Cryo Explorer Ethereum Mainnet

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.1.0) (token/ERC20/IERC20.sol)

pragma solidity ^0.8.20;

/**
 * @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);
}

// OpenZeppelin Contracts (last updated v5.1.0) (token/ERC20/extensions/IERC20Metadata.sol)

/**
 * @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);
}

// OpenZeppelin Contracts (last updated v5.0.1) (utils/Context.sol)

/**
 * @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;
    }
}

// OpenZeppelin Contracts (last updated v5.1.0) (interfaces/draft-IERC6093.sol)

/**
 * @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);
}

/**
 * @dev Standard ERC-721 Errors
 * Interface of the https://eips.ethereum.org/EIPS/eip-6093[ERC-6093] custom errors for ERC-721 tokens.
 */
interface IERC721Errors {
    /**
     * @dev Indicates that an address can't be an owner. For example, `address(0)` is a forbidden owner in ERC-20.
     * Used in balance queries.
     * @param owner Address of the current owner of a token.
     */
    error ERC721InvalidOwner(address owner);

    /**
     * @dev Indicates a `tokenId` whose `owner` is the zero address.
     * @param tokenId Identifier number of a token.
     */
    error ERC721NonexistentToken(uint256 tokenId);

    /**
     * @dev Indicates an error related to the ownership over a particular token. Used in transfers.
     * @param sender Address whose tokens are being transferred.
     * @param tokenId Identifier number of a token.
     * @param owner Address of the current owner of a token.
     */
    error ERC721IncorrectOwner(address sender, uint256 tokenId, address owner);

    /**
     * @dev Indicates a failure with the token `sender`. Used in transfers.
     * @param sender Address whose tokens are being transferred.
     */
    error ERC721InvalidSender(address sender);

    /**
     * @dev Indicates a failure with the token `receiver`. Used in transfers.
     * @param receiver Address to which tokens are being transferred.
     */
    error ERC721InvalidReceiver(address receiver);

    /**
     * @dev Indicates a failure with the `operator`’s approval. Used in transfers.
     * @param operator Address that may be allowed to operate on tokens without being their owner.
     * @param tokenId Identifier number of a token.
     */
    error ERC721InsufficientApproval(address operator, uint256 tokenId);

    /**
     * @dev Indicates a failure with the `approver` of a token to be approved. Used in approvals.
     * @param approver Address initiating an approval operation.
     */
    error ERC721InvalidApprover(address approver);

    /**
     * @dev Indicates a failure with the `operator` to be approved. Used in approvals.
     * @param operator Address that may be allowed to operate on tokens without being their owner.
     */
    error ERC721InvalidOperator(address operator);
}

/**
 * @dev Standard ERC-1155 Errors
 * Interface of the https://eips.ethereum.org/EIPS/eip-6093[ERC-6093] custom errors for ERC-1155 tokens.
 */
interface IERC1155Errors {
    /**
     * @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.
     * @param tokenId Identifier number of a token.
     */
    error ERC1155InsufficientBalance(address sender, uint256 balance, uint256 needed, uint256 tokenId);

    /**
     * @dev Indicates a failure with the token `sender`. Used in transfers.
     * @param sender Address whose tokens are being transferred.
     */
    error ERC1155InvalidSender(address sender);

    /**
     * @dev Indicates a failure with the token `receiver`. Used in transfers.
     * @param receiver Address to which tokens are being transferred.
     */
    error ERC1155InvalidReceiver(address receiver);

    /**
     * @dev Indicates a failure with the `operator`’s approval. Used in transfers.
     * @param operator Address that may be allowed to operate on tokens without being their owner.
     * @param owner Address of the current owner of a token.
     */
    error ERC1155MissingApprovalForAll(address operator, address owner);

    /**
     * @dev Indicates a failure with the `approver` of a token to be approved. Used in approvals.
     * @param approver Address initiating an approval operation.
     */
    error ERC1155InvalidApprover(address approver);

