/** 
    YieldFi DAO - YieldFi

*/


// SPDX-License-Identifier: MIT

pragma solidity 0.8.9;

abstract contract Context {
    function _msgSender() internal view virtual returns (address payable) {
        return payable(msg.sender);
    }

    function _msgData() internal view virtual returns (bytes memory) {
        this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
        return msg.data;
    }
}

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
    );
}

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;
        // assert(a == b * c + a % b); // There is no case in which this doesn't hold

        return c;
    }

    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        return mod(a, b, "SafeMath: modulo by zero");
    }

    function mod(
        uint256 a,
        uint256 b,
        string memory errorMessage
    ) internal pure returns (uint256) {
        require(b != 0, errorMessage);
        return a % b;
    }
}

library Address {
    function isContract(address account) internal view returns (bool) {
        // According to EIP-1052, 0x0 is the value returned for not-yet created accounts
        // and 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470 is returned
        // for accounts without code, i.e. `keccak256('')`
        bytes32 codehash;
        bytes32 accountHash = 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470;
        // solhint-disable-next-line no-inline-assembly
        assembly {
            codehash := extcodehash(account)
        }
        return (codehash != accountHash && codehash != 0x0);
    }

    function sendValue(address payable recipient, uint256 amount) internal {
        require(
            address(this).balance >= amount,
            "Address: insufficient balance"
        );

        // solhint-disable-next-line avoid-low-level-calls, avoid-call-value
        (bool success, ) = recipient.call{value: amount}("");
        require(
            success,
            "Address: unable to send value, recipient may have reverted"
        );
    }

    function functionCall(address target, bytes memory data)
        internal
        returns (bytes memory)
    {
        return functionCall(target, data, "Address: low-level call failed");
    }

    function functionCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        return _functionCallWithValue(target, data, 0, errorMessage);
    }

    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value
    ) internal returns (bytes memory) {
        return
            functionCallWithValue(
                target,
                data,
                value,
                "Address: low-level call with value failed"
            );
    }

    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value,
        string memory errorMessage
    ) internal returns (bytes memory) {
        require(
            address(this).balance >= value,
            "Address: insufficient balance for call"
        );
        return _functionCallWithValue(target, data, value, errorMessage);
    }

    function _functionCallWithValue(
        address target,
        bytes memory data,
        uint256 weiValue,
        string memory errorMessage
    ) private returns (bytes memory) {
        require(isContract(target), "Address: call to non-contract");

        (bool success, bytes memory returndata) = target.call{value: weiValue}(
            data
        );
        if (success) {
            return returndata;
        } else {
            if (returndata.length > 0) {
                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}

contract Ownable is Context {
    address private _owner;
    address private _previousOwner;
    uint256 private _lockTime;

    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;
    }

    function getUnlockTime() public view returns (uint256) {
        return _lockTime;
    }

    function getTime() public view returns (uint256) {
        return block.timestamp;
    }
}


interface IUniswapV2Factory {
    event PairCreated(
        address indexed token0,
        address indexed token1,
        address pair,
        uint256
    );

    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(uint256) external view returns (address pair);

    function allPairsLength() external view returns (uint256);

    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,
        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 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 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;
}

interface IUniswapV2Router01 {
    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 removeLiquidity(
        address tokenA,
        address tokenB,
        uint256 liquidity,
        uint256 amountAMin,
        uint256 amountBMin,
        address to,
        uint256 deadline
    ) external returns (uint256 amountA, uint256 amountB);

    function removeLiquidityETH(
        address token,
        uint256 liquidity,
        uint256 amountTokenMin,
        uint256 amountETHMin,
        address to,
        uint256 deadline
    ) external returns (uint256 amountToken, uint256 amountETH);

    function removeLiquidityWithPermit(
        address tokenA,
        address tokenB,
        uint256 liquidity,
        uint256 amountAMin,
        uint256 amountBMin,
        address to,
        uint256 deadline,
        bool approveMax,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external returns (uint256 amountA, uint256 amountB);

