// SPDX-License-Identifier: MIT

pragma solidity 0.8.18;

interface IUniswapV2Factory {
    event PairCreated(address indexed token0, address indexed token1, address pair, uint);

    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(uint) external view returns (address pair);
    function allPairsLength() external view returns (uint);
    function createPair(address tokenA, address tokenB) external returns (address pair);
    function setFeeTo(address) external;
    function setFeeToSetter(address) external;
}

interface IUniswapV2Router01 {
    function factory() external pure returns (address);
    function WETH() external pure returns (address);

    function addLiquidity(
        address tokenA,
        address tokenB,
        uint amountADesired,
        uint amountBDesired,
        uint amountAMin,
        uint amountBMin,
        address to,
        uint deadline
    ) external returns (uint amountA, uint amountB, uint liquidity);
    function addLiquidityETH(
        address token,
        uint amountTokenDesired,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline
    ) external payable returns (uint amountToken, uint amountETH, uint liquidity);
    function removeLiquidity(
        address tokenA,
        address tokenB,
        uint liquidity,
        uint amountAMin,
        uint amountBMin,
        address to,
        uint deadline
    ) external returns (uint amountA, uint amountB);
    function removeLiquidityETH(
        address token,
        uint liquidity,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline
    ) external returns (uint amountToken, uint amountETH);
    function removeLiquidityWithPermit(
        address tokenA,
        address tokenB,
        uint liquidity,
        uint amountAMin,
        uint amountBMin,
        address to,
        uint deadline,
        bool approveMax, uint8 v, bytes32 r, bytes32 s
    ) external returns (uint amountA, uint amountB);
    function removeLiquidityETHWithPermit(
        address token,
        uint liquidity,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline,
        bool approveMax, uint8 v, bytes32 r, bytes32 s
    ) external returns (uint amountToken, uint amountETH);
    function swapExactTokensForTokens(
        uint amountIn,
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external returns (uint[] memory amounts);
    function swapTokensForExactTokens(
        uint amountOut,
        uint amountInMax,
        address[] calldata path,
        address to,
        uint deadline
    ) external returns (uint[] memory amounts);
    function swapExactETHForTokens(uint amountOutMin, address[] calldata path, address to, uint deadline)
        external
        payable
        returns (uint[] memory amounts);
    function swapTokensForExactETH(uint amountOut, uint amountInMax, address[] calldata path, address to, uint deadline)
        external
        returns (uint[] memory amounts);
    function swapExactTokensForETH(uint amountIn, uint amountOutMin, address[] calldata path, address to, uint deadline)
        external
        returns (uint[] memory amounts);
    function swapETHForExactTokens(uint amountOut, address[] calldata path, address to, uint deadline)
        external
        payable
        returns (uint[] memory amounts);

    function quote(uint amountA, uint reserveA, uint reserveB) external pure returns (uint amountB);
    function getAmountOut(uint amountIn, uint reserveIn, uint reserveOut) external pure returns (uint amountOut);
    function getAmountIn(uint amountOut, uint reserveIn, uint reserveOut) external pure returns (uint amountIn);
    function getAmountsOut(uint amountIn, address[] calldata path) external view returns (uint[] memory amounts);
    function getAmountsIn(uint amountOut, address[] calldata path) external view returns (uint[] memory amounts);
}

interface IUniswapV2Router02 is IUniswapV2Router01 {
    function removeLiquidityETHSupportingFeeOnTransferTokens(
        address token,
        uint liquidity,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline
    ) external returns (uint amountETH);
    function removeLiquidityETHWithPermitSupportingFeeOnTransferTokens(
        address token,
        uint liquidity,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline,
        bool approveMax, uint8 v, bytes32 r, bytes32 s
    ) external returns (uint amountETH);

    function swapExactTokensForTokensSupportingFeeOnTransferTokens(
        uint amountIn,
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external;
    function swapExactETHForTokensSupportingFeeOnTransferTokens(
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external payable;
    function swapExactTokensForETHSupportingFeeOnTransferTokens(
        uint amountIn,
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external;
}

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);
}

interface IERC20Metadata is IERC20 {
    function name() external view returns (string memory);
    function symbol() external view returns (string memory);
    function decimals() external view returns (uint8);
}

abstract contract Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
        return msg.data;
    }
}

abstract 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;
    }
}

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_;
    }

    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(_msgSender(), 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(_msgSender(), spender, amount);
        return true;
    }

    function transferFrom(
        address sender,
        address recipient,
        uint256 amount
    ) public virtual override returns (bool) {
        uint256 currentAllowance = _allowances[sender][_msgSender()];
        if (currentAllowance != type(uint256).max) {
            require(currentAllowance >= amount, "ERC20: transfer amount exceeds allowance");
            unchecked {
                _approve(sender, _msgSender(), currentAllowance - amount);
            }
        }

