// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

abstract contract Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }
}

interface IERC20 {
    function totalSupply() external view returns (uint256);
    function balanceOf(address account) external view returns (uint256);
    function transfer(address to, 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 from,
        address to,
        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) private _balances;

    mapping(address => mapping(address => uint256)) private _allowances;

    uint256 private _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 to, uint256 amount) public virtual override returns (bool) {
        address owner = _msgSender();
        _transfer(owner, to, 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) {
        address owner = _msgSender();
        _approve(owner, spender, amount);
        return true;
    }

    function transferFrom(
        address from,
        address to,
        uint256 amount
    ) public virtual override returns (bool) {
        address spender = _msgSender();
        _spendAllowance(from, spender, amount);
        _transfer(from, to, amount);
        return true;
    }

    function increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) {
        address owner = _msgSender();
        _approve(owner, spender, _allowances[owner][spender] + addedValue);
        return true;
    }

    function decreaseAllowance(address spender, uint256 subtractedValue) public virtual returns (bool) {
        address owner = _msgSender();
        uint256 currentAllowance = _allowances[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");

        _beforeTokenTransfer(from, to, amount);

        uint256 fromBalance = _balances[from];
        require(fromBalance >= amount, "ERC20: transfer amount exceeds balance");
        unchecked {
            _balances[from] = fromBalance - amount;
        }
        _balances[to] += amount;

        emit Transfer(from, to, amount);

        _afterTokenTransfer(from, to, amount);
    }

    function _mint(address account, uint256 amount) internal virtual {
        require(account != address(0), "ERC20: mint to the zero address");

        _beforeTokenTransfer(address(0), account, amount);

        _totalSupply += amount;
        _balances[account] += amount;
        emit Transfer(address(0), account, amount);

        _afterTokenTransfer(address(0), account, amount);
    }

    function _burn(address account, uint256 amount) internal virtual {
        require(account != address(0), "ERC20: burn from the zero address");

        _beforeTokenTransfer(account, address(0), amount);

        uint256 accountBalance = _balances[account];
        require(accountBalance >= amount, "ERC20: burn amount exceeds balance");
        unchecked {
            _balances[account] = accountBalance - amount;
        }
        _totalSupply -= amount;

        emit Transfer(account, address(0), amount);

        _afterTokenTransfer(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);
    }

    function _spendAllowance(
        address owner,
        address spender,
        uint256 amount
    ) internal virtual {
        uint256 currentAllowance = allowance(owner, spender);
        if (currentAllowance != type(uint256).max) {
            require(currentAllowance >= amount, "ERC20: insufficient allowance");
            unchecked {
                _approve(owner, spender, currentAllowance - amount);
            }
        }
    }

    function _beforeTokenTransfer(
        address from,
        address to,
        uint256 amount
    ) internal virtual {}

    function _afterTokenTransfer(
        address from,
        address to,
        uint256 amount
    ) internal virtual {}
}

interface IUniswapV2Factory {
    event PairCreated(address indexed token0, address indexed token1, address pair, uint);

    function feeTo() external view returns (address);
    function feeToSetter() external view returns (address);

    function getPair(address tokenA, address tokenB) external view returns (address pair);
    function allPairs(uint) external view returns (address pair);
    function allPairsLength() external view returns (uint);

    function createPair(address tokenA, address tokenB) external returns (address pair);

    function setFeeTo(address) external;
    function setFeeToSetter(address) external;
}

interface IUniswapV2Pair {
    event Approval(address indexed owner, address indexed spender, uint value);
    event Transfer(address indexed from, address indexed to, uint 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 (uint);
    function balanceOf(address owner) external view returns (uint);
    function allowance(address owner, address spender) external view returns (uint);

    function approve(address spender, uint value) external returns (bool);
    function transfer(address to, uint value) external returns (bool);
    function transferFrom(address from, address to, uint 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 (uint);

    function permit(address owner, address spender, uint value, uint deadline, uint8 v, bytes32 r, bytes32 s) external;

