// File: contracts/Brewlabs_ZapIn.sol



// SPDX-License-Identifier: GPL-2.0

pragma solidity ^0.8.0;
import "./_base/ZapInBaseV3.sol";

// import "@uniswap/lib/contracts/libraries/Babylonian.sol";
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
    }
}

interface IWETH {
    function deposit() external payable;

    function transfer(address to, uint256 value) external returns (bool);

    function withdraw(uint256) external;
}

interface IUniswapV2Factory {
    function getPair(address tokenA, address tokenB)
        external
        view
        returns (address);
}

interface IUniswapV2Router02 {
    function factory() external pure returns (address);

    function WETH() external pure returns (address);

    function addLiquidity(
        address tokenA,
        address tokenB,
        uint256 amountADesired,
        uint256 amountBDesired,
        uint256 amountAMin,
        uint256 amountBMin,
        address to,
        uint256 deadline
    )
        external
        returns (
            uint256 amountA,
            uint256 amountB,
            uint256 liquidity
        );

    function addLiquidityETH(
        address token,
        uint256 amountTokenDesired,
        uint256 amountTokenMin,
        uint256 amountETHMin,
        address to,
        uint256 deadline
    )
        external
        payable
        returns (
            uint256 amountToken,
            uint256 amountETH,
            uint256 liquidity
        );

    function removeLiquidity(
        address tokenA,
        address tokenB,
        uint256 liquidity,
        uint256 amountAMin,
        uint256 amountBMin,
        address to,
        uint256 deadline
    ) external returns (uint256 amountA, uint256 amountB);

    function removeLiquidityETH(
        address token,
        uint256 liquidity,
        uint256 amountTokenMin,
        uint256 amountETHMin,
        address to,
        uint256 deadline
    ) external returns (uint256 amountToken, uint256 amountETH);

    function removeLiquidityWithPermit(
        address tokenA,
        address tokenB,
        uint256 liquidity,
        uint256 amountAMin,
        uint256 amountBMin,
        address to,
        uint256 deadline,
        bool approveMax,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external returns (uint256 amountA, uint256 amountB);

    function removeLiquidityETHWithPermit(
        address token,
        uint256 liquidity,
        uint256 amountTokenMin,
        uint256 amountETHMin,
        address to,
        uint256 deadline,
        bool approveMax,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external returns (uint256 amountToken, uint256 amountETH);

    function swapExactTokensForTokens(
        uint256 amountIn,
        uint256 amountOutMin,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external returns (uint256[] memory amounts);

    function swapTokensForExactTokens(
        uint256 amountOut,
        uint256 amountInMax,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external returns (uint256[] memory amounts);

    function swapExactETHForTokens(
        uint256 amountOutMin,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external payable returns (uint256[] memory amounts);

    function swapTokensForExactETH(
        uint256 amountOut,
        uint256 amountInMax,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external returns (uint256[] memory amounts);

    function swapExactTokensForETH(
        uint256 amountIn,
        uint256 amountOutMin,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external returns (uint256[] memory amounts);

    function swapETHForExactTokens(
        uint256 amountOut,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external payable returns (uint256[] memory amounts);

    function removeLiquidityETHSupportingFeeOnTransferTokens(
        address token,
        uint256 liquidity,
        uint256 amountTokenMin,
        uint256 amountETHMin,
        address to,
        uint256 deadline
    ) external returns (uint256 amountETH);

    function removeLiquidityETHWithPermitSupportingFeeOnTransferTokens(
        address token,
        uint256 liquidity,
        uint256 amountTokenMin,
        uint256 amountETHMin,
        address to,
        uint256 deadline,
        bool approveMax,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external returns (uint256 amountETH);

    function swapExactTokensForTokensSupportingFeeOnTransferTokens(
        uint256 amountIn,
        uint256 amountOutMin,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external;

    function swapExactETHForTokensSupportingFeeOnTransferTokens(
        uint256 amountOutMin,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external payable;

