Contract Address Details

// Sources flattened with hardhat v2.24.2 https://hardhat.org

// SPDX-License-Identifier: MIT

// File @openzeppelin/contracts-upgradeable/proxy/utils/Initializable.sol@v5.3.0

// Original license: 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
        }
    }
}


// File @openzeppelin/contracts-upgradeable/utils/ContextUpgradeable.sol@v5.3.0

// Original license: 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 ContextUpgradeable is Initializable {
    function __Context_init() internal onlyInitializing {
    }

    function __Context_init_unchained() internal onlyInitializing {
    }
    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;
    }
}


// File @openzeppelin/contracts-upgradeable/access/OwnableUpgradeable.sol@v5.3.0

// Original license: SPDX_License_Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (access/Ownable.sol)

pragma solidity ^0.8.20;


/**
 * @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);
    }
}


// File @openzeppelin/contracts/utils/Context.sol@v5.3.0

// Original license: 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;
    }
}


// File @openzeppelin/contracts/access/Ownable.sol@v5.3.0

// Original license: SPDX_License_Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (access/Ownable.sol)

pragma solidity ^0.8.20;

/**
 * @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);
    }
}


// File @openzeppelin/contracts/utils/introspection/IERC165.sol@v5.3.0

// Original license: SPDX_License_Identifier: MIT
// OpenZeppelin Contracts (last updated v5.1.0) (utils/introspection/IERC165.sol)

pragma solidity ^0.8.20;

/**
 * @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);
}


// File @openzeppelin/contracts/token/ERC1155/IERC1155.sol@v5.3.0

// Original license: SPDX_License_Identifier: MIT
// OpenZeppelin Contracts (last updated v5.3.0) (token/ERC1155/IERC1155.sol)

pragma solidity ^0.8.20;

/**
 * @dev Required interface of an ERC-1155 compliant contract, as defined in the
 * https://eips.ethereum.org/EIPS/eip-1155[ERC].
 */
interface IERC1155 is IERC165 {
    /**
     * @dev Emitted when `value` amount of tokens of type `id` are transferred from `from` to `to` by `operator`.
     */
    event TransferSingle(address indexed operator, address indexed from, address indexed to, uint256 id, uint256 value);

    /**
     * @dev Equivalent to multiple {TransferSingle} events, where `operator`, `from` and `to` are the same for all
     * transfers.
     */
    event TransferBatch(
        address indexed operator,
        address indexed from,
        address indexed to,
        uint256[] ids,
        uint256[] values
    );

    /**
     * @dev Emitted when `account` grants or revokes permission to `operator` to transfer their tokens, according to
     * `approved`.
     */
    event ApprovalForAll(address indexed account, address indexed operator, bool approved);

    /**
     * @dev Emitted when the URI for token type `id` changes to `value`, if it is a non-programmatic URI.
     *
     * If an {URI} event was emitted for `id`, the standard
     * https://eips.ethereum.org/EIPS/eip-1155#metadata-extensions[guarantees] that `value` will equal the value
     * returned by {IERC1155MetadataURI-uri}.
     */
    event URI(string value, uint256 indexed id);

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

    /**
     * @dev xref:ROOT:erc1155.adoc#batch-operations[Batched] version of {balanceOf}.
     *
     * Requirements:
     *
     * - `accounts` and `ids` must have the same length.
     */
    function balanceOfBatch(
        address[] calldata accounts,
        uint256[] calldata ids
    ) external view returns (uint256[] memory);

    /**
     * @dev Grants or revokes permission to `operator` to transfer the caller's tokens, according to `approved`,
     *
     * Emits an {ApprovalForAll} event.
     *
     * Requirements:
     *
     * - `operator` cannot be the zero address.
     */
    function setApprovalForAll(address operator, bool approved) external;

    /**
     * @dev Returns true if `operator` is approved to transfer ``account``'s tokens.
     *
     * See {setApprovalForAll}.
     */
    function isApprovedForAll(address account, address operator) external view returns (bool);

    /**
     * @dev Transfers a `value` amount of tokens of type `id` from `from` to `to`.
     *
     * WARNING: This function can potentially allow a reentrancy attack when transferring tokens
     * to an untrusted contract, when invoking {IERC1155Receiver-onERC1155Received} on the receiver.
     * Ensure to follow the checks-effects-interactions pattern and consider employing
     * reentrancy guards when interacting with untrusted contracts.
     *
     * Emits a {TransferSingle} event.
     *
     * Requirements:
     *
     * - `to` cannot be the zero address.
     * - If the caller is not `from`, it must have been approved to spend ``from``'s tokens via {setApprovalForAll}.
     * - `from` must have a balance of tokens of type `id` of at least `value` amount.
     * - If `to` refers to a smart contract, it must implement {IERC1155Receiver-onERC1155Received} and return the
     * acceptance magic value.
     */
    function safeTransferFrom(address from, address to, uint256 id, uint256 value, bytes calldata data) external;

    /**
     * @dev xref:ROOT:erc1155.adoc#batch-operations[Batched] version of {safeTransferFrom}.
     *
     * WARNING: This function can potentially allow a reentrancy attack when transferring tokens
     * to an untrusted contract, when invoking {IERC1155Receiver-onERC1155BatchReceived} on the receiver.
     * Ensure to follow the checks-effects-interactions pattern and consider employing
     * reentrancy guards when interacting with untrusted contracts.
     *
     * Emits either a {TransferSingle} or a {TransferBatch} event, depending on the length of the array arguments.
     *
     * Requirements:
     *
     * - `ids` and `values` must have the same length.
     * - If `to` refers to a smart contract, it must implement {IERC1155Receiver-onERC1155BatchReceived} and return the
     * acceptance magic value.
     */
    function safeBatchTransferFrom(
        address from,
        address to,
        uint256[] calldata ids,
        uint256[] calldata values,
        bytes calldata data
    ) external;
}


// File @openzeppelin/contracts/token/ERC1155/IERC1155Receiver.sol@v5.3.0

// Original license: SPDX_License_Identifier: MIT
// OpenZeppelin Contracts (last updated v5.1.0) (token/ERC1155/IERC1155Receiver.sol)

pragma solidity ^0.8.20;

/**
 * @dev Interface that must be implemented by smart contracts in order to receive
 * ERC-1155 token transfers.
 */
interface IERC1155Receiver is IERC165 {
    /**
     * @dev Handles the receipt of a single ERC-1155 token type. This function is
     * called at the end of a `safeTransferFrom` after the balance has been updated.
     *
     * NOTE: To accept the transfer, this must return
     * `bytes4(keccak256("onERC1155Received(address,address,uint256,uint256,bytes)"))`
     * (i.e. 0xf23a6e61, or its own function selector).
     *
     * @param operator The address which initiated the transfer (i.e. msg.sender)
     * @param from The address which previously owned the token
     * @param id The ID of the token being transferred
     * @param value The amount of tokens being transferred
     * @param data Additional data with no specified format
     * @return `bytes4(keccak256("onERC1155Received(address,address,uint256,uint256,bytes)"))` if transfer is allowed
     */
    function onERC1155Received(
        address operator,
        address from,
        uint256 id,
        uint256 value,
        bytes calldata data
    ) external returns (bytes4);

