SoulboundExpiringNFTUpgradeable

{{
  "language": "Solidity",
  "sources": {
    "UpdatedNFTImageSoul.sol": {
      "content": "// SPDX-License-Identifier: MIT
pragma solidity ^0.8.20;

/*
 * Soulbound + Expiration ERC-721 (Upgradeable) with shared image
 * - Non-transferable (SBT)
 * - Mint: issuer-only; recipient & days specified at mint
 * - Burn: issuer-only
 * - Expiration: per-token expiresAt set at mint; query helpers
 * - ERC-5192 compatible (Locked)
 * - Upgradeable with UUPS pattern
 * - All tokens reference the same metadata / image
 */

import "@openzeppelin/contracts-upgradeable/token/ERC721/ERC721Upgradeable.sol";
import "@openzeppelin/contracts-upgradeable/access/OwnableUpgradeable.sol";
import "@openzeppelin/contracts-upgradeable/proxy/utils/UUPSUpgradeable.sol";
import "@openzeppelin/contracts-upgradeable/proxy/utils/Initializable.sol";

interface IERC5192 {
    event Locked(uint256 tokenId);
    function locked(uint256 tokenId) external view returns (bool);
}

contract SoulboundExpiringNFTUpgradeable is
    Initializable,
    ERC721Upgradeable,
    OwnableUpgradeable,
    UUPSUpgradeable,
    IERC5192
{
    // --- Storage ---
    uint256 private _nextId;
    mapping(uint256 => uint64) public expiresAt;

    string private _baseTokenURI; // Shared metadata URI

    // --- Events ---
    event ExpirationSet(uint256 indexed tokenId, uint64 expiresAt);

    // --- Errors ---
    error Soulbound();
    error ApprovalsDisabled();
    error InvalidDays();
    error NonexistentToken();

    // --- Initializer ---
    function initialize(
        string memory name_,
        string memory symbol_,
        string memory baseTokenURI_
    ) public initializer {
        __ERC721_init(name_, symbol_);
        __Ownable_init(msg.sender);
        __UUPSUpgradeable_init();
        _nextId = 1;
        _baseTokenURI = baseTokenURI_;
    }

    // --- Authorize upgrades ---
    function _authorizeUpgrade(address newImplementation) internal onlyOwner override {}

    // --- Mint/Burn ---
    function mintWithExpiry(address to, uint64 daysValid) external onlyOwner returns (uint256 tokenId) {
        if (daysValid == 0) revert InvalidDays();

        tokenId = _nextId++;
        _safeMint(to, tokenId);

        expiresAt[tokenId] = uint64(block.timestamp + uint256(daysValid) * 1 days);

        emit Locked(tokenId);
        emit ExpirationSet(tokenId, expiresAt[tokenId]);
    }

    function burn(uint256 tokenId) external onlyOwner {
        if (_ownerOf(tokenId) == address(0)) revert NonexistentToken();
        _burn(tokenId);
        delete expiresAt[tokenId];
    }

    // --- Soulbound enforcement (fixed) ---
    function _beforeTokenTransfer(
        address from,
        address to,
        uint256 /*tokenId*/,
        uint256 /*batchSize*/
    ) internal virtual {
        // allow minting (from == 0) and burning (to == 0)
        if (from != address(0) && to != address(0)) {
            revert Soulbound(); // block transfers
        }
        // no super call needed, parent does not implement _beforeTokenTransfer
    }

    // --- Disable approvals ---
    function approve(address, uint256) public pure override {
        revert ApprovalsDisabled();
    }

    function setApprovalForAll(address, bool) public pure override {
        revert ApprovalsDisabled();
    }

    // --- ERC-5192 interface ---
    function locked(uint256 tokenId) external view override returns (bool) {
        if (_ownerOf(tokenId) == address(0)) revert NonexistentToken();
        return true;
    }

    // --- Expiration helpers ---
    function isExpired(uint256 tokenId) public view returns (bool) {
        if (_ownerOf(tokenId) == address(0)) revert NonexistentToken();
        return block.timestamp >= expiresAt[tokenId];
    }

    function secondsUntilExpiry(uint256 tokenId) external view returns (uint256) {
        if (_ownerOf(tokenId) == address(0)) revert NonexistentToken();
        uint64 exp = expiresAt[tokenId];
        return block.timestamp >= exp ? 0 : uint256(exp) - block.timestamp;
    }

    function activeOwnerOf(uint256 tokenId) external view returns (address) {
        if (_ownerOf(tokenId) == address(0)) return address(0);
        return block.timestamp >= expiresAt[tokenId] ? address(0) : ownerOf(tokenId);
    }

    // --- Metadata / Image ---
    function tokenURI(uint256 tokenId) public view override returns (string memory) {
        if (_ownerOf(tokenId) == address(0)) revert NonexistentToken();
        return _baseTokenURI;
    }

    function setBaseTokenURI(string memory newURI) external onlyOwner {
        _baseTokenURI = newURI;
    }

    // --- ERC165 support ---
    function supportsInterface(bytes4 interfaceId) public view override returns (bool) {
        return interfaceId == type(IERC5192).interfaceId || super.supportsInterface(interfaceId);
    }
}

"
    },
    "@openzeppelin/contracts-upgradeable/proxy/utils/Initializable.sol": {
      "content": "// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.3.0) (proxy/utils/Initializable.sol)

pragma solidity ^0.8.20;

