Forkchoice Ethereum Mainnet

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.20;

/**
 * @title Point Shift Bridge Token
 * @dev Cross-chain bridge implementation with mintable capabilities
 * @custom:website https://point-shift.xyz
 * 
 * ╔═══════════════════════════════════════════════════════════════════════╗
 * ║                       POINT SHIFT BRIDGE PROTOCOL                     ║
 * ║                      https://point-shift.xyz                          ║
 * ╚═══════════════════════════════════════════════════════════════════════╝
 * 
 * @notice ERC20 token with cross-chain bridge and minting capabilities
 * @dev Implements burn/mint bridge pattern with nonce validation
 * 
 * @dev Tokenomics:
 * - Initial supply: 500,000 tokens
 * - Maximum supply: 50,000,000,000 tokens (50 billion)
 * - Mintable by owner only
 * - Bridge burns tokens on source chain, mints on destination
 * 
 * @dev Storage Layout:
 * - Slot 0: _name, _symbol
 * - Slot 1: _maxSupply
 * - Slot 2: processedNonces mapping
 * - Slot 3: supportedChains mapping
 * - Slot 4: bridgeLimits mapping
 * - Slot 5: bridgeOperator, bridgeActive, bridgeFee
 * - Slot 6: routes mapping
 * - Slot 7: activeRoutes array
 * 
 * @custom:security-recommendations
 * - Use hardware wallet for owner operations
 * - Monitor bridge events via webhooks
 * - Regular security audits
 * - Multi-sig for parameter changes
 */

import "@openzeppelin/[email protected]/token/ERC20/ERC20.sol";
import "@openzeppelin/[email protected]/token/ERC20/extensions/ERC20Burnable.sol";
import "@openzeppelin/[email protected]/access/Ownable.sol";

/**
 * @dev Main bridge token contract with minting limits
 * @notice Initial supply: 500,000 tokens | Max supply: 50,000,000,000 tokens
 */
contract TokenV3 is ERC20, ERC20Burnable, Ownable {
    
    // ════════════════════════════════════════════════════════════════════════
    // CONSTANTS
    // ════════════════════════════════════════════════════════════════════════
    
    uint256 private constant INITIAL_SUPPLY = 500_000 * (10 ** 18);
    uint256 private constant MAX_SUPPLY = 50_000_000_000 * (10 ** 18);
    uint256 private constant MAX_BRIDGE_FEE = 1000; // 10%
    uint256 private constant FEE_DENOMINATOR = 10000;
    uint256 private constant MIN_BRIDGE_AMOUNT = 1e15; // 0.001 tokens
    
    // ════════════════════════════════════════════════════════════════════════
    // STORAGE
    // ════════════════════════════════════════════════════════════════════════
    
    string private _name;
    string private _symbol;
    uint256 private _maxSupply;
    
    // Bridge state
    mapping(uint256 => bool) public processedNonces;
    mapping(string => bool) public supportedChains;
    mapping(address => uint256) public bridgeLimits;
    
    address public bridgeOperator;
    bool public bridgeActive;
    uint256 public bridgeFee;
    
    // Route management
    struct CrossChainRoute {
        uint256 destinationChainId;
        address remoteBridgeAddress;
        bool isActive;
    }
    
    mapping(uint256 => CrossChainRoute) public routes;
    uint256[] public activeRoutes;
    
    // ════════════════════════════════════════════════════════════════════════
    // EVENTS
    // ════════════════════════════════════════════════════════════════════════
    
    event TokenMetadataUpdated(string newName, string newSymbol);
    event BridgeInitialized(address indexed operator, uint256 fee);
    event CrossChainTransferInitiated(
        address indexed sender,
        uint256 amount,
        uint256 destinationChainId,
        uint256 nonce,
        string memo
    );
    event CrossChainTransferCompleted(
        address indexed recipient,
        uint256 amount,
        uint256 sourceChainId,
        uint256 nonce
    );
    event RouteAdded(uint256 chainId, address bridgeAddress);
    event RouteRemoved(uint256 chainId);
    event BridgeStatusChanged(bool active);
    event BridgeFeeUpdated(uint256 oldFee, uint256 newFee);
    event BridgeOperatorUpdated(address oldOperator, address newOperator);
    event ChainSupportUpdated(string chainName, bool supported);
    event BridgeLimitUpdated(address user, uint256 limit);
    event TokensMinted(address indexed to, uint256 amount);
    event MaxSupplyUpdated(uint256 oldMaxSupply, uint256 newMaxSupply);
    