    function removeLiquidityETHWithPermit(
        address token,
        uint256 liquidity,
        uint256 amountTokenMin,
        uint256 amountETHMin,
        address to,
        uint256 deadline,
        bool approveMax,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external returns (uint256 amountToken, uint256 amountETH);

    function swapExactTokensForTokens(
        uint256 amountIn,
        uint256 amountOutMin,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external returns (uint256[] memory amounts);

    function swapTokensForExactTokens(
        uint256 amountOut,
        uint256 amountInMax,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external returns (uint256[] memory amounts);

    function swapExactETHForTokens(
        uint256 amountOutMin,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external payable returns (uint256[] memory amounts);

    function swapTokensForExactETH(
        uint256 amountOut,
        uint256 amountInMax,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external returns (uint256[] memory amounts);

    function swapExactTokensForETH(
        uint256 amountIn,
        uint256 amountOutMin,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external returns (uint256[] memory amounts);

    function swapETHForExactTokens(
        uint256 amountOut,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external payable returns (uint256[] memory amounts);

    function quote(
        uint256 amountA,
        uint256 reserveA,
        uint256 reserveB
    ) external pure returns (uint256 amountB);

    function getAmountOut(
        uint256 amountIn,
        uint256 reserveIn,
        uint256 reserveOut
    ) external pure returns (uint256 amountOut);

    function getAmountIn(
        uint256 amountOut,
        uint256 reserveIn,
        uint256 reserveOut
    ) external pure returns (uint256 amountIn);

    function getAmountsOut(uint256 amountIn, address[] calldata path)
        external
        view
        returns (uint256[] memory amounts);

    function getAmountsIn(uint256 amountOut, address[] calldata path)
        external
        view
        returns (uint256[] memory amounts);
}

interface IUniswapV2Router02 is IUniswapV2Router01 {
    function removeLiquidityETHSupportingFeeOnTransferTokens(
        address token,
        uint256 liquidity,
        uint256 amountTokenMin,
        uint256 amountETHMin,
        address to,
        uint256 deadline
    ) external returns (uint256 amountETH);

    function removeLiquidityETHWithPermitSupportingFeeOnTransferTokens(
        address token,
        uint256 liquidity,
        uint256 amountTokenMin,
        uint256 amountETHMin,
        address to,
        uint256 deadline,
        bool approveMax,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external returns (uint256 amountETH);

    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;
}

contract YieldFiDAO is Context, IERC20, Ownable {
    using SafeMath for uint256;
    using Address for address;

    address payable public marketingAddress = payable(0xB478F98351622ba52470d5e009f7683F3c37cFE6); // Marketing Address

    address payable public liquidityAddress =
        payable(0xB478F98351622ba52470d5e009f7683F3c37cFE6); // Liquidity Address

    mapping(address => uint256) private _rOwned;
    mapping(address => uint256) private _tOwned;
    mapping(address => mapping(address => uint256)) private _allowances;

    mapping(address => bool) private _isExcludedFromFee;

    mapping(address => bool) private _isExcluded;
    address[] private _excluded;

    uint256 private constant MAX = ~uint256(0);
    uint256 private constant _tTotal = 1 * 1e9 * 1e18;
    uint256 private _rTotal = (MAX - (MAX % _tTotal));
    uint256 private _tFeeTotal;

    string private constant _name = "YieldFi DAO";
    string private constant _symbol = "YieldFi";
    uint8 private constant _decimals = 18;

    uint256 private constant BUY = 1;
    uint256 private constant SELL = 2;
    uint256 private constant TRANSFER = 3;
    uint256 private buyOrSellSwitch;

    // these values are pretty much arbitrary since they get overwritten for every txn, but the placeholders make it easier to work with current contract.
    uint256 private _taxFee;
    uint256 private _previousTaxFee = _taxFee;

    uint256 private _liquidityFee;
    uint256 private _previousLiquidityFee = _liquidityFee;

    uint256 public _buyTaxFee = 2;
    uint256 public _buyLiquidityFee = 2;
    uint256 public _buyMarketingFee = 6;

    uint256 public _sellTaxFee = 15;
    uint256 public _sellLiquidityFee = 10;
    uint256 public _sellMarketingFee = 75;


    bool public limitsInEffect = false;
    bool public tradingActive = true;
    bool public swapEnabled = false;

    mapping (address => bool) public _isExcludedMaxTransactionAmount;