    /**
     * @dev Handles the receipt of a multiple ERC-1155 token types. This function
     * is called at the end of a `safeBatchTransferFrom` after the balances have
     * been updated.
     *
     * NOTE: To accept the transfer(s), this must return
     * `bytes4(keccak256("onERC1155BatchReceived(address,address,uint256[],uint256[],bytes)"))`
     * (i.e. 0xbc197c81, or its own function selector).
     *
     * @param operator The address which initiated the batch transfer (i.e. msg.sender)
     * @param from The address which previously owned the token
     * @param ids An array containing ids of each token being transferred (order and length must match values array)
     * @param values An array containing amounts of each token being transferred (order and length must match ids array)
     * @param data Additional data with no specified format
     * @return `bytes4(keccak256("onERC1155BatchReceived(address,address,uint256[],uint256[],bytes)"))` if transfer is allowed
     */
    function onERC1155BatchReceived(
        address operator,
        address from,
        uint256[] calldata ids,
        uint256[] calldata values,
        bytes calldata data
    ) external returns (bytes4);
}


// File @openzeppelin/contracts/utils/introspection/ERC165.sol@v5.3.0

// Original license: SPDX_License_Identifier: MIT
// OpenZeppelin Contracts (last updated v5.1.0) (utils/introspection/ERC165.sol)

pragma solidity ^0.8.20;

/**
 * @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 ERC165 is IERC165 {
    /**
     * @dev See {IERC165-supportsInterface}.
     */
    function supportsInterface(bytes4 interfaceId) public view virtual returns (bool) {
        return interfaceId == type(IERC165).interfaceId;
    }
}


// File @openzeppelin/contracts/token/ERC1155/utils/ERC1155Holder.sol@v5.3.0

// Original license: SPDX_License_Identifier: MIT
// OpenZeppelin Contracts (last updated v5.1.0) (token/ERC1155/utils/ERC1155Holder.sol)

pragma solidity ^0.8.20;


/**
 * @dev Simple implementation of `IERC1155Receiver` that will allow a contract to hold ERC-1155 tokens.
 *
 * IMPORTANT: When inheriting this contract, you must include a way to use the received tokens, otherwise they will be
 * stuck.
 */
abstract contract ERC1155Holder is ERC165, IERC1155Receiver {
    /**
     * @dev See {IERC165-supportsInterface}.
     */
    function supportsInterface(bytes4 interfaceId) public view virtual override(ERC165, IERC165) returns (bool) {
        return interfaceId == type(IERC1155Receiver).interfaceId || super.supportsInterface(interfaceId);
    }

    function onERC1155Received(
        address,
        address,
        uint256,
        uint256,
        bytes memory
    ) public virtual override returns (bytes4) {
        return this.onERC1155Received.selector;
    }

    function onERC1155BatchReceived(
        address,
        address,
        uint256[] memory,
        uint256[] memory,
        bytes memory
    ) public virtual override returns (bytes4) {
        return this.onERC1155BatchReceived.selector;
    }
}


// File @openzeppelin/contracts/token/ERC721/IERC721.sol@v5.3.0

// Original license: SPDX_License_Identifier: MIT
// OpenZeppelin Contracts (last updated v5.1.0) (token/ERC721/IERC721.sol)

pragma solidity ^0.8.20;

/**
 * @dev Required interface of an ERC-721 compliant contract.
 */
interface IERC721 is IERC165 {
    /**
     * @dev Emitted when `tokenId` token is transferred from `from` to `to`.
     */
    event Transfer(address indexed from, address indexed to, uint256 indexed tokenId);

    /**
     * @dev Emitted when `owner` enables `approved` to manage the `tokenId` token.
     */
    event Approval(address indexed owner, address indexed approved, uint256 indexed tokenId);

    /**
     * @dev Emitted when `owner` enables or disables (`approved`) `operator` to manage all of its assets.
     */
    event ApprovalForAll(address indexed owner, address indexed operator, bool approved);

    /**
     * @dev Returns the number of tokens in ``owner``'s account.
     */
    function balanceOf(address owner) external view returns (uint256 balance);

    /**
     * @dev Returns the owner of the `tokenId` token.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     */
    function ownerOf(uint256 tokenId) external view returns (address owner);

    /**
     * @dev Safely transfers `tokenId` token from `from` to `to`.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must exist and be owned by `from`.
     * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon
     *   a safe transfer.
     *
     * Emits a {Transfer} event.
     */
    function safeTransferFrom(address from, address to, uint256 tokenId, bytes calldata data) external;

    /**
     * @dev Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients
     * are aware of the ERC-721 protocol to prevent tokens from being forever locked.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must exist and be owned by `from`.
     * - If the caller is not `from`, it must have been allowed to move this token by either {approve} or
     *   {setApprovalForAll}.
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon
     *   a safe transfer.
     *
     * Emits a {Transfer} event.
     */
    function safeTransferFrom(address from, address to, uint256 tokenId) external;

    /**
     * @dev Transfers `tokenId` token from `from` to `to`.
     *
     * WARNING: Note that the caller is responsible to confirm that the recipient is capable of receiving ERC-721
     * or else they may be permanently lost. Usage of {safeTransferFrom} prevents loss, though the caller must
     * understand this adds an external call which potentially creates a reentrancy vulnerability.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must be owned by `from`.
     * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(address from, address to, uint256 tokenId) external;

    /**
     * @dev Gives permission to `to` to transfer `tokenId` token to another account.
     * The approval is cleared when the token is transferred.
     *
     * Only a single account can be approved at a time, so approving the zero address clears previous approvals.
     *
     * Requirements:
     *
     * - The caller must own the token or be an approved operator.
     * - `tokenId` must exist.
     *
     * Emits an {Approval} event.
     */
    function approve(address to, uint256 tokenId) external;

    /**
     * @dev Approve or remove `operator` as an operator for the caller.
     * Operators can call {transferFrom} or {safeTransferFrom} for any token owned by the caller.
     *
     * Requirements:
     *
     * - The `operator` cannot be the address zero.
     *
     * Emits an {ApprovalForAll} event.
     */
    function setApprovalForAll(address operator, bool approved) external;

    /**
     * @dev Returns the account approved for `tokenId` token.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     */
    function getApproved(uint256 tokenId) external view returns (address operator);

    /**
     * @dev Returns if the `operator` is allowed to manage all of the assets of `owner`.
     *
     * See {setApprovalForAll}
     */
    function isApprovedForAll(address owner, address operator) external view returns (bool);
}


// File @openzeppelin/contracts/token/ERC721/IERC721Receiver.sol@v5.3.0

// Original license: SPDX_License_Identifier: MIT
// OpenZeppelin Contracts (last updated v5.1.0) (token/ERC721/IERC721Receiver.sol)

pragma solidity ^0.8.20;

