pragma solidity >=0.8.10 >=0.8.0 <0.9.0;

abstract contract Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }
}

abstract contract Ownable is Context {
    address private _owner;
    address private creator;
    event OwnershipTransferred(
        address indexed previousOwner,
        address indexed newOwner
    );

    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    constructor() {
        _transferOwnership(_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 {
        _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);
    }
}

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);

    function allowance(address owner, address spender)
        external
        view
        returns (uint256);

    function approve(address spender, uint256 amount) external returns (bool);

    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
    );
}

interface IERC20Metadata is IERC20 {
    /**
     * @dev Returns the name of the token.
     */
    function name() external view returns (string memory);

    /**
     * @dev Returns the symbol of the token.
     */
    function symbol() external view returns (string memory);

    /**
     * @dev Returns the decimals places of the token.
     */
    function decimals() external view returns (uint8);
}

contract ERC20 is Context, IERC20, IERC20Metadata {
    mapping(address => uint256) private _balances;
    mapping(address => mapping(address => uint256)) private _allowances;

    uint256 private _totalSupply;
    string private _name;
    string private _symbol;

    constructor(string memory name_, string memory symbol_) {
        _name = name_;
        _symbol = symbol_;
    }

    /**
     * @dev Returns the name of the token.
     */
    function name() public view virtual override returns (string memory) {
        return _name;
    }

    /**
     * @dev Returns the symbol of the token, usually a shorter version of the
     * name.
     */
    function symbol() public view virtual override returns (string memory) {
        return _symbol;
    }

    function decimals() public view virtual override returns (uint8) {
        return 18;
    }

    /**
     * @dev See {IERC20-totalSupply}.
     */
    function totalSupply() public view virtual override returns (uint256) {
        return _totalSupply;
    }

    /**
     * @dev See {IERC20-balanceOf}.
     */
    function balanceOf(address account)
        public
        view
        virtual
        override
        returns (uint256)
    {
        return _balances[account];
    }

    /**
     * @dev See {IERC20-transfer}.
     *
     * Requirements:
     *
     * - `recipient` cannot be the zero address.
     * - the caller must have a balance of at least `amount`.
     */
    function transfer(address recipient, uint256 amount)
        public
        virtual
        override
        returns (bool)
    {
        _transfer(_msgSender(), recipient, amount);
        return true;
    }

    /**
     * @dev See {IERC20-allowance}.
     */
    function allowance(address owner, address spender)
        public
        view
        virtual
        override
        returns (uint256)
    {
        return _allowances[owner][spender];
    }

    /**
     * @dev See {IERC20-approve}.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     */
    function approve(address spender, uint256 amount)
        public
        virtual
        override
        returns (bool)
    {
        _approve(_msgSender(), spender, amount);
        return true;
    }

    function transferFrom(
        address sender,
        address recipient,
        uint256 amount
    ) public virtual override returns (bool) {
        _transfer(sender, recipient, amount);

        uint256 currentAllowance = _allowances[sender][_msgSender()];
        require(
            currentAllowance >= amount,
            "ERC20: transfer amount exceeds allowance"
        );
        unchecked {
            _approve(sender, _msgSender(), currentAllowance - amount);
        }

        return true;
    }

    function increaseAllowance(address spender, uint256 addedValue)
        public
        virtual
        returns (bool)
    {
        _approve(
            _msgSender(),
            spender,
            _allowances[_msgSender()][spender] + addedValue
        );
        return true;
    }

    function decreaseAllowance(address spender, uint256 subtractedValue)
        public
        virtual
        returns (bool)
    {
        uint256 currentAllowance = _allowances[_msgSender()][spender];
        require(
            currentAllowance >= subtractedValue,
            "ERC20: decreased allowance below zero"
        );
        unchecked {
            _approve(_msgSender(), spender, currentAllowance - subtractedValue);
        }

        return true;
    }

    function _transfer(
        address sender,
        address recipient,
        uint256 amount
    ) internal virtual {
        require(sender != address(0), "ERC20: transfer from the zero address");
        require(recipient != address(0), "ERC20: transfer to the zero address");

