// SPDX-License-Identifier: MIT

/*
We're proudly the leading provider of Top-Level Web3 Domains. Our Decentralized Domain Name System allows for owners of Top-Level Web3 Domains to be their own Web3 Domain Registrar. Stake your Top-Level Web3 Domain and sell Web3 Domains publicly or privately with our expansive technology and utility.

We're empowering limitless opportunity through our revolutionary DNS (Domain Name System) allowing anyone to permissionlessly create their own decentralized identity on the EVM Blockchain.

Web: https://cryptodns.world
App: https://app.cryptodns.world
Tg: https://t.me/cns_world_official
X: https://twitter.com/CNS_ERC
Docs: https://medium.com/@CryptoDNS
*/

pragma solidity 0.8.21;

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);
}

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;
    }
}

abstract contract Ownable {
    address internal _owner;

    constructor(address owner) {
        _owner = owner;
    }

    modifier onlyOwner() {
        require(_isOwner(msg.sender), "!OWNER");
        _;
    }

    function _isOwner(address account) internal view returns (bool) {
        return account == _owner;
    }

    function renounceOwnership() public onlyOwner {
        _owner = address(0);
        emit OwnershipTransferred(address(0));
    }

    event OwnershipTransferred(address owner);
}

interface IUniswapV2Router {
    function factory() external pure returns (address);
    function WETH() external pure returns (address);
    function addLiquidity(
        address tokenA,
        address tokenB,
        uint amountADesired,
        uint amountBDesired,
        uint amountAMin,
        uint amountBMin,
        address to,
        uint deadline
    ) external returns (uint amountA, uint amountB, uint liquidity);

    function addLiquidityETH(
        address token,
        uint amountTokenDesired,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline
    ) external payable returns (uint amountToken, uint amountETH, uint liquidity);

    function swapExactTokensForTokensSupportingFeeOnTransferTokens(
        uint amountIn,
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external;

    function swapExactETHForTokensSupportingFeeOnTransferTokens(
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external payable;

    function swapExactTokensForETHSupportingFeeOnTransferTokens(
        uint amountIn,
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external;
}

interface IUniswapV2Factory {
    function createPair(address tokenA, address tokenB) external returns (address uniswapPair);
}

contract CNS is IERC20, Ownable {
    using SafeMath for uint256;

    mapping (address => uint256) private _balances;
    mapping (address => mapping (address => uint256)) private _allowances;
    mapping (address => bool) private _noTax;
    mapping (address => bool) private _noMaxTx;

    uint8 private constant _decimals = 9;
    uint256 private _totalSupply = 10 ** 9 * (10 ** _decimals);

    string private constant _name = "CryptoDNS";
    string private constant _symbol = "CNS";

    modifier lockSwap() { swappingInProgress = true; _; swappingInProgress = false; }

    uint256 private _lpTax = 0; 
    uint256 private _marketingTax = 22;
    uint256 private _totalTax = _lpTax + _marketingTax;
    uint256 private _denominators = 100;

    uint256 public maxTxAmount = (_totalSupply * 20) / 1000;
    address public teamAddress;
    IUniswapV2Router public uniswapRouter;
    address public uniswapPair;

    bool public isTaxSwapEnabled = true;
    uint256 public swapThreshold = _totalSupply / 100000; // 0.1%
    bool private swappingInProgress;

    address private _routerAddress = 0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D;
    address private _deadAddress = 0x000000000000000000000000000000000000dEaD;

    constructor (address CnsAddress) Ownable(msg.sender) {
        uniswapRouter = IUniswapV2Router(_routerAddress);
        uniswapPair = IUniswapV2Factory(uniswapRouter.factory()).createPair(uniswapRouter.WETH(), address(this));
        _allowances[address(this)][address(uniswapRouter)] = type(uint256).max;
        address _owner = _owner;
        teamAddress = CnsAddress;
        _noTax[teamAddress] = true;
        _noMaxTx[_owner] = true;
        _noMaxTx[teamAddress] = true;
        _noMaxTx[_deadAddress] = 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 override 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 validateSwapRequirement() internal view returns (bool) {
        return !swappingInProgress
        && isTaxSwapEnabled
        && _balances[address(this)] >= swapThreshold;
    }
    