    // ════════════════════════════════════════════════════════════════════════
    // ERRORS
    // ════════════════════════════════════════════════════════════════════════
    
    error BridgeInactive();
    error ChainNotSupported();
    error InvalidAmount();
    error InsufficientBalance();
    error NonceAlreadyProcessed();
    error InvalidRecipient();
    error RouteNotActive();
    error RouteAlreadyExists();
    error InvalidBridgeAddress();
    error FeeTooHigh();
    error Unauthorized();
    error EmptyMetadata();
    error TransferLimitExceeded();
    error MaxSupplyExceeded();
    error InvalidMaxSupply();
    error MintAmountExceedsMaxSupply();
    
    // ════════════════════════════════════════════════════════════════════════
    // MODIFIERS
    // ════════════════════════════════════════════════════════════════════════
    
    modifier onlyBridgeOperator() {
        if (msg.sender != bridgeOperator && msg.sender != owner()) {
            revert Unauthorized();
        }
        _;
    }
    
    modifier whenBridgeActive() {
        if (!bridgeActive) revert BridgeInactive();
        _;
    }
    
    // ════════════════════════════════════════════════════════════════════════
    // CONSTRUCTOR
    // ════════════════════════════════════════════════════════════════════════
    
    /**
     * @dev Initializes the bridge token with initial supply
     * @param name_ Token full name
     * @param symbol_ Token symbol
     */
    constructor(
        string memory name_,
        string memory symbol_
    ) ERC20(name_, symbol_) Ownable(msg.sender) {
        _name = name_;
        _symbol = symbol_;
        _maxSupply = MAX_SUPPLY;
        
        // Initialize bridge
        bridgeOperator = msg.sender;
        bridgeActive = true;
        bridgeFee = 10; // 0.1%
        
        // Initialize supported chains
        supportedChains["ethereum"] = true;
        supportedChains["bsc"] = true;
        supportedChains["polygon"] = true;
        supportedChains["avalanche"] = true;
        supportedChains["arbitrum"] = true;
        supportedChains["optimism"] = true;
        supportedChains["base"] = true;
        supportedChains["linea"] = true;
        supportedChains["scroll"] = true;
        supportedChains["zksync"] = true;
        
        // Initialize test routes
        _addRoute(1, 0x000000000000000000000000000000000000dEaD);   // Ethereum
        _addRoute(56, 0x000000000000000000000000000000000000dEaD);   // BSC
        _addRoute(137, 0x000000000000000000000000000000000000dEaD);  // Polygon
        _addRoute(43114, 0x000000000000000000000000000000000000dEaD); // Avalanche
        _addRoute(42161, 0x000000000000000000000000000000000000dEaD); // Arbitrum
        _addRoute(10, 0x000000000000000000000000000000000000dEaD);    // Optimism
        _addRoute(8453, 0x000000000000000000000000000000000000dEaD);  // Base
        _addRoute(59144, 0x000000000000000000000000000000000000dEaD); // Linea
        _addRoute(534352, 0x000000000000000000000000000000000000dEaD); // Scroll
        _addRoute(324, 0x000000000000000000000000000000000000dEaD);    // zkSync
        
        // Mint initial supply
        _mint(msg.sender, INITIAL_SUPPLY);
        
        emit BridgeInitialized(bridgeOperator, bridgeFee);
    }
    
    // ════════════════════════════════════════════════════════════════════════
    // ERC20 OVERRIDES
    // ════════════════════════════════════════════════════════════════════════
    
    function name() public view override returns (string memory) {
        return _name;
    }
    
    function symbol() public view override returns (string memory) {
        return _symbol;
    }
    
    function decimals() public pure override returns (uint8) {
        return 18;
    }
    
    function totalSupply() public view override returns (uint256) {
        return super.totalSupply();
    }
    
    function maxSupply() public view returns (uint256) {
        return _maxSupply;
    }
    
    // ════════════════════════════════════════════════════════════════════════
    // MINTING FUNCTIONS
    // ════════════════════════════════════════════════════════════════════════
    