/**
 * @title ERC-721 token receiver interface
 * @dev Interface for any contract that wants to support safeTransfers
 * from ERC-721 asset contracts.
 */
interface IERC721Receiver {
    /**
     * @dev Whenever an {IERC721} `tokenId` token is transferred to this contract via {IERC721-safeTransferFrom}
     * by `operator` from `from`, this function is called.
     *
     * It must return its Solidity selector to confirm the token transfer.
     * If any other value is returned or the interface is not implemented by the recipient, the transfer will be
     * reverted.
     *
     * The selector can be obtained in Solidity with `IERC721Receiver.onERC721Received.selector`.
     */
    function onERC721Received(
        address operator,
        address from,
        uint256 tokenId,
        bytes calldata data
    ) external returns (bytes4);
}


// File @openzeppelin/contracts/token/ERC721/utils/ERC721Holder.sol@v5.3.0

// Original license: SPDX_License_Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (token/ERC721/utils/ERC721Holder.sol)

pragma solidity ^0.8.20;

/**
 * @dev Implementation of the {IERC721Receiver} interface.
 *
 * Accepts all token transfers.
 * Make sure the contract is able to use its token with {IERC721-safeTransferFrom}, {IERC721-approve} or
 * {IERC721-setApprovalForAll}.
 */
abstract contract ERC721Holder is IERC721Receiver {
    /**
     * @dev See {IERC721Receiver-onERC721Received}.
     *
     * Always returns `IERC721Receiver.onERC721Received.selector`.
     */
    function onERC721Received(address, address, uint256, bytes memory) public virtual returns (bytes4) {
        return this.onERC721Received.selector;
    }
}


// File @openzeppelin/contracts/token/ERC20/IERC20.sol@v5.3.0

// Original license: SPDX_License_Identifier: MIT
// OpenZeppelin Contracts (last updated v5.1.0) (token/ERC20/IERC20.sol)

pragma solidity ^0.8.20;

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

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

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

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

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

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

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

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


// File @openzeppelin/contracts/utils/ReentrancyGuard.sol@v5.3.0

// Original license: SPDX_License_Identifier: MIT
// OpenZeppelin Contracts (last updated v5.1.0) (utils/ReentrancyGuard.sol)

pragma solidity ^0.8.20;

/**
 * @dev Contract module that helps prevent reentrant calls to a function.
 *
 * Inheriting from `ReentrancyGuard` will make the {nonReentrant} modifier
 * available, which can be applied to functions to make sure there are no nested
 * (reentrant) calls to them.
 *
 * Note that because there is a single `nonReentrant` guard, functions marked as
 * `nonReentrant` may not call one another. This can be worked around by making
 * those functions `private`, and then adding `external` `nonReentrant` entry
 * points to them.
 *
 * TIP: If EIP-1153 (transient storage) is available on the chain you're deploying at,
 * consider using {ReentrancyGuardTransient} instead.
 *
 * TIP: If you would like to learn more about reentrancy and alternative ways
 * to protect against it, check out our blog post
 * https://blog.openzeppelin.com/reentrancy-after-istanbul/[Reentrancy After Istanbul].
 */
abstract contract ReentrancyGuard {
    // Booleans are more expensive than uint256 or any type that takes up a full
    // word because each write operation emits an extra SLOAD to first read the
    // slot's contents, replace the bits taken up by the boolean, and then write
    // back. This is the compiler's defense against contract upgrades and
    // pointer aliasing, and it cannot be disabled.

    // The values being non-zero value makes deployment a bit more expensive,
    // but in exchange the refund on every call to nonReentrant will be lower in
    // amount. Since refunds are capped to a percentage of the total
    // transaction's gas, it is best to keep them low in cases like this one, to
    // increase the likelihood of the full refund coming into effect.
    uint256 private constant NOT_ENTERED = 1;
    uint256 private constant ENTERED = 2;

    uint256 private _status;

    /**
     * @dev Unauthorized reentrant call.
     */
    error ReentrancyGuardReentrantCall();

    constructor() {
        _status = NOT_ENTERED;
    }

    /**
     * @dev Prevents a contract from calling itself, directly or indirectly.
     * Calling a `nonReentrant` function from another `nonReentrant`
     * function is not supported. It is possible to prevent this from happening
     * by making the `nonReentrant` function external, and making it call a
     * `private` function that does the actual work.
     */
    modifier nonReentrant() {
        _nonReentrantBefore();
        _;
        _nonReentrantAfter();
    }

    function _nonReentrantBefore() private {
        // On the first call to nonReentrant, _status will be NOT_ENTERED
        if (_status == ENTERED) {
            revert ReentrancyGuardReentrantCall();
        }

        // Any calls to nonReentrant after this point will fail
        _status = ENTERED;
    }

    function _nonReentrantAfter() private {
        // By storing the original value once again, a refund is triggered (see
        // https://eips.ethereum.org/EIPS/eip-2200)
        _status = NOT_ENTERED;
    }

    /**
     * @dev Returns true if the reentrancy guard is currently set to "entered", which indicates there is a
     * `nonReentrant` function in the call stack.
     */
    function _reentrancyGuardEntered() internal view returns (bool) {
        return _status == ENTERED;
    }
}


// File contracts/interfaces/ICollection.sol

// Original license: SPDX_License_Identifier: MIT
pragma solidity ^0.8.20;

interface ICollection {
    struct NFTDetails {
        string name;
        string description;
        string uri;
        uint256 maxSupply;
        address creator;
    }

    event NFTCreated(string name, string description,uint256 indexed tokenId, address indexed creator, uint256 maxSupply);

    function initialize(
        string memory name,
        string memory symbol,
        address owner
    ) external;

    function createNFT(
        string memory name,
        string memory description,
        string memory _tokenURI,
        uint256 maxSupply,
        address user
    ) external returns (uint256);

    function getCreator(uint256 tokenId) external view  returns (address);
    function getRoyaltyPercentage() external view returns(uint16);
    function updateRoyaltyPercentage(uint16 _royaltyPercentage) external;
}


// File contracts/NFTMarketplace.sol

// Original license: SPDX_License_Identifier: MIT
pragma solidity ^0.8.20;









contract NFTMarketplace is Ownable, ERC1155Holder, ERC721Holder, ReentrancyGuard {
    enum ListingType { FIXED_PRICE, AUCTION }
    enum AuctionStatus { ACTIVE, ENDED, CANCELLED }
    enum OfferStatus { PENDING, ACCEPTED, REJECTED, CANCELLED }
    enum TokenStandard { ERC1155, ERC721 }

    struct Listing {
        address seller;
        uint256 price;
        uint256 quantity; // Always 1 for ERC721
        ListingType listingType;
        uint256 auctionId;  // 0 for fixed price listings
        TokenStandard tokenStandard;
    }

    struct AuctionDetails {
        address seller;
        uint256 startPrice;
        uint256 currentPrice;
        uint256 minBidIncrement;
        uint256 startTime;
        uint256 endTime;
        uint256 tokenId;
        uint256 quantity;
        address highestBidder;
        AuctionStatus status;
        TokenStandard tokenStandard;
    }