/**
 * @dev This is a base contract to aid in writing upgradeable contracts, or any kind of contract that will be deployed
 * behind a proxy. Since proxied contracts do not make use of a constructor, it's common to move constructor logic to an
 * external initializer function, usually called `initialize`. It then becomes necessary to protect this initializer
 * function so it can only be called once. The {initializer} modifier provided by this contract will have this effect.
 *
 * The initialization functions use a version number. Once a version number is used, it is consumed and cannot be
 * reused. This mechanism prevents re-execution of each "step" but allows the creation of new initialization steps in
 * case an upgrade adds a module that needs to be initialized.
 *
 * For example:
 *
 * [.hljs-theme-light.nopadding]
 * ```solidity
 * contract MyToken is ERC20Upgradeable {
 *     function initialize() initializer public {
 *         __ERC20_init("MyToken", "MTK");
 *     }
 * }
 *
 * contract MyTokenV2 is MyToken, ERC20PermitUpgradeable {
 *     function initializeV2() reinitializer(2) public {
 *         __ERC20Permit_init("MyToken");
 *     }
 * }
 * ```
 *
 * TIP: To avoid leaving the proxy in an uninitialized state, the initializer function should be called as early as
 * possible by providing the encoded function call as the `_data` argument to {ERC1967Proxy-constructor}.
 *
 * CAUTION: When used with inheritance, manual care must be taken to not invoke a parent initializer twice, or to ensure
 * that all initializers are idempotent. This is not verified automatically as constructors are by Solidity.
 *
 * [CAUTION]
 * ====
 * Avoid leaving a contract uninitialized.
 *
 * An uninitialized contract can be taken over by an attacker. This applies to both a proxy and its implementation
 * contract, which may impact the proxy. To prevent the implementation contract from being used, you should invoke
 * the {_disableInitializers} function in the constructor to automatically lock it when it is deployed:
 *
 * [.hljs-theme-light.nopadding]
 * ```
 * /// @custom:oz-upgrades-unsafe-allow constructor
 * constructor() {
 *     _disableInitializers();
 * }
 * ```
 * ====
 */
abstract contract Initializable {
    /**
     * @dev Storage of the initializable contract.
     *
     * It's implemented on a custom ERC-7201 namespace to reduce the risk of storage collisions
     * when using with upgradeable contracts.
     *
     * @custom:storage-location erc7201:openzeppelin.storage.Initializable
     */
    struct InitializableStorage {
        /**
         * @dev Indicates that the contract has been initialized.
         */
        uint64 _initialized;
        /**
         * @dev Indicates that the contract is in the process of being initialized.
         */
        bool _initializing;
    }

    // keccak256(abi.encode(uint256(keccak256("openzeppelin.storage.Initializable")) - 1)) & ~bytes32(uint256(0xff))
    bytes32 private constant INITIALIZABLE_STORAGE = 0xf0c57e16840df040f15088dc2f81fe391c3923bec73e23a9662efc9c229c6a00;

    /**
     * @dev The contract is already initialized.
     */
    error InvalidInitialization();

    /**
     * @dev The contract is not initializing.
     */
    error NotInitializing();

    /**
     * @dev Triggered when the contract has been initialized or reinitialized.
     */
    event Initialized(uint64 version);

    /**
     * @dev A modifier that defines a protected initializer function that can be invoked at most once. In its scope,
     * `onlyInitializing` functions can be used to initialize parent contracts.
     *
     * Similar to `reinitializer(1)`, except that in the context of a constructor an `initializer` may be invoked any
     * number of times. This behavior in the constructor can be useful during testing and is not expected to be used in
     * production.
     *
     * Emits an {Initialized} event.
     */
    modifier initializer() {
        // solhint-disable-next-line var-name-mixedcase
        InitializableStorage storage $ = _getInitializableStorage();

        // Cache values to avoid duplicated sloads
        bool isTopLevelCall = !$._initializing;
        uint64 initialized = $._initialized;

        // Allowed calls:
        // - initialSetup: the contract is not in the initializing state and no previous version was
        //                 initialized
        // - construction: the contract is initialized at version 1 (no reinitialization) and the
        //                 current contract is just being deployed
        bool initialSetup = initialized == 0 && isTopLevelCall;
        bool construction = initialized == 1 && address(this).code.length == 0;

        if (!initialSetup && !construction) {
            revert InvalidInitialization();
        }
        $._initialized = 1;
        if (isTopLevelCall) {
            $._initializing = true;
        }
        _;
        if (isTopLevelCall) {
            $._initializing = false;
            emit Initialized(1);
        }
    }

    /**
     * @dev A modifier that defines a protected reinitializer function that can be invoked at most once, and only if the
     * contract hasn't been initialized to a greater version before. In its scope, `onlyInitializing` functions can be
     * used to initialize parent contracts.
     *
     * A reinitializer may be used after the original initialization step. This is essential to configure modules that
     * are added through upgrades and that require initialization.
     *
     * When `version` is 1, this modifier is similar to `initializer`, except that functions marked with `reinitializer`
     * cannot be nested. If one is invoked in the context of another, execution will revert.
     *
     * Note that versions can jump in increments greater than 1; this implies that if multiple reinitializers coexist in
     * a contract, executing them in the right order is up to the developer or operator.
     *
     * WARNING: Setting the version to 2**64 - 1 will prevent any future reinitialization.
     *
     * Emits an {Initialized} event.
     */
    modifier reinitializer(uint64 version) {
        // solhint-disable-next-line var-name-mixedcase
        InitializableStorage storage $ = _getInitializableStorage();

        if ($._initializing || $._initialized >= version) {
            revert InvalidInitialization();
        }
        $._initialized = version;
        $._initializing = true;
        _;
        $._initializing = false;
        emit Initialized(version);
    }

    /**
     * @dev Modifier to protect an initialization function so that it can only be invoked by functions with the
     * {initializer} and {reinitializer} modifiers, directly or indirectly.
     */
    modifier onlyInitializing() {
        _checkInitializing();
        _;
    }

    /**
     * @dev Reverts if the contract is not in an initializing state. See {onlyInitializing}.
     */
    function _checkInitializing() internal view virtual {
        if (!_isInitializing()) {
            revert NotInitializing();
        }
    }

    /**
     * @dev Locks the contract, preventing any future reinitialization. This cannot be part of an initializer call.
     * Calling this in the constructor of a contract will prevent that contract from being initialized or reinitialized
     * to any version. It is recommended to use this to lock implementation contracts that are designed to be called
     * through proxies.
     *
     * Emits an {Initialized} event the first time it is successfully executed.
     */
    function _disableInitializers() internal virtual {
        // solhint-disable-next-line var-name-mixedcase
        InitializableStorage storage $ = _getInitializableStorage();

        if ($._initializing) {
            revert InvalidInitialization();
        }
        if ($._initialized != type(uint64).max) {
            $._initialized = type(uint64).max;
            emit Initialized(type(uint64).max);
        }
    }

    /**
     * @dev Returns the highest version that has been initialized. See {reinitializer}.
     */
    function _getInitializedVersion() internal view returns (uint64) {
        return _getInitializableStorage()._initialized;
    }

    /**
     * @dev Returns `true` if the contract is currently initializing. See {onlyInitializing}.
     */
    function _isInitializing() internal view returns (bool) {
        return _getInitializableStorage()._initializing;
    }

