        if (_token.allowance(address(this), spender) > 0) return;
        else {
            _token.safeApprove(spender, type(uint256).max);
        }
    }

    function _approveToken(
        address token,
        address spender,
        uint256 amount
    ) internal {
        IERC20(token).safeApprove(spender, 0);
        IERC20(token).safeApprove(spender, amount);
    }

    function _getPairTokens(address _pairAddress)
        internal
        view
        returns (address token0, address token1)
    {
        IUniswapV2Pair uniPair = IUniswapV2Pair(_pairAddress);
        token0 = uniPair.token0();
        token1 = uniPair.token1();
    }

    function calculateSwapInAmount(uint256 reserveIn, uint256 userIn)
        internal
        pure
        returns (uint256)
    {
        return
            (Babylonian.sqrt(
                reserveIn * ((userIn * 3988000) + (reserveIn * 3988009))
            ) - (reserveIn * 1997)) / 1994;
    }

    function isETH(address token) internal pure returns (bool) {
        return (token == ETHAddress || token == address(0));
    }
}

// File: @openzeppelin/contracts/access/Ownable.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.7.0) (access/Ownable.sol)

pragma solidity ^0.8.0;

import "../utils/Context.sol";

/**
 * @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.
 *
 * By default, the owner account will be the one that deploys the contract. This
 * can later be changed with {transferOwnership}.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be applied to your functions to restrict their use to
 * the owner.
 */
abstract contract Ownable is Context {
    address private _owner;

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

    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    constructor() {
        _transferOwnership(_msgSender());
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        _checkOwner();
        _;
    }

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

    /**
     * @dev Throws if the sender is not the owner.
     */
    function _checkOwner() internal view virtual {
        require(owner() == _msgSender(), "Ownable: caller is not the 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 virtual onlyOwner {
        _transferOwnership(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 virtual onlyOwner {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        _transferOwnership(newOwner);
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Internal function without access restriction.
     */
    function _transferOwnership(address newOwner) internal virtual {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}

// File: @openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.7.0) (token/ERC20/utils/SafeERC20.sol)

pragma solidity ^0.8.0;

import "../IERC20.sol";
import "../extensions/draft-IERC20Permit.sol";
import "../../../utils/Address.sol";

/**
 * @title SafeERC20
 * @dev Wrappers around ERC20 operations that throw on failure (when the token
 * contract returns false). Tokens that return no value (and instead revert or
 * throw on failure) are also supported, non-reverting calls are assumed to be
 * successful.
 * To use this library you can add a `using SafeERC20 for IERC20;` statement to your contract,
 * which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
 */
library SafeERC20 {
    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));
    }

    /**
     * @dev Deprecated. This function has issues similar to the ones found in
     * {IERC20-approve}, and its usage is discouraged.
     *
     * Whenever possible, use {safeIncreaseAllowance} and
     * {safeDecreaseAllowance} instead.
     */
    function safeApprove(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
        // safeApprove should only be called when setting an initial allowance,
        // or when resetting it to zero. To increase and decrease it, use
        // 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
        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 safeIncreaseAllowance(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
        uint256 newAllowance = token.allowance(address(this), spender) + value;
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
    }

    function safeDecreaseAllowance(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
        unchecked {
            uint256 oldAllowance = token.allowance(address(this), spender);
            require(oldAllowance >= value, "SafeERC20: decreased allowance below zero");
            uint256 newAllowance = oldAllowance - value;
            _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
        }
    }

    function safePermit(
        IERC20Permit token,
        address owner,
        address spender,
        uint256 value,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) internal {
        uint256 nonceBefore = token.nonces(owner);
        token.permit(owner, spender, value, deadline, v, r, s);
        uint256 nonceAfter = token.nonces(owner);
        require(nonceAfter == nonceBefore + 1, "SafeERC20: permit did not succeed");
    }

    /**
     * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
     * on the return value: the return value is optional (but if data is returned, it must not be false).
     * @param token The token targeted by the call.
     * @param data The call data (encoded using abi.encode or one of its variants).
     */
    function _callOptionalReturn(IERC20 token, bytes memory data) private {
        // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
        // we're implementing it ourselves. We use {Address.functionCall} to perform this call, which verifies that
        // the target address contains contract code and also asserts for success in the low-level call.

        bytes memory returndata = address(token).functionCall(data, "SafeERC20: low-level call failed");
        if (returndata.length > 0) {
            // Return data is optional
            require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
        }
    }
}

// File: @openzeppelin/contracts/utils/Context.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)

pragma solidity ^0.8.0;

/**
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
abstract contract Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }
}

// File: @openzeppelin/contracts/token/ERC20/IERC20.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.6.0) (token/ERC20/IERC20.sol)

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @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);

    /**
     * @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 `to`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address to, 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.
     *
     * IMPORTANT: 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 `from` to `to` 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 from,
        address to,
        uint256 amount
    ) external returns (bool);
}

// File: @openzeppelin/contracts/utils/Address.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.7.0) (utils/Address.sol)

pragma solidity ^0.8.1;