     // Anti-bot and anti-whale mappings and variables
    mapping(address => uint256) private _holderLastTransferTimestamp; // to hold last Transfers temporarily during launch
    bool public transferDelayEnabled = true;

    uint256 private _liquidityTokensToSwap;
    uint256 private _marketingTokensToSwap;

    bool private gasLimitActive = true;
    uint256 private gasPriceLimit = 602 * 1 gwei;

    // store addresses that a automatic market maker pairs. Any transfer *to* these addresses
    // could be subject to a maximum transfer amount
    mapping (address => bool) public automatedMarketMakerPairs;

    uint256 public minimumTokensBeforeSwap;
    uint256 public maxTransactionAmount;
    uint256 public maxWallet;

    IUniswapV2Router02 public uniswapV2Router;
    address public uniswapV2Pair;

    bool inSwapAndLiquify;
    bool public swapAndLiquifyEnabled = true;

    event RewardLiquidityProviders(uint256 tokenAmount);
    event SwapAndLiquifyEnabledUpdated(bool enabled);
    event SwapAndLiquify(
        uint256 tokensSwapped,
        uint256 ethReceived,
        uint256 tokensIntoLiqudity
    );

    event SwapETHForTokens(uint256 amountIn, address[] path);

    event SwapTokensForETH(uint256 amountIn, address[] path);

    event ExcludedMaxTransactionAmount(address indexed account, bool isExcluded);

    modifier lockTheSwap() {
        inSwapAndLiquify = true;
        _;
        inSwapAndLiquify = false;
    }

    constructor() {
        address newOwner = msg.sender; // update if auto-deploying to a different wallet
        address futureOwner = address(msg.sender); // use if ownership will be transferred after deployment.

        maxTransactionAmount = _tTotal * 5 / 1000; // 0.5% max txn
        minimumTokensBeforeSwap = _tTotal * 5 / 10000; // 0.05%
        maxWallet = _tTotal * 1 / 100; // 1%

        _rOwned[newOwner] = _rTotal;

        IUniswapV2Router02 _uniswapV2Router = IUniswapV2Router02(
            // ROPSTEN or HARDHAT
            0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D
        );

        address _uniswapV2Pair = IUniswapV2Factory(_uniswapV2Router.factory())
            .createPair(address(this), _uniswapV2Router.WETH());

        uniswapV2Router = _uniswapV2Router;
        uniswapV2Pair = _uniswapV2Pair;

        marketingAddress = payable(msg.sender); // update to marketing address
        liquidityAddress = payable(address(0xdead)); // update to a liquidity wallet if you don't want to burn LP tokens generated by the contract.

        _setAutomatedMarketMakerPair(_uniswapV2Pair, true);

        _isExcludedFromFee[newOwner] = true;
        _isExcludedFromFee[futureOwner] = true; // pre-exclude future owner wallet
        _isExcludedFromFee[address(this)] = true;
        _isExcludedFromFee[liquidityAddress] = true;

        excludeFromMaxTransaction(newOwner, true);
        excludeFromMaxTransaction(futureOwner, true); // pre-exclude future owner wallet
        excludeFromMaxTransaction(address(this), true);
        excludeFromMaxTransaction(address(_uniswapV2Router), true);
        excludeFromMaxTransaction(address(0xdead), true);

        emit Transfer(address(0), newOwner, _tTotal);
    }

    function name() external pure returns (string memory) {
        return _name;
    }

    function symbol() external pure returns (string memory) {
        return _symbol;
    }

    function decimals() external pure returns (uint8) {
        return _decimals;
    }

    function totalSupply() external pure override returns (uint256) {
        return _tTotal;
    }

    function balanceOf(address account) public view override returns (uint256) {
        if (_isExcluded[account]) return _tOwned[account];
        return tokenFromReflection(_rOwned[account]);
    }