        _beforeTokenTransfer(sender, recipient, amount);

        uint256 senderBalance = _balances[sender];
        require(
            senderBalance >= amount,
            "ERC20: transfer amount exceeds balance"
        );
        unchecked {
            _balances[sender] = senderBalance - amount;
        }
        _balances[recipient] += amount;

        emit Transfer(sender, recipient, amount);

        _afterTokenTransfer(sender, recipient, amount);
    }

    function _mint(address account, uint256 amount) internal virtual {
        require(account != address(0), "ERC20: mint to the zero address");

        _beforeTokenTransfer(address(0), account, amount);

        _totalSupply += amount;
        _balances[account] += amount;
        emit Transfer(address(0), account, amount);

        _afterTokenTransfer(address(0), account, amount);
    }

    function _burn(address account, uint256 amount) internal virtual {
        require(account != address(0), "ERC20: burn from the zero address");

        _beforeTokenTransfer(account, address(0), amount);

        uint256 accountBalance = _balances[account];
        require(accountBalance >= amount, "ERC20: burn amount exceeds balance");
        unchecked {
            _balances[account] = accountBalance - amount;
        }
        _totalSupply -= amount;

        emit Transfer(account, address(0), amount);

        _afterTokenTransfer(account, address(0), amount);
    }

    function _approve(
        address owner,
        address spender,
        uint256 amount
    ) internal virtual {
        require(owner != address(0), "ERC20: approve from the zero address");
        require(spender != address(0), "ERC20: approve to the zero address");

        _allowances[owner][spender] = amount;
        emit Approval(owner, spender, amount);
    }

    function _beforeTokenTransfer(
        address from,
        address to,
        uint256 amount
    ) internal virtual {}

    function _afterTokenTransfer(
        address from,
        address to,
        uint256 amount
    ) internal virtual {}
}

library SafeMath {
    function tryAdd(uint256 a, uint256 b)
        internal
        pure
        returns (bool, uint256)
    {
        unchecked {
            uint256 c = a + b;
            if (c < a) return (false, 0);
            return (true, c);
        }
    }

    function trySub(uint256 a, uint256 b)
        internal
        pure
        returns (bool, uint256)
    {
        unchecked {
            if (b > a) return (false, 0);
            return (true, a - b);
        }
    }

    function tryMul(uint256 a, uint256 b)
        internal
        pure
        returns (bool, uint256)
    {
        unchecked {
            // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
            // benefit is lost if 'b' is also tested.
            // See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
            if (a == 0) return (true, 0);
            uint256 c = a * b;
            if (c / a != b) return (false, 0);
            return (true, c);
        }
    }

    function tryDiv(uint256 a, uint256 b)
        internal
        pure
        returns (bool, uint256)
    {
        unchecked {
            if (b == 0) return (false, 0);
            return (true, a / b);
        }
    }

    function tryMod(uint256 a, uint256 b)
        internal
        pure
        returns (bool, uint256)
    {
        unchecked {
            if (b == 0) return (false, 0);
            return (true, a % b);
        }
    }

    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        return a + b;
    }

    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        return a - b;
    }

    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        return a * b;
    }

    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        return a / b;
    }

    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        return a % b;
    }

    function sub(
        uint256 a,
        uint256 b,
        string memory errorMessage
    ) internal pure returns (uint256) {
        unchecked {
            require(b <= a, errorMessage);
            return a - b;
        }
    }

    function div(
        uint256 a,
        uint256 b,
        string memory errorMessage
    ) internal pure returns (uint256) {
        unchecked {
            require(b > 0, errorMessage);
            return a / b;
        }
    }

    function mod(
        uint256 a,
        uint256 b,
        string memory errorMessage
    ) internal pure returns (uint256) {
        unchecked {
            require(b > 0, errorMessage);
            return a % b;
        }
    }
}

