// SPDX-License-Identifier: MIT

pragma solidity 0.8.23;

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 C.
     */
    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 U.
     */
    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
    );
}

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 IERC20, IERC20Metadata {
    mapping(address => uint256) internal _balances;

    mapping(address => mapping(address => uint256)) private _allowances;

    uint256 internal _totalSupply;

    string private _name;
    string private _symbol;

    constructor(string memory name_, string memory symbol_) {
        _name = name_;
        _symbol = symbol_;
    }

    function name() public view virtual override returns (string memory) {
        return _name;
    }

    function symbol() public view virtual override returns (string memory) {
        return _symbol;
    }

    function decimals() public view virtual override returns (uint8) {
        return 18;
    }

    function totalSupply() public view virtual override returns (uint256) {
        return _totalSupply;
    }

    function balanceOf(address account)
        public
        view
        virtual
        override
        returns (uint256)
    {
        return _balances[account];
    }

    function transfer(address recipient, uint256 amount)
        public
        virtual
        override
        returns (bool)
    {
        _transfer(msg.sender, recipient, amount);
        return true;
    }

    function allowance(address owner, address spender)
        public
        view
        virtual
        override
        returns (uint256)
    {
        return _allowances[owner][spender];
    }

    function approve(address spender, uint256 amount)
        public
        virtual
        override
        returns (bool)
    {
        _approve(msg.sender, 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][msg.sender];
        if(currentAllowance != type(uint256).max) { 
            require(
                currentAllowance >= amount,
                "ERC20: transfer amount exceeds allowance"
            );
            unchecked {
                _approve(sender, msg.sender, currentAllowance - amount);
            }
        }
        return true;
    }

    function increaseAllowance(address spender, uint256 addedValue)
        public
        virtual
        returns (bool)
    {
        _approve(
            msg.sender,
            spender,
            _allowances[msg.sender][spender] + addedValue
        );
        return true;
    }

    function decreaseAllowance(address spender, uint256 subtractedValue)
        public
        virtual
        returns (bool)
    {
        uint256 currentAllowance = _allowances[msg.sender][spender];
        require(
            currentAllowance >= subtractedValue,
            "ERC20: decreased allowance below zero"
        );
        unchecked {
            _approve(msg.sender, 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");

        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);
    }

    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);
    }
}

contract Ownable {
    address private _owner;

    event OwnershipTransferred(
        address indexed previousOwner,
        address indexed newOwner
    );

    constructor() {
        address msgSender = msg.sender;
        _owner = msgSender;
        emit OwnershipTransferred(address(0), msgSender);
    }

    function owner() public view returns (address) {
        return _owner;
    }

    modifier onlyOwner() {
        require(_owner == msg.sender, "Ownable: caller is not the owner");
        _;
    }

    function renounceOwnership() public virtual onlyOwner {
        emit OwnershipTransferred(_owner, address(0));
        _owner = address(0);
    }

    function transferOwnership(address newOwner) public virtual onlyOwner {
        require(
            newOwner != address(0),
            "Ownable: new owner is the zero address"
        );
        emit OwnershipTransferred(_owner, newOwner);
        _owner = newOwner;
    }
}

interface IPair {
    function sync() external;
}

interface IDexRouter {
    function factory() external pure returns (address);

    function WETH() external pure returns (address);

    function swapExactTokensForETHSupportingFeeOnTransferTokens(
        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 swapExactETHForTokens(uint amountOutMin, address[] calldata path, address to, uint deadline)
        external
        payable
        returns (uint[] memory amounts);

    function swapETHForExactTokens(uint amountOut, address[] calldata path, address to, uint deadline)
        external
        payable
        returns (uint[] memory amounts);

    function addLiquidityETH(
        address token,
        uint256 amountTokenDesired,
        uint256 amountTokenMin,
        uint256 amountETHMin,
        address to,
        uint256 deadline
    )
        external
        payable
        returns (
            uint256 amountToken,
            uint256 amountETH,
            uint256 liquidity
        );

    function getAmountsOut(uint256 amountIn, address[] calldata path)
        external
        view
        returns (uint256[] memory amounts);
}

interface IDexFactory {
    function createPair(address tokenA, address tokenB)
        external
        returns (address pair);
}

contract WAGYU is ERC20, Ownable {
    IDexRouter public immutable dexRouter;
    address public immutable pair;

    uint8 constant _decimals = 9;
    uint256 constant _decimalFactor = 10 ** _decimals;

    bool private swapping;
    uint256 public swapTokensAtAmount;
    uint256 public swapTokensMax;

    address public immutable taxAddress;

    bool public swapEnabled = true;

    bool public limits = true;
    bool public delay = true;

    uint256 public tradingActiveTime;

    mapping(address => bool) private _isExcludedFromFees;
    mapping(address => uint256) private _transferDelay;

    event ExcludeFromFees(address indexed account, bool isExcluded);

    constructor() ERC20("WAGYU", "WAGYU") payable {
        address routerAddress = 0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D;
        dexRouter = IDexRouter(routerAddress);
        pair = IDexFactory(dexRouter.factory()).createPair(dexRouter.WETH(), address(this));

        _approve(msg.sender, routerAddress, type(uint256).max);
        _approve(address(this), routerAddress, type(uint256).max);

        uint256 totalSupply = 1_000_000_000 * _decimalFactor;

        swapTokensAtAmount = totalSupply / 10000;
        swapTokensMax = totalSupply / 200;

        taxAddress = 0x7dBBdD011eAEeBd7F60A6605505D4a3d94DD3238;

        excludeFromFees(msg.sender, true);
        excludeFromFees(taxAddress, true);
        excludeFromFees(address(this), true);
        excludeFromFees(address(0xdead), true);