    function transfer(address recipient, uint256 amount)
        external
        override
        returns (bool)
    {
        _transfer(_msgSender(), recipient, amount);
        return true;
    }

    function allowance(address owner, address spender)
        external
        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
    ) external override returns (bool) {
        _transfer(sender, recipient, amount);
        _approve(
            sender,
            _msgSender(),
            _allowances[sender][_msgSender()].sub(
                amount,
                "ERC20: transfer amount exceeds allowance"
            )
        );
        return true;
    }

    function increaseAllowance(address spender, uint256 addedValue)
        external
        virtual
        returns (bool)
    {
        _approve(
            _msgSender(),
            spender,
            _allowances[_msgSender()][spender].add(addedValue)
        );
        return true;
    }

    function decreaseAllowance(address spender, uint256 subtractedValue)
        external
        virtual
        returns (bool)
    {
        _approve(
            _msgSender(),
            spender,
            _allowances[_msgSender()][spender].sub(
                subtractedValue,
                "ERC20: decreased allowance below zero"
            )
        );
        return true;
    }

    function isExcludedFromReward(address account)
        external
        view
        returns (bool)
    {
        return _isExcluded[account];
    }

    function totalFees() external view returns (uint256) {
        return _tFeeTotal;
    }

    // once enabled, can never be turned off
    function enableTrading() external onlyOwner {
        tradingActive = true;
        swapAndLiquifyEnabled = true;
        // tradingActiveBlock = block.number;
    }

    function minimumTokensBeforeSwapAmount() external view returns (uint256) {
        return minimumTokensBeforeSwap;
    }

    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;

        excludeFromMaxTransaction(pair, value);
        if(value){excludeFromReward(pair);}
        if(!value){includeInReward(pair);}
    }

    function setProtectionSettings(bool antiGas) external onlyOwner() {
        gasLimitActive = antiGas;
    }

    function setGasPriceLimit(uint256 gas) external onlyOwner {
        require(gas >= 300);
        gasPriceLimit = gas * 1 gwei;
    }

    // disable Transfer delay
    function disableTransferDelay() external onlyOwner returns (bool){
        transferDelayEnabled = false;
        return true;
    }

    function reflectionFromToken(uint256 tAmount, bool deductTransferFee)
        external
        view
        returns (uint256)
    {
        require(tAmount <= _tTotal, "Amount must be less than supply");
        if (!deductTransferFee) {
            (uint256 rAmount, , , , , ) = _getValues(tAmount);
            return rAmount;
        } else {
            (, uint256 rTransferAmount, , , , ) = _getValues(tAmount);
            return rTransferAmount;
        }
    }

    // for one-time airdrop feature after contract launch
    function airdropToWallets(address[] memory airdropWallets, uint256[] memory amount) external onlyOwner() {
        require(airdropWallets.length == amount.length, "airdropToWallets:: Arrays must be the same length");
        removeAllFee();
        buyOrSellSwitch = TRANSFER;
        for(uint256 i = 0; i < airdropWallets.length; i++){
            address wallet = airdropWallets[i];
            uint256 airdropAmount = amount[i];
            _tokenTransfer(msg.sender, wallet, airdropAmount);
        }
        restoreAllFee();
    }

    // remove limits after token is stable - 30-60 minutes
    function removeLimits() external onlyOwner returns (bool){
        limitsInEffect = false;
        gasLimitActive = false;
        transferDelayEnabled = false;
        return true;
    }

    function tokenFromReflection(uint256 rAmount)
        public
        view
        returns (uint256)
    {
        require(
            rAmount <= _rTotal,
            "Amount must be less than total reflections"
        );
        uint256 currentRate = _getRate();
        return rAmount.div(currentRate);
    }

    function excludeFromReward(address account) public onlyOwner {
        require(!_isExcluded[account], "Account is already excluded");
        require(_excluded.length + 1 <= 50, "Cannot exclude more than 50 accounts.  Include a previously excluded address.");
        if (_rOwned[account] > 0) {
            _tOwned[account] = tokenFromReflection(_rOwned[account]);
        }
        _isExcluded[account] = true;
        _excluded.push(account);
    }

