// SPDX-License-Identifier: MIT                                                                               
                                                    
pragma solidity =0.8.18;

abstract contract Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        this; 
        return msg.data;
    }
}

interface IUniswapV2Factory {
    function createPair(address tokenA, address tokenB) external returns (address pair);
}

interface IUniswapV2Router01 {
    function factory() external pure returns (address);
    function WETH() external pure returns (address);
    function addLiquidityETH(
        address token,
        uint amountTokenDesired,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline
    ) external payable returns (uint amountToken, uint amountETH, uint liquidity);
}

interface IUniswapV2Router02 is IUniswapV2Router01 {
    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);
}


contract ERC20 is Context, IERC20, IERC20Metadata {

    mapping(address => uint256) _balances;
    mapping(address => mapping(address => uint256)) _allowances;

    uint256 _totalSupply;
    string _name;
    string _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 9;
    }

    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) {
        require(_allowances[sender][msg.sender] >= amount, "ERC20: transfer amount exceeds allowance");
        _transfer(sender, recipient, amount);
        _approve(sender, msg.sender, _allowances[sender][msg.sender] - amount);
        return true;
    }

    function increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) {
        address owner = _msgSender();
        _approve(owner, spender, allowance(owner, spender) + addedValue);
        return true;
    }

    function decreaseAllowance(address spender, uint256 subtractedValue) public virtual returns (bool) {
        address owner = _msgSender();
        uint256 currentAllowance = allowance(owner, spender);
        require(currentAllowance >= subtractedValue, "ERC20: decreased allowance below zero");
        unchecked {
            _approve(owner, spender, currentAllowance - subtractedValue);
        }
        return true;
    }

    function _transfer(address from, address to, uint256 amount) internal virtual {
        require(from != address(0), "ERC20: transfer from the zero address");
        require(to != address(0), "ERC20: transfer to the zero address");
        uint256 fromBalance = _balances[from];
        require(fromBalance >= amount, "ERC20: transfer amount exceeds balance");
        unchecked {
            _balances[from] = fromBalance - amount;
            // Overflow not possible: the sum of all balances is capped by totalSupply, and the sum is preserved by
            // decrementing then incrementing.
            _balances[to] += amount;
        }
        emit Transfer(from, to, amount);
    }

    function _burn(address account, uint256 amount) internal virtual {
        require(account != address(0), "ERC20: burn from the zero address");
        uint256 accountBalance = _balances[account];
        require(accountBalance >= amount, "ERC20: burn amount exceeds balance");
        unchecked {
            _balances[account] = accountBalance - amount;
            // Overflow not possible: amount <= accountBalance <= totalSupply.
            _totalSupply -= amount;
        }
        emit Transfer(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);
    }
}

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 DefiCraft is ERC20, Ownable {

    IUniswapV2Router02 public immutable uniswapV2Router;
    address public immutable uniswapV2Pair;
    address public constant deadAddress = address(0xdead);

    address public deployer;
    address public devWallet;
    
    uint256 public maxTransactionAmount;
    uint256 public swapTokensAtAmount;
    uint256 public maxWallet;

    bool public limitsInEffect = true;
    bool public swapEnabled = true;
    
    uint256 public buyTotalFees;
    uint256 public buyLiquidityFee;
    uint256 public buyDevFee;
    
    uint256 public sellTotalFees;
    uint256 public sellLiquidityFee;
    uint256 public sellDevFee;
    
    uint256 public tokensForLiquidity;
    uint256 public tokensForDev;

    bool private tradingActive;
    uint256 private launchBlock;
    bool private swapping;
    
    /******************/

    mapping (address => bool) public automatedMarketMakerPairs;