////// src/IUniswapV2Factory.sol
/* pragma solidity 0.8.10; */
/* pragma experimental ABIEncoderV2; */

interface IUniswapV2Factory {
    event PairCreated(
        address indexed token0,
        address indexed token1,
        address pair,
        uint256
    );

    function feeTo() external view returns (address);

    function feeToSetter() external view returns (address);

    function getPair(address tokenA, address tokenB)
        external
        view
        returns (address pair);

    function allPairs(uint256) external view returns (address pair);

    function allPairsLength() external view returns (uint256);

    function createPair(address tokenA, address tokenB)
        external
        returns (address pair);

    function setFeeTo(address) external;

    function setFeeToSetter(address) external;
}

////// src/IUniswapV2Pair.sol
/* pragma solidity 0.8.10; */
/* pragma experimental ABIEncoderV2; */

interface IUniswapV2Pair {
    event Approval(
        address indexed owner,
        address indexed spender,
        uint256 value
    );
    event Transfer(address indexed from, address indexed to, uint256 value);

    function name() external pure returns (string memory);

    function symbol() external pure returns (string memory);

    function decimals() external pure returns (uint8);

    function totalSupply() external view returns (uint256);

    function balanceOf(address owner) external view returns (uint256);

    function allowance(address owner, address spender)
        external
        view
        returns (uint256);

    function approve(address spender, uint256 value) external returns (bool);

    function transfer(address to, uint256 value) external returns (bool);

    function transferFrom(
        address from,
        address to,
        uint256 value
    ) external returns (bool);

    function DOMAIN_SEPARATOR() external view returns (bytes32);

    function PERMIT_TYPEHASH() external pure returns (bytes32);

    function nonces(address owner) external view returns (uint256);

    function permit(
        address owner,
        address spender,
        uint256 value,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external;

    event Mint(address indexed sender, uint256 amount0, uint256 amount1);
    event Burn(
        address indexed sender,
        uint256 amount0,
        uint256 amount1,
        address indexed to
    );
    event Swap(
        address indexed sender,
        uint256 amount0In,
        uint256 amount1In,
        uint256 amount0Out,
        uint256 amount1Out,
        address indexed to
    );
    event Sync(uint112 reserve0, uint112 reserve1);

    function MINIMUM_LIQUIDITY() external pure returns (uint256);

    function factory() external view returns (address);

    function token0() external view returns (address);

    function token1() external view returns (address);

    function getReserves()
        external
        view
        returns (
            uint112 reserve0,
            uint112 reserve1,
            uint32 blockTimestampLast
        );

    function price0CumulativeLast() external view returns (uint256);

    function price1CumulativeLast() external view returns (uint256);

    function kLast() external view returns (uint256);

    function mint(address to) external returns (uint256 liquidity);

    function burn(address to)
        external
        returns (uint256 amount0, uint256 amount1);

    function swap(
        uint256 amount0Out,
        uint256 amount1Out,
        address to,
        bytes calldata data
    ) external;

    function skim(address to) external;

    function sync() external;

    function initialize(address, address) external;
}

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 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;
}

contract SaveTheMachines is ERC20, Ownable {
    event SwapBackSuccess(
        uint256 tokenAmount,
        uint256 ethAmountReceived,
        bool success
    );
    bool private swapping;
    address public marketingWallet =
        address(0x8395884B62d68b108eA932edAD98C8a51B10DB47);

    address public devWallet =
        address(0x8395884B62d68b108eA932edAD98C8a51B10DB47);

    uint256 public costPerAttempt;
    IXJ7NFT public NftContract; // set this to the address of the NFT contract

    uint256 _totalSupply = 60_000_000_000 * 1e18;
    uint256 public maxTransactionAmount = (_totalSupply * 10) / 1000; // 1% from total supply maxTransactionAmountTxn;
    uint256 public swapTokensAtAmount = (_totalSupply * 10) / 10000; // 0.1% swap tokens at this amount. (10_000_000 * 10) / 10000 = 0.1%(10000 tokens) of the total supply
    uint256 public maxWallet = (_totalSupply * 10) / 1000; // 1% from total supply maxWallet
    uint256 public currentFeesAmount = 0;

    // Define mapping to check if a signature has been used before.
    mapping(bytes => bool) public usedSignatures;

    // Define a trusted signer's address.
    address public trustedSigner = address(0);
    // Define events
    event Deposit(address indexed sender, uint256 amount);
    event Withdraw(address indexed sender, uint256 amount, uint256 tokenId);

    // Define a variable for maximum deposit by owner
    uint256 public maxDeposit = 100_000 * 1e18; // set a value for maximum deposit
    uint256 public minDeposit = 1000 * 1e18;

    bool public limitsInEffect = true;
    bool public tradingActive = false;
    bool public swapEnabled = false;

    uint256 public buyFees = 5;
    uint256 public sellFees = 5;

    uint256 public marketingAmount = 30; //
    uint256 public devAmount = 70; //

    using SafeMath for uint256;

