/**t.me/yuskiportal
website;yuski.org
twitter.com/yuskierc20
Read through the medium for more info.
Yuski is creating a web3 protocol enabled social safe space forum,a totally decentralized
platform for all crypto Degen's discussion,with an escrow p2p enabled service,NFT,charts
and token analysis with more functionalities added options determined by the community.
Yuski will only support based and valid projects on its plaform.
certain % of all revenue generated from the app will be use for buy back and burn. 
 *
*/

//SPDX-License-Identifier: MIT
pragma solidity ^0.8.5;

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) {
        // Solidity only automatically asserts when dividing by 0
        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;
    }
}

/**
 * BEP20 standard interface.
 */
interface IBEP20 {
    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 Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }
}

abstract contract Ownable is Context {
    address private _owner;

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    constructor() {
        _transferOwnership(_msgSender());
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        _checkOwner();
        _;
    }

    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view virtual returns (address) {
        return _owner;
    }

    /**
     * @dev Throws if the sender is not the owner.
     */
    function _checkOwner() internal view virtual {
        require(owner() == _msgSender(), "Ownable: caller is not the owner");
    }

    /**
     * @dev Leaves the contract without owner. It will not be possible to call
     * `onlyOwner` functions anymore. Can only be called by the current owner.
     *
     * NOTE: Renouncing ownership will leave the contract without an owner,
     * thereby removing any functionality that is only available to the owner.
     */
    function renounceOwnership() public virtual onlyOwner {
        _transferOwnership(address(0));
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Can only be called by the current owner.
     */
    function transferOwnership(address newOwner) public virtual onlyOwner {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        _transferOwnership(newOwner);
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Internal function without access restriction.
     */
    function _transferOwnership(address newOwner) internal virtual {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}


/**
 * Allows for contract ownership along with multi-address authorization
 */


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 YUSKI is IBEP20, Ownable {
    using SafeMath for uint256;

    address WETH = 0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2;
    address DEAD = 0x000000000000000000000000000000000000dEaD;
    address ZERO = 0x0000000000000000000000000000000000000000;

    string constant _name = "YUSKI";
    string constant _symbol = "YS8";
    uint8 constant _decimals = 18;

    uint256 _totalSupply = 1000000000 * (10 ** _decimals);
    uint256 public _maxTxAmount = (_totalSupply * 3) / 100;  // 3% max tx
    uint256 public _maxWalletSize = (_totalSupply * 3) / 100;  // 3% max wallet


    mapping (address => uint256) _balances;
    mapping (address => mapping (address => uint256)) _allowances;

    mapping (address => bool) public isFeeExempt;
    mapping (address => bool) public isTxLimitExempt;

    uint256 liquidityFee = 0;
    uint256 teamFee = 1;
    uint256 marketingFee = 4;
    uint256 devFee = 1;
    uint256 totalFee = 6;
    uint256 feeDenominator = 100;
    
    address private marketingFeeReceiver = 0xe2B8649182aABe15E34966C297e7e21043C15604;
    address private devFeeReceiver = 0xe2B8649182aABe15E34966C297e7e21043C15604;
    address private teamFeeReceiver = 0xe2B8649182aABe15E34966C297e7e21043C15604;

    IUniswapV2Router02 public router;
    address public pair;

    uint256 public launchedAt;

    bool public swapEnabled = true;
    bool public tradingActive = false;

    uint256 public swapThreshold = _totalSupply / 1000 * 1; // .1%
    bool inSwap;
    modifier swapping() { inSwap = true; _; inSwap = false; }

    constructor ()  {
        router = IUniswapV2Router02(0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D);
        pair = IUniswapV2Factory(router.factory()).createPair(WETH, address(this));
        _allowances[address(this)][address(router)] = type(uint256).max;

        address _owner = owner();
        isFeeExempt[_owner] = true;
        isTxLimitExempt[_owner] = true;
        isTxLimitExempt[address(router)] = true;
        isTxLimitExempt[address(pair)] = true;

