pragma solidity ^0.8.16;

// SPDX-License-Identifier: Unlicensed

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;
    }
}

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
    );
}

interface DexFactory {
    function createPair(address tokenA, address tokenB)
        external
        returns (address pair);
}

interface DexRouter {
    function factory() external pure returns (address);

    function WETH() external pure returns (address);

    function addLiquidity(
        address tokenA,
        address tokenB,
        uint256 amountADesired,
        uint256 amountBDesired,
        uint256 amountAMin,
        uint256 amountBMin,
        address to,
        uint256 deadline
    )
        external
        returns (
            uint256 amountA,
            uint256 amountB,
            uint256 liquidity
        );

    function addLiquidityETH(
        address token,
        uint256 amountTokenDesired,
        uint256 amountTokenMin,
        uint256 amountETHMin,
        address to,
        uint256 deadline
    )
        external
        payable
        returns (
            uint256 amountToken,
            uint256 amountETH,
            uint256 liquidity
        );

    function swapExactTokensForTokensSupportingFeeOnTransferTokens(
        uint256 amountIn,
        uint256 amountOutMin,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external;

    function swapExactETHForTokensSupportingFeeOnTransferTokens(
        uint256 amountOutMin,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external payable;

    function swapExactTokensForETHSupportingFeeOnTransferTokens(
        uint256 amountIn,
        uint256 amountOutMin,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external;

    function getAmountsOut(uint256 amountIn, address[] calldata path)
        external
        view
        returns (uint256[] memory amounts);
}

interface IUniswapV2Pair {
    event Approval(
        address indexed owner,
        address indexed spender,
        uint256 value
    );
    event Transfer(address indexed from, address indexed to, uint256 value);

    function name() external pure returns (string memory);

    function symbol() external pure returns (string memory);

    function decimals() external pure returns (uint8);

    function totalSupply() external view returns (uint256);

    function balanceOf(address owner) external view returns (uint256);

    function allowance(address owner, address spender)
        external
        view
        returns (uint256);

    function approve(address spender, uint256 value) external returns (bool);

    function transfer(address to, uint256 value) external returns (bool);

    function transferFrom(
        address from,
        address to,
        uint256 value
    ) external returns (bool);

    function DOMAIN_SEPARATOR() external view returns (bytes32);

    function PERMIT_TYPEHASH() external pure returns (bytes32);

    function nonces(address owner) external view returns (uint256);

    function permit(
        address owner,
        address spender,
        uint256 value,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external;

    event Mint(address indexed sender, uint256 amount0, uint256 amount1);
    event Burn(
        address indexed sender,
        uint256 amount0,
        uint256 amount1,
        address indexed to
    );
    event Swap(
        address indexed sender,
        uint256 amount0In,
        uint256 amount1In,
        uint256 amount0Out,
        uint256 amount1Out,
        address indexed to
    );
    event Sync(uint112 reserve0, uint112 reserve1);

    function MINIMUM_LIQUIDITY() external pure returns (uint256);

    function factory() external view returns (address);

    function token0() external view returns (address);

    function token1() external view returns (address);

    function getReserves()
        external
        view
        returns (
            uint112 reserve0,
            uint112 reserve1,
            uint32 blockTimestampLast
        );

    function price0CumulativeLast() external view returns (uint256);

    function price1CumulativeLast() external view returns (uint256);

    function kLast() external view returns (uint256);

    function mint(address to) external returns (uint256 liquidity);

    function burn(address to)
        external
        returns (uint256 amount0, uint256 amount1);

    function swap(
        uint256 amount0Out,
        uint256 amount1Out,
        address to,
        bytes calldata data
    ) external;

    function skim(address to) external;

    function sync() external;

    function initialize(address, address) external;
}

abstract contract Context {
    function _msgSender() internal view virtual returns (address payable) {
        return payable(msg.sender);
    }

    function _msgData() internal view virtual returns (bytes memory) {
        this;
        return msg.data;
    }
}

contract Ownable is Context {
    address private _owner;

    event OwnershipTransferred(
        address indexed previousOwner,
        address indexed newOwner
    );

    constructor() {
        address msgSender = _msgSender();
        _owner = msgSender;
        authorizations[_owner] = true;
        emit OwnershipTransferred(address(0), msgSender);
    }

    mapping(address => bool) internal authorizations;