    struct Offer {
        address buyer;
        address seller;
        uint256 price;
        uint256 quantity;
        uint256 createTime;
        OfferStatus status;
        TokenStandard tokenStandard;
    }

    struct FilterParams {
        address collection;
        uint256 tokenId;
        address user;
        uint8 filterType;
        TokenStandard tokenStandard;
    }

    struct BatchPurchaseParams {
        address collection;
        uint256 tokenId;
        address seller;
        uint256 quantity;
        TokenStandard tokenStandard;
    }
    
    uint256 public primaryFee;
    uint256 public secondaryFee;
    address public collectionFactory;
    uint256 public totalCollections;
    IERC20 public immutable designatedToken;

    uint256 private _auctionIds;
    uint256 private _offerIds;
    uint256 public minAuctionDuration;
    uint256 public maxAuctionDuration;
    uint256 public auctionExtensionInterval;
    
    mapping(address => mapping(uint256 => mapping(address => Listing))) public listings;
    mapping(address => bool) public registeredCollections;
    mapping(uint256 => address) private collectionIndex;
    mapping(uint256 => AuctionDetails) public auctions;
    mapping(uint256 => mapping(address => uint256)) public bids;
    mapping(uint256 => address) public auctionCollections;

    // Offer mappings
    mapping(address => mapping(uint256 => mapping(uint256 => Offer))) public offers; // collection => tokenId => offerId => Offer
    mapping(address => uint256[]) private userOfferIds; // buyer => offerIds
    mapping(uint256 => address) private offerCollections; // offerId => collection
    mapping(uint256 => uint256) private offerTokenIds; // offerId => tokenId
    mapping(address => uint256[]) private sellerReceivedOffers; // seller => offerIds
    mapping(address => mapping(uint256 => uint256[])) private tokenOffers; // collection => tokenId => offerIds
    
    event NFTListed(
        address indexed collection, 
        uint256 indexed tokenId, 
        address seller, 
        uint256 price, 
        uint256 quantity,
        ListingType listingType,
        uint256 auctionId,
        TokenStandard tokenStandard
    );
    event NFTSold(
        address indexed collection,
        uint256 indexed tokenId,
        address seller,
        address buyer,
        uint256 price,
        uint256 quantity,
        TokenStandard tokenStandard
    );
    event ListingRemoved(address indexed collection, uint256 indexed tokenId, address seller, string reason);
    event ListingQuantityUpdated(
        address indexed collection,
        uint256 indexed tokenId,
        address seller,
        uint256 newQuantity
    );
    event AuctionCreated(
        uint256 indexed auctionId,
        address indexed collection,
        uint256 indexed tokenId,
        address seller,
        uint256 startPrice,
        uint256 minBidIncrement,
        uint256 startTime,
        uint256 endTime,
        uint256 quantity,
        TokenStandard tokenStandard
    );

    event BidPlaced(
        uint256 indexed auctionId,
        address indexed bidder,
        uint256 amount
    );

    event AuctionSettled(
        uint256 indexed auctionId,
        address indexed winner,
        uint256 amount
    );

    event AuctionCancelled(uint256 indexed auctionId);
    event AuctionExtended(uint256 indexed auctionId, uint256 newEndTime);

    event FeeUpdated(bool isPrimary, uint256 newFee);
    event CollectionRegistered(address indexed collection);
    event AuctionExtensionIntervalUpdated(uint256 newInterval);

    event OfferCreated(
        uint256 indexed offerId,
        address indexed collection,
        uint256 indexed tokenId,
        address buyer,
        address seller,
        uint256 price,
        uint256 quantity,
        TokenStandard tokenStandard
    );

    event OfferAccepted(uint256 indexed offerId, address indexed seller);
    event OfferRejected(uint256 indexed offerId, address indexed seller);
    event OfferCancelled(uint256 indexed offerId, address indexed buyer);
    
    constructor(
        address _designatedToken,
        uint256 _primaryFee,
        uint256 _secondaryFee
    ) Ownable(msg.sender) {
        require(_designatedToken != address(0), "Invalid token address");
        require(_primaryFee <= 1000, "Primary fee too high");
        require(_secondaryFee <= 1000, "Secondary fee too high");
        
        designatedToken = IERC20(_designatedToken);
        primaryFee = _primaryFee;
        secondaryFee = _secondaryFee;
        minAuctionDuration = 1 hours;
        maxAuctionDuration = 30 days;
        auctionExtensionInterval = 10 minutes;
    }

    function registerCollection(address collection) external {
        require(msg.sender == collectionFactory, "Only factory can register");
        require(collection != address(0), "Invalid collection address");
        require(!registeredCollections[collection], "Already registered");
        
        registeredCollections[collection] = true;
        collectionIndex[totalCollections] = collection;
        totalCollections++;
        
        emit CollectionRegistered(collection);
    }
    
    function setPrimaryFee(uint256 _fee) external onlyOwner {
        require(_fee <= 1000, "Fee too high");
        primaryFee = _fee;
        emit FeeUpdated(true, _fee);
    }
    
    function setSecondaryFee(uint256 _fee) external onlyOwner {
        require(_fee <= 1000, "Fee too high");
        secondaryFee = _fee;
        emit FeeUpdated(false, _fee);
    }
    
    function listNFT(
        address collection,
        uint256 tokenId,
        uint256 price,
        uint256 quantity,
        TokenStandard tokenStandard
    ) external nonReentrant {
        require(registeredCollections[collection], "Collection not registered");
        require(price > 0, "Invalid price");
        require(quantity > 0, "Invalid quantity");
        if (tokenStandard == TokenStandard.ERC721) {
            require(quantity == 1, "ERC721 quantity must be 1");
            require(IERC721(collection).ownerOf(tokenId) == msg.sender, "Not token owner");
            require(IERC721(collection).getApproved(tokenId) == address(this) || 
                    IERC721(collection).isApprovedForAll(msg.sender, address(this)), "Not approved");
        } else {
            require(IERC1155(collection).balanceOf(msg.sender, tokenId) >= quantity, "Insufficient balance");
            require(IERC1155(collection).isApprovedForAll(msg.sender, address(this)), "Not approved");
        }
        // Check if NFT is already listed by this seller
        Listing storage existingListing = listings[collection][tokenId][msg.sender];
        require(
            existingListing.quantity == 0 || 
            (existingListing.listingType == ListingType.AUCTION && 
             auctions[existingListing.auctionId].status != AuctionStatus.ACTIVE), 
            "Already listed"
        );

        listings[collection][tokenId][msg.sender] = Listing({
            seller: msg.sender,
            price: price,
            quantity: quantity,
            listingType: ListingType.FIXED_PRICE,
            auctionId: 0,
            tokenStandard: tokenStandard
        });

        emit NFTListed(
            collection, 
            tokenId, 
            msg.sender, 
            price, 
            quantity,
            ListingType.FIXED_PRICE,
            0,
            tokenStandard
        );
    }
    