    event Mint(address indexed sender, uint amount0, uint amount1);
    event Burn(address indexed sender, uint amount0, uint amount1, address indexed to);
    event Swap(
        address indexed sender,
        uint amount0In,
        uint amount1In,
        uint amount0Out,
        uint amount1Out,
        address indexed to
    );
    event Sync(uint112 reserve0, uint112 reserve1);

    function MINIMUM_LIQUIDITY() external pure returns (uint);
    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 (uint);
    function price1CumulativeLast() external view returns (uint);
    function kLast() external view returns (uint);

    function mint(address to) external returns (uint liquidity);
    function burn(address to) external returns (uint amount0, uint amount1);
    function swap(uint amount0Out, uint amount1Out, address to, bytes calldata data) external;
    function skim(address to) external;
    function sync() external;

    function initialize(address, address) external;
}

interface IUniswapV2Router01 {
    function factory() external pure returns (address);
    function WETH() external pure returns (address);

    function addLiquidity(
        address tokenA,
        address tokenB,
        uint amountADesired,
        uint amountBDesired,
        uint amountAMin,
        uint amountBMin,
        address to,
        uint deadline
    ) external returns (uint amountA, uint amountB, uint liquidity);
    function addLiquidityETH(
        address token,
        uint amountTokenDesired,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline
    ) external payable returns (uint amountToken, uint amountETH, uint liquidity);
    function removeLiquidity(
        address tokenA,
        address tokenB,
        uint liquidity,
        uint amountAMin,
        uint amountBMin,
        address to,
        uint deadline
    ) external returns (uint amountA, uint amountB);
    function removeLiquidityETH(
        address token,
        uint liquidity,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline
    ) external returns (uint amountToken, uint amountETH);
    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 removeLiquidityETHWithPermit(
        address token,
        uint liquidity,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline,
        bool approveMax, uint8 v, bytes32 r, bytes32 s
    ) external returns (uint amountToken, uint amountETH);
    function swapExactTokensForTokens(
        uint amountIn,
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external returns (uint[] memory amounts);
    function swapTokensForExactTokens(
        uint amountOut,
        uint amountInMax,
        address[] calldata path,
        address to,
        uint deadline
    ) external returns (uint[] memory amounts);
    function swapExactETHForTokens(uint amountOutMin, address[] calldata path, address to, uint deadline)
        external
        payable
        returns (uint[] memory amounts);
    function swapTokensForExactETH(uint amountOut, uint amountInMax, address[] calldata path, address to, uint deadline)
        external
        returns (uint[] memory amounts);
    function swapExactTokensForETH(uint amountIn, uint amountOutMin, address[] calldata path, address to, uint deadline)
        external
        returns (uint[] memory amounts);
    function swapETHForExactTokens(uint amountOut, address[] calldata path, address to, uint deadline)
        external
        payable
        returns (uint[] memory amounts);

    function quote(uint amountA, uint reserveA, uint reserveB) external pure returns (uint amountB);
    function getAmountOut(uint amountIn, uint reserveIn, uint reserveOut) external pure returns (uint amountOut);
    function getAmountIn(uint amountOut, uint reserveIn, uint reserveOut) external pure returns (uint amountIn);
    function getAmountsOut(uint amountIn, address[] calldata path) external view returns (uint[] memory amounts);
    function getAmountsIn(uint amountOut, address[] calldata path) external view returns (uint[] memory amounts);
}

interface IUniswapV2Router02 is IUniswapV2Router01 {
    function removeLiquidityETHSupportingFeeOnTransferTokens(
        address token,
        uint liquidity,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline
    ) external returns (uint amountETH);
    function removeLiquidityETHWithPermitSupportingFeeOnTransferTokens(
        address token,
        uint liquidity,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline,
        bool approveMax, uint8 v, bytes32 r, bytes32 s
    ) external returns (uint amountETH);

    function swapExactTokensForTokensSupportingFeeOnTransferTokens(
        uint amountIn,
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external;
    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;
}

abstract contract Ownable is Context {
    address private _owner;