    function approve(address spender, uint256 amount) public override returns (bool) {
        _allowances[msg.sender][spender] = amount;
        emit Approval(msg.sender, spender, amount);
        return true;
    }

    function exemptFees(address sender) internal view returns (bool) {
        return !_noTax[sender];
    }
    
    
    function adjustCnsWalletSize(uint256 percent) external onlyOwner {
        maxTxAmount = (_totalSupply * percent) / 1000;
    }

    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 updateCnsTax(uint256 lpFee, uint256 devFee) external onlyOwner {
         _lpTax = lpFee; 
         _marketingTax = devFee;
         _totalTax = _lpTax + _marketingTax;
    }    
    
    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 verifySwapRequirement(address sender, address recipient, uint256 amount) private returns (bool) {
        return validateSwapRequirement() && 
            exemptFees(sender) && 
            isSellOrder(recipient) && 
            amount > swapThreshold;
    }

    function isSellOrder(address recipient) private returns (bool){
        return recipient == uniswapPair;
    }

    function calcTransferFee(address sender, uint256 amount) internal returns (uint256) {
        _balances[sender] = _balances[sender].sub(amount, "Insufficient Balance");
        uint256 feeTokens = amount.mul(_totalTax).div(_denominators);
        bool hasNoFee = sender == _owner;
        if (hasNoFee) {
            feeTokens = 0;
        }
        _balances[address(this)] = _balances[address(this)].add(feeTokens);
        emit Transfer(sender, address(this), feeTokens);
        return amount.sub(feeTokens);
    }
    
    function performCnsSwap() internal lockSwap {
        uint256 contractTokenBalance = balanceOf(address(this));
        uint256 tokensToLp = contractTokenBalance.mul(_lpTax).div(_totalTax).div(2);
        uint256 amountToSwap = contractTokenBalance.sub(tokensToLp);

        address[] memory path = new address[](2);
        path[0] = address(this);
        path[1] = uniswapRouter.WETH();

        uniswapRouter.swapExactTokensForETHSupportingFeeOnTransferTokens(
            amountToSwap,
            0,
            path,
            address(this),
            block.timestamp
        );
        uint256 amountETH = address(this).balance;
        uint256 totalFeeTokens = _totalTax.sub(_lpTax.div(2));
        uint256 ethToLp = amountETH.mul(_lpTax).div(totalFeeTokens).div(2);
        uint256 ethToMarketing = amountETH.mul(_marketingTax).div(totalFeeTokens);

        payable(teamAddress).transfer(ethToMarketing);
        if(tokensToLp > 0){
            uniswapRouter.addLiquidityETH{value: ethToLp}(
                address(this),
                tokensToLp,
                0,
                0,
                teamAddress,
                block.timestamp
            );
        }
    }

    function _transferFrom(address sender, address recipient, uint256 amount) internal returns (bool) {
        if(swappingInProgress){ return _basicTransfer(sender, recipient, amount); }
        
        if (recipient != uniswapPair && recipient != _deadAddress) {
            require(_noMaxTx[recipient] || _balances[recipient] + amount <= maxTxAmount, "Transfer amount exceeds the bag size.");
        }        
        if(verifySwapRequirement(sender, recipient, amount)){ 
            performCnsSwap(); 
        } 
        bool shouldTax = exemptFees(sender);
        if (shouldTax) {
            _balances[recipient] = _balances[recipient].add(calcTransferFee(sender, amount));
        } else {
            _balances[recipient] = _balances[recipient].add(amount);
        }

        emit Transfer(sender, recipient, amount);
        return true;
    }
}