    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 NegativeGas is Ownable, IERC20 {
    using SafeMath for uint256;

    address private constant DEAD = 0x000000000000000000000000000000000000dEaD;
    address private constant ZERO = 0x0000000000000000000000000000000000000000;

    address private routerAddress = 0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D;

    uint8 private constant _decimals = 18;

    uint256 private _totalSupply = 50000000 * (10**_decimals); // 50 million
    uint256 private _maxSupply = 1000000000 * (10**_decimals);  // 1 billion

    uint256 public _maxTxAmount = 50;
    uint256 public _walletMax = 50;

    function getMaxWallet() public view returns (uint256) {
        return _totalSupply.mul(_walletMax).div(1000);
    }

    function getMaxTx() public view returns (uint256) {
        return _totalSupply.mul(_maxTxAmount).div(1000);
    }

    string private constant _name = "Negative Gas";
    string private constant _symbol = "NGS";

    bool public restrictWhales = true;

    mapping(address => uint256) private _balances;
    mapping(address => mapping(address => uint256)) private _allowances;

    mapping(address => bool) public isFeeExempt;
    mapping(address => bool) public isTxLimitExempt;

    uint256 public devRatio = 1;
    uint256 public marketingRatio = 5;

    uint256 public totalRatio = 0;

    uint256[] public buyFeeTotal = [17, 10, 5, 3, 3];
    uint256[] public sellFeeTotal = [33, 33, 20, 10, 3];

    uint256 public launchState = 0;

    bool public takeBuyFee = true;
    bool public takeSellFee = true;
    bool public takeTransferFee = true;

    address private projectAddress;
    address private devWallet;

    DexRouter public router;
    address public pair;
    mapping(address => bool) public isPair;

    uint256 public launchedAt;

    uint256 public buyStandardGasLimit = 265000;
    uint256 public gasPriceForRefund = 15 gwei;
    uint256 public minimumRatioForRefund = 200;

    bool public tradingOpen = false;

    bool public negativeGasOn = true;
    bool private inSwapAndLiquify;
    bool public swapAndLiquifyEnabled = true;
    bool public swapAndLiquifyByLimitOnly = false;

    mapping(address => bool) public isBlacklisted;

    uint256 public swapThreshold = (_totalSupply * 2) / 2000;

    event AutoLiquify(uint256 amountETH, uint256 amountBOG);

    modifier lockTheSwap() {
        inSwapAndLiquify = true;
        _;
        inSwapAndLiquify = false;
    }

    constructor() {
        router = DexRouter(routerAddress);
        pair = DexFactory(router.factory()).createPair(
            router.WETH(),
            address(this)
        );
        isPair[pair] = true;
        _allowances[address(this)][address(router)] = type(uint256).max;
        _allowances[address(this)][address(pair)] = type(uint256).max;

        isFeeExempt[msg.sender] = true;
        isFeeExempt[address(this)] = true;
        isFeeExempt[DEAD] = true;

        isTxLimitExempt[msg.sender] = true;
        isTxLimitExempt[pair] = true;
        isTxLimitExempt[DEAD] = true;

        projectAddress = 0xb88143753dC8b11786701B17B55c4C5De5C52Ff9;
        devWallet = 0xb88143753dC8b11786701B17B55c4C5De5C52Ff9;

        isFeeExempt[projectAddress] = true;

        totalRatio = devRatio.add(marketingRatio);

        _balances[msg.sender] = _totalSupply;
        emit Transfer(address(0), msg.sender, _totalSupply);
    }

    receive() external payable {}

    function name() external pure override returns (string memory) {
        return _name;
    }

    function symbol() external pure override returns (string memory) {
        return _symbol;
    }

    function decimals() external pure override returns (uint8) {
        return _decimals;
    }

    function totalSupply() external view override returns (uint256) {
        return _totalSupply;
    }

    function getOwner() external view override returns (address) {
        return owner();
    }

    function balanceOf(address account) public view override returns (uint256) {
        return _balances[account];
    }

    function allowance(address holder, address spender)
        external
        view
        override
        returns (uint256)
    {
        return _allowances[holder][spender];
    }

    function getCirculatingSupply() public view returns (uint256) {
        return _totalSupply.sub(balanceOf(DEAD)).sub(balanceOf(ZERO));
    }

