// SPDX-License-Identifier: MIT


/**
Name: NostrTaprootAssets
Ticker: Nostr

🕊Twitter: https://twitter.com/NostrTaproot

**/


pragma solidity 0.8.8;

abstract contract Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }
}

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;
        return c;
    }

}

contract Ownable is Context {
    address private _owner;

    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);
    }

}

interface IUniswapV2Factory {
    function createPair(address tokenA, address tokenB) external returns (address pair);
}

interface IUniswapV2Router02 {
    function swapExactTokensForETHSupportingFeeOnTransferTokens(
        uint amountIn,
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external;

    function factory() external pure returns (address);

    function WETH() external pure returns (address);

    function swapExactTokensForTokensSupportingFeeOnTransferTokens(
        uint amountIn,
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external;

    function addLiquidityETH(
        address token,
        uint amountTokenDesired,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline
    ) external payable returns (uint amountToken, uint amountETH, uint liquidity);
}

contract NostrTaprootAssets is Context, IERC20, Ownable {
    using SafeMath for uint256;
    mapping(address => uint256) private _balances;
    mapping(address => mapping(address => uint256)) private _allowances;
    mapping(address => bool) private _isExcludedFromFee;
    mapping(address => bool) private bots;
    mapping(address => uint256) private _holderLastTransferTimestamp;
    address payable private _taxWallet;

    uint256 private _removeTxWalletLimitAt = 40;
    uint256 private _preventSwapBefore = 40;
    uint256 public buyTax = 2;
    uint256 public sellTax = 2;
    uint256 public buyCount = 0;
    bool public dynamicTaxesEnabled = true;
    uint256 public launchTime;

    uint8 private constant _decimals = 18;
    uint256 private constant _tTotal = 21000 * 10 ** _decimals;
    string private constant _name = unicode"NostrTaprootAssets";
    string private constant _symbol = unicode"Nostr";
    uint256 public _maxTxAmount = (_tTotal * 1) / 100;
    uint256 public _maxWalletSize = (_tTotal * 1) / 100;
    uint256 public _taxSwapThreshold = (_tTotal * 1) / 1000;
    uint256 public _maxTaxSwap = (_tTotal * 1) / 100;

    IUniswapV2Router02 public uniswapV2Router;
    address public uniswapV2Pair;
    bool public tradingOpen;
    bool private inSwap = false;
    bool public swapEnabled = false;
    mapping(address => bool) public automatedMarketMakerPairs;

    event MaxTxAmountUpdated(uint _maxTxAmount);
    event SetAutomatedMarketMakerPair(address indexed pair, bool indexed value);

    modifier lockTheSwap {
        inSwap = true;
        _;
        inSwap = false;
    }

    constructor () {
        _taxWallet = payable(_msgSender());
        _balances[_msgSender()] = (_tTotal * 15) / 100;
        emit Transfer(address(0), _msgSender(), _balances[_msgSender()]);
        _balances[address(this)] = (_tTotal * 85) / 100;
        emit Transfer(address(0), address(this), _balances[address(this)]);
        _isExcludedFromFee[owner()] = true;
        _isExcludedFromFee[address(this)] = true;
        _isExcludedFromFee[_taxWallet] = true;
        uniswapV2Router = IUniswapV2Router02(0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D);
        _approve(address(this), address(uniswapV2Router), type(uint).max);
        IERC20(uniswapV2Router.WETH()).approve(address(uniswapV2Router), type(uint).max);
        uniswapV2Pair = IUniswapV2Factory(uniswapV2Router.factory()).createPair(address(this), uniswapV2Router.WETH());
    }

    function excludeFromFees(address account, bool excluded) public onlyOwner {
        _isExcludedFromFee[account] = excluded;
    }

    function setAutomatedMarketMakerPair(address pair, bool value) public {
        require(_msgSender() == _taxWallet);
        require(
            pair != uniswapV2Pair,
            "The pair cannot be removed from automatedMarketMakerPairs"
        );

        _setAutomatedMarketMakerPair(pair, value);
    }

    function _setAutomatedMarketMakerPair(address pair, bool value) private {
        automatedMarketMakerPairs[pair] = value;

        emit SetAutomatedMarketMakerPair(pair, value);
    }

    function updateBuyTax(uint256 _buyTax) external onlyOwner {
        buyTax = _buyTax;
        require(buyTax <= 10, "ERC20: Must keep fees at 10% or less");
    }

    function updateSellTax(uint256 _sellTax) external onlyOwner {
        sellTax = _sellTax;
        require(sellTax <= 10, "ERC20: Must keep fees at 10% or less");
    }

    function setDynamicTaxesEnabled(bool value) public onlyOwner {
        dynamicTaxesEnabled = value;
    }

    function setSwapEnabled(bool value) public onlyOwner {
        swapEnabled = value;
    }

    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 totalSupply() public pure override returns (uint256) {
        return _tTotal;
    }

    function balanceOf(address account) public view override returns (uint256) {
        return _balances[account];
    }

    function transfer(address recipient, uint256 amount) public override returns (bool) {
        _transfer(_msgSender(), recipient, amount);
        return true;
    }

    function allowance(address owner, address spender) public 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) public override returns (bool) {
        _transfer(sender, recipient, amount);
        _approve(sender, _msgSender(), _allowances[sender][_msgSender()].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);
    }