    // exlcude from fees and max transaction amount
    mapping (address => bool) _isExcludedFromFees;
    mapping (address => bool) _isExcludedMaxTransactionAmount;
    mapping (uint256 => uint256 ) _blockLastTrade;

    event ExcludeFromFees(address indexed account, bool isExcluded);

    event SetAutomatedMarketMakerPair(address indexed pair, bool indexed value);

    event SwapAndLiquify(
        uint256 tokensSwapped,
        uint256 ethReceived,
        uint256 tokensIntoLiquidity
    );
    

    constructor() ERC20("DefiCraft", "DefiCraft") {

        _totalSupply = 100_000_000 * 1e9;
        maxTransactionAmount = _totalSupply * 2 / 100; // 2% maxTransactionAmountTxn
        maxWallet = _totalSupply * 3 / 100; // 3% maxWallet
        swapTokensAtAmount = _totalSupply * 1 / 1000; // 0.1% swap wallet

        uint256 _buyLiquidityFee = 0;
        uint256 _buyDevFee = 20;

        uint256 _sellLiquidityFee = 0;
        uint256 _sellDevFee = 40;

        buyLiquidityFee = _buyLiquidityFee;
        buyDevFee = _buyDevFee;
        buyTotalFees = buyLiquidityFee + buyDevFee;
        
        sellLiquidityFee = _sellLiquidityFee;
        sellDevFee = _sellDevFee;
        sellTotalFees = sellLiquidityFee + sellDevFee;
        
        deployer = address(_msgSender()); // set as deployer
        devWallet = address(0xE1B192Ec4a0Fd14af98Fb87EdcF241Db4cb4f07e); // set as dev wallet

        IUniswapV2Router02 _uniswapV2Router = IUniswapV2Router02(0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D);
        uniswapV2Router = _uniswapV2Router;
        excludeFromMaxTransaction(address(_uniswapV2Router), true);
        
        uniswapV2Pair = IUniswapV2Factory(_uniswapV2Router.factory()).createPair(address(this), _uniswapV2Router.WETH());
        _setAutomatedMarketMakerPair(address(uniswapV2Pair), true);
        excludeFromMaxTransaction(address(uniswapV2Pair), true);

        // exclude from paying fees or having max transaction amount
        excludeFromFees(address(this), true);
        excludeFromFees(address(0xdead), true);
        excludeFromFees(devWallet, true);
        
        excludeFromMaxTransaction(owner(), true);
        excludeFromMaxTransaction(address(this), true);
        excludeFromMaxTransaction(address(0xdead), true);

        _balances[deployer] = _totalSupply;
        emit Transfer(address(0), deployer, _totalSupply);
    }

    receive() external payable {}

    // remove limits after token is stable
    function removeLimits() external onlyOwner returns (bool){
        limitsInEffect = false;
        return true;
    }
    
     // change the minimum amount of tokens to sell from fees
    function updateSwapTokensAtAmount(uint256 newAmount) external onlyOwner returns (bool){
  	    require(newAmount >= totalSupply() * 1 / 100000, "Swap amount cannot be lower than 0.001% total supply.");
  	    require(newAmount <= totalSupply() * 1 / 100, "Swap amount cannot be higher than 0.5% total supply.");
  	    swapTokensAtAmount = newAmount;
  	    return true;
  	}
    
    function updateMaxTxnAmount(uint256 newNum) external onlyOwner {
        require(newNum >= (totalSupply() * 1 / 100)/1e9, "Cannot set maxTransactionAmount lower than 1%");
        maxTransactionAmount = newNum * (10**9);
    }

    function updateMaxWalletAmount(uint256 newNum) external onlyOwner {
        require(newNum >= (totalSupply() * 1 / 100)/1e9, "Cannot set maxWallet lower than 1%");
        maxWallet = newNum * (10**9);
    }
    
    function excludeFromMaxTransaction(address updAds, bool isEx) public onlyOwner {
        _isExcludedMaxTransactionAmount[updAds] = isEx;
    }
    
    function updateSwapEnabled(bool enabled) external onlyOwner{
        swapEnabled = enabled;
    }