    /**
     * @dev Pointer to storage slot. Allows integrators to override it with a custom storage location.
     *
     * NOTE: Consider following the ERC-7201 formula to derive storage locations.
     */
    function _initializableStorageSlot() internal pure virtual returns (bytes32) {
        return INITIALIZABLE_STORAGE;
    }

    /**
     * @dev Returns a pointer to the storage namespace.
     */
    // solhint-disable-next-line var-name-mixedcase
    function _getInitializableStorage() private pure returns (InitializableStorage storage $) {
        bytes32 slot = _initializableStorageSlot();
        assembly {
            $.slot := slot
        }
    }
}
"
    },
    "@openzeppelin/contracts-upgradeable/proxy/utils/UUPSUpgradeable.sol": {
      "content": "// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.3.0) (proxy/utils/UUPSUpgradeable.sol)

pragma solidity ^0.8.22;

import {IERC1822Proxiable} from "@openzeppelin/contracts/interfaces/draft-IERC1822.sol";
import {ERC1967Utils} from "@openzeppelin/contracts/proxy/ERC1967/ERC1967Utils.sol";
import {Initializable} from "./Initializable.sol";

/**
 * @dev An upgradeability mechanism designed for UUPS proxies. The functions included here can perform an upgrade of an
 * {ERC1967Proxy}, when this contract is set as the implementation behind such a proxy.
 *
 * A security mechanism ensures that an upgrade does not turn off upgradeability accidentally, although this risk is
 * reinstated if the upgrade retains upgradeability but removes the security mechanism, e.g. by replacing
 * `UUPSUpgradeable` with a custom implementation of upgrades.
 *
 * The {_authorizeUpgrade} function must be overridden to include access restriction to the upgrade mechanism.
 */
abstract contract UUPSUpgradeable is Initializable, IERC1822Proxiable {
    /// @custom:oz-upgrades-unsafe-allow state-variable-immutable
    address private immutable __self = address(this);

    /**
     * @dev The version of the upgrade interface of the contract. If this getter is missing, both `upgradeTo(address)`
     * and `upgradeToAndCall(address,bytes)` are present, and `upgradeTo` must be used if no function should be called,
     * while `upgradeToAndCall` will invoke the `receive` function if the second argument is the empty byte string.
     * If the getter returns `"5.0.0"`, only `upgradeToAndCall(address,bytes)` is present, and the second argument must
     * be the empty byte string if no function should be called, making it impossible to invoke the `receive` function
     * during an upgrade.
     */
    string public constant UPGRADE_INTERFACE_VERSION = "5.0.0";

    /**
     * @dev The call is from an unauthorized context.
     */
    error UUPSUnauthorizedCallContext();

    /**
     * @dev The storage `slot` is unsupported as a UUID.
     */
    error UUPSUnsupportedProxiableUUID(bytes32 slot);

    /**
     * @dev Check that the execution is being performed through a delegatecall call and that the execution context is
     * a proxy contract with an implementation (as defined in ERC-1967) pointing to self. This should only be the case
     * for UUPS and transparent proxies that are using the current contract as their implementation. Execution of a
     * function through ERC-1167 minimal proxies (clones) would not normally pass this test, but is not guaranteed to
     * fail.
     */
    modifier onlyProxy() {
        _checkProxy();
        _;
    }

    /**
     * @dev Check that the execution is not being performed through a delegate call. This allows a function to be
     * callable on the implementing contract but not through proxies.
     */
    modifier notDelegated() {
        _checkNotDelegated();
        _;
    }

    function __UUPSUpgradeable_init() internal onlyInitializing {
    }

    function __UUPSUpgradeable_init_unchained() internal onlyInitializing {
    }
    /**
     * @dev Implementation of the ERC-1822 {proxiableUUID} function. This returns the storage slot used by the
     * implementation. It is used to validate the implementation's compatibility when performing an upgrade.
     *
     * IMPORTANT: A proxy pointing at a proxiable contract should not be considered proxiable itself, because this risks
     * bricking a proxy that upgrades to it, by delegating to itself until out of gas. Thus it is critical that this
     * function revert if invoked through a proxy. This is guaranteed by the `notDelegated` modifier.
     */
    function proxiableUUID() external view virtual notDelegated returns (bytes32) {
        return ERC1967Utils.IMPLEMENTATION_SLOT;
    }

    /**
     * @dev Upgrade the implementation of the proxy to `newImplementation`, and subsequently execute the function call
     * encoded in `data`.
     *
     * Calls {_authorizeUpgrade}.
     *
     * Emits an {Upgraded} event.
     *
     * @custom:oz-upgrades-unsafe-allow-reachable delegatecall
     */
    function upgradeToAndCall(address newImplementation, bytes memory data) public payable virtual onlyProxy {
        _authorizeUpgrade(newImplementation);
        _upgradeToAndCallUUPS(newImplementation, data);
    }

    /**
     * @dev Reverts if the execution is not performed via delegatecall or the execution
     * context is not of a proxy with an ERC-1967 compliant implementation pointing to self.
     */
    function _checkProxy() internal view virtual {
        if (
            address(this) == __self || // Must be called through delegatecall
            ERC1967Utils.getImplementation() != __self // Must be called through an active proxy
        ) {
            revert UUPSUnauthorizedCallContext();
        }
    }

    /**
     * @dev Reverts if the execution is performed via delegatecall.
     * See {notDelegated}.
     */
    function _checkNotDelegated() internal view virtual {
        if (address(this) != __self) {
            // Must not be called through delegatecall
            revert UUPSUnauthorizedCallContext();
        }
    }

    /**
     * @dev Function that should revert when `msg.sender` is not authorized to upgrade the contract. Called by
     * {upgradeToAndCall}.
     *
     * Normally, this function will use an xref:access.adoc[access control] modifier such as {Ownable-onlyOwner}.
     *
     * ```solidity
     * function _authorizeUpgrade(address) internal onlyOwner {}
     * ```
     */
    function _authorizeUpgrade(address newImplementation) internal virtual;