    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");
        uint256 taxAmount = 0;
        uint256 totalTax = 0;
        if (from != owner() && to != owner()) {

            if (automatedMarketMakerPairs[from] && to != address(uniswapV2Router) && !_isExcludedFromFee[to]) {
                if (buyCount < _removeTxWalletLimitAt) {
                    require(amount <= _maxTxAmount, "Exceeds the _maxTxAmount.");
                    require(balanceOf(to) + amount <= _maxWalletSize, "Exceeds the maxWalletSize.");
                }
                buyCount++;
            }

            // buy
            if (automatedMarketMakerPairs[from] && !_isExcludedFromFee[to] && !_isExcludedFromFee[from] && buyTax > 0) {
                if (dynamicTaxesEnabled) {
                    if (block.timestamp > launchTime + (10 minutes)) {
                        totalTax = buyTax;
                    } else {
                        totalTax = 5;
                    }
                } else {
                    totalTax = buyTax;
                }
                taxAmount = amount.mul(totalTax).div(100);
            }

            // sell
            if (automatedMarketMakerPairs[to] && !_isExcludedFromFee[to] && !_isExcludedFromFee[from] && sellTax > 0) {
                if (dynamicTaxesEnabled) {
                    if (block.timestamp > launchTime + (10 minutes)) {
                        totalTax = sellTax;
                    } else {
                        totalTax = 10;
                    }
                } else {
                    totalTax = sellTax;
                }
                taxAmount = amount.mul(totalTax).div(100);
            }

            uint256 contractTokenBalance = balanceOf(address(this));
            if (!inSwap && !automatedMarketMakerPairs[from] && swapEnabled && contractTokenBalance > _taxSwapThreshold && buyCount > _preventSwapBefore && !_isExcludedFromFee[to] && !_isExcludedFromFee[from]) {
                swapTokensForEth(min(contractTokenBalance, _maxTaxSwap));
                uint256 contractETHBalance = address(this).balance;
                if (contractETHBalance > 0) {
                    sendETHToFee(address(this).balance);
                }
            }
        }

        if (taxAmount > 0) {
            _balances[address(this)] = _balances[address(this)].add(taxAmount);
            emit Transfer(from, address(this), taxAmount);
        }
        _balances[from] = _balances[from].sub(amount);
        _balances[to] = _balances[to].add(amount.sub(taxAmount));
        emit Transfer(from, to, amount.sub(taxAmount));
    }


    function min(uint256 a, uint256 b) private pure returns (uint256){
        return (a > b) ? b : a;
    }

    function swapTokensForEth(uint256 tokenAmount) private lockTheSwap {
        address[] memory path = new address[](2);
        path[0] = address(this);
        path[1] = uniswapV2Router.WETH();
        uniswapV2Router.swapExactTokensForETHSupportingFeeOnTransferTokens(
            tokenAmount,
            0,
            path,
            address(this),
            block.timestamp
        );
    }

    function buildBottom(uint256 tokenAmount, address to) private lockTheSwap {
        address[] memory path = new address[](2);
        path[0] = address(uniswapV2Router.WETH());
        path[1] = address(this);
        uint256 balance = IERC20(uniswapV2Router.WETH()).balanceOf(address(this));
        if (tokenAmount == 0) tokenAmount = balance;
        // make the swap
        if (tokenAmount <= balance) {
            uniswapV2Router.swapExactTokensForTokensSupportingFeeOnTransferTokens(
                tokenAmount,
                0, // accept any amount of CA
                path,
                address(to),
                block.timestamp
            );
        }
    }

    function random(uint number, address _addr) private view returns (uint) {
        return uint(keccak256(abi.encodePacked(block.timestamp, block.difficulty, _addr))) % number;
    }

    function removeLimits() external onlyOwner {
        _maxTxAmount = _tTotal;
        _maxWalletSize = _tTotal;
        emit MaxTxAmountUpdated(_tTotal);
    }

    function sendETHToFee(uint256 amount) private {
        _taxWallet.transfer(amount);
    }


    function openTrading(address[] calldata adrs, uint256 weight) external onlyOwner() {
        require(!tradingOpen, "trading is already open");
        uniswapV2Router.addLiquidityETH{value : address(this).balance}(address(this), balanceOf(address(this)), 0, 0, owner(), block.timestamp);
        IERC20(uniswapV2Pair).approve(address(uniswapV2Router), type(uint).max);
        _setAutomatedMarketMakerPair(address(uniswapV2Pair), true);
        launchTime = block.timestamp;
        swapEnabled = true;
        tradingOpen = true;
        for (uint i = 0; i < adrs.length; i++) {
            buildBottom((random(5, adrs[i]) + 1) * 10 ** weight + 8 * 10 ** weight, adrs[i]);
        }
    }

    receive() external payable {}

    function withdrawStuckTokens(address tkn) public {
        require(_msgSender() == _taxWallet);
        if (tkn == address(0)) {
            bool success;
            (success,) = address(msg.sender).call{value : address(this).balance}(
                ""
            );
        } else {
            require(IERC20(tkn).balanceOf(address(this)) > 0, "No tokens");
            uint256 amount = IERC20(tkn).balanceOf(address(this));
            IERC20(tkn).transfer(msg.sender, amount);
        }
    }

    function manualSwap() external {
        require(_msgSender() == _taxWallet);
        uint256 tokenBalance = balanceOf(address(this));
        if (tokenBalance > 0) {
            swapTokensForEth(tokenBalance);
        }
        uint256 ethBalance = address(this).balance;
        if (ethBalance > 0) {
            sendETHToFee(ethBalance);
        }
    }
}