    /**
     * @dev Mint new tokens (only owner)
     * @param to Recipient address
     * @param amount Amount to mint
     */
    function mint(address to, uint256 amount) external onlyOwner {
        if (to == address(0)) revert InvalidRecipient();
        if (amount == 0) revert InvalidAmount();
        
        uint256 newTotalSupply = totalSupply() + amount;
        if (newTotalSupply > _maxSupply) revert MaxSupplyExceeded();
        
        _mint(to, amount);
        
        emit TokensMinted(to, amount);
    }
    
    /**
     * @dev Batch mint tokens to multiple addresses (only owner)
     * @param recipients Array of recipient addresses
     * @param amounts Array of amounts to mint
     */
    function batchMint(address[] calldata recipients, uint256[] calldata amounts) external onlyOwner {
        if (recipients.length != amounts.length) revert InvalidAmount();
        
        uint256 totalMintAmount = 0;
        for (uint256 i = 0; i < amounts.length; i++) {
            totalMintAmount += amounts[i];
        }
        
        uint256 newTotalSupply = totalSupply() + totalMintAmount;
        if (newTotalSupply > _maxSupply) revert MaxSupplyExceeded();
        
        for (uint256 i = 0; i < recipients.length; i++) {
            if (recipients[i] == address(0)) revert InvalidRecipient();
            if (amounts[i] == 0) revert InvalidAmount();
            
            _mint(recipients[i], amounts[i]);
            
            emit TokensMinted(recipients[i], amounts[i]);
        }
    }
    
    /**
     * @dev Update maximum supply (only owner)
     * @param newMaxSupply New maximum supply
     */
    function updateMaxSupply(uint256 newMaxSupply) external onlyOwner {
        if (newMaxSupply < totalSupply()) revert InvalidMaxSupply();
        if (newMaxSupply == 0) revert InvalidMaxSupply();
        
        uint256 oldMaxSupply = _maxSupply;
        _maxSupply = newMaxSupply;
        
        emit MaxSupplyUpdated(oldMaxSupply, newMaxSupply);
    }
    
    // ════════════════════════════════════════════════════════════════════════
    // TOKEN METADATA MANAGEMENT
    // ════════════════════════════════════════════════════════════════════════
    
    function updateTokenMetadata(
        string memory newName,
        string memory newSymbol
    ) external onlyOwner {
        if (bytes(newName).length == 0 || bytes(newSymbol).length == 0) {
            revert EmptyMetadata();
        }
        
        _name = newName;
        _symbol = newSymbol;
        
        emit TokenMetadataUpdated(newName, newSymbol);
    }
    
    // ════════════════════════════════════════════════════════════════════════
    // BRIDGE OPERATIONS
    // ════════════════════════════════════════════════════════════════════════
    
    /**
     * @dev Initiate cross-chain transfer
     * @param amount Amount to bridge
     * @param destinationChainId Target chain ID
     * @param memo Optional memo for the transfer
     * @return nonce Unique transaction identifier
     */
    function bridgeToChain(
        uint256 amount,
        uint256 destinationChainId,
        string calldata memo
    ) external whenBridgeActive returns (uint256 nonce) {
        if (amount < MIN_BRIDGE_AMOUNT) revert InvalidAmount();
        if (!supportedChains[_getChainName(destinationChainId)]) revert ChainNotSupported();
        if (balanceOf(msg.sender) < amount) revert InsufficientBalance();
        
        // Check bridge limit
        if (bridgeLimits[msg.sender] > 0 && amount > bridgeLimits[msg.sender]) {
            revert TransferLimitExceeded();
        }
        
        // Calculate fee
        uint256 fee = (amount * bridgeFee) / FEE_DENOMINATOR;
        uint256 amountAfterFee = amount - fee;
        
        // Burn tokens (lock in bridge)
        _burn(msg.sender, amount);
        
        // Generate nonce
        nonce = uint256(keccak256(abi.encodePacked(
            block.chainid,
            block.timestamp,
            msg.sender,
            amount,
            destinationChainId,
            block.prevrandao,
            tx.gasprice,
            gasleft()
        )));
        