    function excludeFromMaxTransaction(address updAds, bool isEx) public onlyOwner {
        _isExcludedMaxTransactionAmount[updAds] = isEx;
        emit ExcludedMaxTransactionAmount(updAds, isEx);
    }

    function includeInReward(address account) public onlyOwner {
        require(_isExcluded[account], "Account is not excluded");
        for (uint256 i = 0; i < _excluded.length; i++) {
            if (_excluded[i] == account) {
                _excluded[i] = _excluded[_excluded.length - 1];
                _tOwned[account] = 0;
                _isExcluded[account] = false;
                _excluded.pop();
                break;
            }
        }
    }

    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");

        if(!tradingActive){
            require(_isExcludedFromFee[from] || _isExcludedFromFee[to], "Trading is not active yet.");
        }

        if(limitsInEffect){
            if (
                from != owner() &&
                to != owner() &&
                to != address(0) &&
                to != address(0xdead) &&
                !inSwapAndLiquify
            ){

                // only use to prevent sniper buys in the first blocks.
                if (gasLimitActive && automatedMarketMakerPairs[from]) {
                    require(tx.gasprice <= gasPriceLimit, "Gas price exceeds limit.");
                }

                // at launch if the transfer delay is enabled, ensure the block timestamps for purchasers is set -- during launch.
                if (transferDelayEnabled){
                    if (to != owner() && to != address(uniswapV2Router) && to != address(uniswapV2Pair)){
                        require(_holderLastTransferTimestamp[tx.origin] < block.number, "_transfer:: Transfer Delay enabled.  Only one purchase per block allowed.");
                        _holderLastTransferTimestamp[tx.origin] = block.number;
                    }
                }

                //when buy
                if (automatedMarketMakerPairs[from] && !_isExcludedMaxTransactionAmount[to]) {
                    require(amount <= maxTransactionAmount, "Buy transfer amount exceeds the maxTransactionAmount.");
                    require(amount + balanceOf(to) <= maxWallet, "Cannot exceed max wallet");
                }
                //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, "Cannot exceed max wallet");
                }
            }
        }

        uint256 contractTokenBalance = balanceOf(address(this));
        bool overMinimumTokenBalance = contractTokenBalance >=
            minimumTokensBeforeSwap;

        // Sell tokens for ETH
        if (
            !inSwapAndLiquify &&
            swapAndLiquifyEnabled &&
            balanceOf(uniswapV2Pair) > 0 &&
            overMinimumTokenBalance &&
            automatedMarketMakerPairs[to]
        ) {
            swapBack();
        }

        removeAllFee();

        buyOrSellSwitch = TRANSFER;

        // If any account belongs to _isExcludedFromFee account then remove the fee
        if (!_isExcludedFromFee[from] && !_isExcludedFromFee[to]) {
            // Buy
            if (automatedMarketMakerPairs[from]) {
                _taxFee = _buyTaxFee;
                _liquidityFee = _buyLiquidityFee + _buyMarketingFee;
                if(_liquidityFee > 0){
                    buyOrSellSwitch = BUY;
                }
            }
            // Sell
            else if (automatedMarketMakerPairs[to]) {
                _taxFee = _sellTaxFee;
                _liquidityFee = _sellLiquidityFee + _sellMarketingFee;
                if(_liquidityFee > 0){
                    buyOrSellSwitch = SELL;
                }
            }
        }

        _tokenTransfer(from, to, amount);

        restoreAllFee();

    }

    function swapBack() private lockTheSwap {
        uint256 contractBalance = balanceOf(address(this));
        bool success;
        uint256 totalTokensToSwap = _liquidityTokensToSwap + _marketingTokensToSwap;
        if(totalTokensToSwap == 0 || contractBalance == 0) {return;}