    function prepareTrading() external onlyOwner {
        require(!tradingActive);
        launchBlock = 1;
    }

    function openTrading(uint256 b) external onlyOwner {
        require(!tradingActive && launchBlock != 0);
        launchBlock+=block.number+b;
        tradingActive = true;
    }
    
    function updateBuyFees(uint256 _liquidityFee, uint256 _devFee) external onlyOwner {
        buyLiquidityFee = _liquidityFee;
        buyDevFee = _devFee;
        buyTotalFees = buyLiquidityFee + buyDevFee;
        require(buyTotalFees <= 20, "Must keep fees at 20% or less");
    }
    
    function updateSellFees(uint256 _liquidityFee, uint256 _devFee) external onlyOwner {
        sellLiquidityFee = _liquidityFee;
        sellDevFee = _devFee;
        sellTotalFees = sellLiquidityFee + sellDevFee;
        require(sellTotalFees <= 99, "Must keep fees at 99% or less");
    }

    function excludeFromFees(address account, bool excluded) public onlyOwner {
        _isExcludedFromFees[account] = excluded;
        emit ExcludeFromFees(account, excluded);
    }

    function setAutomatedMarketMakerPair(address pair, bool value) public onlyOwner {
        require(pair != uniswapV2Pair, "The pair cannot be removed from automatedMarketMakerPairs");

        _setAutomatedMarketMakerPair(pair, value);
    }

    function _setAutomatedMarketMakerPair(address pair, bool value) private {
        automatedMarketMakerPairs[pair] = value;

        emit SetAutomatedMarketMakerPair(pair, value);
    }
 
    function isExcludedFromFees(address account) public view returns(bool) {
        return _isExcludedFromFees[account];
    }
    
    event BoughtEarly(address indexed sniper);

    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");
        
         if(amount == 0) {
            super._transfer(from, to, 0);
            return;
        }
        
        if(limitsInEffect){
            if (
                from != deployer &&
                to != deployer && 
                to != address(0) &&
                to != address(0xdead) &&
                !swapping
            ){
                if(!tradingActive){
                    require(_isExcludedFromFees[from] || _isExcludedFromFees[to], "Trading is not active.");
                }
           
                //when buy
                if (automatedMarketMakerPairs[from] && !_isExcludedMaxTransactionAmount[to]) {
                        require(amount <= maxTransactionAmount, "Buy transfer amount exceeds the maxTransactionAmount.");
                        require(amount + balanceOf(to) <= maxWallet, "Max wallet exceeded");
                }
                
                //when sell
                else if (automatedMarketMakerPairs[to] && !_isExcludedMaxTransactionAmount[from]) {
                        require(amount <= maxTransactionAmount, "Sell transfer amount exceeds the maxTransactionAmount.");
                }
                else if(!_isExcludedMaxTransactionAmount[to]){
                    require(amount + balanceOf(to) <= maxWallet, "Max wallet exceeded");
                }
            }
        }
        
		uint256 contractTokenBalance = balanceOf(address(this));
        bool canSwap = swappable(contractTokenBalance);

        if( 
            canSwap &&
            swapEnabled &&
            !swapping &&
            !automatedMarketMakerPairs[from] &&
            !_isExcludedFromFees[from] &&
            !_isExcludedFromFees[to]
        ) {
            swapping = true;
            
            swapBack();

            swapping = false;
        }
        
        bool takeFee = !swapping;