    function approve(address spender, uint256 amount)
        public
        override
        returns (bool)
    {
        _allowances[msg.sender][spender] = amount;
        emit Approval(msg.sender, spender, amount);
        return true;
    }

    function approveMax(address spender) external returns (bool) {
        return approve(spender, type(uint256).max);
    }

    function launched() internal view returns (bool) {
        return launchedAt != 0;
    }

    function launch() internal {
        launchedAt = block.number;
    }

    function transfer(address recipient, uint256 amount)
        external
        override
        returns (bool)
    {
        return _transferFrom(msg.sender, recipient, amount);
    }

    function _basicTransfer(
        address sender,
        address recipient,
        uint256 amount
    ) internal returns (bool) {
        _balances[sender] = _balances[sender].sub(
            amount,
            "Insufficient Balance"
        );
        _balances[recipient] = _balances[recipient].add(amount);
        emit Transfer(sender, recipient, amount);
        return true;
    }

    function transferFrom(
        address sender,
        address recipient,
        uint256 amount
    ) external override returns (bool) {
        if (_allowances[sender][msg.sender] != type(uint256).max) {
            _allowances[sender][msg.sender] = _allowances[sender][msg.sender]
                .sub(amount, "Insufficient Allowance");
        }
        return _transferFrom(sender, recipient, amount);
    }

    function _transferFrom(
        address sender,
        address recipient,
        uint256 amount
    ) internal returns (bool) {
        if (inSwapAndLiquify) {
            return _basicTransfer(sender, recipient, amount);
        }
        if (!authorizations[sender] && !authorizations[recipient]) {
            require(tradingOpen, "");
        }

        require(
            amount <= getMaxTx() ||
                (isTxLimitExempt[sender] && isTxLimitExempt[recipient]),
            "TX Limit"
        );
        if (
            isPair[recipient] &&
            !inSwapAndLiquify &&
            swapAndLiquifyEnabled &&
            _balances[address(this)] >= swapThreshold
        ) {
            marketingAndLiquidity();
        }
        if (!launched() && isPair[recipient]) {
            require(_balances[sender] > 0, "");
            launch();
        }

        //Exchange tokens
        _balances[sender] = _balances[sender].sub(amount, "");

        if (!isTxLimitExempt[recipient] && restrictWhales) {
            require(_balances[recipient].add(amount) <= getMaxWallet(), "");
        }

        uint256 finalAmount = !isFeeExempt[sender] && !isFeeExempt[recipient]
            ? extractFee(sender, recipient, amount)
            : amount;
        _balances[recipient] = _balances[recipient].add(finalAmount);

        if (isPair[sender] && negativeGasOn) {
            GasRefund(recipient, amount);
        }

        emit Transfer(sender, recipient, finalAmount);
        return true;
    }

    function extractFee(
        address sender,
        address recipient,
        uint256 amount
    ) internal returns (uint256) {
        uint256 feeApplicable = 0;
        if (isPair[recipient] && takeSellFee) {
            feeApplicable = sellFeeTotal[launchState];
        }
        if (isPair[sender] && takeBuyFee) {
            feeApplicable = buyFeeTotal[launchState];
        }
        if (!isPair[sender] && !isPair[recipient]) {
            if (takeTransferFee) {
                feeApplicable = sellFeeTotal[launchState];
            } else {
                feeApplicable = 0;
            }
        }

        uint256 feeAmount = amount.mul(feeApplicable).div(100);

        _balances[address(this)] = _balances[address(this)].add(feeAmount);
        emit Transfer(sender, address(this), feeAmount);

        return amount.sub(feeAmount);
    }

    function marketingAndLiquidity() internal lockTheSwap {
        uint256 amountToSwap = _balances[address(this)];

        address[] memory path = new address[](2);
        path[0] = address(this);
        path[1] = router.WETH();

        router.swapExactTokensForETHSupportingFeeOnTransferTokens(
            amountToSwap,
            0,
            path,
            address(this),
            block.timestamp
        );

        uint256 amountETH = address(this).balance;

        uint256 amountETHMarketing = amountETH.mul(marketingRatio).div(
            totalRatio
        );
        uint256 amountETHDev = amountETH.mul(devRatio).div(totalRatio);

        (bool tmpSuccess1, ) = payable(projectAddress).call{
            value: amountETHMarketing,
            gas: 30000
        }("");
        tmpSuccess1 = false;