    /**
     * @dev Performs an implementation upgrade with a security check for UUPS proxies, and additional setup call.
     *
     * As a security check, {proxiableUUID} is invoked in the new implementation, and the return value
     * is expected to be the implementation slot in ERC-1967.
     *
     * Emits an {IERC1967-Upgraded} event.
     */
    function _upgradeToAndCallUUPS(address newImplementation, bytes memory data) private {
        try IERC1822Proxiable(newImplementation).proxiableUUID() returns (bytes32 slot) {
            if (slot != ERC1967Utils.IMPLEMENTATION_SLOT) {
                revert UUPSUnsupportedProxiableUUID(slot);
            }
            ERC1967Utils.upgradeToAndCall(newImplementation, data);
        } catch {
            // The implementation is not UUPS
            revert ERC1967Utils.ERC1967InvalidImplementation(newImplementation);
        }
    }
}
"
    },
    "@openzeppelin/contracts-upgradeable/access/OwnableUpgradeable.sol": {
      "content": "// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (access/Ownable.sol)

pragma solidity ^0.8.20;

import {ContextUpgradeable} from "../utils/ContextUpgradeable.sol";
import {Initializable} from "../proxy/utils/Initializable.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 OwnableUpgradeable is Initializable, ContextUpgradeable {
    /// @custom:storage-location erc7201:openzeppelin.storage.Ownable
    struct OwnableStorage {
        address _owner;
    }

    // keccak256(abi.encode(uint256(keccak256("openzeppelin.storage.Ownable")) - 1)) & ~bytes32(uint256(0xff))
    bytes32 private constant OwnableStorageLocation = 0x9016d09d72d40fdae2fd8ceac6b6234c7706214fd39c1cd1e609a0528c199300;

    function _getOwnableStorage() private pure returns (OwnableStorage storage $) {
        assembly {
            $.slot := OwnableStorageLocation
        }
    }

    /**
     * @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.
     */
    function __Ownable_init(address initialOwner) internal onlyInitializing {
        __Ownable_init_unchained(initialOwner);
    }

    function __Ownable_init_unchained(address initialOwner) internal onlyInitializing {
        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) {
        OwnableStorage storage $ = _getOwnableStorage();
        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 {
        OwnableStorage storage $ = _getOwnableStorage();
        address oldOwner = $._owner;
        $._owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}
"
    },
    "@openzeppelin/contracts-upgradeable/token/ERC721/ERC721Upgradeable.sol": {
      "content": "// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.4.0) (token/ERC721/ERC721.sol)

pragma solidity ^0.8.20;

import {IERC721} from "@openzeppelin/contracts/token/ERC721/IERC721.sol";
import {IERC721Metadata} from "@openzeppelin/contracts/token/ERC721/extensions/IERC721Metadata.sol";
import {ERC721Utils} from "@openzeppelin/contracts/token/ERC721/utils/ERC721Utils.sol";
import {ContextUpgradeable} from "../../utils/ContextUpgradeable.sol";
import {Strings} from "@openzeppelin/contracts/utils/Strings.sol";
import {IERC165} from "@openzeppelin/contracts/utils/introspection/IERC165.sol";
import {ERC165Upgradeable} from "../../utils/introspection/ERC165Upgradeable.sol";
import {IERC721Errors} from "@openzeppelin/contracts/interfaces/draft-IERC6093.sol";
import {Initializable} from "../../proxy/utils/Initializable.sol";

/**
 * @dev Implementation of https://eips.ethereum.org/EIPS/eip-721[ERC-721] Non-Fungible Token Standard, including
 * the Metadata extension, but not including the Enumerable extension, which is available separately as
 * {ERC721Enumerable}.
 */
abstract contract ERC721Upgradeable is Initializable, ContextUpgradeable, ERC165Upgradeable, IERC721, IERC721Metadata, IERC721Errors {
    using Strings for uint256;

    /// @custom:storage-location erc7201:openzeppelin.storage.ERC721
    struct ERC721Storage {
        // Token name
        string _name;

        // Token symbol
        string _symbol;

        mapping(uint256 tokenId => address) _owners;

        mapping(address owner => uint256) _balances;

        mapping(uint256 tokenId => address) _tokenApprovals;

        mapping(address owner => mapping(address operator => bool)) _operatorApprovals;
    }

    // keccak256(abi.encode(uint256(keccak256("openzeppelin.storage.ERC721")) - 1)) & ~bytes32(uint256(0xff))
    bytes32 private constant ERC721StorageLocation = 0x80bb2b638cc20bc4d0a60d66940f3ab4a00c1d7b313497ca82fb0b4ab0079300;

    function _getERC721Storage() private pure returns (ERC721Storage storage $) {
        assembly {
            $.slot := ERC721StorageLocation
        }
    }

    /**
     * @dev Initializes the contract by setting a `name` and a `symbol` to the token collection.
     */
    function __ERC721_init(string memory name_, string memory symbol_) internal onlyInitializing {
        __ERC721_init_unchained(name_, symbol_);
    }

    function __ERC721_init_unchained(string memory name_, string memory symbol_) internal onlyInitializing {
        ERC721Storage storage $ = _getERC721Storage();
        $._name = name_;
        $._symbol = symbol_;
    }

    /// @inheritdoc IERC165
    function supportsInterface(bytes4 interfaceId) public view virtual override(ERC165Upgradeable, IERC165) returns (bool) {
        return
            interfaceId == type(IERC721).interfaceId ||
            interfaceId == type(IERC721Metadata).interfaceId ||
            super.supportsInterface(interfaceId);
    }

    /// @inheritdoc IERC721
    function balanceOf(address owner) public view virtual returns (uint256) {
        ERC721Storage storage $ = _getERC721Storage();
        if (owner == address(0)) {
            revert ERC721InvalidOwner(address(0));
        }
        return $._balances[owner];
    }

    /// @inheritdoc IERC721
    function ownerOf(uint256 tokenId) public view virtual returns (address) {
        return _requireOwned(tokenId);
    }

    /// @inheritdoc IERC721Metadata
    function name() public view virtual returns (string memory) {
        ERC721Storage storage $ = _getERC721Storage();
        return $._name;
    }

    /// @inheritdoc IERC721Metadata
    function symbol() public view virtual returns (string memory) {
        ERC721Storage storage $ = _getERC721Storage();
        return $._symbol;
    }

    /// @inheritdoc IERC721Metadata
    function tokenURI(uint256 tokenId) public view virtual returns (string memory) {
        _requireOwned(tokenId);

        string memory baseURI = _baseURI();
        return bytes(baseURI).length > 0 ? string.concat(baseURI, tokenId.toString()) : "";
    }

    /**
     * @dev Base URI for computing {tokenURI}. If set, the resulting URI for each
     * token will be the concatenation of the `baseURI` and the `tokenId`. Empty
     * by default, can be overridden in child contracts.
     */
    function _baseURI() internal view virtual returns (string memory) {
        return "";
    }