    function swapExactTokensForETHSupportingFeeOnTransferTokens(
        uint256 amountIn,
        uint256 amountOutMin,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external;

    function quote(
        uint256 amountA,
        uint256 reserveA,
        uint256 reserveB
    ) external pure returns (uint256 amountB);

    function getAmountOut(
        uint256 amountIn,
        uint256 reserveIn,
        uint256 reserveOut
    ) external pure returns (uint256 amountOut);

    function getAmountIn(
        uint256 amountOut,
        uint256 reserveIn,
        uint256 reserveOut
    ) external pure returns (uint256 amountIn);

    function getAmountsOut(uint256 amountIn, address[] calldata path)
        external
        view
        returns (uint256[] memory amounts);

    function getAmountsIn(uint256 amountOut, address[] calldata path)
        external
        view
        returns (uint256[] memory amounts);
}

interface IUniswapV2Pair {
    function token0() external pure returns (address);

    function token1() external pure returns (address);

    function getReserves()
        external
        view
        returns (
            uint112 _reserve0,
            uint112 _reserve1,
            uint32 _blockTimestampLast
        );
}

contract Brewlabs_ZapIn is ZapInBaseV3 {
    using SafeERC20 for IERC20;

    IUniswapV2Factory private constant UniSwapV2FactoryAddress =
        IUniswapV2Factory(0x5C69bEe701ef814a2B6a3EDD4B1652CB9cc5aA6f);

    IUniswapV2Router02 private constant uniswapRouter =
        IUniswapV2Router02(0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D);

    address private constant wethTokenAddress =
        0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2;

    uint256 private constant deadline =
        0xf000000000000000000000000000000000000000000000000000000000000000;

    uint256 public feeAmount;
    address payable public feeAddress;

    constructor(
        uint256 _goodwill,
        uint256 _affiliateSplit,
        uint256 _feeAmount,
        address payable _feeAddress
    ) ZapBaseV2(_goodwill, _affiliateSplit) {
        // 0x exchange
        approvedTargets[0xDef1C0ded9bec7F1a1670819833240f027b25EfF] = true;
        feeAmount = _feeAmount;
        feeAddress = _feeAddress;
    }

    event zapIn(address sender, address pool, uint256 tokensRec);

    function setFeeAmount(uint256 _feeAmount) public onlyOwner {
        feeAmount = _feeAmount;
    }

    function setFeeAddress(address payable _feeAddress) public onlyOwner {
        feeAddress = _feeAddress;
    }

    /**
    @notice This function is used to invest in given Uniswap V2 pair through ETH/ERC20 Tokens
    @param _FromTokenContractAddress The ERC20 token used for investment (address(0x00) if ether)
    @param _pairAddress The Uniswap pair address
    @param _amount The amount of fromToken to invest
    @param _minPoolTokens Reverts if less tokens received than this
    @param _swapTarget Excecution target for the first swap
    @param swapData DEX quote data
    @param affiliate Affiliate address
    @param transferResidual Set false to save gas by donating the residual remaining after a Zap
    @param shouldSellEntireBalance If True transfers entrire allowable amount from another contract
    @return Amount of LP bought
     */
    function ZapIn(
        address _FromTokenContractAddress,
        address _pairAddress,
        uint256 _amount,
        uint256 _minPoolTokens,
        address _swapTarget,
        bytes calldata swapData,
        address affiliate,
        bool transferResidual,
        bool shouldSellEntireBalance
    ) external payable stopInEmergency returns (uint256) {
        require(msg.value - _amount >= feeAmount, "Zapper: fee is not enough");
        feeAddress.transfer(feeAmount);

        uint256 toInvest = _pullTokens(
            _FromTokenContractAddress,
            _amount,
            affiliate,
            true,
            shouldSellEntireBalance
        );

        uint256 LPBought = _performZapIn(
            _FromTokenContractAddress,
            _pairAddress,
            toInvest,
            _swapTarget,
            swapData,
            transferResidual
        );
        require(LPBought >= _minPoolTokens, "High Slippage");

        emit zapIn(msg.sender, _pairAddress, LPBought);