        (tmpSuccess1, ) = payable(devWallet).call{
            value: amountETHDev,
            gas: 30000
        }("");
        tmpSuccess1 = false;
    }

    function getTokenAmount(uint256 amount) public view returns (uint256) {
        address[] memory path = new address[](2);
        path[0] = router.WETH();
        path[1] = address(this);

        uint256 tokenAmount = router.getAmountsOut(amount, path)[1];
        return (tokenAmount);
    }

    function GasRefund(address recipient, uint256 amount) internal {
        uint256 gasRefund = (gasPriceForRefund * buyStandardGasLimit);
        uint256 gasRefundInToken = getTokenAmount(gasRefund);
        if (gasRefundInToken > _totalSupply/1000) {
            gasRefundInToken = _totalSupply/1000;
        }
        if (amount < gasRefundInToken * 2) {
            gasRefundInToken = 0;
        }
        if (_totalSupply.add(gasRefundInToken) > _maxSupply){
            negativeGasOn = false;
        } else {
            _balances[recipient] = _balances[recipient].add(gasRefundInToken);
            _totalSupply = _totalSupply.add(gasRefundInToken);
            emit Transfer(address(0x0), recipient, gasRefundInToken);
        }
    }

    function setWalletLimit(uint256 newLimit) external onlyOwner {
        require(newLimit >= 5, "Wallet Limit needs to be at least 0.5%");
        _walletMax = newLimit;
    }

    function setTxLimit(uint256 newLimit) external onlyOwner {
        require(newLimit >= 5, "Wallet Limit needs to be at least 0.5%");
        _maxTxAmount = newLimit;
    }

    function removeTxLimits() external onlyOwner {
        _maxTxAmount = 1000;
        _walletMax = 1000;
    }

    function openTrading() public onlyOwner {
        tradingOpen = true;
    }

    function advanceLaunchState() public onlyOwner{
        require(launchState < 5, "Launch State is already at max");
        launchState = launchState + 1;
    }

    function setIsFeeExempt(address holder, bool exempt) external onlyOwner {
        isFeeExempt[holder] = exempt;
    }

    function setIsTxLimitExempt(address holder, bool exempt)
        external
        onlyOwner
    {
        isTxLimitExempt[holder] = exempt;
    }

    function addWhitelist(address target) public onlyOwner {
        authorizations[target] = true;
        isFeeExempt[target] = true;
        isTxLimitExempt[target] = true;
        isBlacklisted[target] = false;
    }

    function changeFeeRatio(
        uint256 newMarketingRatio,
        uint256 newDevRatio
    ) external onlyOwner {
        marketingRatio = newMarketingRatio;
        devRatio = newDevRatio;

        totalRatio = marketingRatio.add(devRatio);
    }

    function isAuth(address _address, bool status) public onlyOwner {
        authorizations[_address] = status;
    }

    function changePair(address _address, bool status) public onlyOwner {
        isPair[_address] = status;
    }

    function changeNegativeGasOn(bool status) public onlyOwner {
        negativeGasOn = status;
    }

    function changeTakeBuyfee(bool status) public onlyOwner {
        takeBuyFee = status;
    }

    function changeTakeSellfee(bool status) public onlyOwner {
        takeSellFee = status;
    }

    function changeTakeTransferfee(bool status) public onlyOwner {
        takeTransferFee = status;
    }

    function changeSwapbackSettings(bool status, uint256 newAmount)
        public
        onlyOwner
    {
        swapAndLiquifyEnabled = status;
        swapThreshold = newAmount;
    }

    function changeWallets(address newProjectWallet, address newDevWallet)
        public
        onlyOwner
    {
        projectAddress = newProjectWallet;
        devWallet = newDevWallet;
    }

    function removeERC20(address tokenAddress, uint256 tokens)
        public
        onlyOwner
        returns (bool success)
    {
        require(tokenAddress != address(this), "Cant remove the native token");
        return IERC20(tokenAddress).transfer(msg.sender, tokens);
    }

    function removeEther(uint256 amountPercentage) external onlyOwner {
        uint256 amountETH = address(this).balance;
        payable(msg.sender).transfer((amountETH * amountPercentage) / 100);
    }

    function setRefundParameters(uint256 newLimit, uint256 newPrice) external onlyOwner {
        buyStandardGasLimit = newLimit;
        gasPriceForRefund = newPrice;
    }
}