    /**
     * @dev Indicates a failure with the `operator` to be approved. Used in approvals.
     * @param operator Address that may be allowed to operate on tokens without being their owner.
     */
    error ERC1155InvalidOperator(address operator);

    /**
     * @dev Indicates an array length mismatch between ids and values in a safeBatchTransferFrom operation.
     * Used in batch transfers.
     * @param idsLength Length of the array of token identifiers
     * @param valuesLength Length of the array of token amounts
     */
    error ERC1155InvalidArrayLength(uint256 idsLength, uint256 valuesLength);
}

// OpenZeppelin Contracts (last updated v5.3.0) (token/ERC20/ERC20.sol)

/**
 * @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.
 */
abstract contract ERC20 is Context, IERC20, IERC20Metadata, IERC20Errors {
    mapping(address account => uint256) private _balances;

    mapping(address account => mapping(address spender => uint256)) private _allowances;

    uint256 private _totalSupply;

    string private _name;
    string private _symbol;

    /**
     * @dev Sets the values for {name} and {symbol}.
     *
     * Both values are immutable: they can only be set once during construction.
     */
    constructor(string memory name_, string memory symbol_) {
        _name = name_;
        _symbol = symbol_;
    }

    /**
     * @dev Returns the name of the token.
     */
    function name() public view virtual returns (string memory) {
        return _name;
    }

    /**
     * @dev Returns the symbol of the token, usually a shorter version of the
     * name.
     */
    function symbol() public view virtual returns (string memory) {
        return _symbol;
    }

    /**
     * @dev Returns the number of decimals used to get its user representation.
     * For example, if `decimals` equals `2`, a balance of `505` tokens should
     * be displayed to a user as `5.05` (`505 / 10 ** 2`).
     *
     * Tokens usually opt for a value of 18, imitating the relationship between
     * Ether and Wei. This is the default value returned by this function, unless
     * it's overridden.
     *
     * NOTE: This information is only used for _display_ purposes: it in
     * no way affects any of the arithmetic of the contract, including
     * {IERC20-balanceOf} and {IERC20-transfer}.
     */
    function decimals() public view virtual returns (uint8) {
        return 18;
    }

    /**
     * @dev See {IERC20-totalSupply}.
     */
    function totalSupply() public view virtual returns (uint256) {
        return _totalSupply;
    }

    /**
     * @dev See {IERC20-balanceOf}.
     */
    function balanceOf(address account) public view virtual returns (uint256) {
        return _balances[account];
    }

    /**
     * @dev See {IERC20-transfer}.
     *
     * Requirements:
     *
     * - `to` cannot be the zero address.
     * - the caller must have a balance of at least `value`.
     */
    function transfer(address to, uint256 value) public virtual returns (bool) {
        address owner = _msgSender();
        _transfer(owner, to, value);
        return true;
    }

    /**
     * @dev See {IERC20-allowance}.
     */
    function allowance(address owner, address spender) public view virtual returns (uint256) {
        return _allowances[owner][spender];
    }

    /**
     * @dev See {IERC20-approve}.
     *
     * NOTE: If `value` is the maximum `uint256`, the allowance is not updated on
     * `transferFrom`. This is semantically equivalent to an infinite approval.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     */
    function approve(address spender, uint256 value) public virtual returns (bool) {
        address owner = _msgSender();
        _approve(owner, spender, value);
        return true;
    }

    /**
     * @dev See {IERC20-transferFrom}.
     *
     * Skips emitting an {Approval} event indicating an allowance update. This is not
     * required by the ERC. See {xref-ERC20-_approve-address-address-uint256-bool-}[_approve].
     *
     * NOTE: Does not update the allowance if the current allowance
     * is the maximum `uint256`.
     *
     * Requirements:
     *
     * - `from` and `to` cannot be the zero address.
     * - `from` must have a balance of at least `value`.
     * - the caller must have allowance for ``from``'s tokens of at least
     * `value`.
     */
    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;
    }