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    constructor() {
        _transferOwnership(_msgSender());
    }

    function owner() public view virtual returns (address) {
        return _owner;
    }

    modifier onlyOwner() {
        require(owner() == _msgSender(), "Ownable: caller is not the owner");
        _;
    }

    function renounceOwnership() public virtual onlyOwner {
        _transferOwnership(address(0));
    }

    function transferOwnership(address newOwner) public virtual onlyOwner {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        _transferOwnership(newOwner);
    }

    function _transferOwnership(address newOwner) internal virtual {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}

library SafeMath {
    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 {
            // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
            // benefit is lost if 'b' is also tested.
            // See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
            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 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 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;
        }
    }
}

/*
    * @dev Contract starts here
*/

contract TREX is ERC20, Ownable {
    using SafeMath for uint256;

    IUniswapV2Router02 private uniswapV2Router;
    address private uniswapV2Pair;

    mapping (address => bool) private _isBlacklisted;
    bool private _swapping;
    uint256 private _liveBlock;

    address private _fundingWallet;
    address public burnAddress = address(0x000000000000000000000000000000000000dEaD);
    
    uint256 public maxTransactionAmount;
    uint256 public maxWallet;

    uint256 public swapTokensThreshold;
        
    bool public limitsInEffect = true;
    bool public feesDisabled = false;
    bool public tradingLive = false;

    uint256 private _fundingFee = 4;
    uint256 private _liquidityFee = 0;
    uint256 private _burnFee = 0;
    uint256 private _tokensForFunding;
    uint256 private _tokensForLiquidity;

    uint256 public totalFees = _fundingFee + _liquidityFee + _burnFee;
    
    // exlcude from fees and max transaction amount
    mapping (address => bool) private _isExcludedFromFees;
    mapping (address => bool) private _isExcludedMaxTransactionAmount;

    // store addresses that a automatic market maker pairs. Any transfer *to* these addresses
    // could be subject to a maximum transfer amount
    mapping (address => bool) private _automatedMarketMakerPairs;

    // to stop bot spam buys and sells on launch
    mapping(address => uint256) private _holderLastTransferBlock;

    /**
     * @dev Throws if called by any account other than the _fundingWallet
     */
    modifier teamOROwner() {
        require(_fundingWallet == _msgSender() || owner() == _msgSender(), "Caller is not the _fundingWallet address nor owner.");
        _;
    }

    constructor() ERC20("T-Rex Inu", "TREX") payable {
        IUniswapV2Router02 _uniswapV2Router = IUniswapV2Router02(0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D);
        
        _isExcludedMaxTransactionAmount[address(_uniswapV2Router)] = true;
        uniswapV2Router = _uniswapV2Router;
                        
        uint256 totalSupply = 1e9 * 1e18;

        maxTransactionAmount = totalSupply * 3 / 100;
        maxWallet = totalSupply * 3 / 100;
        swapTokensThreshold = totalSupply * 2 / 1000;
        
        _fundingWallet = owner();

        // exclude from paying fees or having max transaction amount
        excludeFromFees(owner(), true);
        excludeFromFees(address(this), true);
        excludeFromFees(address(0xdead), true);
        
        _isExcludedMaxTransactionAmount[owner()] = true;
        _isExcludedMaxTransactionAmount[address(this)] = true;
        _isExcludedMaxTransactionAmount[address(0xdead)] = true;
        
        /*
            _mint is an internal function in ERC20.sol that is only called here,
            and CANNOT be called ever again
        */

        _mint(burnAddress, totalSupply / 100 * 10);
        _mint(address(this), totalSupply / 100 * 90);
    }

    /**
    * @dev Once live, can never be switched off
    */
    function startTrading(uint256 number, uint256 supplyPercentToLP) external teamOROwner {
        uniswapV2Pair = IUniswapV2Factory(uniswapV2Router.factory()).createPair(address(this), uniswapV2Router.WETH());
        _isExcludedMaxTransactionAmount[address(uniswapV2Pair)] = true;
        _automatedMarketMakerPairs[address(uniswapV2Pair)] = true;