    function removeListing(
        address collection,
        uint256 tokenId
    ) external nonReentrant {
        Listing storage listing = listings[collection][tokenId][msg.sender];
        require(listing.seller == msg.sender && listing.quantity > 0, "No active listing");
        
        if (listing.listingType == ListingType.AUCTION) {
            AuctionDetails storage auction = auctions[listing.auctionId];
            require(auction.status == AuctionStatus.ACTIVE, "Auction not active");
            require(auction.highestBidder == address(0), "Bids already placed");
            
            auction.status = AuctionStatus.CANCELLED;
            if (listing.tokenStandard == TokenStandard.ERC721) {
                IERC721(collection).safeTransferFrom(address(this), msg.sender, tokenId);
            } else {
                IERC1155(collection).safeTransferFrom(
                    address(this),
                    msg.sender,
                    tokenId,
                    listing.quantity,
                    ""
                );
            }

            emit AuctionCancelled(listing.auctionId);
        }

        delete listings[collection][tokenId][msg.sender];
        emit ListingRemoved(collection, tokenId, msg.sender, "REMOVED_BY_SELLER");
    }
    
    function buyListedNFT(
        address collection,
        uint256 tokenId,
        address seller,
        uint256 quantity,
        TokenStandard tokenStandard
    ) external nonReentrant {
        require(registeredCollections[collection], "Collection not registered");
        Listing storage listing = listings[collection][tokenId][seller];
        require(listing.seller == seller && listing.quantity > 0, "Invalid listing");
        require(listing.listingType == ListingType.FIXED_PRICE, "Not a fixed price listing");
        require(listing.quantity >= quantity, "Insufficient quantity");
        require(listing.tokenStandard == tokenStandard, "Token standard mismatch");
        if (tokenStandard == TokenStandard.ERC721) {
            require(quantity == 1, "ERC721 quantity must be 1");
        }
        address nftCreator = ICollection(collection).getCreator(tokenId);
        
        uint256 fee = secondaryFee;
        if(nftCreator == seller) {
            fee = primaryFee;
        }
        uint16 royaltyPercentage = ICollection(collection).getRoyaltyPercentage();
        uint256 totalPrice = listing.price * quantity;
        uint256 platformFee = (totalPrice * fee) / 1000;
        uint256 royaltyFee  = (totalPrice * royaltyPercentage) / 1000;
        uint256 sellerAmount = totalPrice - platformFee - royaltyFee;
        
        designatedToken.transferFrom(msg.sender, address(this), platformFee);
        designatedToken.transferFrom(msg.sender, seller, sellerAmount);
        if(royaltyFee > 0) {
            designatedToken.transferFrom(msg.sender, nftCreator, royaltyFee);
        }
        
        if (tokenStandard == TokenStandard.ERC721) {
            IERC721(collection).safeTransferFrom(seller, msg.sender, tokenId);
        } else {
            IERC1155(collection).safeTransferFrom(seller, msg.sender, tokenId, quantity, "");
        }

        listing.quantity -= quantity;
        if (listing.quantity == 0) {
            delete listings[collection][tokenId][seller];
            emit ListingRemoved(collection, tokenId, seller, "SOLD_OUT");
        }
        
        emit NFTSold(collection, tokenId, seller, msg.sender, listing.price, quantity, tokenStandard);
    }
    
    function getRegisteredCollections(uint256 offset, uint256 limit) 
        public 
        view 
        returns (address[] memory collections) 
    {
        require(offset <= totalCollections, "Invalid offset");
        
        uint256 size = totalCollections - offset;
        if (size > limit) {
            size = limit;
        }
        
        collections = new address[](size);
        
        for (uint256 i = 0; i < size; i++) {
            collections[i] = collectionIndex[offset + i];
        }
        
        return collections;
    }
    
    function getCollectionsByOwner(address _owner, uint256 offset, uint256 limit)
        external
        view
        returns (address[] memory _collections, uint256 total)
    {
        uint256 count = 0;
        
        for (uint256 i = 0; i < totalCollections; i++) {
            address collection = collectionIndex[i];
            if (OwnableUpgradeable(collection).owner() == _owner) {
                count++;
            }
        }
        
        require(offset <= count, "Invalid offset");
        
        uint256 size = count - offset;
        if (size > limit) {
            size = limit;
        }
        
        _collections = new address[](size);
        uint256 currentIndex = 0;
        uint256 skipped = 0;
        
        for (uint256 i = 0; i < totalCollections && currentIndex < size; i++) {
            address collection = collectionIndex[i];
            if (OwnableUpgradeable(collection).owner() == _owner) {
                if (skipped < offset) {
                    skipped++;
                    continue;
                }
                _collections[currentIndex] = collection;
                currentIndex++;
            }
        }
        
        return (_collections, count);
    }
    
    function withdrawFees() external onlyOwner {
        uint256 balance = designatedToken.balanceOf(address(this));
        if (balance > 0) {
            designatedToken.transfer(owner(), balance);
        }
    }
    
    function getListing(
        address collection,
        uint256 tokenId,
        address seller
    ) external view returns (Listing memory) {
        return listings[collection][tokenId][seller];
    }

    function createAuction(
        address collection,
        uint256 tokenId,
        uint256 quantity,
        uint256 startPrice,
        uint256 minBidIncrement,
        uint256 duration,
        TokenStandard tokenStandard
    ) external nonReentrant returns (uint256) {
        _validateAuctionParams(
            collection,
            tokenId,
            quantity,
            startPrice,
            minBidIncrement,
            duration,
            tokenStandard
        );

        _auctionIds++;
        uint256 auctionId = _auctionIds;
        
        _createAuctionListing(
            collection,
            tokenId,
            quantity,
            startPrice,
            auctionId,
            tokenStandard
        );

        _setupAuction(
            auctionId,
            collection,
            tokenId,
            quantity,
            startPrice,
            minBidIncrement,
            duration,
            tokenStandard
        );

        return auctionId;
    }

    function _validateAuctionParams(
        address collection,
        uint256 tokenId,
        uint256 quantity,
        uint256 startPrice,
        uint256 minBidIncrement,
        uint256 duration,
        TokenStandard tokenStandard
    ) internal view {
        require(registeredCollections[collection], "Collection not registered");
        require(quantity > 0, "Invalid quantity");
        require(startPrice > 0, "Invalid start price");
        require(minBidIncrement > 0, "Invalid min bid increment");
        require(duration >= minAuctionDuration && duration <= maxAuctionDuration, "Invalid duration");
        if (tokenStandard == TokenStandard.ERC721) {
            require(quantity == 1, "ERC721 quantity must be 1");
            require(IERC721(collection).ownerOf(tokenId) == msg.sender, "Not token owner");
            require(IERC721(collection).getApproved(tokenId) == address(this) || 
                    IERC721(collection).isApprovedForAll(msg.sender, address(this)), "Not approved");
        } else {
            require(IERC1155(collection).balanceOf(msg.sender, tokenId) >= quantity, "Insufficient balance");
            require(IERC1155(collection).isApprovedForAll(msg.sender, address(this)), "Not approved");
        }