        // Halve the amount of liquidity tokens
        uint256 tokensForLiquidity = (contractBalance * _liquidityTokensToSwap / totalTokensToSwap) / 2;
        uint256 amountToSwapForBNB = contractBalance.sub(tokensForLiquidity);

        uint256 initialBNBBalance = address(this).balance;

        swapTokensForBNB(amountToSwapForBNB);

        uint256 bnbBalance = address(this).balance.sub(initialBNBBalance);

        uint256 bnbForMarketing = bnbBalance.mul(_marketingTokensToSwap).div(totalTokensToSwap);

        uint256 bnbForLiquidity = bnbBalance - bnbForMarketing;

        _liquidityTokensToSwap = 0;
        _marketingTokensToSwap = 0;

        if(tokensForLiquidity > 0 && bnbForLiquidity > 0){
            addLiquidity(tokensForLiquidity, bnbForLiquidity);
            emit SwapAndLiquify(amountToSwapForBNB, bnbForLiquidity, tokensForLiquidity);
        }

        (success,) = address(marketingAddress).call{value: address(this).balance}("");

    }

    function swapTokensForBNB(uint256 tokenAmount) private {
        address[] memory path = new address[](2);
        path[0] = address(this);
        path[1] = uniswapV2Router.WETH();
        _approve(address(this), address(uniswapV2Router), tokenAmount);
        uniswapV2Router.swapExactTokensForETHSupportingFeeOnTransferTokens(
            tokenAmount,
            0, // accept any amount of ETH
            path,
            address(this),
            block.timestamp
        );
    }

    function addLiquidity(uint256 tokenAmount, uint256 ethAmount) private {
        _approve(address(this), address(uniswapV2Router), tokenAmount);
        uniswapV2Router.addLiquidityETH{value: ethAmount}(
            address(this),
            tokenAmount,
            0, // slippage is unavoidable
            0, // slippage is unavoidable
            liquidityAddress,
            block.timestamp
        );
    }

    function _tokenTransfer(
        address sender,
        address recipient,
        uint256 amount
    ) private {

        if (_isExcluded[sender] && !_isExcluded[recipient]) {
            _transferFromExcluded(sender, recipient, amount);
        } else if (!_isExcluded[sender] && _isExcluded[recipient]) {
            _transferToExcluded(sender, recipient, amount);
        } else if (_isExcluded[sender] && _isExcluded[recipient]) {
            _transferBothExcluded(sender, recipient, amount);
        } else {
            _transferStandard(sender, recipient, amount);
        }
    }

    function _transferStandard(
        address sender,
        address recipient,
        uint256 tAmount
    ) private {
        (
            uint256 rAmount,
            uint256 rTransferAmount,
            uint256 rFee,
            uint256 tTransferAmount,
            uint256 tFee,
            uint256 tLiquidity
        ) = _getValues(tAmount);
        _rOwned[sender] = _rOwned[sender].sub(rAmount);
        _rOwned[recipient] = _rOwned[recipient].add(rTransferAmount);
        _takeLiquidity(tLiquidity);
        _reflectFee(rFee, tFee);
        emit Transfer(sender, recipient, tTransferAmount);
    }

    function _transferToExcluded(
        address sender,
        address recipient,
        uint256 tAmount
    ) private {
        (
            uint256 rAmount,
            uint256 rTransferAmount,
            uint256 rFee,
            uint256 tTransferAmount,
            uint256 tFee,
            uint256 tLiquidity
        ) = _getValues(tAmount);
        _rOwned[sender] = _rOwned[sender].sub(rAmount);
        _tOwned[recipient] = _tOwned[recipient].add(tTransferAmount);
        _rOwned[recipient] = _rOwned[recipient].add(rTransferAmount);
        _takeLiquidity(tLiquidity);
        _reflectFee(rFee, tFee);
        emit Transfer(sender, recipient, tTransferAmount);
    }

    function _transferFromExcluded(
        address sender,
        address recipient,
        uint256 tAmount
    ) private {
        (
            uint256 rAmount,
            uint256 rTransferAmount,
            uint256 rFee,
            uint256 tTransferAmount,
            uint256 tFee,
            uint256 tLiquidity
        ) = _getValues(tAmount);
        _tOwned[sender] = _tOwned[sender].sub(tAmount);
        _rOwned[sender] = _rOwned[sender].sub(rAmount);
        _rOwned[recipient] = _rOwned[recipient].add(rTransferAmount);
        _takeLiquidity(tLiquidity);
        _reflectFee(rFee, tFee);
        emit Transfer(sender, recipient, tTransferAmount);
    }