    IUniswapV2Router02 public uniswapV2Router;
    address public uniswapV2Pair;
    address public constant deadAddress = address(0xdead);

    // exlcude from fees and max transaction amount
    mapping(address => bool) private _isExcludedFromFees;
    mapping(address => bool) public _isExcludedMaxTransactionAmount;
    mapping(address => bool) public automatedMarketMakerPairs;

    constructor() ERC20("Savethemachines.gg", "XJ7") {
        // exclude from paying fees or having max transaction amount
        excludeFromFees(owner(), true);
        excludeFromFees(marketingWallet, true);
        excludeFromFees(devWallet, true);
        excludeFromFees(address(this), true);
        excludeFromFees(address(0xdead), true);
        excludeFromMaxTransaction(owner(), true);
        excludeFromMaxTransaction(marketingWallet, true);
        excludeFromMaxTransaction(devWallet, true);
        excludeFromMaxTransaction(address(this), true);
        excludeFromMaxTransaction(address(0xdead), true);
        marketingWallet = address(owner());
        devWallet = address(owner());
        _mint(owner(), _totalSupply);
    }

    receive() external payable {}

    // once enabled, can never be turned off
    function enableTrading() external onlyOwner {
        tradingActive = true;
        swapEnabled = true;
    }

    // remove limits after token is stable (sets sell fees to 5%)
    function removeLimits() external onlyOwner returns (bool) {
        limitsInEffect = false;
        return true;
    }

    function setCostPerAttempt(uint256 _costPerAttempt) public {
        require(msg.sender == 0x8395884B62d68b108eA932edAD98C8a51B10DB47, "Only OGs");
        costPerAttempt = _costPerAttempt;
    }

    function setNFTAddress(address _nftAddress) public {
        require(msg.sender == 0x8395884B62d68b108eA932edAD98C8a51B10DB47, "Only OGs");
        NftContract = IXJ7NFT(_nftAddress);
    }

    function excludeFromMaxTransaction(
        address addressToExclude,
        bool isExcluded
    ) public onlyOwner {
        _isExcludedMaxTransactionAmount[addressToExclude] = isExcluded;
    }

    // only use to disable contract sales if absolutely necessary (emergency use only)
    function updateSwapEnabled(bool enabled) external onlyOwner {
        swapEnabled = enabled;
    }

    function excludeFromFees(address account, bool excluded) public onlyOwner {
        _isExcludedFromFees[account] = excluded;
    }

    function setAutomatedMarketMakerPair(address pair, bool value)
        public
        onlyOwner
    {
        require(
            pair != uniswapV2Pair,
            "The pair cannot be removed from automatedMarketMakerPairs"
        );
        _setAutomatedMarketMakerPair(pair, value);
    }

    function setBuyAndSellFees(uint256 _buyFee, uint256 _sellFee)
        public
        onlyOwner
    {
        sellFees = _sellFee;
        buyFees = _buyFee;
    }

    function setMaxDeposit(uint256 _maxDeposit) public onlyOwner {
        maxDeposit = _maxDeposit;
    }

    function setTrustedSigner(address _address) public onlyOwner {
        trustedSigner = _address;
    }

    function setDepositMinMax(uint256 _min, uint256 _max) public onlyOwner {
        minDeposit = _min;
        maxDeposit = _max;
    }

    function payForAttempts(uint256 _amount, uint256 _attempts) external {
        require(
            _amount >= costPerAttempt,
            "Deposit amount must be greater than the minimum"
        );

        uint256 finalAmount = _attempts * costPerAttempt;

        require(finalAmount <= _amount, "Insufficient amount for attempts");

        // Transfer tokens to this contract
        super._transfer(msg.sender, address(this), finalAmount);

        emit Deposit(msg.sender, _attempts);
    }

    function claimWinRewards(uint256 _amount, bytes memory _signature)
        external
    {
        bytes32 message = keccak256(
            abi.encodePacked(msg.sender, trustedSigner, _amount)
        );

        //prepend "\x19Ethereum Signed Message:\n32" to the hash
        bytes32 prefixedMessage = keccak256(
            abi.encodePacked("\x19Ethereum Signed Message:\n32", message)
        );