    /// @inheritdoc IERC721
    function approve(address to, uint256 tokenId) public virtual {
        _approve(to, tokenId, _msgSender());
    }

    /// @inheritdoc IERC721
    function getApproved(uint256 tokenId) public view virtual returns (address) {
        _requireOwned(tokenId);

        return _getApproved(tokenId);
    }

    /// @inheritdoc IERC721
    function setApprovalForAll(address operator, bool approved) public virtual {
        _setApprovalForAll(_msgSender(), operator, approved);
    }

    /// @inheritdoc IERC721
    function isApprovedForAll(address owner, address operator) public view virtual returns (bool) {
        ERC721Storage storage $ = _getERC721Storage();
        return $._operatorApprovals[owner][operator];
    }

    /// @inheritdoc IERC721
    function transferFrom(address from, address to, uint256 tokenId) public virtual {
        if (to == address(0)) {
            revert ERC721InvalidReceiver(address(0));
        }
        // Setting an "auth" arguments enables the `_isAuthorized` check which verifies that the token exists
        // (from != 0). Therefore, it is not needed to verify that the return value is not 0 here.
        address previousOwner = _update(to, tokenId, _msgSender());
        if (previousOwner != from) {
            revert ERC721IncorrectOwner(from, tokenId, previousOwner);
        }
    }

    /// @inheritdoc IERC721
    function safeTransferFrom(address from, address to, uint256 tokenId) public {
        safeTransferFrom(from, to, tokenId, "");
    }

    /// @inheritdoc IERC721
    function safeTransferFrom(address from, address to, uint256 tokenId, bytes memory data) public virtual {
        transferFrom(from, to, tokenId);
        ERC721Utils.checkOnERC721Received(_msgSender(), from, to, tokenId, data);
    }

    /**
     * @dev Returns the owner of the `tokenId`. Does NOT revert if token doesn't exist
     *
     * IMPORTANT: Any overrides to this function that add ownership of tokens not tracked by the
     * core ERC-721 logic MUST be matched with the use of {_increaseBalance} to keep balances
     * consistent with ownership. The invariant to preserve is that for any address `a` the value returned by
     * `balanceOf(a)` must be equal to the number of tokens such that `_ownerOf(tokenId)` is `a`.
     */
    function _ownerOf(uint256 tokenId) internal view virtual returns (address) {
        ERC721Storage storage $ = _getERC721Storage();
        return $._owners[tokenId];
    }

    /**
     * @dev Returns the approved address for `tokenId`. Returns 0 if `tokenId` is not minted.
     */
    function _getApproved(uint256 tokenId) internal view virtual returns (address) {
        ERC721Storage storage $ = _getERC721Storage();
        return $._tokenApprovals[tokenId];
    }

    /**
     * @dev Returns whether `spender` is allowed to manage `owner`'s tokens, or `tokenId` in
     * particular (ignoring whether it is owned by `owner`).
     *
     * WARNING: This function assumes that `owner` is the actual owner of `tokenId` and does not verify this
     * assumption.
     */
    function _isAuthorized(address owner, address spender, uint256 tokenId) internal view virtual returns (bool) {
        return
            spender != address(0) &&
            (owner == spender || isApprovedForAll(owner, spender) || _getApproved(tokenId) == spender);
    }

    /**
     * @dev Checks if `spender` can operate on `tokenId`, assuming the provided `owner` is the actual owner.
     * Reverts if:
     * - `spender` does not have approval from `owner` for `tokenId`.
     * - `spender` does not have approval to manage all of `owner`'s assets.
     *
     * WARNING: This function assumes that `owner` is the actual owner of `tokenId` and does not verify this
     * assumption.
     */
    function _checkAuthorized(address owner, address spender, uint256 tokenId) internal view virtual {
        if (!_isAuthorized(owner, spender, tokenId)) {
            if (owner == address(0)) {
                revert ERC721NonexistentToken(tokenId);
            } else {
                revert ERC721InsufficientApproval(spender, tokenId);
            }
        }
    }

    /**
     * @dev Unsafe write access to the balances, used by extensions that "mint" tokens using an {ownerOf} override.
     *
     * NOTE: the value is limited to type(uint128).max. This protect against _balance overflow. It is unrealistic that
     * a uint256 would ever overflow from increments when these increments are bounded to uint128 values.
     *
     * WARNING: Increasing an account's balance using this function tends to be paired with an override of the
     * {_ownerOf} function to resolve the ownership of the corresponding tokens so that balances and ownership
     * remain consistent with one another.
     */
    function _increaseBalance(address account, uint128 value) internal virtual {
        ERC721Storage storage $ = _getERC721Storage();
        unchecked {
            $._balances[account] += value;
        }
    }

    /**
     * @dev Transfers `tokenId` from its current owner to `to`, or alternatively mints (or burns) if the current owner
     * (or `to`) is the zero address. Returns the owner of the `tokenId` before the update.
     *
     * The `auth` argument is optional. If the value passed is non 0, then this function will check that
     * `auth` is either the owner of the token, or approved to operate on the token (by the owner).
     *
     * Emits a {Transfer} event.
     *
     * NOTE: If overriding this function in a way that tracks balances, see also {_increaseBalance}.
     */
    function _update(address to, uint256 tokenId, address auth) internal virtual returns (address) {
        ERC721Storage storage $ = _getERC721Storage();
        address from = _ownerOf(tokenId);

        // Perform (optional) operator check
        if (auth != address(0)) {
            _checkAuthorized(from, auth, tokenId);
        }

        // Execute the update
        if (from != address(0)) {
            // Clear approval. No need to re-authorize or emit the Approval event
            _approve(address(0), tokenId, address(0), false);

            unchecked {
                $._balances[from] -= 1;
            }
        }

        if (to != address(0)) {
            unchecked {
                $._balances[to] += 1;
            }
        }

        $._owners[tokenId] = to;

        emit Transfer(from, to, tokenId);

        return from;
    }

    /**
     * @dev Mints `tokenId` and transfers it to `to`.
     *
     * WARNING: Usage of this method is discouraged, use {_safeMint} whenever possible
     *
     * Requirements:
     *
     * - `tokenId` must not exist.
     * - `to` cannot be the zero address.
     *
     * Emits a {Transfer} event.
     */
    function _mint(address to, uint256 tokenId) internal {
        if (to == address(0)) {
            revert ERC721InvalidReceiver(address(0));
        }
        address previousOwner = _update(to, tokenId, address(0));
        if (previousOwner != address(0)) {
            revert ERC721InvalidSender(address(0));
        }
    }