    /**
     * @dev Moves a `value` amount of tokens from `from` to `to`.
     *
     * This internal function is equivalent to {transfer}, and can be used to
     * e.g. implement automatic token fees, slashing mechanisms, etc.
     *
     * Emits a {Transfer} event.
     *
     * NOTE: This function is not virtual, {_update} should be overridden instead.
     */
    function _transfer(address from, address to, uint256 value) internal {
        if (from == address(0)) {
            revert ERC20InvalidSender(address(0));
        }
        if (to == address(0)) {
            revert ERC20InvalidReceiver(address(0));
        }
        _update(from, to, value);
    }

    /**
     * @dev Transfers a `value` amount of tokens from `from` to `to`, or alternatively mints (or burns) if `from`
     * (or `to`) is the zero address. All customizations to transfers, mints, and burns should be done by overriding
     * this function.
     *
     * Emits a {Transfer} event.
     */
    function _update(address from, address to, uint256 value) internal virtual {
        if (from == address(0)) {
            // Overflow check required: The rest of the code assumes that totalSupply never overflows
            _totalSupply += value;
        } else {
            uint256 fromBalance = _balances[from];
            if (fromBalance < value) {
                revert ERC20InsufficientBalance(from, fromBalance, value);
            }
            unchecked {
                // Overflow not possible: value <= fromBalance <= totalSupply.
                _balances[from] = fromBalance - value;
            }
        }

        if (to == address(0)) {
            unchecked {
                // Overflow not possible: value <= totalSupply or value <= fromBalance <= totalSupply.
                _totalSupply -= value;
            }
        } else {
            unchecked {
                // Overflow not possible: balance + value is at most totalSupply, which we know fits into a uint256.
                _balances[to] += value;
            }
        }

        emit Transfer(from, to, value);
    }

    /**
     * @dev Creates a `value` amount of tokens and assigns them to `account`, by transferring it from address(0).
     * Relies on the `_update` mechanism
     *
     * Emits a {Transfer} event with `from` set to the zero address.
     *
     * NOTE: This function is not virtual, {_update} should be overridden instead.
     */
    function _mint(address account, uint256 value) internal {
        if (account == address(0)) {
            revert ERC20InvalidReceiver(address(0));
        }
        _update(address(0), account, value);
    }

    /**
     * @dev Destroys a `value` amount of tokens from `account`, lowering the total supply.
     * Relies on the `_update` mechanism.
     *
     * Emits a {Transfer} event with `to` set to the zero address.
     *
     * NOTE: This function is not virtual, {_update} should be overridden instead
     */
    function _burn(address account, uint256 value) internal {
        if (account == address(0)) {
            revert ERC20InvalidSender(address(0));
        }
        _update(account, address(0), value);
    }

    /**
     * @dev Sets `value` as the allowance of `spender` over the `owner`'s tokens.
     *
     * This internal function is equivalent to `approve`, and can be used to
     * e.g. set automatic allowances for certain subsystems, etc.
     *
     * Emits an {Approval} event.
     *
     * Requirements:
     *
     * - `owner` cannot be the zero address.
     * - `spender` cannot be the zero address.
     *
     * Overrides to this logic should be done to the variant with an additional `bool emitEvent` argument.
     */
    function _approve(address owner, address spender, uint256 value) internal {
        _approve(owner, spender, value, true);
    }

    /**
     * @dev Variant of {_approve} with an optional flag to enable or disable the {Approval} event.
     *
     * By default (when calling {_approve}) the flag is set to true. On the other hand, approval changes made by
     * `_spendAllowance` during the `transferFrom` operation set the flag to false. This saves gas by not emitting any
     * `Approval` event during `transferFrom` operations.
     *
     * Anyone who wishes to continue emitting `Approval` events on the`transferFrom` operation can force the flag to
     * true using the following override:
     *
     * ```solidity
     * function _approve(address owner, address spender, uint256 value, bool) internal virtual override {
     *     super._approve(owner, spender, value, true);
     * }
     * ```
     *
     * Requirements are the same as {_approve}.
     */
    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);
        }
    }