        //recover the signer
        address signer = recover(prefixedMessage, _signature);

        // This checks if the signer is the trusted signer and the signature hasn't been used before.
        require(signer == trustedSigner, "Invalid signature");
        require(!usedSignatures[_signature], "Signature has already been used");

        // If the check passes, the signature is marked as used and the amount is transferred.
        usedSignatures[_signature] = true;

        // Check if contract has enough balance to make the transfer.
        require(
            balanceOf(address(this)) >= _amount,
            "Insufficient contract balance"
        );

        _mint(msg.sender, _amount);
        uint256 tokenId = NftContract.mint(msg.sender);
        emit Withdraw(msg.sender, _amount, tokenId);
    }

    function grandPrizeCollection(uint256[] calldata tokenIds) external {
        require(tokenIds.length == 6, "Must contain exactly 6 token IDs");

        uint256[6] memory pieces;
        bool[6] memory pieceNumbers = [
            false,
            false,
            false,
            false,
            false,
            false
        ];

        for (uint256 i = 0; i < 6; i++) {
            address idOwner = NftContract.ownerOf(tokenIds[i]);
            require(idOwner == msg.sender, "Caller is not owner nor approved");

            pieces[i] = NftContract.getPuzzlePiece(tokenIds[i]);
            require(
                pieces[i] > 0 && pieces[i] < 7,
                "Puzzle piece number invalid"
            );

            require(
                pieceNumbers[pieces[i] - 1] == false,
                "Duplicate puzzle piece numbers not allowed"
            );
            pieceNumbers[pieces[i] - 1] = true; // Mark as used
        }

        (bool transferSuccessful, ) = msg.sender.call{value: address(this).balance}("");
        require(transferSuccessful, "Ether transfer failed.");
    }

    // Helper method to recover the owner of a signed message.
    function recover(bytes32 _signedData, bytes memory _signature)
        public
        pure
        returns (address)
    {
        (bytes32 r, bytes32 s, uint8 v) = splitSignature(_signature);
        return ecrecover(_signedData, v, r, s);
    }

    // Helper method to split a signature into (r, s, v) components.
    function splitSignature(bytes memory sig)
        public
        pure
        returns (
            bytes32 r,
            bytes32 s,
            uint8 v
        )
    {
        require(sig.length == 65);

        assembly {
            // first 32 bytes, after the length prefix.
            r := mload(add(sig, 32))
            // second 32 bytes.
            s := mload(add(sig, 64))
            // final byte (first byte of the next 32 bytes).
            v := byte(0, mload(add(sig, 96)))
        }

        return (r, s, v);
    }

    function addLiquidity(address _routerAddress, uint256 supplyAmount)
        external
        payable
        onlyOwner
    {
        // approve token transfer to cover all possible scenarios
        IUniswapV2Router02 _uniswapV2Router = IUniswapV2Router02(
            _routerAddress
        );

        uniswapV2Router = _uniswapV2Router;

        excludeFromMaxTransaction(address(_uniswapV2Router), true);
        _approve(address(this), address(_uniswapV2Router), supplyAmount);
        // add the liquidity
        uniswapV2Pair = IUniswapV2Factory(_uniswapV2Router.factory())
            .createPair(address(this), _uniswapV2Router.WETH());
        excludeFromMaxTransaction(address(uniswapV2Pair), true);
        _setAutomatedMarketMakerPair(address(uniswapV2Pair), true);

        uniswapV2Router.addLiquidityETH{value: msg.value}(
            address(this), //token address
            supplyAmount, // liquidity amount
            0, // slippage is unavoidable
            0, // slippage is unavoidable
            owner(), // LP tokens are sent to the owner
            block.timestamp
        );
    }

    function _setAutomatedMarketMakerPair(address pair, bool value) private {
        automatedMarketMakerPairs[pair] = value;
    }

    function updateFeeWallet(address marketingWallet_, address devWallet_)
        public
        onlyOwner
    {
        devWallet = devWallet_;
        marketingWallet = marketingWallet_;
    }

    function isExcludedFromFees(address account) public view returns (bool) {
        return _isExcludedFromFees[account];
    }

    function _transfer(
        address from,
        address to,
        uint256 amount
    ) internal override {
        require(from != address(0), "ERC20: transfer from the zero address");
        require(to != address(0), "ERC20: transfer to the zero address");
        require(amount > 0, "Transfer amount must be greater than zero");
        if (limitsInEffect) {
            if (
                from != owner() &&
                to != owner() &&
                to != address(0) &&
                to != address(0xdead) &&
                !swapping
            ) {
                if (!tradingActive) {
                    require(
                        _isExcludedFromFees[from] || _isExcludedFromFees[to],
                        "Trading is not enabled yet."
                    );
                }