    /**
     * @dev Mints `tokenId`, transfers it to `to` and checks for `to` acceptance.
     *
     * Requirements:
     *
     * - `tokenId` must not exist.
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
     *
     * Emits a {Transfer} event.
     */
    function _safeMint(address to, uint256 tokenId) internal {
        _safeMint(to, tokenId, "");
    }

    /**
     * @dev Same as {xref-ERC721-_safeMint-address-uint256-}[`_safeMint`], with an additional `data` parameter which is
     * forwarded in {IERC721Receiver-onERC721Received} to contract recipients.
     */
    function _safeMint(address to, uint256 tokenId, bytes memory data) internal virtual {
        _mint(to, tokenId);
        ERC721Utils.checkOnERC721Received(_msgSender(), address(0), to, tokenId, data);
    }

    /**
     * @dev Destroys `tokenId`.
     * The approval is cleared when the token is burned.
     * This is an internal function that does not check if the sender is authorized to operate on the token.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     *
     * Emits a {Transfer} event.
     */
    function _burn(uint256 tokenId) internal {
        address previousOwner = _update(address(0), tokenId, address(0));
        if (previousOwner == address(0)) {
            revert ERC721NonexistentToken(tokenId);
        }
    }

    /**
     * @dev Transfers `tokenId` from `from` to `to`.
     *  As opposed to {transferFrom}, this imposes no restrictions on msg.sender.
     *
     * Requirements:
     *
     * - `to` cannot be the zero address.
     * - `tokenId` token must be owned by `from`.
     *
     * Emits a {Transfer} event.
     */
    function _transfer(address from, address to, uint256 tokenId) internal {
        if (to == address(0)) {
            revert ERC721InvalidReceiver(address(0));
        }
        address previousOwner = _update(to, tokenId, address(0));
        if (previousOwner == address(0)) {
            revert ERC721NonexistentToken(tokenId);
        } else if (previousOwner != from) {
            revert ERC721IncorrectOwner(from, tokenId, previousOwner);
        }
    }

    /**
     * @dev Safely transfers `tokenId` token from `from` to `to`, checking that contract recipients
     * are aware of the ERC-721 standard to prevent tokens from being forever locked.
     *
     * `data` is additional data, it has no specified format and it is sent in call to `to`.
     *
     * This internal function is like {safeTransferFrom} in the sense that it invokes
     * {IERC721Receiver-onERC721Received} on the receiver, and can be used to e.g.
     * implement alternative mechanisms to perform token transfer, such as signature-based.
     *
     * Requirements:
     *
     * - `tokenId` token must exist and be owned by `from`.
     * - `to` cannot be the zero address.
     * - `from` cannot be the zero address.
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
     *
     * Emits a {Transfer} event.
     */
    function _safeTransfer(address from, address to, uint256 tokenId) internal {
        _safeTransfer(from, to, tokenId, "");
    }

    /**
     * @dev Same as {xref-ERC721-_safeTransfer-address-address-uint256-}[`_safeTransfer`], with an additional `data` parameter which is
     * forwarded in {IERC721Receiver-onERC721Received} to contract recipients.
     */
    function _safeTransfer(address from, address to, uint256 tokenId, bytes memory data) internal virtual {
        _transfer(from, to, tokenId);
        ERC721Utils.checkOnERC721Received(_msgSender(), from, to, tokenId, data);
    }

    /**
     * @dev Approve `to` to operate on `tokenId`
     *
     * The `auth` argument is optional. If the value passed is non 0, then this function will check that `auth` is
     * either the owner of the token, or approved to operate on all tokens held by this owner.
     *
     * Emits an {Approval} event.
     *
     * Overrides to this logic should be done to the variant with an additional `bool emitEvent` argument.
     */
    function _approve(address to, uint256 tokenId, address auth) internal {
        _approve(to, tokenId, auth, true);
    }

    /**
     * @dev Variant of `_approve` with an optional flag to enable or disable the {Approval} event. The event is not
     * emitted in the context of transfers.
     */
    function _approve(address to, uint256 tokenId, address auth, bool emitEvent) internal virtual {
        ERC721Storage storage $ = _getERC721Storage();
        // Avoid reading the owner unless necessary
        if (emitEvent || auth != address(0)) {
            address owner = _requireOwned(tokenId);

            // We do not use _isAuthorized because single-token approvals should not be able to call approve
            if (auth != address(0) && owner != auth && !isApprovedForAll(owner, auth)) {
                revert ERC721InvalidApprover(auth);
            }

            if (emitEvent) {
                emit Approval(owner, to, tokenId);
            }
        }

        $._tokenApprovals[tokenId] = to;
    }

    /**
     * @dev Approve `operator` to operate on all of `owner` tokens
     *
     * Requirements:
     * - operator can't be the address zero.
     *
     * Emits an {ApprovalForAll} event.
     */
    function _setApprovalForAll(address owner, address operator, bool approved) internal virtual {
        ERC721Storage storage $ = _getERC721Storage();
        if (operator == address(0)) {
            revert ERC721InvalidOperator(operator);
        }
        $._operatorApprovals[owner][operator] = approved;
        emit ApprovalForAll(owner, operator, approved);
    }

    /**
     * @dev Reverts if the `tokenId` doesn't have a current owner (it hasn't been minted, or it has been burned).
     * Returns the owner.
     *
     * Overrides to ownership logic should be done to {_ownerOf}.
     */
    function _requireOwned(uint256 tokenId) internal view returns (address) {
        address owner = _ownerOf(tokenId);
        if (owner == address(0)) {
            revert ERC721NonexistentToken(tokenId);
        }
        return owner;
    }
}
"
    },
    "@openzeppelin/contracts/interfaces/draft-IERC6093.sol": {
      "content": "// 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);
}
"
    },
    "@openzeppelin/contracts-upgradeable/utils/introspection/ERC165Upgradeable.sol": {
      "content": "// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.4.0) (utils/introspection/ERC165.sol)

pragma solidity ^0.8.20;

import {IERC165} from "@openzeppelin/contracts/utils/introspection/IERC165.sol";
import {Initializable} from "../../proxy/utils/Initializable.sol";