    /**
     * @dev Updates `owner`'s allowance for `spender` based on spent `value`.
     *
     * Does not update the allowance value in case of infinite allowance.
     * Revert if not enough allowance is available.
     *
     * Does not emit an {Approval} event.
     */
    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);
            }
        }
    }
}

// OpenZeppelin Contracts (last updated v5.0.0) (access/Ownable.sol)

/**
 * @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);
    }
}

/**
 * @title PSN
 */
contract PSN is ERC20, Ownable {
    // Constants
    uint8 private constant DECIMALS = 18;
    uint256 private constant INITIAL_SUPPLY = 8_205_771_000 * 10**18;
    uint256 private constant MAX_TAX = 80;
    uint256 public constant MAX_ARRAY_BATCH = 30;
    
    // State variables
    uint256 public taxFee;
    uint256 public maxTxAmount;
    uint256 public maxWalletSize;
    address public feeWallet;
    bool public isPerBlockDelayEnabled;
    
    // Mappings
    mapping(address => bool) private _isBot;
    mapping(address => bool) private _isExcludedFromFee;
    mapping(address => bool) private _isExcludedFromLimits;
    mapping(address => uint256) private _lastTransferBlock;
    mapping(address => uint256) private _lastReceiveBlock;
    
    // Public getters for private mappings
    /**
     * @notice Returns true if the address is blacklisted as a bot.
     * @param account The address to check.
     * @return True if the address is a bot, false otherwise.
     */
    function isBot(address account) public view returns (bool) {
        return _isBot[account];
    }

    /**
     * @notice Returns true if the address is excluded from tax fees.
     * @param account The address to check.
     * @return True if the address is excluded from fees, false otherwise.
     */
    function isExcludedFromFee(address account) public view returns (bool) {
        return _isExcludedFromFee[account];
    }
    
    /**
     * @notice Returns true if the address is excluded from transaction and wallet limits.
     * @param account The address to check.
     * @return True if the address is excluded from limits, false otherwise.
     */
    function isExcludedFromLimits(address account) public view returns (bool) {
        return _isExcludedFromLimits[account];
    }
    
    // Events
    event TaxFeeUpdated(uint256 taxFee);
    event LimitsUpdated(uint256 maxTxAmount, uint256 maxWalletSize);
    event FeeWalletUpdated(address newFeeWallet);
    event PerBlockDelayToggled(bool enabled);
    event BotUpdated(address indexed bot, bool isBlacklisted);
    event ExcludedFromFeeUpdated(address indexed account, bool isExcluded);
    event ExcludedFromLimitsUpdated(address indexed account, bool isExcluded);
    event BotsBatchUpdated(address[] bots, bool enabled);
    
    /**
     * @dev Initializes the PSN token with the given owner and fee wallet.
     * @param initialOwner The address that will be assigned as the contract owner and receive the initial supply.
     * @param _feeWallet The address that will receive collected tax fees and be excluded from fees and limits by default.
     */
    constructor(
        address initialOwner,
        address _feeWallet
    ) ERC20("PSN", "PSN") Ownable(initialOwner) {
        require(_feeWallet != address(0), "PSN: zero fee wallet");

        taxFee = 3;
        maxTxAmount = INITIAL_SUPPLY / 100;
        maxWalletSize = INITIAL_SUPPLY / 50;
        feeWallet = _feeWallet;
        isPerBlockDelayEnabled = true; 
        _mint(initialOwner, INITIAL_SUPPLY);
        // Exclude after mint for warm SSTORE
        _isExcludedFromLimits[address(this)] = true;
        _isExcludedFromLimits[initialOwner] = true;
        _isExcludedFromLimits[_feeWallet] = true;
        _isExcludedFromFee[address(this)] = true;
        _isExcludedFromFee[initialOwner] = true;
        _isExcludedFromFee[_feeWallet] = true;
    }
    
    /**
     * @dev Returns the number of decimals used to get its user representation
     */
    function decimals() public view virtual override returns (uint8) {
        return DECIMALS;
    }
    