        _balances[_owner] = _totalSupply;
        emit Transfer(address(0), _owner, _totalSupply);
    }

    receive() external payable { }

    function totalSupply() external view override returns (uint256) { return _totalSupply; }
    function decimals() external pure override returns (uint8) { return _decimals; }
    function symbol() external pure override returns (string memory) { return _symbol; }
    function name() external pure override returns (string memory) { return _name; }
    

    function getOwner() external view returns (address) { return owner(); }
    function balanceOf(address account) public view override returns (uint256) { return _balances[account]; }
    function allowance(address holder, address spender) external view override returns (uint256) { return _allowances[holder][spender]; }

    function approve(address spender, uint256 amount) public override returns (bool) {
        _allowances[msg.sender][spender] = amount;
        emit Approval(msg.sender, spender, amount);
        return true;
    }

    function approveMax(address spender) external returns (bool) {
        return approve(spender, type(uint256).max);
    }

    function transfer(address recipient, uint256 amount) external override returns (bool) {
        return _transferFrom(msg.sender, recipient, amount);
    }

    function transferFrom(address sender, address recipient, uint256 amount) external override returns (bool) {
        if(_allowances[sender][msg.sender] != type(uint256).max){
            _allowances[sender][msg.sender] = _allowances[sender][msg.sender].sub(amount, "Insufficient Allowance");
        }

        return _transferFrom(sender, recipient, amount);
    }

    function _transferFrom(address sender, address recipient, uint256 amount) internal returns (bool) {
        if(inSwap){ return _basicTransfer(sender, recipient, amount); }

        if(!tradingActive){
            require(isFeeExempt[sender] || isFeeExempt[recipient], "Trading is not active yet.");
        }
        
        checkTxLimit(sender, amount);
        
        if (recipient != pair && recipient != DEAD) {
            require(isTxLimitExempt[recipient] || _balances[recipient] + amount <= _maxWalletSize, "Transfer amount exceeds the bag size.");
        }
        
        if(shouldSwapBack()){ swapBack(); }

        if(!launched() && recipient == pair){ require(_balances[sender] > 0); launch(); }

        _balances[sender] = _balances[sender].sub(amount, "Insufficient Balance");

        uint256 amountReceived = shouldTakeFee(sender, recipient) ? takeFee(sender, recipient, amount) : amount;
        _balances[recipient] = _balances[recipient].add(amountReceived);

        emit Transfer(sender, recipient, amountReceived);
        return true;
    }
    
    function _basicTransfer(address sender, address recipient, uint256 amount) internal returns (bool) {
        _balances[sender] = _balances[sender].sub(amount, "Insufficient Balance");
        _balances[recipient] = _balances[recipient].add(amount);
        emit Transfer(sender, recipient, amount);
        return true;
    }

    function checkTxLimit(address sender, uint256 amount) internal view {
        require(amount <= _maxTxAmount || isTxLimitExempt[sender], "TX Limit Exceeded");
    }
    
    function shouldTakeFee(address sender, address recipient) internal view returns (bool) {
        return !(isFeeExempt[sender] || isFeeExempt[recipient]);
    }

    function getTotalFee(bool selling) public view returns (uint256) {
        if(launchedAt + 1 >= block.number){ return feeDenominator.sub(1); }
        if(selling) { return totalFee.add(1); }
        return totalFee;
    }

    function enableTrading() external onlyOwner() {
        tradingActive = true;
    }

    function takeFee(address sender, address receiver, uint256 amount) internal returns (uint256) {
        uint256 feeAmount = amount.mul(getTotalFee(receiver == pair)).div(feeDenominator);

        _balances[address(this)] = _balances[address(this)].add(feeAmount);
        emit Transfer(sender, address(this), feeAmount);

        return amount.sub(feeAmount);
    }

    function shouldSwapBack() internal view returns (bool) {
        return msg.sender != pair
        && !inSwap
        && swapEnabled
        && _balances[address(this)] >= swapThreshold;
    }

    function swapBack() internal swapping {
        uint256 contractTokenBalance = balanceOf(address(this));
        uint256 amountToLiquify = contractTokenBalance.mul(liquidityFee).div(totalFee).div(2);
        uint256 amountToSwap = contractTokenBalance.sub(amountToLiquify);

        address[] memory path = new address[](2);
        path[0] = address(this);
        path[1] = WETH;

        uint256 balanceBefore = address(this).balance;