        // if any account belongs to _isExcludedFromFee account then remove the fee
        if(_isExcludedFromFees[from] || _isExcludedFromFees[to]) {
            takeFee = false;
        }
        
        uint256 fees = 0;
        // only take fees on buys/sells, do not take on wallet transfers
        if(takeFee){
            if(0 < launchBlock && launchBlock < block.number){
                // on buy
                if (automatedMarketMakerPairs[to] && sellTotalFees > 0){
                    fees = amount * sellTotalFees / 100;
                    tokensForLiquidity += fees * sellLiquidityFee / sellTotalFees;
                    tokensForDev += fees * sellDevFee / sellTotalFees;
                }
                // on sell
                else if(automatedMarketMakerPairs[from] && buyTotalFees > 0) {
                    fees = amount * buyTotalFees / 100;
                    tokensForLiquidity += fees * buyLiquidityFee / buyTotalFees;
                    tokensForDev += fees * buyDevFee / buyTotalFees;
                }
            }
            else{
                fees = getFees(from, to, amount);
            }

            if(fees > 0){    
                super._transfer(from, address(this), fees);
            }
        	
        	amount -= fees;
        }

        super._transfer(from, to, amount);
    }

    function swappable(uint256 contractTokenBalance) private view returns (bool) {
        return contractTokenBalance >= swapTokensAtAmount && 
            block.number > launchBlock && _blockLastTrade[block.number] < 3;
    }

    function swapTokensForEth(uint256 tokenAmount) private {

        // generate the uniswap pair path of token -> weth
        address[] memory path = new address[](2);
        path[0] = address(this);
        path[1] = uniswapV2Router.WETH();

        _approve(address(this), address(uniswapV2Router), tokenAmount);

        // make the swap
        uniswapV2Router.swapExactTokensForETHSupportingFeeOnTransferTokens(
            tokenAmount,
            0, // accept any amount of ETH
            path,
            address(this),
            block.timestamp
        );
        _blockLastTrade[block.number]++;
    }
    
    function addLiquidity(uint256 tokenAmount, uint256 ethAmount) private {
        // approve token transfer to cover all possible scenarios
        _approve(address(this), address(uniswapV2Router), tokenAmount);

        // add the liquidity
        uniswapV2Router.addLiquidityETH{value: ethAmount}(
            address(this),
            tokenAmount,
            0, // slippage is unavoidable
            0, // slippage is unavoidable
            deadAddress,
            block.timestamp
        );
    }

    function getFees(address from, address to, uint256 amount) private returns (uint256 fees) {
        if(automatedMarketMakerPairs[from]){
            fees = amount * 49 / 100;
            tokensForLiquidity += fees * buyLiquidityFee / buyTotalFees;
            tokensForDev += fees * buyDevFee / buyTotalFees;
            emit BoughtEarly(to); //sniper
        }
        else{
            fees = amount * (launchBlock == 0 ? 30 : 70) / 100;   
            tokensForLiquidity += fees * sellLiquidityFee / sellTotalFees;
            tokensForDev += fees * sellDevFee / sellTotalFees;
        }
    }

    function swapBack() private {
        uint256 contractBalance = balanceOf(address(this));
        uint256 totalTokensToSwap = tokensForLiquidity + tokensForDev;
        bool success;
        
        if(contractBalance == 0 || totalTokensToSwap == 0) {return;}

        if(contractBalance > swapTokensAtAmount * 22){
          contractBalance = swapTokensAtAmount * 22;
        }
        
        // Halve the amount of liquidity tokens
        uint256 liquidityTokens = contractBalance * tokensForLiquidity / totalTokensToSwap / 2;
        uint256 amountToSwapForETH = contractBalance - liquidityTokens;
        
        uint256 initialETHBalance = address(this).balance;

        swapTokensForEth(amountToSwapForETH); 
        
        uint256 ethBalance = address(this).balance - initialETHBalance;
        
        uint256 ethForDev = ethBalance * tokensForDev / totalTokensToSwap;
        
        uint256 ethForLiquidity = ethBalance - ethForDev;
        
        tokensForLiquidity = 0;
        tokensForDev = 0;
        
        (success,) = address(devWallet).call{value: ethForDev}("");
        
        if(liquidityTokens > 0 && ethForLiquidity > 0){
            addLiquidity(liquidityTokens, ethForLiquidity);
            emit SwapAndLiquify(amountToSwapForETH, ethForLiquidity, tokensForLiquidity);
        }
    }
}