    /**
     * @dev Updates tax fee
     * @param _taxFee New tax fee rate (0-MAX_TAX)
     */
    function updateTaxFee(uint256 _taxFee) external onlyOwner {
        require(_taxFee <= MAX_TAX, "PSN: tax too high");
        taxFee = _taxFee;
        emit TaxFeeUpdated(_taxFee);
    }
    
    /**
     * @dev Updates transaction and wallet limits
     * @param _maxTxAmount New maximum transaction amount
     * @param _maxWalletSize New maximum wallet size
     */
    function updateLimits(uint256 _maxTxAmount, uint256 _maxWalletSize) external onlyOwner {
        require(_maxTxAmount > 0 && _maxWalletSize > 0, "PSN: zero limit");
        maxTxAmount = _maxTxAmount;
        maxWalletSize = _maxWalletSize;
        emit LimitsUpdated(_maxTxAmount, _maxWalletSize);
    }
    
    /**
     * @dev Updates the fee wallet address
     * @param _feeWallet New fee wallet address
     */
    function updateFeeWallet(address _feeWallet) external onlyOwner {
        require(_feeWallet != address(0), "PSN: zero fee wallet");
        feeWallet = _feeWallet;
        _isExcludedFromLimits[_feeWallet] = true;
        _isExcludedFromFee[_feeWallet] = true;
        emit ExcludedFromLimitsUpdated(_feeWallet, true);
        emit ExcludedFromFeeUpdated(_feeWallet, true);
        emit FeeWalletUpdated(_feeWallet);
    }
    
    /**
     * @dev Toggles the per-block transfer delay feature
     * @param enabled Whether to enable or disable the feature
     */
    function togglePerBlockDelay(bool enabled) external onlyOwner {
        isPerBlockDelayEnabled = enabled;
        emit PerBlockDelayToggled(enabled);
    }
    
    /**
     * @dev Adds addresses to the bot blacklist
     * @param _bots Array of addresses to blacklist
     */
    function addBots(address[] calldata _bots) external onlyOwner {
        uint256 length = _bots.length;
        require(length > 0, "PSN: no addresses");
        require(length <= MAX_ARRAY_BATCH, "PSN: batch too big");
        for (uint256 i; i < length;) {
            address bot = _bots[i];
            if (!_isBot[bot]) {
                _isBot[bot] = true;
                emit BotUpdated(bot, true);
            }
            unchecked { ++i; }
        }
        emit BotsBatchUpdated(_bots, true);
    }
    
    /**
     * @dev Removes addresses from the bot blacklist
     * @param _bots Array of addresses to remove from blacklist
     */
    function removeBots(address[] calldata _bots) external onlyOwner {
        uint256 length = _bots.length;
        require(length > 0, "PSN: no addresses");
        require(length <= MAX_ARRAY_BATCH, "PSN: batch too big");
        for (uint256 i; i < length;) {
            address bot = _bots[i];
            if (_isBot[bot]) {
                _isBot[bot] = false;
                emit BotUpdated(bot, false);
            }
            unchecked { ++i; }
        }
        emit BotsBatchUpdated(_bots, false);
    }
    
    /**
     * @dev Adds addresses to the limits exclusion list
     * @param accounts Array of addresses to exclude from limits
     */
    function addExcludedFromLimits(address[] calldata accounts) external onlyOwner {
        uint256 len = accounts.length;
        require(len > 0, "PSN: no addresses");
        require(len <= MAX_ARRAY_BATCH, "PSN: batch too big");
        for (uint256 i; i < len;) {
            address a = accounts[i];
            if (!_isExcludedFromLimits[a]) {
                _isExcludedFromLimits[a] = true;
                emit ExcludedFromLimitsUpdated(a, true);
            }
            unchecked { ++i; }
        }
    }
    