/**
 * @dev Implementation of the {IERC165} interface.
 *
 * Contracts that want to implement ERC-165 should inherit from this contract and override {supportsInterface} to check
 * for the additional interface id that will be supported. For example:
 *
 * ```solidity
 * function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
 *     return interfaceId == type(MyInterface).interfaceId || super.supportsInterface(interfaceId);
 * }
 * ```
 */
abstract contract ERC165Upgradeable is Initializable, IERC165 {
    function __ERC165_init() internal onlyInitializing {
    }

    function __ERC165_init_unchained() internal onlyInitializing {
    }
    /// @inheritdoc IERC165
    function supportsInterface(bytes4 interfaceId) public view virtual returns (bool) {
        return interfaceId == type(IERC165).interfaceId;
    }
}
"
    },
    "@openzeppelin/contracts/utils/introspection/IERC165.sol": {
      "content": "// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.4.0) (utils/introspection/IERC165.sol)

pragma solidity >=0.4.16;

/**
 * @dev Interface of the ERC-165 standard, as defined in the
 * https://eips.ethereum.org/EIPS/eip-165[ERC].
 *
 * Implementers can declare support of contract interfaces, which can then be
 * queried by others ({ERC165Checker}).
 *
 * For an implementation, see {ERC165}.
 */
interface IERC165 {
    /**
     * @dev Returns true if this contract implements the interface defined by
     * `interfaceId`. See the corresponding
     * https://eips.ethereum.org/EIPS/eip-165#how-interfaces-are-identified[ERC section]
     * to learn more about how these ids are created.
     *
     * This function call must use less than 30 000 gas.
     */
    function supportsInterface(bytes4 interfaceId) external view returns (bool);
}
"
    },
    "@openzeppelin/contracts/utils/Strings.sol": {
      "content": "// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.4.0) (utils/Strings.sol)

pragma solidity ^0.8.20;

import {Math} from "./math/Math.sol";
import {SafeCast} from "./math/SafeCast.sol";
import {SignedMath} from "./math/SignedMath.sol";

/**
 * @dev String operations.
 */
library Strings {
    using SafeCast for *;

    bytes16 private constant HEX_DIGITS = "0123456789abcdef";
    uint8 private constant ADDRESS_LENGTH = 20;
    uint256 private constant SPECIAL_CHARS_LOOKUP =
        (1 << 0x08) | // backspace
            (1 << 0x09) | // tab
            (1 << 0x0a) | // newline
            (1 << 0x0c) | // form feed
            (1 << 0x0d) | // carriage return
            (1 << 0x22) | // double quote
            (1 << 0x5c); // backslash

    /**
     * @dev The `value` string doesn't fit in the specified `length`.
     */
    error StringsInsufficientHexLength(uint256 value, uint256 length);

    /**
     * @dev The string being parsed contains characters that are not in scope of the given base.
     */
    error StringsInvalidChar();

    /**
     * @dev The string being parsed is not a properly formatted address.
     */
    error StringsInvalidAddressFormat();

    /**
     * @dev Converts a `uint256` to its ASCII `string` decimal representation.
     */
    function toString(uint256 value) internal pure returns (string memory) {
        unchecked {
            uint256 length = Math.log10(value) + 1;
            string memory buffer = new string(length);
            uint256 ptr;
            assembly ("memory-safe") {
                ptr := add(add(buffer, 0x20), length)
            }
            while (true) {
                ptr--;
                assembly ("memory-safe") {
                    mstore8(ptr, byte(mod(value, 10), HEX_DIGITS))
                }
                value /= 10;
                if (value == 0) break;
            }
            return buffer;
        }
    }

    /**
     * @dev Converts a `int256` to its ASCII `string` decimal representation.
     */
    function toStringSigned(int256 value) internal pure returns (string memory) {
        return string.concat(value < 0 ? "-" : "", toString(SignedMath.abs(value)));
    }

    /**
     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation.
     */
    function toHexString(uint256 value) internal pure returns (string memory) {
        unchecked {
            return toHexString(value, Math.log256(value) + 1);
        }
    }

    /**
     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation with fixed length.
     */
    function toHexString(uint256 value, uint256 length) internal pure returns (string memory) {
        uint256 localValue = value;
        bytes memory buffer = new bytes(2 * length + 2);
        buffer[0] = "0";
        buffer[1] = "x";
        for (uint256 i = 2 * length + 1; i > 1; --i) {
            buffer[i] = HEX_DIGITS[localValue & 0xf];
            localValue >>= 4;
        }
        if (localValue != 0) {
            revert StringsInsufficientHexLength(value, length);
        }
        return string(buffer);
    }

    /**
     * @dev Converts an `address` with fixed length of 20 bytes to its not checksummed ASCII `string` hexadecimal
     * representation.
     */
    function toHexString(address addr) internal pure returns (string memory) {
        return toHexString(uint256(uint160(addr)), ADDRESS_LENGTH);
    }

    /**
     * @dev Converts an `address` with fixed length of 20 bytes to its checksummed ASCII `string` hexadecimal
     * representation, according to EIP-55.
     */
    function toChecksumHexString(address addr) internal pure returns (string memory) {
        bytes memory buffer = bytes(toHexString(addr));

        // hash the hex part of buffer (skip length + 2 bytes, length 40)
        uint256 hashValue;
        assembly ("memory-safe") {
            hashValue := shr(96, keccak256(add(buffer, 0x22), 40))
        }

        for (uint256 i = 41; i > 1; --i) {
            // possible values for buffer[i] are 48 (0) to 57 (9) and 97 (a) to 102 (f)
            if (hashValue & 0xf > 7 && uint8(buffer[i]) > 96) {
                // case shift by xoring with 0x20
                buffer[i] ^= 0x20;
            }
            hashValue >>= 4;
        }
        return string(buffer);
    }

    /**
     * @dev Returns true if the two strings are equal.
     */
    function equal(string memory a, string memory b) internal pure returns (bool) {
        return bytes(a).length == bytes(b).length && keccak256(bytes(a)) == keccak256(bytes(b));
    }

    /**
     * @dev Parse a decimal string and returns the value as a `uint256`.
     *
     * Requirements:
     * - The string must be formatted as `[0-9]*`
     * - The result must fit into an `uint256` type
     */
    function parseUint(string memory input) internal pure returns (uint256) {
        return parseUint(input, 0, bytes(input).length);
    }

