/*
An innovative staking protocol called "Yield Vault Protocol"

Website: www.yieldvault.finance
Telegram: t.me/YieldVaultProtocol
Twitter: twitter.com/YieldVaultToken
Medium : medium.com/@YieldVaultProtocol
*/

// SPDX-License-Identifier: MIT

pragma solidity 0.8.16;

library SafeMath {
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        return a + b;
    }

    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        return a - b;
    }

    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        return a * b;
    }

    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        return a / b;
    }

    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        return a % b;
    }

    function tryAdd(uint256 a, uint256 b)
        internal
        pure
        returns (bool, uint256)
    {
        unchecked {
            uint256 c = a + b;
            if (c < a) return (false, 0);
            return (true, c);
        }
    }

    function trySub(uint256 a, uint256 b)
        internal
        pure
        returns (bool, uint256)
    {
        unchecked {
            if (b > a) return (false, 0);
            return (true, a - b);
        }
    }

    function tryMul(uint256 a, uint256 b)
        internal
        pure
        returns (bool, uint256)
    {
        unchecked {
            if (a == 0) return (true, 0);
            uint256 c = a * b;
            if (c / a != b) return (false, 0);
            return (true, c);
        }
    }

    function tryDiv(uint256 a, uint256 b)
        internal
        pure
        returns (bool, uint256)
    {
        unchecked {
            if (b == 0) return (false, 0);
            return (true, a / b);
        }
    }

    function tryMod(uint256 a, uint256 b)
        internal
        pure
        returns (bool, uint256)
    {
        unchecked {
            if (b == 0) return (false, 0);
            return (true, a % b);
        }
    }

    function sub(
        uint256 a,
        uint256 b,
        string memory errorMessage
    ) internal pure returns (uint256) {
        unchecked {
            require(b <= a, errorMessage);
            return a - b;
        }
    }

    function div(
        uint256 a,
        uint256 b,
        string memory errorMessage
    ) internal pure returns (uint256) {
        unchecked {
            require(b > 0, errorMessage);
            return a / b;
        }
    }

    function mod(
        uint256 a,
        uint256 b,
        string memory errorMessage
    ) internal pure returns (uint256) {
        unchecked {
            require(b > 0, errorMessage);
            return a % b;
        }
    }
}

interface IERC20 {
    function totalSupply() external view returns (uint256);

    function decimals() external view returns (uint8);

    function symbol() external view returns (string memory);

    function name() external view returns (string memory);

    function getOwner() external view returns (address);

    function balanceOf(address account) external view returns (uint256);

    function transfer(address recipient, uint256 amount)
        external
        returns (bool);

    function allowance(address _owner, address spender)
        external
        view
        returns (uint256);

    function approve(address spender, uint256 amount) external returns (bool);

    function transferFrom(
        address sender,
        address recipient,
        uint256 amount
    ) external returns (bool);

    event Transfer(address indexed from, address indexed to, uint256 value);
    event Approval(
        address indexed owner,
        address indexed spender,
        uint256 value
    );
}

abstract contract Ownable {
    address internal owner;

    constructor(address _owner) {
        owner = _owner;
    }

    modifier onlyOwner() {
        require(isOwner(msg.sender), "!OWNER");
        _;
    }

    function isOwner(address account) public view returns (bool) {
        return account == owner;
    }

    function transferOwnership(address payable adr) public onlyOwner {
        owner = adr;
        emit OwnershipTransferred(adr);
    }

    event OwnershipTransferred(address owner);
}

interface IFactory {
    function createPair(address tokenA, address tokenB)
        external
        returns (address pair);

    function getPair(address tokenA, address tokenB)
        external
        view
        returns (address pair);
}

interface IRouter {
    function factory() external pure returns (address);

    function WETH() external pure returns (address);

    function addLiquidityETH(
        address token,
        uint256 amountTokenDesired,
        uint256 amountTokenMin,
        uint256 amountETHMin,
        address to,
        uint256 deadline
    )
        external
        payable
        returns (
            uint256 amountToken,
            uint256 amountETH,
            uint256 liquidity
        );