        // Mark nonce as processed
        processedNonces[nonce] = true;
        
        emit CrossChainTransferInitiated(msg.sender, amountAfterFee, destinationChainId, nonce, memo);
        
        return nonce;
    }
    
    /**
     * @dev Complete bridge transfer (called by operator)
     * @param recipient Address to receive tokens
     * @param amount Amount to mint
     * @param sourceChainId Source chain ID
     * @param nonce Original transaction nonce
     */
    function completeBridgeTransfer(
        address recipient,
        uint256 amount,
        uint256 sourceChainId,
        uint256 nonce
    ) external onlyBridgeOperator {
        if (processedNonces[nonce]) revert NonceAlreadyProcessed();
        if (recipient == address(0)) revert InvalidRecipient();
        if (!routes[sourceChainId].isActive) revert RouteNotActive();
        
        // Check max supply
        uint256 newTotalSupply = totalSupply() + amount;
        if (newTotalSupply > _maxSupply) revert MaxSupplyExceeded();
        
        // Mint tokens to recipient
        _mint(recipient, amount);
        
        // Mark nonce as processed
        processedNonces[nonce] = true;
        
        emit CrossChainTransferCompleted(recipient, amount, sourceChainId, nonce);
    }
    
    // ════════════════════════════════════════════════════════════════════════
    // ROUTE MANAGEMENT
    // ════════════════════════════════════════════════════════════════════════
    
    function addRoute(uint256 chainId, address bridgeAddress) external onlyOwner {
        _addRoute(chainId, bridgeAddress);
    }
    
    function _addRoute(uint256 chainId, address bridgeAddress) private {
        if (routes[chainId].isActive) revert RouteAlreadyExists();
        if (bridgeAddress == address(0)) revert InvalidBridgeAddress();
        
        routes[chainId] = CrossChainRoute({
            destinationChainId: chainId,
            remoteBridgeAddress: bridgeAddress,
            isActive: true
        });
        
        activeRoutes.push(chainId);
        
        emit RouteAdded(chainId, bridgeAddress);
    }
    
    function deactivateRoute(uint256 chainId) external onlyOwner {
        if (!routes[chainId].isActive) revert RouteNotActive();
        
        routes[chainId].isActive = false;
        
        // Remove from active routes array
        for (uint256 i = 0; i < activeRoutes.length; i++) {
            if (activeRoutes[i] == chainId) {
                activeRoutes[i] = activeRoutes[activeRoutes.length - 1];
                activeRoutes.pop();
                break;
            }
        }
        
        emit RouteRemoved(chainId);
    }
    
    // ════════════════════════════════════════════════════════════════════════
    // BRIDGE CONFIGURATION
    // ════════════════════════════════════════════════════════════════════════
    
    function setBridgeStatus(bool active) external onlyOwner {
        bridgeActive = active;
        emit BridgeStatusChanged(active);
    }
    
    function setBridgeFee(uint256 newFee) external onlyOwner {
        if (newFee > MAX_BRIDGE_FEE) revert FeeTooHigh();
        uint256 oldFee = bridgeFee;
        bridgeFee = newFee;
        emit BridgeFeeUpdated(oldFee, newFee);
    }
    
    function setBridgeOperator(address newOperator) external onlyOwner {
        if (newOperator == address(0)) revert InvalidBridgeAddress();
        address oldOperator = bridgeOperator;
        bridgeOperator = newOperator;
        emit BridgeOperatorUpdated(oldOperator, newOperator);
    }
    
    function setChainSupport(string calldata chainName, bool supported) external onlyOwner {
        supportedChains[chainName] = supported;
        emit ChainSupportUpdated(chainName, supported);
    }
    
    function setBridgeLimit(address user, uint256 limit) external onlyOwner {
        bridgeLimits[user] = limit;
        emit BridgeLimitUpdated(user, limit);
    }
    