        IERC20(_pairAddress).safeTransfer(msg.sender, LPBought);
        return LPBought;
    }

    function _getPairTokens(address _pairAddress)
        internal
        pure
        returns (address token0, address token1)
    {
        IUniswapV2Pair uniPair = IUniswapV2Pair(_pairAddress);
        token0 = uniPair.token0();
        token1 = uniPair.token1();
    }

    function _performZapIn(
        address _FromTokenContractAddress,
        address _pairAddress,
        uint256 _amount,
        address _swapTarget,
        bytes memory swapData,
        bool transferResidual
    ) internal returns (uint256) {
        uint256 intermediateAmt;
        address intermediateToken;
        (address _ToUniswapToken0, address _ToUniswapToken1) = _getPairTokens(
            _pairAddress
        );

        if (
            _FromTokenContractAddress != _ToUniswapToken0 &&
            _FromTokenContractAddress != _ToUniswapToken1
        ) {
            // swap to intermediate
            (intermediateAmt, intermediateToken) = _fillQuote(
                _FromTokenContractAddress,
                _pairAddress,
                _amount,
                _swapTarget,
                swapData
            );
        } else {
            intermediateToken = _FromTokenContractAddress;
            intermediateAmt = _amount;
        }

        // divide intermediate into appropriate amount to add liquidity
        _swapIntermediate(
            intermediateToken,
            _ToUniswapToken0,
            _ToUniswapToken1,
            intermediateAmt
        );

        return
            _uniDeposit(
                _ToUniswapToken0,
                _ToUniswapToken1,
                IERC20(_ToUniswapToken0).balanceOf(address(this)),
                IERC20(_ToUniswapToken1).balanceOf(address(this)),
                transferResidual
            );
    }

    function _uniDeposit(
        address _ToUnipoolToken0,
        address _ToUnipoolToken1,
        uint256 token0Bought,
        uint256 token1Bought,
        bool transferResidual
    ) internal returns (uint256) {
        _approveToken(_ToUnipoolToken0, address(uniswapRouter), token0Bought);
        _approveToken(_ToUnipoolToken1, address(uniswapRouter), token1Bought);

        (uint256 amountA, uint256 amountB, uint256 LP) = uniswapRouter
            .addLiquidity(
                _ToUnipoolToken0,
                _ToUnipoolToken1,
                token0Bought,
                token1Bought,
                1,
                1,
                address(this),
                deadline
            );

        if (transferResidual) {
            //Returning Residue in token0, if any.
            if (token0Bought - amountA > 0) {
                IERC20(_ToUnipoolToken0).safeTransfer(
                    msg.sender,
                    token0Bought - amountA
                );
            }

            //Returning Residue in token1, if any
            if (token1Bought - amountB > 0) {
                IERC20(_ToUnipoolToken1).safeTransfer(
                    msg.sender,
                    token1Bought - amountB
                );
            }
        }

        return LP;
    }

    function _fillQuote(
        address _fromTokenAddress,
        address _pairAddress,
        uint256 _amount,
        address _swapTarget,
        bytes memory swapData
    ) internal returns (uint256 amountBought, address intermediateToken) {
        if (_swapTarget == wethTokenAddress) {
            IWETH(wethTokenAddress).deposit{value: _amount}();
            return (_amount, wethTokenAddress);
        }

        uint256 valueToSend;
        if (_fromTokenAddress == address(0)) {
            valueToSend = _amount;
        } else {
            _approveToken(_fromTokenAddress, _swapTarget, _amount);
        }