    /**
     * @dev Removes addresses from the limits exclusion list
     * @param accounts Array of addresses to remove from exclusion
     */
    function removeExcludedFromLimits(address[] calldata accounts) external onlyOwner {
        uint256 len = accounts.length;
        require(len > 0, "PSN: no addresses");
        require(len <= MAX_ARRAY_BATCH, "PSN: batch too big");
        for (uint256 i; i < len;) {
            address a = accounts[i];
            if (_isExcludedFromLimits[a]) {
                _isExcludedFromLimits[a] = false;
                emit ExcludedFromLimitsUpdated(a, false);
            }
            unchecked { ++i; }
        }
    }
    
    /**
     * @dev Adds addresses to the fee exclusion list
     * @param accounts Array of addresses to exclude from fee
     */
    function addExcludedFromFee(address[] calldata accounts) external onlyOwner {
        uint256 len = accounts.length;
        require(len > 0, "PSN: no addresses");
        require(len <= MAX_ARRAY_BATCH, "PSN: batch too big");
        for (uint256 i; i < len;) {
            address a = accounts[i];
            if (!_isExcludedFromFee[a]) {
                _isExcludedFromFee[a] = true;
                emit ExcludedFromFeeUpdated(a, true);
            }
            unchecked { ++i; }
        }
    }
    
    /**
     * @dev Removes addresses from the fee exclusion list
     * @param accounts Array of addresses to remove from exclusion
     */
    function removeExcludedFromFee(address[] calldata accounts) external onlyOwner {
        uint256 len = accounts.length;
        require(len > 0, "PSN: no addresses");
        require(len <= MAX_ARRAY_BATCH, "PSN: batch too big");
        for (uint256 i; i < len;) {
            address a = accounts[i];
            if (_isExcludedFromFee[a]) {
                _isExcludedFromFee[a] = false;
                emit ExcludedFromFeeUpdated(a, false);
            }
            unchecked { ++i; }
        }
    }
    
    /**
     * @dev Override _update function to include tax and limit checks
     * @param from Sender address
     * @param to Recipient address
     * @param amount Amount to transfer
     */
    function _update(
        address from,
        address to,
        uint256 amount
    ) internal virtual override {
        // Skip all checks for minting
        if (from == address(0)) {
            super._update(from, to, amount);
            return;
        }
        
        // Check for bots first to save gas on reverts
        require(!_isBot[from] && !_isBot[to], "PSN: bot");
        
        // Cache excluded status to save SLOADs
        bool fromExcluded = _isExcludedFromLimits[from];
        bool toExcluded = _isExcludedFromLimits[to];
        
        // Per-block transfer delay check (only if enabled)
        if (isPerBlockDelayEnabled) {
            require(
                _lastTransferBlock[from] < block.number,
                "PSN: one tx per block"
            );
            require(
                _lastReceiveBlock[to] < block.number,
                "PSN: one receive per block"
            );
            _lastTransferBlock[from] = block.number;
            _lastReceiveBlock[to] = block.number;
        }

        // Short-circuit self-transfers after per-block checks
        if (from == to) {
            super._update(from, to, amount);
            return;
        }
        
        // Apply tax fee unless sender or receiver is excluded
        uint256 taxAmount = 0;
        uint256 transferAmount = amount;
        if (!_isExcludedFromFee[from] && !_isExcludedFromFee[to] && taxFee > 0) {
            taxAmount = amount * taxFee / 100;
            transferAmount = amount - taxAmount;
        }
        
        // Short-circuit for owner transfers
        if (from != owner() && to != owner()) {
            // Check maxTxAmount for non-excluded senders
            if (!fromExcluded) {
                require(amount <= maxTxAmount, "PSN: tx exceeds limit");
            }
            
            // Check maxWalletSize for non-excluded receivers
            if (!toExcluded) {
                // Cache balanceOf(to) to save an SLOAD
                uint256 toBalance = balanceOf(to);
                require(toBalance + transferAmount <= maxWalletSize, "PSN: wallet exceeds limit");
            }
        }
        
        if (taxAmount > 0) {
            super._update(from, feeWallet, taxAmount);
        }
        
        super._update(from, to, transferAmount);
    }
}