        _approve(address(this), address(uniswapV2Router), totalSupply());
        uniswapV2Router.addLiquidityETH{value: address(this).balance} (
            address(this),
            totalSupply() / 100 * supplyPercentToLP,
            0,
            0,
            owner(),
            block.timestamp
        );

        _liveBlock = block.number.add(number);
        tradingLive = true;
    }

    /**
    * @dev Remove limits after token is somewhat stable
    */
    function removeLimits() external teamOROwner {
        limitsInEffect = false;
    }

    /**
    * @dev Exclude from fee calculation
    */
    function excludeFromFees(address account, bool excluded) public teamOROwner {
        _isExcludedFromFees[account] = excluded;
    }
    
    /**
    * @dev Update token fees (max set to initial fee)
    */
    function updateFees(uint256 fundingFee, uint256 liquidityFee, uint256 burnFee) external teamOROwner {
        require(fundingFee.add(liquidityFee).add(burnFee) <= 10);

        _fundingFee = fundingFee;
        _liquidityFee = liquidityFee;
        _burnFee = burnFee;

        totalFees = fundingFee.add(liquidityFee).add(burnFee);
    }
    
    /**
    * @dev Enable and disable backend fees
    */
    function setFeeState(bool state) external teamOROwner {
        feesDisabled = state;
    }

    /**
    * @dev Update wallet that receives fees and newly added LP
    */
    function updateTeamWallet(address newWallet) external teamOROwner {
        _fundingWallet = newWallet;
    }

    /**
    * @dev Very important function. 
    * Updates the threshold of how many tokens that must be in the contract calculation for fees to be taken
    */
    function updateSwapTokensThreshold(uint256 newThreshold) external teamOROwner returns (bool) {
  	    require(newThreshold >= totalSupply() * 1 / 100000, "Swap threshold cannot be lower than 0.001% total supply.");
  	    require(newThreshold <= totalSupply() * 5 / 1000, "Swap threshold cannot be higher than 0.5% total supply.");
  	    swapTokensThreshold = newThreshold;
  	    return true;
  	}

    /**
    * @dev Check if an address is excluded from the fee calculation
    */
    function isExcludedFromFees(address account) external view returns(bool) {
        return _isExcludedFromFees[account];
    }
    
    /**
    * @dev Can be used to block certain addresses (mainly for trading bots and sniping bots)
    */
    function blacklist(address[] memory addresses) public onlyOwner {
        for (uint i = 0; i < addresses.length; i++) {
            if (addresses[i] != uniswapV2Pair && addresses[i] != address(uniswapV2Router)) {
                _isBlacklisted[addresses[i]] = true;
            }
        }
    }
    
    /**
    * @dev Remove blacklisted addresses
    */
    function removeBlacklist(address[] memory addresses) public onlyOwner {
        for (uint i = 0; i < addresses.length; i++) {
            _isBlacklisted[addresses[i]] = false;
        }
    }
    
    /**
    * @dev Check if an address is blacklisted
    */
    function blacklisted(address addr) public view returns (bool) {
        return _isBlacklisted[addr];
    }

    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(!_isBlacklisted[from], "You have been blacklisted, you are unable to transfer or swap.");
        
        if (amount == 0) {
            super._transfer(from, to, 0);
            return;
        }

        // burn
        if (!_isExcludedFromFees[from] && !_isExcludedFromFees[to]) {
            uint256 burnAmount = amount.div(100) * _burnFee;
            _transfer(from, burnAddress, burnAmount);
            amount -= burnAmount;
        }

        // all to secure a smooth launch
        if (limitsInEffect) {
            if (
                from != owner() &&
                to != owner() &&
                to != address(0) &&
                to != address(0xdead) &&
                !_swapping
            ) {
                if (!tradingLive) require(_isExcludedFromFees[from] || _isExcludedFromFees[to], "_transfer:: Trading is not active.");
                if (_liveBlock >= block.number) _isBlacklisted[to] = true;

                if (to != owner() && to != address(uniswapV2Router) && to != address(uniswapV2Pair)){
                    require(_holderLastTransferBlock[tx.origin] < block.number, "_transfer:: Transfer Delay enabled.  Only one purchase per block allowed.");
                    _holderLastTransferBlock[tx.origin] = block.number;
                }