        (address _token0, address _token1) = _getPairTokens(_pairAddress);
        IERC20 token0 = IERC20(_token0);
        IERC20 token1 = IERC20(_token1);
        uint256 initialBalance0 = token0.balanceOf(address(this));
        uint256 initialBalance1 = token1.balanceOf(address(this));

        require(approvedTargets[_swapTarget], "Target not Authorized");
        (bool success, ) = _swapTarget.call{value: valueToSend}(swapData);
        require(success, "Error Swapping Tokens 1");

        uint256 finalBalance0 = token0.balanceOf(address(this)) -
            initialBalance0;
        uint256 finalBalance1 = token1.balanceOf(address(this)) -
            initialBalance1;

        if (finalBalance0 > finalBalance1) {
            amountBought = finalBalance0;
            intermediateToken = _token0;
        } else {
            amountBought = finalBalance1;
            intermediateToken = _token1;
        }

        require(amountBought > 0, "Swapped to Invalid Intermediate");
    }

    function _swapIntermediate(
        address _toContractAddress,
        address _ToUnipoolToken0,
        address _ToUnipoolToken1,
        uint256 _amount
    ) internal returns (uint256 token0Bought, uint256 token1Bought) {
        IUniswapV2Pair pair = IUniswapV2Pair(
            UniSwapV2FactoryAddress.getPair(_ToUnipoolToken0, _ToUnipoolToken1)
        );
        (uint256 res0, uint256 res1, ) = pair.getReserves();
        if (_toContractAddress == _ToUnipoolToken0) {
            uint256 amountToSwap = calculateSwapInAmount(res0, _amount);
            //if no reserve or a new pair is created
            if (amountToSwap <= 0) amountToSwap = _amount / 2;
            token1Bought = _token2Token(
                _toContractAddress,
                _ToUnipoolToken1,
                amountToSwap
            );
            token0Bought = _amount - amountToSwap;
        } else if (_toContractAddress == _ToUnipoolToken1) {
            uint256 amountToSwap = calculateSwapInAmount(res1, _amount);
            //if no reserve or a new pair is created
            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 calculateSwapInAmount(uint256 reserveIn, uint256 userIn)
        internal
        pure
        returns (uint256)
    {
        return
            (Babylonian.sqrt(
                reserveIn * ((userIn * 3988000) + (reserveIn * 3988009))
            ) - (reserveIn * 1997)) / 1994;
    }

    /**
    @notice This function is used to swap ERC20 <> ERC20
    @param _FromTokenContractAddress The token address to swap from.
    @param _ToTokenContractAddress The token address to swap to. 
    @param tokens2Trade The amount of tokens to swap
    @return tokenBought The quantity of tokens bought
    */
    function _token2Token(
        address _FromTokenContractAddress,
        address _ToTokenContractAddress,
        uint256 tokens2Trade
    ) internal returns (uint256 tokenBought) {
        if (_FromTokenContractAddress == _ToTokenContractAddress) {
            return tokens2Trade;
        }

        _approveToken(
            _FromTokenContractAddress,
            address(uniswapRouter),
            tokens2Trade
        );

        address pair = UniSwapV2FactoryAddress.getPair(
            _FromTokenContractAddress,
            _ToTokenContractAddress
        );
        require(pair != address(0), "No Swap Available");
        address[] memory path = new address[](2);
        path[0] = _FromTokenContractAddress;
        path[1] = _ToTokenContractAddress;

        tokenBought = uniswapRouter.swapExactTokensForTokens(
            tokens2Trade,
            1,
            path,
            address(this),
            deadline
        )[path.length - 1];

        require(tokenBought > 0, "Error Swapping Tokens 2");
    }
}

// File: contracts/_base/ZapInBaseV3.sol



// SPDX-License-Identifier: GPL-2.0

pragma solidity ^0.8.0;
import "./ZapBaseV2.sol";

abstract contract ZapInBaseV3 is ZapBaseV2 {
    using SafeERC20 for IERC20;

    function _pullTokens(
        address token,
        uint256 amount,
        address affiliate,
        bool enableGoodwill,
        bool shouldSellEntireBalance
    ) internal returns (uint256 value) {
        uint256 totalGoodwillPortion;

        if (token == address(0)) {
            require(msg.value > 0, "No eth sent");

            // subtract goodwill
            totalGoodwillPortion = _subtractGoodwill(
                ETHAddress,
                amount,
                affiliate,
                enableGoodwill
            );

            return amount - totalGoodwillPortion;
        }
        require(amount > 0, "Invalid token amount");
        require(msg.value == 0, "Eth sent with token");