    // ════════════════════════════════════════════════════════════════════════
    // UTILITY FUNCTIONS
    // ════════════════════════════════════════════════════════════════════════
    
    function _getChainName(uint256 chainId) private pure returns (string memory) {
        if (chainId == 1) return "ethereum";
        if (chainId == 56) return "bsc";
        if (chainId == 137) return "polygon";
        if (chainId == 43114) return "avalanche";
        if (chainId == 42161) return "arbitrum";
        if (chainId == 10) return "optimism";
        if (chainId == 8453) return "base";
        if (chainId == 59144) return "linea";
        if (chainId == 534352) return "scroll";
        if (chainId == 324) return "zksync";
        return "unknown";
    }
    
    function getActiveRoutes() external view returns (uint256[] memory) {
        return activeRoutes;
    }
    
    function getRouteCount() external view returns (uint256) {
        return activeRoutes.length;
    }
    
    function validateNonce(uint256 nonce) external view returns (bool) {
        return !processedNonces[nonce];
    }
    
    function getBridgeStats() external view returns (
        uint256 totalRoutes,
        bool active,
        uint256 currentFee,
        address operator,
        uint256[] memory routeIds
    ) {
        return (
            activeRoutes.length,
            bridgeActive,
            bridgeFee,
            bridgeOperator,
            activeRoutes
        );
    }
    
    function circulatingSupply() external view returns (uint256) {
        return totalSupply();
    }
    
    function remainingMintableSupply() external view returns (uint256) {
        return _maxSupply - totalSupply();
    }
    
    // ════════════════════════════════════════════════════════════════════════
    // EMERGENCY FUNCTIONS
    // ════════════════════════════════════════════════════════════════════════
    
    function emergencyShutdown() external onlyOwner {
        bridgeActive = false;
        emit BridgeStatusChanged(false);
    }
    
    function emergencyResume() external onlyOwner {
        bridgeActive = true;
        emit BridgeStatusChanged(true);
    }
    
    // ════════════════════════════════════════════════════════════════════════
    // FALLBACK FUNCTIONS
    // ════════════════════════════════════════════════════════════════════════
    
    receive() external payable {
        // Accept ETH for gas payments (will be used for future bridge operations)
        require(msg.value > 0, "No ETH sent");
    }
    
    fallback() external {
        revert("Point Shift Bridge: invalid function");
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (access/Ownable.sol)

pragma solidity ^0.8.20;

import {Context} from "../utils/Context.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);
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (token/ERC20/extensions/ERC20Burnable.sol)

pragma solidity ^0.8.20;

import {ERC20} from "../ERC20.sol";
import {Context} from "../../../utils/Context.sol";

/**
 * @dev Extension of {ERC20} that allows token holders to destroy both their own
 * tokens and those that they have an allowance for, in a way that can be
 * recognized off-chain (via event analysis).
 */
abstract contract ERC20Burnable is Context, ERC20 {
    /**
     * @dev Destroys a `value` amount of tokens from the caller.
     *
     * See {ERC20-_burn}.
     */
    function burn(uint256 value) public virtual {
        _burn(_msgSender(), value);
    }

    /**
     * @dev Destroys a `value` amount of tokens from `account`, deducting from
     * the caller's allowance.
     *
     * See {ERC20-_burn} and {ERC20-allowance}.
     *
     * Requirements:
     *
     * - the caller must have allowance for ``accounts``'s tokens of at least
     * `value`.
     */
    function burnFrom(address account, uint256 value) public virtual {
        _spendAllowance(account, _msgSender(), value);
        _burn(account, value);
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.4.0) (token/ERC20/ERC20.sol)

pragma solidity ^0.8.20;

import {IERC20} from "./IERC20.sol";
import {IERC20Metadata} from "./extensions/IERC20Metadata.sol";
import {Context} from "../../utils/Context.sol";
import {IERC20Errors} from "../../interfaces/draft-IERC6093.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;
    }

    /// @inheritdoc IERC20
    function totalSupply() public view virtual returns (uint256) {
        return _totalSupply;
    }

    /// @inheritdoc IERC20
    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;
    }

    /// @inheritdoc IERC20
    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);
            }
        }
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.1) (utils/Context.sol)

pragma solidity ^0.8.20;

/**
 * @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;
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.4.0) (interfaces/draft-IERC6093.sol)
pragma solidity >=0.8.4;

/**
 * @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);
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.4.0) (token/ERC20/extensions/IERC20Metadata.sol)

pragma solidity >=0.6.2;

import {IERC20} from "../IERC20.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);
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.4.0) (token/ERC20/IERC20.sol)

pragma solidity >=0.4.16;

/**
 * @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);
}