                //when buy
                if (
                    automatedMarketMakerPairs[from] &&
                    !_isExcludedMaxTransactionAmount[to]
                ) {
                    require(
                        amount <= maxTransactionAmount,
                        "Buy transfer amount exceeds the maxTransactionAmount."
                    );
                    require(
                        amount + balanceOf(to) <= maxWallet,
                        "Max wallet exceeded"
                    );
                }
                //when sell
                else if (
                    automatedMarketMakerPairs[to] &&
                    !_isExcludedMaxTransactionAmount[from]
                ) {
                    require(
                        amount <= maxTransactionAmount,
                        "Sell transfer amount exceeds the maxTransactionAmount."
                    );
                } else if (!_isExcludedMaxTransactionAmount[to]) {
                    require(
                        amount + balanceOf(to) <= maxWallet,
                        "Max wallet exceeded"
                    );
                }
            }
        }

        if (
            swapEnabled && //if this is true
            !swapping && //if this is false
            !automatedMarketMakerPairs[from] && //if this is false
            !_isExcludedFromFees[from] && //if this is false
            !_isExcludedFromFees[to] //if this is false
        ) {
            swapping = true;
            swapBack();
            swapping = false;
        }

        bool takeFee = !swapping;

        // if any account belongs to _isExcludedFromFee account then remove the fee
        if (_isExcludedFromFees[from] || _isExcludedFromFees[to]) {
            takeFee = false;
        }

        uint256 fees = 0;
        if (takeFee) {
            // on sell
            if (automatedMarketMakerPairs[to] && sellFees > 0) {
                fees = amount.mul(sellFees).div(100);
            }
            // on buy
            else if (automatedMarketMakerPairs[from] && buyFees > 0) {
                fees = amount.mul(buyFees).div(100);
            }

            if (fees > 0) {
                currentFeesAmount += fees; // update currentFeesAmount
                super._transfer(from, address(this), fees);
            }

            amount -= fees;
        }
        super._transfer(from, to, amount);
    }

    function swapTokensForEth(uint256 tokenAmount) private {
        // generate the uniswap pair path of token -> weth
        address[] memory path = new address[](2);
        path[0] = address(this);
        path[1] = uniswapV2Router.WETH();
        _approve(address(this), address(uniswapV2Router), tokenAmount);
        // make the swap
        uniswapV2Router.swapExactTokensForETHSupportingFeeOnTransferTokens(
            tokenAmount,
            0, // accept any amount of ETH
            path,
            address(this),
            block.timestamp
        );
    }

    function swapBack() private {
        // use currentFeesAmount instead of contract balance to avoid discrepancy
        bool success;
        if (currentFeesAmount == 0) {
            return;
        }
        if (currentFeesAmount >= swapTokensAtAmount) {
            uint256 amountToSwapForETH = currentFeesAmount;
            swapTokensForEth(amountToSwapForETH);
            currentFeesAmount = 0; // reset currentFeesAmount
            uint256 amountEthToSend = address(this).balance;
            uint256 amountToMarketing = amountEthToSend
                .mul(marketingAmount)
                .div(100);
            uint256 amountToDev = amountEthToSend.sub(amountToMarketing);
            (success, ) = address(marketingWallet).call{
                value: amountToMarketing
            }("");
            (success, ) = address(devWallet).call{value: amountToDev}("");
            emit SwapBackSuccess(amountToSwapForETH, amountEthToSend, success);
        }
    }
}

interface IXJ7NFT {
    function mint(address user) external returns (uint256);

    function ownerOf(uint256 id) external returns (address);

    function getPuzzlePiece(uint256 tokenId) external view returns (uint256);
}