    /**
     * @dev Variant of {parseUint-string} that parses a substring of `input` located between position `begin` (included) and
     * `end` (excluded).
     *
     * Requirements:
     * - The substring must be formatted as `[0-9]*`
     * - The result must fit into an `uint256` type
     */
    function parseUint(string memory input, uint256 begin, uint256 end) internal pure returns (uint256) {
        (bool success, uint256 value) = tryParseUint(input, begin, end);
        if (!success) revert StringsInvalidChar();
        return value;
    }

    /**
     * @dev Variant of {parseUint-string} that returns false if the parsing fails because of an invalid character.
     *
     * NOTE: This function will revert if the result does not fit in a `uint256`.
     */
    function tryParseUint(string memory input) internal pure returns (bool success, uint256 value) {
        return _tryParseUintUncheckedBounds(input, 0, bytes(input).length);
    }

    /**
     * @dev Variant of {parseUint-string-uint256-uint256} that returns false if the parsing fails because of an invalid
     * character.
     *
     * NOTE: This function will revert if the result does not fit in a `uint256`.
     */
    function tryParseUint(
        string memory input,
        uint256 begin,
        uint256 end
    ) internal pure returns (bool success, uint256 value) {
        if (end > bytes(input).length || begin > end) return (false, 0);
        return _tryParseUintUncheckedBounds(input, begin, end);
    }

    /**
     * @dev Implementation of {tryParseUint-string-uint256-uint256} that does not check bounds. Caller should make sure that
     * `begin <= end <= input.length`. Other inputs would result in undefined behavior.
     */
    function _tryParseUintUncheckedBounds(
        string memory input,
        uint256 begin,
        uint256 end
    ) private pure returns (bool success, uint256 value) {
        bytes memory buffer = bytes(input);

        uint256 result = 0;
        for (uint256 i = begin; i < end; ++i) {
            uint8 chr = _tryParseChr(bytes1(_unsafeReadBytesOffset(buffer, i)));
            if (chr > 9) return (false, 0);
            result *= 10;
            result += chr;
        }
        return (true, result);
    }

    /**
     * @dev Parse a decimal string and returns the value as a `int256`.
     *
     * Requirements:
     * - The string must be formatted as `[-+]?[0-9]*`
     * - The result must fit in an `int256` type.
     */
    function parseInt(string memory input) internal pure returns (int256) {
        return parseInt(input, 0, bytes(input).length);
    }

    /**
     * @dev Variant of {parseInt-string} that parses a substring of `input` located between position `begin` (included) and
     * `end` (excluded).
     *
     * Requirements:
     * - The substring must be formatted as `[-+]?[0-9]*`
     * - The result must fit in an `int256` type.
     */
    function parseInt(string memory input, uint256 begin, uint256 end) internal pure returns (int256) {
        (bool success, int256 value) = tryParseInt(input, begin, end);
        if (!success) revert StringsInvalidChar();
        return value;
    }

    /**
     * @dev Variant of {parseInt-string} that returns false if the parsing fails because of an invalid character or if
     * the result does not fit in a `int256`.
     *
     * NOTE: This function will revert if the absolute value of the result does not fit in a `uint256`.
     */
    function tryParseInt(string memory input) internal pure returns (bool success, int256 value) {
        return _tryParseIntUncheckedBounds(input, 0, bytes(input).length);
    }

    uint256 private constant ABS_MIN_INT256 = 2 ** 255;

    /**
     * @dev Variant of {parseInt-string-uint256-uint256} that returns false if the parsing fails because of an invalid
     * character or if the result does not fit in a `int256`.
     *
     * NOTE: This function will revert if the absolute value of the result does not fit in a `uint256`.
     */
    function tryParseInt(
        string memory input,
        uint256 begin,
        uint256 end
    ) internal pure returns (bool success, int256 value) {
        if (end > bytes(input).length || begin > end) return (false, 0);
        return _tryParseIntUncheckedBounds(input, begin, end);
    }

    /**
     * @dev Implementation of {tryParseInt-string-uint256-uint256} that does not check bounds. Caller should make sure that
     * `begin <= end <= input.length`. Other inputs would result in undefined behavior.
     */
    function _tryParseIntUncheckedBounds(
        string memory input,
        uint256 begin,
        uint256 end
    ) private pure returns (bool success, int256 value) {
        bytes memory buffer = bytes(input);

        // Check presence of a negative sign.
        bytes1 sign = begin == end ? bytes1(0) : bytes1(_unsafeReadBytesOffset(buffer, begin)); // don't do out-of-bound (possibly unsafe) read if sub-string is empty
        bool positiveSign = sign == bytes1("+");
        bool negativeSign = sign == bytes1("-");
        uint256 offset = (positiveSign || negativeSign).toUint();

        (bool absSuccess, uint256 absValue) = tryParseUint(input, begin + offset, end);

        if (absSuccess && absValue < ABS_MIN_INT256) {
            return (true, negativeSign ? -int256(absValue) : int256(absValue));
        } else if (absSuccess && negativeSign && absValue == ABS_MIN_INT256) {
            return (true, type(int256).min);
        } else return (false, 0);
    }

    /**
     * @dev Parse a hexadecimal string (with or without "0x" prefix), and returns the value as a `uint256`.
     *
     * Requirements:
     * - The string must be formatted as `(0x)?[0-9a-fA-F]*`
     * - The result must fit in an `uint256` type.
     */
    function parseHexUint(string memory input) internal pure returns (uint256) {
        return parseHexUint(input, 0, bytes(input).length);
    }

    /**
     * @dev Variant of {parseHexUint-string} that parses a substring of `input` located between position `begin` (included) and
     * `end` (excluded).
     *
     * Requirements:
     * - The substring must be formatted as `(0x)?[0-9a-fA-F]*`
     * - The result must fit in an `uint256` type.
     */
    function parseHexUint(string memory input, uint256 begin, uint256 end) internal pure returns (uint256) {
        (bool success, uint256 value) = tryParseHexUint(input, begin, end);
        if (!success) revert StringsInvalidChar();
        return value;
    }

    /**
     * @dev Variant of {parseHexUint-string} that returns false if the parsing fails because of an invalid character.
     *
     * NOTE: This function will revert if the result does not fit in a `uint256`.
     */
    function tryParseHexUint(string memory input) internal pure returns (bool success, uint256 value) {
        return _tryParseHexUintUncheckedBounds(input, 0, bytes(input).length);
    }

    /**
     * @dev