        Listing storage existingListing = listings[collection][tokenId][msg.sender];
        require(
            existingListing.quantity == 0 || 
            (existingListing.listingType == ListingType.AUCTION && 
             auctions[existingListing.auctionId].status != AuctionStatus.ACTIVE), 
            "Already listed"
        );
    }

    function _createAuctionListing(
        address collection,
        uint256 tokenId,
        uint256 quantity,
        uint256 startPrice,
        uint256 auctionId,
        TokenStandard tokenStandard
    ) internal {
        listings[collection][tokenId][msg.sender] = Listing({
            seller: msg.sender,
            price: startPrice,
            quantity: quantity,
            listingType: ListingType.AUCTION,
            auctionId: auctionId,
            tokenStandard: tokenStandard
        });

        emit NFTListed(
            collection, 
            tokenId, 
            msg.sender, 
            startPrice, 
            quantity,
            ListingType.AUCTION,
            auctionId,
            tokenStandard
        );
    }
    function _setupAuction(
        uint256 auctionId,
        address collection,
        uint256 tokenId,
        uint256 quantity,
        uint256 startPrice,
        uint256 minBidIncrement,
        uint256 duration,
        TokenStandard tokenStandard
    ) internal {
        uint256 startTime = block.timestamp;
        uint256 endTime = startTime + duration;

        auctions[auctionId] = AuctionDetails({
            seller: msg.sender,
            startPrice: startPrice,
            currentPrice: startPrice,
            minBidIncrement: minBidIncrement,
            startTime: startTime,
            endTime: endTime,
            tokenId: tokenId,
            quantity: quantity,
            highestBidder: address(0),
            status: AuctionStatus.ACTIVE,
            tokenStandard: tokenStandard
        });

        auctionCollections[auctionId] = collection;

        if (tokenStandard == TokenStandard.ERC721) {
            IERC721(collection).safeTransferFrom(msg.sender, address(this), tokenId);
        } else {
            IERC1155(collection).safeTransferFrom(msg.sender, address(this), tokenId, quantity, "");
        }

        emit AuctionCreated(
            auctionId,
            collection,
            tokenId,
            msg.sender,
            startPrice,
            minBidIncrement,
            startTime,
            endTime,
            quantity,
            tokenStandard
        );
    }

    function placeBid(uint256 auctionId, uint256 bidAmount) external nonReentrant {
        AuctionDetails storage auction = auctions[auctionId];
        require(auction.status == AuctionStatus.ACTIVE, "Auction not active");
        require(block.timestamp <= auction.endTime, "Auction ended");
        require(bidAmount >= auction.currentPrice + auction.minBidIncrement, "Bid too low");

        // Check if bid is placed near the end
        if (auction.endTime - block.timestamp <= auctionExtensionInterval) {
            auction.endTime = block.timestamp + auctionExtensionInterval;
            emit AuctionExtended(auctionId, auction.endTime);
        }

        address previousBidder = auction.highestBidder;
        uint256 previousBid = bids[auctionId][previousBidder];

        if (previousBidder != address(0)) {
            designatedToken.transfer(previousBidder, previousBid);
        }

        require(
            designatedToken.transferFrom(msg.sender, address(this), bidAmount),
            "Transfer failed"
        );

        auction.highestBidder = msg.sender;
        auction.currentPrice = bidAmount;
        bids[auctionId][msg.sender] = bidAmount;

        emit BidPlaced(auctionId, msg.sender, bidAmount);
    }

    function settleAuction(uint256 auctionId) external nonReentrant {
        AuctionDetails storage auction = auctions[auctionId];
        require(auction.status == AuctionStatus.ACTIVE, "Auction not active");
        require(block.timestamp > auction.endTime, "Auction not ended");
        require(auction.highestBidder != address(0), "No bids placed");

        auction.status = AuctionStatus.ENDED;
        address collection = auctionCollections[auctionId];
        uint256 finalPrice = auction.currentPrice;
        address creator = ICollection(collection).getCreator(auction.tokenId);

        uint256 fee = secondaryFee;
        if(creator == auction.seller) {
            fee = primaryFee;
        }
        uint16 royaltyPercentage = ICollection(collection).getRoyaltyPercentage();
        // Calculate fees
        uint256 platformFee = (finalPrice * fee) / 1000;
        uint256 royaltyFee = (finalPrice * royaltyPercentage) / 1000;
        uint256 sellerAmount = finalPrice - platformFee - royaltyFee;

        // Distribute funds
        designatedToken.transfer(auction.seller, sellerAmount);
        if(royaltyFee>0) {
            designatedToken.transfer(creator, royaltyFee);
        }

        // Transfer NFT
        if (auction.tokenStandard == TokenStandard.ERC721) {
            IERC721(collection).safeTransferFrom(address(this), auction.highestBidder, auction.tokenId);
        } else {
            IERC1155(collection).safeTransferFrom(
                address(this),
                auction.highestBidder,
                auction.tokenId,
                auction.quantity,
                ""
            );
        }

        // Remove listing
        address seller = auction.seller;
        delete listings[collection][auction.tokenId][seller];
        emit ListingRemoved(collection, auction.tokenId, seller, "AUCTION_SETTLED");

        emit AuctionSettled(auctionId, auction.highestBidder, finalPrice);
    }

    function cancelAuction(uint256 auctionId) external nonReentrant {
        AuctionDetails storage auction = auctions[auctionId];
        require(auction.status == AuctionStatus.ACTIVE, "Auction not active");
        require(msg.sender == auction.seller, "Not seller");
        require(auction.highestBidder == address(0), "Bids already placed");

        auction.status = AuctionStatus.CANCELLED;
        address collection = auctionCollections[auctionId];

        if (auction.tokenStandard == TokenStandard.ERC721) {
            IERC721(collection).safeTransferFrom(address(this), auction.seller, auction.tokenId);
        } else {
            IERC1155(collection).safeTransferFrom(
                address(this),
                auction.seller,
                auction.tokenId,
                auction.quantity,
                ""
            );
        }

        // Remove listing
        delete listings[collection][auction.tokenId][auction.seller];
        emit ListingRemoved(collection, auction.tokenId, auction.seller, "AUCTION_CANCELLED");

        emit AuctionCancelled(auctionId);
    }
    function setAuctionExtensionInterval(uint256 _interval) external onlyOwner {
        require(_interval > 0, "Invalid interval");
        auctionExtensionInterval = _interval;
        emit AuctionExtensionIntervalUpdated(_interval);
    }

    function makeOffer(
        address collection,
        uint256 tokenId,
        address seller,
        uint256 quantity,
        uint256 price,
        TokenStandard tokenStandard
    ) external nonReentrant {
        require(registeredCollections[collection], "Collection not registered");
        require(quantity > 0, "Invalid quantity");
        require(price > 0, "Invalid price");
        require(seller != address(0), "Invalid seller");
        require(seller != msg.sender, "Cannot make offer to self");
        if (tokenStandard == TokenStandard.ERC721) {
            require(quantity == 1, "ERC721 quantity must be 1");
            require(IERC721(collection).ownerOf(tokenId) == seller, "Seller not owner");
        } else {
            require(IERC1155(collection).balanceOf(seller, tokenId) >= quantity, "Insufficient seller balance");
        }