        //transfer token
        if (shouldSellEntireBalance) {
            require(
                Address.isContract(msg.sender),
                "ERR: shouldSellEntireBalance is true for EOA"
            );
            amount = IERC20(token).allowance(msg.sender, address(this));
        }
        IERC20(token).safeTransferFrom(msg.sender, address(this), amount);

        // subtract goodwill
        totalGoodwillPortion = _subtractGoodwill(
            token,
            amount,
            affiliate,
            enableGoodwill
        );

        return amount - totalGoodwillPortion;
    }

    function _subtractGoodwill(
        address token,
        uint256 amount,
        address affiliate,
        bool enableGoodwill
    ) internal returns (uint256 totalGoodwillPortion) {
        bool whitelisted = feeWhitelist[msg.sender];
        if (enableGoodwill && !whitelisted && goodwill > 0) {
            totalGoodwillPortion = (amount * goodwill) / 10000;

            if (affiliates[affiliate]) {
                if (token == address(0)) {
                    token = ETHAddress;
                }

                uint256 affiliatePortion = (totalGoodwillPortion *
                    affiliateSplit) / 100;
                affiliateBalance[affiliate][token] =
                    affiliateBalance[affiliate][token] +
                    affiliatePortion;
                totalAffiliateBalance[token] =
                    totalAffiliateBalance[token] +
                    affiliatePortion;
            }
        }
    }
}

// File: contracts/_base/ZapBaseV2.sol



// SPDX-License-Identifier: GPL-2.0
pragma solidity ^0.8.0;

import "../oz/0.8.0/access/Ownable.sol";
import "../oz/0.8.0/token/ERC20/utils/SafeERC20.sol";

abstract contract ZapBaseV2 is Ownable {
    using SafeERC20 for IERC20;
    bool public stopped = false;

    // if true, goodwill is not deducted
    mapping(address => bool) public feeWhitelist;

    uint256 public goodwill;
    // % share of goodwill (0-100 %)
    uint256 affiliateSplit;
    // restrict affiliates
    mapping(address => bool) public affiliates;
    // affiliate => token => amount
    mapping(address => mapping(address => uint256)) public affiliateBalance;
    // token => amount
    mapping(address => uint256) public totalAffiliateBalance;
    // swapTarget => approval status
    mapping(address => bool) public approvedTargets;

    address internal constant ETHAddress =
        0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE;

    constructor(uint256 _goodwill, uint256 _affiliateSplit) {
        goodwill = _goodwill;
        affiliateSplit = _affiliateSplit;
    }

    // circuit breaker modifiers
    modifier stopInEmergency() {
        if (stopped) {
            revert("Temporarily Paused");
        } else {
            _;
        }
    }

    function _getBalance(address token)
        internal
        view
        returns (uint256 balance)
    {
        if (token == address(0)) {
            balance = address(this).balance;
        } else {
            balance = IERC20(token).balanceOf(address(this));
        }
    }

    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 = IERC20(token);
        _token.safeApprove(spender, 0);
        _token.safeApprove(spender, amount);
    }

    // - to Pause the contract
    function toggleContractActive() public onlyOwner {
        stopped = !stopped;
    }

    function set_feeWhitelist(address zapAddress, bool status)
        external
        onlyOwner
    {
        feeWhitelist[zapAddress] = status;
    }

    function set_new_goodwill(uint256 _new_goodwill) public onlyOwner {
        require(
            _new_goodwill >= 0 && _new_goodwill <= 100,
            "GoodWill Value not allowed"
        );
        goodwill = _new_goodwill;
    }

    function set_new_affiliateSplit(uint256 _new_affiliateSplit)
        external
        onlyOwner
    {
        require(
            _new_affiliateSplit <= 100,
            "Affiliate Split Value not allowed"
        );
        affiliateSplit = _new_affiliateSplit;
    }

    function set_affiliate(address _affiliate, bool _status)
        external
        onlyOwner
    {
        affiliates[_affiliate] = _status;
    }