/**
 * @dev Collection of functions related to the address type
 */
library Address {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * [IMPORTANT]
     * ====
     * It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     *
     * Among others, `isContract` will return false for the following
     * types of addresses:
     *
     *  - an externally-owned account
     *  - a contract in construction
     *  - an address where a contract will be created
     *  - an address where a contract lived, but was destroyed
     * ====
     *
     * [IMPORTANT]
     * ====
     * You shouldn't rely on `isContract` to protect against flash loan attacks!
     *
     * Preventing calls from contracts is highly discouraged. It breaks composability, breaks support for smart wallets
     * like Gnosis Safe, and does not provide security since it can be circumvented by calling from a contract
     * constructor.
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize/address.code.length, which returns 0
        // for contracts in construction, since the code is only stored at the end
        // of the constructor execution.

        return account.code.length > 0;
    }

    /**
     * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
     * `recipient`, forwarding all available gas and reverting on errors.
     *
     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
     * of certain opcodes, possibly making contracts go over the 2300 gas limit
     * imposed by `transfer`, making them unable to receive funds via
     * `transfer`. {sendValue} removes this limitation.
     *
     * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
     *
     * IMPORTANT: because control is transferred to `recipient`, care must be
     * taken to not create reentrancy vulnerabilities. Consider using
     * {ReentrancyGuard} or the
     * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     */
    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");
    }

    /**
     * @dev Performs a Solidity function call using a low level `call`. A
     * plain `call` is an unsafe replacement for a function call: use this
     * function instead.
     *
     * If `target` reverts with a revert reason, it is bubbled up by this
     * function (like regular Solidity function calls).
     *
     * Returns the raw returned data. To convert to the expected return value,
     * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
     *
     * Requirements:
     *
     * - `target` must be a contract.
     * - calling `target` with `data` must not revert.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionCall(target, data, "Address: low-level call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
     * `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but also transferring `value` wei to `target`.
     *
     * Requirements:
     *
     * - the calling contract must have an ETH balance of at least `value`.
     * - the called Solidity function must be `payable`.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value
    ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
    }

    /**
     * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
     * with `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value,
        string memory errorMessage
    ) internal returns (bytes memory) {
        require(address(this).balance >= value, "Address: insufficient balance for call");
        require(isContract(target), "Address: call to non-contract");

        (bool success, bytes memory returndata) = target.call{value: value}(data);
        return verifyCallResult(success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
        return functionStaticCall(target, data, "Address: low-level static call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal view returns (bytes memory) {
        require(isContract(target), "Address: static call to non-contract");

        (bool success, bytes memory returndata) = target.staticcall(data);
        return verifyCallResult(success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionDelegateCall(target, data, "Address: low-level delegate call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        require(isContract(target), "Address: delegate call to non-contract");

        (bool success, bytes memory returndata) = target.delegatecall(data);
        return verifyCallResult(success, returndata, errorMessage);
    }

    /**
     * @dev Tool to verifies that a low level call was successful, and revert if it wasn't, either by bubbling the
     * revert reason using the provided one.
     *
     * _Available since v4.3._
     */
    function verifyCallResult(
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal pure returns (bytes memory) {
        if (success) {
            return returndata;
        } else {
            // Look for revert reason and bubble it up if present
            if (returndata.length > 0) {
                // The easiest way to bubble the revert reason is using memory via assembly
                /// @solidity memory-safe-assembly
                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}

// File: @openzeppelin/contracts/token/ERC20/extensions/draft-IERC20Permit.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC20/extensions/draft-IERC20Permit.sol)

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 Permit extension allowing approvals to be made via signatures, as defined in
 * https://eips.ethereum.org/EIPS/eip-2612[EIP-2612].
 *
 * Adds the {permit} method, which can be used to change an account's ERC20 allowance (see {IERC20-allowance}) by
 * presenting a message signed by the account. By not relying on {IERC20-approve}, the token holder account doesn't
 * need to send a transaction, and thus is not required to hold Ether at all.
 */
interface IERC20Permit {
    /**
     * @dev Sets `value` as the allowance of `spender` over ``owner``'s tokens,
     * given ``owner``'s signed approval.
     *
     * IMPORTANT: The same issues {IERC20-approve} has related to transaction
     * ordering also apply here.
     *
     * Emits an {Approval} event.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     * - `deadline` must be a timestamp in the future.
     * - `v`, `r` and `s` must be a valid `secp256k1` signature from `owner`
     * over the EIP712-formatted function arguments.
     * - the signature must use ``owner``'s current nonce (see {nonces}).
     *
     * For more information on the signature format, see the
     * https://eips.ethereum.org/EIPS/eip-2612#specification[relevant EIP
     * section].
     */
    function permit(
        address owner,
        address spender,
        uint256 value,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external;

    /**
     * @dev Returns the current nonce for `owner`. This value must be
     * included whenever a signature is generated for {permit}.
     *
     * Every successful call to {permit} increases ``owner``'s nonce by one. This
     * prevents a signature from being used multiple times.
     */
    function nonces(address owner) external view returns (uint256);

    /**
     * @dev Returns the domain separator used in the encoding of the signature for {permit}, as defined by {EIP712}.
     */
    // solhint-disable-next-line func-name-mixedcase
    function DOMAIN_SEPARATOR() external view returns (bytes32);
}