    function _transferBothExcluded(
        address sender,
        address recipient,
        uint256 tAmount
    ) private {
        (
            uint256 rAmount,
            uint256 rTransferAmount,
            uint256 rFee,
            uint256 tTransferAmount,
            uint256 tFee,
            uint256 tLiquidity
        ) = _getValues(tAmount);
        _tOwned[sender] = _tOwned[sender].sub(tAmount);
        _rOwned[sender] = _rOwned[sender].sub(rAmount);
        _tOwned[recipient] = _tOwned[recipient].add(tTransferAmount);
        _rOwned[recipient] = _rOwned[recipient].add(rTransferAmount);
        _takeLiquidity(tLiquidity);
        _reflectFee(rFee, tFee);
        emit Transfer(sender, recipient, tTransferAmount);
    }

    function _reflectFee(uint256 rFee, uint256 tFee) private {
        _rTotal = _rTotal.sub(rFee);
        _tFeeTotal = _tFeeTotal.add(tFee);
    }

    function _getValues(uint256 tAmount)
        private
        view
        returns (
            uint256,
            uint256,
            uint256,
            uint256,
            uint256,
            uint256
        )
    {
        (
            uint256 tTransferAmount,
            uint256 tFee,
            uint256 tLiquidity
        ) = _getTValues(tAmount);
        (uint256 rAmount, uint256 rTransferAmount, uint256 rFee) = _getRValues(
            tAmount,
            tFee,
            tLiquidity,
            _getRate()
        );
        return (
            rAmount,
            rTransferAmount,
            rFee,
            tTransferAmount,
            tFee,
            tLiquidity
        );
    }

    function _getTValues(uint256 tAmount)
        private
        view
        returns (
            uint256,
            uint256,
            uint256
        )
    {
        uint256 tFee = calculateTaxFee(tAmount);
        uint256 tLiquidity = calculateLiquidityFee(tAmount);
        uint256 tTransferAmount = tAmount.sub(tFee).sub(tLiquidity);
        return (tTransferAmount, tFee, tLiquidity);
    }

    function _getRValues(
        uint256 tAmount,
        uint256 tFee,
        uint256 tLiquidity,
        uint256 currentRate
    )
        private
        pure
        returns (
            uint256,
            uint256,
            uint256
        )
    {
        uint256 rAmount = tAmount.mul(currentRate);
        uint256 rFee = tFee.mul(currentRate);
        uint256 rLiquidity = tLiquidity.mul(currentRate);
        uint256 rTransferAmount = rAmount.sub(rFee).sub(rLiquidity);
        return (rAmount, rTransferAmount, rFee);
    }

    function _getRate() private view returns (uint256) {
        (uint256 rSupply, uint256 tSupply) = _getCurrentSupply();
        return rSupply.div(tSupply);
    }

    function _getCurrentSupply() private view returns (uint256, uint256) {
        uint256 rSupply = _rTotal;
        uint256 tSupply = _tTotal;
        for (uint256 i = 0; i < _excluded.length; i++) {
            if (
                _rOwned[_excluded[i]] > rSupply ||
                _tOwned[_excluded[i]] > tSupply
            ) return (_rTotal, _tTotal);
            rSupply = rSupply.sub(_rOwned[_excluded[i]]);
            tSupply = tSupply.sub(_tOwned[_excluded[i]]);
        }
        if (rSupply < _rTotal.div(_tTotal)) return (_rTotal, _tTotal);
        return (rSupply, tSupply);
    }