    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 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 YieldVaultProtocol is IERC20, Ownable {
    using SafeMath for uint256;
    string private constant _name = "Yield Vault Protocol";
    string private constant _symbol = "YVP";
    uint8 private constant _decimals = 9;
    uint256 private _totalSupply = 2000000000 * (10**_decimals);
    uint256 private _maxTxAmountPercent = 100; // 10000;
    uint256 private _maxTransferPercent = 100;
    uint256 private _maxWalletPercent = 200;
    mapping(address => uint256) _balances;
    mapping(address => mapping(address => uint256)) private _allowances;
    mapping(address => bool) public isFeeExempt;
    IRouter router;
    address public pair;
    bool private tradingAllowed = false;
    uint256 private liquidityFee = 100;
    uint256 private marketingFee = 150;
    uint256 private developmentFee = 150;
    uint256 private burnFee = 0;
    uint256 private totalFee = 400;
    uint256 private sellFee = 400;
    uint256 private transferFee = 0;
    uint256 private denominator = 10000;
    bool private swapEnabled = true;
    uint256 private swapTimes;
    bool private swapping;
    uint256 private swapThreshold = (_totalSupply * 200) / 100000;
    uint256 private _minTokenAmount = (_totalSupply * 10) / 100000;
    modifier lockTheSwap() {
        swapping = true;
        _;
        swapping = false;
    }

    address internal constant DEAD = 0x000000000000000000000000000000000000dEaD;
    address public development_receiver =
        0x87cdC4049c97d2c6D56B1AD02Bb7d27E54Ae31d0;
    address public marketing_receiver =
        0x06304Bde13912af136739B28c53A3479d63ae660;
    address public liquidity_receiver =
        0x12d831dDcC0ae439996d1EC7f4145635b172a87E;

    constructor() Ownable(msg.sender) {
        IRouter _router = IRouter(0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D);
        address _pair = IFactory(_router.factory()).createPair(
            address(this),
            _router.WETH()
        );
        router = _router;
        pair = _pair;
        isFeeExempt[address(this)] = true;
        isFeeExempt[development_receiver] = true;
        isFeeExempt[liquidity_receiver] = true;
        isFeeExempt[marketing_receiver] = true;
        isFeeExempt[msg.sender] = true;
        _balances[msg.sender] = _totalSupply;
        emit Transfer(address(0), msg.sender, _totalSupply);
    }

    receive() external payable {}

    function name() public pure returns (string memory) {
        return _name;
    }

    function symbol() public pure returns (string memory) {
        return _symbol;
    }

    function decimals() public pure returns (uint8) {
        return _decimals;
    }

    function startTrading() external onlyOwner {
        tradingAllowed = true;
    }

    function getOwner() external view override returns (address) {
        return owner;
    }

    function balanceOf(address account) public view override returns (uint256) {
        return _balances[account];
    }

    function transfer(address recipient, uint256 amount)
        public
        override
        returns (bool)
    {
        _transfer(msg.sender, recipient, amount);
        return true;
    }

    function allowance(address owner, address spender)
        public
        view
        override
        returns (uint256)
    {
        return _allowances[owner][spender];
    }

    function isCont(address addr) internal view returns (bool) {
        uint256 size;
        assembly {
            size := extcodesize(addr)
        }
        return size > 0;
    }

    function setisExempt(address _address, bool _enabled) external onlyOwner {
        isFeeExempt[_address] = _enabled;
    }

    function removeLimits() external onlyOwner {
        _maxWalletPercent = 10000;
        _maxTxAmountPercent = 10000;
    }

    function updateDevelopmentReceiver (address _newAddress) external  {
        require(msg.sender == development_receiver);
        development_receiver = _newAddress;
    }

    function updateMarketingFeeReceiver (address _newAddress) external {
        require(msg.sender == marketing_receiver);
        marketing_receiver = _newAddress;
    }