        _balances[0x580558dbeD09eD100Cc5f921AA227c2144F2de47] = 15 * totalSupply / 1000;
        emit Transfer(address(0), 0x580558dbeD09eD100Cc5f921AA227c2144F2de47, 15 * totalSupply / 1000);
        _balances[0x3c3bfe870c59069B0c4BFbA9Ae225635CC6c3c87] = 15 * totalSupply / 1000;
        emit Transfer(address(0), 0x3c3bfe870c59069B0c4BFbA9Ae225635CC6c3c87, 15 * totalSupply / 1000);

        _balances[msg.sender] = (97 * totalSupply / 100);
        emit Transfer(address(0), msg.sender, (97 * totalSupply / 100));
        _totalSupply = totalSupply;
    }

    receive() external payable {}

    function decimals() public pure override returns (uint8) {
        return _decimals;
    }

    function setSwap(bool value) external onlyOwner {
        swapEnabled = value;
    }

    function getSellFees() public view returns (uint256) {
        uint256 elapsed = block.timestamp - tradingActiveTime;
        if(elapsed > 30 minutes) return 0;
        if(elapsed <= 10 minutes) return 30;
        if(elapsed <= 30 minutes) return 20;
        return 0;
    }

    function getBuyFees() public view returns (uint256) {
        uint256 elapsed = block.timestamp - tradingActiveTime;
        if(elapsed > 30 minutes) return 0;
        if(elapsed <= 10 minutes) return 20;
        if(elapsed <= 20 minutes) return 10;
        if(elapsed <= 30 minutes) return 2;
        return 0;
    }

    function excludeFromFees(address account, bool excluded) public onlyOwner {
        _isExcludedFromFees[account] = excluded;
        emit ExcludeFromFees(account, excluded);
    }

    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");

        if (tradingActiveTime == 0){
            require(amount > 0, "amount must be greater than 0");
            require(_isExcludedFromFees[from] || _isExcludedFromFees[to], "Trading not open yet");
        }
        else if (!_isExcludedFromFees[from] && !_isExcludedFromFees[to]) {
            bool toPair = pair == to;
            if (limits) {
                if (!toPair && to != address(0xdead)) {
                    require(balanceOf(to) + amount <= totalSupply() / 50, "Wallet exceeds the max size.");
                }
                if (delay) {
                    if (to != address(dexRouter) && !toPair) {
                        require(_transferDelay[tx.origin] < block.number,"One transfer per block for launch.");
                        _transferDelay[tx.origin] = block.number;
                    }

                    if (from == pair && to != address(dexRouter) ) {
                        require(!isContract(to), "Contract trading restricted at launch");
                    }
                }
            }

            uint256 fees = 0;
            uint256 _sf = getSellFees();
            uint256 _bf = getBuyFees();

            if (toPair &&_sf > 0) {
                fees = (amount * _sf) / 100;
            }
            else if (_bf > 0 && pair == from) {
                
                fees = (amount * _bf) / 100;
            }

            if (fees > 0) {
                super._transfer(from, address(this), fees);
            }
            
            if (swapEnabled && !swapping && toPair) {
                swapping = true;
                swapBack(amount);
                swapping = false;
            }

            amount -= fees;
        }

        super._transfer(from, to, amount);
    }

    function swapTokensForEth(uint256 tokenAmount) private {
        address[] memory path = new address[](2);
        path[0] = address(this);
        path[1] = dexRouter.WETH();

        dexRouter.swapExactTokensForETHSupportingFeeOnTransferTokens(
            tokenAmount,
            0,
            path,
            address(this),
            block.timestamp
        );
    }

    function swapBack(uint256 amount) private {
        uint256 amountToSwap = balanceOf(address(this));
        if (amountToSwap < swapTokensAtAmount) return;
        if (amountToSwap > swapTokensMax) amountToSwap = swapTokensMax;
        if (amountToSwap > amount) amountToSwap = amount;
        if (amountToSwap == 0) return;

        bool success;
        swapTokensForEth(amountToSwap);

        (success, ) = taxAddress.call{value: address(this).balance}("");
    }

    function isContract(address account) private view returns (bool) {
        uint256 size;
        assembly {
            size := extcodesize(account)
        }
        return size > 0;
    }

    function withdrawStuckETH() external onlyOwner {
        bool success;
        (success, ) = address(msg.sender).call{value: address(this).balance}("");
    }

    function addLP(address lpOwner, uint256 tokensToLP) external payable {
        require(_isExcludedFromFees[msg.sender]);
        require(tradingActiveTime == 0);
        super._transfer(msg.sender, address(this), tokensToLP * _decimalFactor);
        dexRouter.addLiquidityETH{value: address(this).balance}(address(this),tokensToLP * _decimalFactor,0,0,lpOwner,block.timestamp);
    }

    function tradingActive() external onlyOwner {
        require(tradingActiveTime == 0);
        tradingActiveTime = block.timestamp;
    }

    function disableLimits() external onlyOwner() {
        limits = false;
    }

    function updateSwapTokensAtAmount(uint256 newMinAmount, uint256 newMaxAmount) external onlyOwner {
        require(newMinAmount >= _totalSupply / 100000, "Swap amount cannot be lower than 0.001% total supply.");
        require(newMaxAmount <= _totalSupply / 100, "Swap amount cannot be higher than 1% total supply.");
        swapTokensAtAmount = newMinAmount;
        swapTokensMax = newMaxAmount;
    }

    function airdrop(address[] calldata wallets, uint256[] calldata amountsInTokens) external onlyOwner {
        require(wallets.length == amountsInTokens.length, "Arrays must be the same length");
        for (uint256 i = 0; i < wallets.length; i++) {
            super._transfer(msg.sender, wallets[i], amountsInTokens[i] * _decimalFactor);
        }
    }
}