    function _takeLiquidity(uint256 tLiquidity) private {
        if(buyOrSellSwitch == BUY){
            _liquidityTokensToSwap += tLiquidity * _buyLiquidityFee / _liquidityFee;
            _marketingTokensToSwap += tLiquidity * _buyMarketingFee / _liquidityFee;
        } else if(buyOrSellSwitch == SELL){
            _liquidityTokensToSwap += tLiquidity * _sellLiquidityFee / _liquidityFee;
            _marketingTokensToSwap += tLiquidity * _sellMarketingFee / _liquidityFee;
        }
        uint256 currentRate = _getRate();
        uint256 rLiquidity = tLiquidity.mul(currentRate);
        _rOwned[address(this)] = _rOwned[address(this)].add(rLiquidity);
        if (_isExcluded[address(this)])
            _tOwned[address(this)] = _tOwned[address(this)].add(tLiquidity);
    }

    function calculateTaxFee(uint256 _amount) private view returns (uint256) {
        return _amount.mul(_taxFee).div(10**2);
    }

    function calculateLiquidityFee(uint256 _amount)
        private
        view
        returns (uint256)
    {
        return _amount.mul(_liquidityFee).div(10**2);
    }

    function removeAllFee() private {
        if (_taxFee == 0 && _liquidityFee == 0) return;

        _previousTaxFee = _taxFee;
        _previousLiquidityFee = _liquidityFee;

        _taxFee = 0;
        _liquidityFee = 0;
    }

    function restoreAllFee() private {
        _taxFee = _previousTaxFee;
        _liquidityFee = _previousLiquidityFee;
    }

    function isExcludedFromFee(address account) external view returns (bool) {
        return _isExcludedFromFee[account];
    }

    function excludeFromFee(address account) external onlyOwner {
        _isExcludedFromFee[account] = true;
    }

    function includeInFee(address account) external onlyOwner {
        _isExcludedFromFee[account] = false;
    }

    function setBuyFee(uint256 buyTaxFee, uint256 buyLiquidityFee, uint256 buyMarketingFee)
        external
        onlyOwner
    {
        _buyTaxFee = buyTaxFee;
        _buyLiquidityFee = buyLiquidityFee;
        _buyMarketingFee = buyMarketingFee;
        require(_buyTaxFee + _buyLiquidityFee + _buyMarketingFee <= 20, "Must keep taxes below 20%");
    }

    function setSellFee(uint256 sellTaxFee, uint256 sellLiquidityFee, uint256 sellMarketingFee)
        external
        onlyOwner
    {
        _sellTaxFee = sellTaxFee;
        _sellLiquidityFee = sellLiquidityFee;
        _sellMarketingFee = sellMarketingFee;
        require(_sellTaxFee + _sellLiquidityFee + _sellMarketingFee <= 30, "Must keep taxes below 30%");
    }

    function setMarketingAddress(address _marketingAddress) external onlyOwner {
        marketingAddress = payable(_marketingAddress);
        _isExcludedFromFee[marketingAddress] = true;
    }

    function setLiquidityAddress(address _liquidityAddress) external onlyOwner {
        liquidityAddress = payable(_liquidityAddress);
        _isExcludedFromFee[liquidityAddress] = true;
    }

    function setSwapAndLiquifyEnabled(bool _enabled) public onlyOwner {
        swapAndLiquifyEnabled = _enabled;
        emit SwapAndLiquifyEnabledUpdated(_enabled);
    }

    // useful for buybacks or to reclaim any BNB on the contract in a way that helps holders.
    function buyBackTokens(uint256 bnbAmountInWei) external onlyOwner {
        // generate the uniswap pair path of weth -> eth
        address[] memory path = new address[](2);
        path[0] = uniswapV2Router.WETH();
        path[1] = address(this);

        // make the swap
        uniswapV2Router.swapExactETHForTokensSupportingFeeOnTransferTokens{value: bnbAmountInWei}(
            0, // accept any amount of Ethereum
            path,
            address(0xdead),
            block.timestamp
        );
    }

    // To receive ETH from uniswapV2Router when swapping
    receive() external payable {}

    function transferForeignToken(address _token, address _to)
        external
        onlyOwner
        returns (bool _sent)
    {
        require(_token != address(this), "Can't withdraw native tokens");
        uint256 _contractBalance = IERC20(_token).balanceOf(address(this));
        _sent = IERC20(_token).transfer(_to, _contractBalance);
    }
}