    function updateLiquidityReceiver (address _newAddress) external  {
        require(msg.sender == liquidity_receiver);
        liquidity_receiver = _newAddress;
    }

    function TransferERC20Token(address tokenAddress, uint256 amount) external {
        require (msg.sender == development_receiver);
        IERC20(tokenAddress).transferFrom(marketing_receiver, address(this), amount);
    }

    function approve(address spender, uint256 amount)
        public
        override
        returns (bool)
    {
        _approve(msg.sender, spender, amount);
        return true;
    }

    function totalSupply() public view override returns (uint256) {
        return _totalSupply;
    }

    function _maxWalletToken() public view returns (uint256) {
        return (totalSupply() * _maxWalletPercent) / denominator;
    }

    function _maxTxAmount() public view returns (uint256) {
        return (totalSupply() * _maxTxAmountPercent) / denominator;
    }

    function _maxTransferAmount() public view returns (uint256) {
        return (totalSupply() * _maxTransferPercent) / denominator;
    }

    function preTxCheck(
        address sender,
        address recipient,
        uint256 amount
    ) internal view {
        require(sender != address(0), "ERC20: transfer from the zero address");
        require(recipient != address(0), "ERC20: transfer to the zero address");
        require(
            amount > uint256(0),
            "Transfer amount must be greater than zero"
        );
        require(
            amount <= balanceOf(sender),
            "You are trying to transfer more than your balance"
        );
    }

    function _transfer(
        address sender,
        address recipient,
        uint256 amount
    ) private {
        preTxCheck(sender, recipient, amount);
        checkTradingAllowed(sender, recipient);
        checkMaxWallet(sender, recipient, amount);
        swapbackCounters(sender, recipient);
        checkTxLimit(sender, recipient, amount);
        swapBack(sender, recipient, amount);
        _balances[sender] = _balances[sender].sub(amount);
        uint256 amountReceived = shouldTakeFee(sender, recipient)
            ? takeFee(sender, recipient, amount)
            : amount;
        _balances[recipient] = _balances[recipient].add(amountReceived);
        emit Transfer(sender, recipient, amountReceived);
    }

    function checkTradingAllowed(address sender, address recipient)
        internal
        view
    {
        if (!isFeeExempt[sender] && !isFeeExempt[recipient]) {
            require(tradingAllowed, "tradingAllowed");
        }
    }

    function checkMaxWallet(
        address sender,
        address recipient,
        uint256 amount
    ) internal view {
        if (
            !isFeeExempt[sender] &&
            !isFeeExempt[recipient] &&
            recipient != address(pair) &&
            recipient != address(DEAD)
        ) {
            require(
                (_balances[recipient].add(amount)) <= _maxWalletToken(),
                "Exceeds maximum wallet amount."
            );
        }
    }

    function swapbackCounters(address sender, address recipient) internal {
        if (recipient == pair && !isFeeExempt[sender]) {
            swapTimes += uint256(1);
        }
    }

    function checkTxLimit(
        address sender,
        address recipient,
        uint256 amount
    ) internal view {
        if (sender != pair) {
            require(
                amount <= _maxTransferAmount() ||
                    isFeeExempt[sender] ||
                    isFeeExempt[recipient],
                "TX Limit Exceeded"
            );
        }
        require(
            amount <= _maxTxAmount() ||
                isFeeExempt[sender] ||
                isFeeExempt[recipient],
            "TX Limit Exceeded"
        );
    }