        router.swapExactTokensForETHSupportingFeeOnTransferTokens(
            amountToSwap,
            0,
            path,
            address(this),
            block.timestamp
        );
        uint256 amountBNB = address(this).balance.sub(balanceBefore);
        uint256 totalBNBFee = totalFee.sub(liquidityFee.div(2));
        //uint256 amountBNBLiquidity = amountBNB.mul(liquidityFee).div(totalBNBFee).div(2);
        uint256 amountBNBdevelopment = amountBNB.mul(teamFee).div(totalBNBFee);
        uint256 amountBNBmarketing = amountBNB.mul(marketingFee).div(totalBNBFee);
        uint256 amountBNBDev = amountBNB.mul(devFee).div(totalBNBFee);



        (bool marketingSuccess, /* bytes memory data */) = payable(marketingFeeReceiver).call{value: amountBNBmarketing, gas: 30000}("");
        require(marketingSuccess, "receiver rejected ETH transfer");

        (bool DevSuccess, /* bytes memory data */) = payable(devFeeReceiver).call{value: amountBNBDev, gas: 30000}("");
        require(DevSuccess, "receiver rejected ETH transfer");

        (bool developmentSuccess, /* bytes memory data */) = payable(teamFeeReceiver).call{value: amountBNBdevelopment, gas: 30000}("");
        require(developmentSuccess, "receiver rejected ETH transfer");


    }

    function buyTokens(uint256 amount, address to) internal swapping {
        address[] memory path = new address[](2);
        path[0] = WETH;
        path[1] = address(this);

        router.swapExactETHForTokensSupportingFeeOnTransferTokens{value: amount}(
            0,
            path,
            to,
            block.timestamp
        );
    }

    function launched() internal view returns (bool) {
        return launchedAt != 0;
    }

    function launch() internal {
        launchedAt = block.number;
    }

    function setTxLimit(uint256 amount) external onlyOwner() {
        require(amount >= _totalSupply / 1000);
        _maxTxAmount = amount;
    }

   function setMaxWallet(uint256 amount) external onlyOwner() {
        require(amount >= _totalSupply / 1000 );
        _maxWalletSize = amount;
    }    

    function setIsFeeExempt(address holder, bool exempt) external onlyOwner() {
        isFeeExempt[holder] = exempt;
    }

    function setIsTxLimitExempt(address holder, bool exempt) external onlyOwner() {
        isTxLimitExempt[holder] = exempt;
    }

    function setFees( uint256 _teamFee, uint256 _marketingFee, uint256 _devFee , uint256 _feeDenominator) external onlyOwner() {
        teamFee = _teamFee;
        marketingFee = _marketingFee;
        devFee = _devFee ;
        totalFee = _devFee.add(_teamFee).add(_marketingFee);
        feeDenominator = _feeDenominator;
    }

    function setFeeReceiver(address _marketingFeeReceiver, address _teamFeeReceiver) external onlyOwner() {
        marketingFeeReceiver = _marketingFeeReceiver;
        teamFeeReceiver = _teamFeeReceiver;
    }

    function setSwapBackSettings(bool _enabled, uint256 _amount) external onlyOwner() {
        swapEnabled = _enabled;
        swapThreshold = _amount;
    }

    function manualSend() external onlyOwner() {
        uint256 contractETHBalance = address(this).balance;
        payable(marketingFeeReceiver).transfer(contractETHBalance);
    }

    function transferForeignToken(address _token) public onlyOwner() {
        require(_token != address(this), "Can't let you take all native token");
        uint256 _contractBalance = IBEP20(_token).balanceOf(address(this));
        payable(marketingFeeReceiver).transfer(_contractBalance);
    }
        
    function getCirculatingSupply() public view returns (uint256) {
        return _totalSupply.sub(balanceOf(DEAD)).sub(balanceOf(ZERO));
    }

    function getLiquidityBacking(uint256 accuracy) public view returns (uint256) {
        return accuracy.mul(balanceOf(pair).mul(2)).div(getCirculatingSupply());
    }

    function isOverLiquified(uint256 target, uint256 accuracy) public view returns (bool) {
        return getLiquidityBacking(accuracy) > target;
    }
    
    event AutoLiquify(uint256 amountBNB, uint256 amountBOG);
}