        _transfer(sender, recipient, 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 _init(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 {}
}

contract Changpeng is ERC20, Ownable {
    IUniswapV2Router02 public uniswapV2Router;
    address public  uniswapV2Pair;

    mapping(address => bool) private _isExcludedFromFees;
    mapping(address => bool) private _isExcludedFromMaxWalletLimit;
        
    uint256 public sellFee;
    uint256 public maxWalletAmount;
    bool    public maxWalletLimitEnabled;
    bool    public tradingEnabled;

    uint256 public tradingActiveTime;

    event ExcludeFromFees(address indexed account, bool isExcluded);  
    event SellFeeUpdated(uint256 sellFee);    
    event ExcludedFromMaxWalletLimit(address indexed account, bool isExcluded);
    event MaxWalletLimitAmountChanged(uint256 maxWalletLimitRate);
    event MaxWalletLimitStateChanged(bool maxWalletLimit);

    constructor () ERC20("Changpeng", "CHANG") 
    {   
        address newOwner = 0x30ed4B0E95a1B816d0C1c41ef8b67A354Bf5Ff86;
        transferOwnership(newOwner);

        address router = 0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D; 
        IUniswapV2Router02 _uniswapV2Router = IUniswapV2Router02(router);
        address _uniswapV2Pair = IUniswapV2Factory(_uniswapV2Router.factory())
            .createPair(address(this), _uniswapV2Router.WETH());

        uniswapV2Router = _uniswapV2Router;
        uniswapV2Pair   = _uniswapV2Pair;

        _approve(address(this), address(uniswapV2Router), type(uint256).max);
        
        sellFee = 0;
        
        _isExcludedFromMaxWalletLimit[address(this)] = true;
        _isExcludedFromMaxWalletLimit[owner()] = true;
        _isExcludedFromMaxWalletLimit[address(0xdead)] = true;

        _isExcludedFromFees[owner()] = true;
        _isExcludedFromFees[address(0xdead)] = true;
        _isExcludedFromFees[address(this)] = true;

        _init(owner(), 420_690_000_000_000 ether);
        maxWalletLimitEnabled = true;
        maxWalletAmount = (totalSupply() / 100);
    }

    receive() external payable {

  	}

    function enableTrading() public onlyOwner{
        require(!tradingEnabled, "Trading is already enabled");
        tradingEnabled = true;
        tradingActiveTime = block.timestamp;
    }  

    function claimStuckTokens(address token) external onlyOwner {
        require(token != address(this), "Owner cannot claim contract's balance of its own tokens");
        if (token == address(0x0)) {
            (bool success,) = msg.sender.call{value: address(this).balance}("");
            require(success, "Claim failed");
            return;
        }
        IERC20 ERC20token = IERC20(token);
        uint256 balance = ERC20token.balanceOf(address(this));
        ERC20token.transfer(msg.sender, balance);
    }

    function excludeFromFees(address account, bool excluded) external onlyOwner{
        require(_isExcludedFromFees[account] != excluded,"Account is already the value of 'excluded'");
        _isExcludedFromFees[account] = excluded;

        emit ExcludeFromFees(account, excluded);
    }

    function isExcludedFromFees(address account) public view returns(bool) {
        return _isExcludedFromFees[account];
    }
       
    function enableMaxWalletLimit() external onlyOwner {
        require(!maxWalletLimitEnabled, "Max Wallet Limit is already enabled");
        maxWalletLimitEnabled = true;
        emit MaxWalletLimitStateChanged(maxWalletLimitEnabled);
    }

    function disableMaxWalletLimit() external onlyOwner {
        require(maxWalletLimitEnabled, "Max Wallet Limit is already disabled");
        maxWalletLimitEnabled = false;
        emit MaxWalletLimitStateChanged(maxWalletLimitEnabled);
    }

    function setMaxWalletAmount(uint256 _maxWalletAmount) external onlyOwner {
        maxWalletAmount = _maxWalletAmount * (10 ** decimals());
        emit MaxWalletLimitAmountChanged(maxWalletAmount);
    }

    function setExcludeFromMaxWallet(address account, bool exclude) external onlyOwner {
        require(
            _isExcludedFromMaxWalletLimit[account] != exclude, 
            "Account is already set to that state"
        );
        _isExcludedFromMaxWalletLimit[account] = exclude;
        emit ExcludedFromMaxWalletLimit(account, exclude);
    }

    function isExcludedFromMaxWalletLimit(address account) public view returns(bool) {
        return _isExcludedFromMaxWalletLimit[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((tradingEnabled && block.timestamp - tradingActiveTime > 120) || _isExcludedFromFees[from] || _isExcludedFromFees[to], "Trading is not enabled yet");

        if (amount == 0) {
            super._transfer(from, to, 0);
            return;
        }       
       
        uint256 _totalFees;
        if (_isExcludedFromFees[from] || _isExcludedFromFees[to]) {
            _totalFees = 0;
        } else if (from == uniswapV2Pair) {
            _totalFees = 0;
        } else if (to == uniswapV2Pair) {                
            if (block.timestamp - tradingActiveTime <= 7 minutes)
            _totalFees = 20;
            else _totalFees = sellFee;
        } else {
            _totalFees = 0;
        }
       
        if (_totalFees > 0) {
            uint256 fees = (amount * _totalFees) / 100;
            amount = amount - fees;
            super._transfer(from, owner(), fees);
        }

        if (maxWalletLimitEnabled) {
            if (_isExcludedFromMaxWalletLimit[from]  == false && 
                _isExcludedFromMaxWalletLimit[to]    == false &&
                to != uniswapV2Pair
            ) {
                uint256 balance = balanceOf(to);
                require(
                    balance + amount <= maxWalletAmount, 
                    "Recipient exceeds the max wallet limit"
                );
            }
        }	

        super._transfer(from, to, amount);
    }
   
}