    ///@notice Withdraw goodwill share, retaining affilliate share
    function withdrawTokens(address[] calldata tokens) external onlyOwner {
        for (uint256 i = 0; i < tokens.length; i++) {
            uint256 qty;

            if (tokens[i] == ETHAddress) {
                qty = address(this).balance - totalAffiliateBalance[tokens[i]];

                Address.sendValue(payable(owner()), qty);
            } else {
                qty =
                    IERC20(tokens[i]).balanceOf(address(this)) -
                    totalAffiliateBalance[tokens[i]];
                IERC20(tokens[i]).safeTransfer(owner(), qty);
            }
        }
    }

    ///@notice Withdraw affilliate share, retaining goodwill share
    function affilliateWithdraw(address[] calldata tokens) external {
        uint256 tokenBal;
        for (uint256 i = 0; i < tokens.length; i++) {
            tokenBal = affiliateBalance[msg.sender][tokens[i]];
            affiliateBalance[msg.sender][tokens[i]] = 0;
            totalAffiliateBalance[tokens[i]] =
                totalAffiliateBalance[tokens[i]] -
                tokenBal;

            if (tokens[i] == ETHAddress) {
                Address.sendValue(payable(msg.sender), tokenBal);
            } else {
                IERC20(tokens[i]).safeTransfer(msg.sender, tokenBal);
            }
        }
    }

    function setApprovedTargets(
        address[] calldata targets,
        bool[] calldata isApproved
    ) external onlyOwner {
        require(targets.length == isApproved.length, "Invalid Input length");

        for (uint256 i = 0; i < targets.length; i++) {
            approvedTargets[targets[i]] = isApproved[i];
        }
    }

    receive() external payable {
        require(msg.sender != tx.origin, "Do not send ETH directly");
    }
}

// File: contracts/oz/0.8.0/access/Ownable.sol



// SPDX-License-Identifier: MIT

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() {
        address msgSender = _msgSender();
        _owner = msgSender;
        emit OwnershipTransferred(address(0), msgSender);
    }

    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view virtual returns (address) {
        return _owner;
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        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 {
        emit OwnershipTransferred(_owner, address(0));
        _owner = 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"
        );
        emit OwnershipTransferred(_owner, newOwner);
        _owner = newOwner;
    }
}

// File: contracts/oz/0.8.0/token/ERC20/utils/SafeERC20.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import "../IERC20.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'
        // solhint-disable-next-line max-line-length
        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
                )
            );
        }
    }

    /**
     * @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
            // solhint-disable-next-line max-line-length
            require(
                abi.decode(returndata, (bool)),
                "SafeERC20: ERC20 operation did not succeed"
            );
        }
    }
}

// File: contracts/oz/0.8.0/utils/Context.sol



// SPDX-License-Identifier: MIT

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) {
        this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
        return msg.data;
    }
}

// File: contracts/oz/0.8.0/token/ERC20/IERC20.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @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 `recipient`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address recipient, 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 `sender` to `recipient` 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 sender,
        address recipient,
        uint256 amount
    ) external returns (bool);

    /**
     * @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
    );
}

// File: contracts/oz/0.8.0/utils/Address.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

/**
 * @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
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize, which returns 0 for contracts in
        // construction, since the code is only stored at the end of the
        // constructor execution.

        uint256 size;
        // solhint-disable-next-line no-inline-assembly
        assembly {
            size := extcodesize(account)
        }
        return size > 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"
        );

        // solhint-disable-next-line avoid-low-level-calls, avoid-call-value
        (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");

        // solhint-disable-next-line avoid-low-level-calls
        (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");

        // solhint-disable-next-line avoid-low-level-calls
        (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");

        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = target.delegatecall(data);
        return _verifyCallResult(success, returndata, errorMessage);
    }

    function _verifyCallResult(
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) private 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

                // solhint-disable-next-line no-inline-assembly
                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}