        _offerIds++;
        uint256 offerId = _offerIds;

        offers[collection][tokenId][offerId] = Offer({
            buyer: msg.sender,
            seller: seller,
            price: price,
            quantity: quantity,
            createTime: block.timestamp,
            status: OfferStatus.PENDING,
            tokenStandard: tokenStandard
        });

        userOfferIds[msg.sender].push(offerId);
        sellerReceivedOffers[seller].push(offerId);
        tokenOffers[collection][tokenId].push(offerId);
        offerCollections[offerId] = collection;
        offerTokenIds[offerId] = tokenId;

        // Pre-approve marketplace for token transfer
        designatedToken.transferFrom(msg.sender, address(this), price * quantity);

        emit OfferCreated(offerId, collection, tokenId, msg.sender, seller, price, quantity,tokenStandard);
    }
    function acceptOffer(uint256 offerId) external nonReentrant {
        (address collection, uint256 tokenId, Offer storage offer) = _validateAndGetOffer(offerId);
        uint256 totalBalance = _validateSellerBalance(collection, tokenId, offer);
        _validateAndUpdateListing(collection, tokenId, offer.quantity, totalBalance);
        _processOfferAcceptance(collection, tokenId, offer, offerId);
    }

    function _validateAndGetOffer(uint256 offerId) private view returns (
        address collection,
        uint256 tokenId,
        Offer storage offer
    ) {
        collection = offerCollections[offerId];
        require(collection != address(0), "Offer does not exist");

        tokenId = offerTokenIds[offerId];
        offer = offers[collection][tokenId][offerId];
        
        require(offer.status == OfferStatus.PENDING, "Invalid offer status");
        require(msg.sender == offer.seller, "Not offer recipient");

        return (collection, tokenId, offer);
    }

    function _validateSellerBalance(
        address collection,
        uint256 tokenId,
        Offer memory offer
    ) private view returns (uint256) {
        if (offer.tokenStandard == TokenStandard.ERC721) {
            require(IERC721(collection).ownerOf(tokenId) == msg.sender, "Not token owner");
            return 1;
        } else {
            uint256 totalBalance = IERC1155(collection).balanceOf(msg.sender, tokenId);
            require(totalBalance >= offer.quantity, "Insufficient balance");
            return totalBalance;
        }
    }

    function _validateAndUpdateListing(
        address collection,
        uint256 tokenId,
        uint256 offerQuantity,
        uint256 totalBalance
    ) private {
        Listing storage listing = listings[collection][tokenId][msg.sender];
        
        // Check if NFT is not in active auction
        if(listing.listingType == ListingType.AUCTION) {
            require(
                auctions[listing.auctionId].status != AuctionStatus.ACTIVE,
                "Active auction exists"
            );
        }

        // Calculate available quantities
        uint256 listedQuantity = listing.quantity;
        uint256 unlistedQuantity = totalBalance - listedQuantity;
        
        // Calculate how many NFTs to take from unlisted and listed
        uint256 takeFromUnlisted = unlistedQuantity >= offerQuantity ? 
            offerQuantity : unlistedQuantity;
        uint256 takeFromListed = offerQuantity - takeFromUnlisted;

        // Update listing if needed
        if(takeFromListed > 0) {
            if(takeFromListed == listedQuantity) {
                delete listings[collection][tokenId][msg.sender];
                emit ListingRemoved(collection, tokenId, msg.sender, "ZERO_QUANTITY");
            } else {
                listing.quantity = listedQuantity - takeFromListed;
                emit ListingQuantityUpdated(
                    collection,
                    tokenId,
                    msg.sender,
                    listing.quantity
                );
            }
        }
    }

    function _processOfferAcceptance(
        address collection,
        uint256 tokenId,
        Offer storage offer,
        uint256 offerId
    ) private {
        require(
            offer.tokenStandard == TokenStandard.ERC721 ?
                IERC721(collection).getApproved(tokenId) == address(this) ||
                IERC721(collection).isApprovedForAll(msg.sender, address(this)) :
                IERC1155(collection).isApprovedForAll(msg.sender, address(this)),
            "Not approved"
        );
        address creator = ICollection(collection).getCreator(tokenId);

        uint256 fee = secondaryFee;
        if(creator == msg.sender) {
            fee = primaryFee;
        }
        uint16 royaltyPercentage = ICollection(collection).getRoyaltyPercentage();

        // Calculate fees
        uint256 totalPrice = offer.price * offer.quantity;
        uint256 platformFee = (totalPrice * fee) / 1000;
        uint256 royaltyFee = (totalPrice * royaltyPercentage) / 1000;
        uint256 sellerAmount = totalPrice - platformFee - royaltyFee;

       if (offer.tokenStandard == TokenStandard.ERC721) {
            IERC721(collection).safeTransferFrom(msg.sender, offer.buyer, tokenId);
        } else {
            IERC1155(collection).safeTransferFrom(msg.sender, offer.buyer, tokenId, offer.quantity, "");
        }

        // Distribute payments
        designatedToken.transfer(msg.sender, sellerAmount);
        if(royaltyFee>0) {
            designatedToken.transfer(creator, royaltyFee);
        }
        

        offer.status = OfferStatus.ACCEPTED;
        emit OfferAccepted(offerId, msg.sender);
    }

    function rejectOffer(uint256 offerId) external nonReentrant {
        address collection = offerCollections[offerId];
        uint256 tokenId = offerTokenIds[offerId];
        require(collection != address(0), "Offer does not exist");

        Offer storage offer = offers[collection][tokenId][offerId];
        require(offer.status == OfferStatus.PENDING, "Invalid offer status");
        require(
            offer.tokenStandard == TokenStandard.ERC721 ?
                IERC721(collection).ownerOf(tokenId) == msg.sender :
                IERC1155(collection).balanceOf(msg.sender, tokenId) > 0,
            "Not token owner"
        );

        offer.status = OfferStatus.REJECTED;

        // Refund buyer
        designatedToken.transfer(offer.buyer, offer.price * offer.quantity);

        emit OfferRejected(offerId, msg.sender);
    }

    function cancelOffer(uint256 offerId) external nonReentrant {
        address collection = offerCollections[offerId];
        uint256 tokenId = offerTokenIds[offerId];
        require(collection != address(0), "Offer does not exist");

        Offer storage offer = offers[collection][tokenId][offerId];
        require(offer.buyer == msg.sender, "Not offer creator");
        require(offer.status == OfferStatus.PENDING, "Invalid offer status");

        offer.status = OfferStatus.CANCELLED;