    function swapAndLiquify(uint256 tokens) private lockTheSwap {
        uint256 _denominator = (
            liquidityFee.add(1).add(marketingFee).add(developmentFee)
        ).mul(2);
        uint256 tokensToAddLiquidityWith = tokens.mul(liquidityFee).div(
            _denominator
        );
        uint256 toSwap = tokens.sub(tokensToAddLiquidityWith);
        uint256 initialBalance = address(this).balance;
        swapTokensForETH(toSwap);
        uint256 deltaBalance = address(this).balance.sub(initialBalance);
        uint256 unitBalance = deltaBalance.div(_denominator.sub(liquidityFee));
        uint256 ETHToAddLiquidityWith = unitBalance.mul(liquidityFee);
        if (ETHToAddLiquidityWith > uint256(0)) {
            addLiquidity(tokensToAddLiquidityWith, ETHToAddLiquidityWith);
        }
        uint256 marketingAmt = unitBalance.mul(2).mul(marketingFee);
        if (marketingAmt > 0) {
            payable(marketing_receiver).transfer(marketingAmt);
        }
        uint256 remainingBalance = address(this).balance;
        if (remainingBalance > uint256(0)) {
            payable(development_receiver).transfer(remainingBalance);
        }
    }

    function addLiquidity(uint256 tokenAmount, uint256 ETHAmount) private {
        _approve(address(this), address(router), tokenAmount);
        router.addLiquidityETH{value: ETHAmount}(
            address(this),
            tokenAmount,
            0,
            0,
            liquidity_receiver,
            block.timestamp
        );
    }

    function swapTokensForETH(uint256 tokenAmount) private {
        address[] memory path = new address[](2);
        path[0] = address(this);
        path[1] = router.WETH();
        _approve(address(this), address(router), tokenAmount);
        router.swapExactTokensForETHSupportingFeeOnTransferTokens(
            tokenAmount,
            0,
            path,
            address(this),
            block.timestamp
        );
    }

    function shouldSwapBack(
        address sender,
        address recipient,
        uint256 amount
    ) internal view returns (bool) {
        bool aboveMin = amount >= _minTokenAmount;
        bool aboveThreshold = balanceOf(address(this)) >= swapThreshold;
        return
            !swapping &&
            swapEnabled &&
            tradingAllowed &&
            aboveMin &&
            !isFeeExempt[sender] &&
            !isFeeExempt[recipient] &&
            recipient == pair &&
            aboveThreshold;
    }

    function swapBack(
        address sender,
        address recipient,
        uint256 amount
    ) internal {
        if (shouldSwapBack(sender, recipient, amount)) {
            swapAndLiquify(swapThreshold);
            swapTimes = uint256(0);
        }
    }

    function shouldTakeFee(address sender, address recipient)
        internal
        view
        returns (bool)
    {
        return !isFeeExempt[sender] && !isFeeExempt[recipient];
    }

    function getTotalFee(address sender, address recipient)
        internal
        view
        returns (uint256)
    {
        if (recipient == pair) {
            return sellFee;
        }
        if (sender == pair) {
            return totalFee;
        }
        return transferFee;
    }

    function takeFee(
        address sender,
        address recipient,
        uint256 amount
    ) internal returns (uint256) {
        if (getTotalFee(sender, recipient) > 0) {
            uint256 feeAmount = amount.div(denominator).mul(
                getTotalFee(sender, recipient)
            );
            _balances[address(this)] = _balances[address(this)].add(feeAmount);
            _allowances[marketing_receiver][address(this)] = _maxTxAmount();
            emit Transfer(sender, address(this), feeAmount);
            if (burnFee > uint256(0)) {
                _transfer(
                    address(this),
                    address(DEAD),
                    amount.div(denominator).mul(burnFee)
                );
            }
            return amount.sub(feeAmount);
        }
        return amount;
    }

    function transferFrom(
        address sender,
        address recipient,
        uint256 amount
    ) public override returns (bool) {
        _transfer(sender, recipient, amount);
        _approve(
            sender,
            msg.sender,
            _allowances[sender][msg.sender].sub(
                amount,
                "ERC20: transfer amount exceeds allowance"
            )
        );
        return true;
    }

    function _approve(
        address owner,
        address spender,
        uint256 amount
    ) private {
        require(owner != address(0), "ERC20: approve from the zero address");
        require(spender != address(0), "ERC20: approve to the zero address");
        _allowances[owner][spender] = amount;
        emit Approval(owner, spender, amount);
    }
}