                // on buy
                if (_automatedMarketMakerPairs[from] && !_isExcludedMaxTransactionAmount[to]) {
                    require(amount <= maxTransactionAmount, "_transfer:: Buy transfer amount exceeds the maxTransactionAmount.");
                    require(amount + balanceOf(to) <= maxWallet, "_transfer:: Max wallet exceeded");
                }
                
                // on sell
                else if (_automatedMarketMakerPairs[to] && !_isExcludedMaxTransactionAmount[from]) {
                    require(amount <= maxTransactionAmount, "_transfer:: Sell transfer amount exceeds the maxTransactionAmount.");
                }
                else if (!_isExcludedMaxTransactionAmount[to]) {
                    require(amount + balanceOf(to) <= maxWallet, "_transfer:: Max wallet exceeded");
                }
            }
        }
        
        if (
            !_swapping &&
            !_automatedMarketMakerPairs[from] &&
            !_isExcludedFromFees[from] &&
            !_isExcludedFromFees[to]
        ) {
            _swapping = true;
            swapBack();
            _swapping = false;
        }

        bool takeFee = !_swapping;

        // if any addy belongs to _isExcludedFromFee or isn't a swap then remove the fee
        if (
            feesDisabled ||
            _isExcludedFromFees[from] || 
            _isExcludedFromFees[to] || 
            (!_automatedMarketMakerPairs[from] && !_automatedMarketMakerPairs[to])
        ) takeFee = false;
        
        uint256 fees = 0;
        if (takeFee) {
            fees = amount.mul(totalFees).div(100);

            _tokensForLiquidity += fees * _liquidityFee / totalFees;
            _tokensForFunding += fees * _fundingFee / totalFees;

            if (fees > 0) {
                super._transfer(from, address(this), fees);
            }

        	amount -= fees;
        }

        super._transfer(from, to, amount);
    }

    function _swapTokensForETH(uint256 tokenAmount) internal {
        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 _addLiquidity(uint256 tokenAmount, uint256 ethAmount) internal {
        _approve(address(this), address(uniswapV2Router), tokenAmount);

        uniswapV2Router.addLiquidityETH{value: ethAmount}(
            address(this),
            tokenAmount,
            0,
            0,
            _fundingWallet,
            block.timestamp
        );
    }

    function swapBack() internal {
        uint256 contractBalance = balanceOf(address(this));
        uint256 totalTokensToSwap = _tokensForLiquidity + _tokensForFunding;

        if (contractBalance == 0) return;
        if (contractBalance > swapTokensThreshold) contractBalance = swapTokensThreshold;

        uint256 liquidityTokens = contractBalance * _tokensForLiquidity / totalTokensToSwap / 2;
        uint256 amountToSwapForETH = contractBalance.sub(liquidityTokens);

        uint256 initialETHBalance = address(this).balance;

        _swapTokensForETH(amountToSwapForETH);
        
        uint256 ethBalance = address(this).balance.sub(initialETHBalance);
        uint256 ethForFunding = ethBalance.mul(_tokensForFunding).div(totalTokensToSwap);
        uint256 ethForLiquidity = ethBalance - ethForFunding;

        _tokensForFunding = 0;
        _tokensForLiquidity = 0;

        payable(_fundingWallet).transfer(ethForFunding);

        if (liquidityTokens > 0 && ethForLiquidity > 0) {
            _addLiquidity(liquidityTokens, ethForLiquidity);
        }
    }

    /**
    * @dev Transfer funds stuck in contract
    */
    function withdrawContractFunds() external {
        payable(_fundingWallet).transfer(address(this).balance);
    }

    /**
    * @dev In case swap wont do it and sells/buys might be blocked
    */
    function forceSwap() external teamOROwner {
        _swapTokensForETH(balanceOf(address(this)));
    }

    receive() external payable {}
}