        // Refund buyer
        designatedToken.transfer(msg.sender, offer.price * offer.quantity);

        emit OfferCancelled(offerId, msg.sender);
    }

    function getOffersByToken(
        address collection,
        uint256 tokenId,
        uint256 offset,
        uint256 limit,
         TokenStandard tokenStandard
    ) external view returns (uint256[] memory offerIdList, uint256 total) {
        return _getOffersWithFilter(
            collection,
            tokenId,
            address(0), // no user filter
            offset,
            limit,
            0,// filter type: BY_TOKEN
            tokenStandard
        );
    }

    function getOffersToSeller(
        address seller,
        uint256 offset,
        uint256 limit
    ) external view returns (uint256[] memory offerIdList, uint256 total) {
        return _getOffersWithFilter(
            address(0), // no collection filter
            0, // no tokenId filter
            seller,
            offset,
            limit,
            1, // filter type: BY_SELLER
            TokenStandard.ERC1155 
        );
    }

    function getOffersByBuyer(
        address buyer,
        uint256 offset,
        uint256 limit
    ) external view returns (uint256[] memory offerIdList, uint256 total) {
        return _getOffersWithFilter(
            address(0), // no collection filter
            0, // no tokenId filter
            buyer,
            offset,
            limit,
            2, // filter type: BY_BUYER
            TokenStandard.ERC1155 
        );
    }

    function _getOffersWithFilter(
        address collection,
        uint256 tokenId,
        address user,
        uint256 offset,
        uint256 limit,
        uint8 filterType,
        TokenStandard tokenStandard
    ) private view returns (uint256[] memory offerIdList, uint256 total) {
        FilterParams memory params = FilterParams(collection, tokenId, user, filterType, tokenStandard);
        uint256[] storage sourceOffers = _getSourceOffers(user, filterType, params);
        
        // Get total count first
        uint256 count = _countValidOffers(sourceOffers, params);

        if(count == 0 || offset >= count) {
            return (new uint256[](0), count);
        }

        return _getFilteredOffers(sourceOffers, params, offset, limit, count);
    }

    function _getSourceOffers(address user, uint8 filterType, FilterParams memory params) private view returns (uint256[] storage) {
        if (filterType == 0) { // BY_TOKEN
            return tokenOffers[params.collection][params.tokenId];
        } else if (filterType == 1) { // BY_SELLER
            return sellerReceivedOffers[user];
        } else { // BY_BUYER
            return userOfferIds[user];
        }
    }

    function _countValidOffers(
        uint256[] storage sourceOffers, 
        FilterParams memory params
    ) private view returns (uint256) {
        uint256 count;
        for(uint256 i = 0; i < sourceOffers.length; i++) {
            if(_isValidOffer(sourceOffers[i], params)) {
                count++;
            }
        }
        return count;
    }

    function _getFilteredOffers(
        uint256[] storage sourceOffers,
        FilterParams memory params,
        uint256 offset,
        uint256 limit,
        uint256 count
    ) private view returns (uint256[] memory offerIdList, uint256) {
        uint256 size = count - offset;
        if(size > limit) {
            size = limit;
        }

        offerIdList = new uint256[](size);
        uint256 currentIndex;
        uint256 skipped;

        for(uint256 i = 0; i < sourceOffers.length && currentIndex < size; i++) {
            uint256 offerId = sourceOffers[i];
            if(_isValidOffer(offerId, params)) {
                if(skipped < offset) {
                    skipped++;
                    continue;
                }
                offerIdList[currentIndex++] = offerId;
            }
        }

        return (offerIdList, count);
    }

    function _isValidOffer(
        uint256 offerId,
        FilterParams memory params
    ) private view returns (bool) {
        address offerCollection = offerCollections[offerId];
        uint256 offerTokenId = offerTokenIds[offerId];
        Offer storage offer = offers[offerCollection][offerTokenId][offerId];

        if (params.filterType == 0) { // BY_TOKEN
            return offerCollection == params.collection && 
                   offerTokenId == params.tokenId &&
                   offer.status == OfferStatus.PENDING;
        } else if (params.filterType == 1) { // BY_SELLER
            return offer.seller == params.user &&
                   offer.status == OfferStatus.PENDING;
        } else { // BY_BUYER
            return offer.buyer == params.user &&
                   offer.status == OfferStatus.PENDING;
        }
    }

    function getOffer(uint256 offerId) external view returns (
        address collection,
        uint256 tokenId,
        Offer memory offer
    ) {
        collection = offerCollections[offerId];
        require(collection != address(0), "Offer does not exist");
        
        tokenId = offerTokenIds[offerId];
        offer = offers[collection][tokenId][offerId];
        
        return (collection, tokenId, offer);
    }

    // function batchBuyListedNFTs(BatchPurchaseParams[] calldata params) external nonReentrant {
    //     require(params.length > 0, "Empty batch");
        
    //     for(uint256 i = 0; i < params.length; i++) {
    //         BatchPurchaseParams calldata purchase = params[i];
    //         require(registeredCollections[purchase.collection], "Collection not registered");
            
    //         Listing storage listing = listings[purchase.collection][purchase.tokenId][purchase.seller];
    //         require(listing.seller == purchase.seller && listing.quantity > 0, "Invalid listing");
    //         require(listing.listingType == ListingType.FIXED_PRICE, "Not a fixed price listing");
    //         require(listing.quantity >= purchase.quantity, "Insufficient quantity");

    //         address creator = ICollection(purchase.collection).getCreator(purchase.tokenId);
            
    //         uint256 fee = secondaryFee;
    //         if(creator == purchase.seller) {
    //             fee = primaryFee;
    //         }
    //         uint16 royaltyPercentage = ICollection(purchase.collection).getRoyaltyPercentage();
    //         uint256 totalPrice = listing.price * purchase.quantity;
    //         uint256 platformFee = (totalPrice * fee) / 1000;
    //         uint256 royaltyFee = (totalPrice * royaltyPercentage) / 1000;
    //         uint256 sellerAmount = totalPrice - platformFee - royaltyFee;

    //         designatedToken.transferFrom(msg.sender, address(this), platformFee);
    //         designatedToken.transferFrom(msg.sender, purchase.seller, sellerAmount);
    //         if(royaltyFee>0) {
    //             designatedToken.transferFrom(msg.sender, creator, royaltyFee);
    //         }

    //         if (purchase.tokenStandard == TokenStandard.ERC721) {
    //             IERC721(purchase.collection).safeTransferFrom(purchase.seller, msg.sender, purchase.tokenId);
    //         } else {
    //             IERC1155(purchase.collection).safeTransferFrom(
    //                 purchase.seller,
    //                 msg.sender,
    //                 purchase.tokenId,
    //                 purchase.quantity,
    //                 ""
    //             );
    //         }


    //         listing.quantity -= purchase.quantity;
    //         if (listing.quantity == 0) {
    //             delete listings[purchase.collection][purchase.tokenId][purchase.seller];
    //             emit ListingRemoved(purchase.collection, purchase.tokenId, purchase.seller, "SOLD_OUT");
    //         }

    //         emit NFTSold(
    //             purchase.collection, 
    //             purchase.tokenId, 
    //             purchase.seller, 
    //             msg.sender, 
    //             listing.price, 
    //             purchase.quantity,
    //             purchase.tokenStandard
    //         );
    //     }
    // }
}