organized_contracts/1e/1e12589e0dc298d196b504935872951b2e3267e2384509377483c53f337ca5a0/main.sol

// This contract is part of Zellic’s smart contract dataset, which is a collection of publicly available contract code gathered as of March 2023.

// Sources flattened with hardhat v2.11.2 https://hardhat.org

// File @openzeppelin/contracts/access/IAccessControl.sol@v4.7.3


// OpenZeppelin Contracts v4.4.1 (access/IAccessControl.sol)

pragma solidity ^0.8.0;

/**

 * @dev External interface of AccessControl declared to support ERC165 detection.

 */
interface IAccessControl {
    /**

     * @dev Emitted when `newAdminRole` is set as ``role``'s admin role, replacing `previousAdminRole`

     *

     * `DEFAULT_ADMIN_ROLE` is the starting admin for all roles, despite

     * {RoleAdminChanged} not being emitted signaling this.

     *

     * _Available since v3.1._

     */
    event RoleAdminChanged(bytes32 indexed role, bytes32 indexed previousAdminRole, bytes32 indexed newAdminRole);

    /**

     * @dev Emitted when `account` is granted `role`.

     *

     * `sender` is the account that originated the contract call, an admin role

     * bearer except when using {AccessControl-_setupRole}.

     */
    event RoleGranted(bytes32 indexed role, address indexed account, address indexed sender);

    /**

     * @dev Emitted when `account` is revoked `role`.

     *

     * `sender` is the account that originated the contract call:

     *   - if using `revokeRole`, it is the admin role bearer

     *   - if using `renounceRole`, it is the role bearer (i.e. `account`)

     */
    event RoleRevoked(bytes32 indexed role, address indexed account, address indexed sender);

    /**

     * @dev Returns `true` if `account` has been granted `role`.

     */
    function hasRole(bytes32 role, address account) external view returns (bool);

    /**

     * @dev Returns the admin role that controls `role`. See {grantRole} and

     * {revokeRole}.

     *

     * To change a role's admin, use {AccessControl-_setRoleAdmin}.

     */
    function getRoleAdmin(bytes32 role) external view returns (bytes32);

    /**

     * @dev Grants `role` to `account`.

     *

     * If `account` had not been already granted `role`, emits a {RoleGranted}

     * event.

     *

     * Requirements:

     *

     * - the caller must have ``role``'s admin role.

     */
    function grantRole(bytes32 role, address account) external;

    /**

     * @dev Revokes `role` from `account`.

     *

     * If `account` had been granted `role`, emits a {RoleRevoked} event.

     *

     * Requirements:

     *

     * - the caller must have ``role``'s admin role.

     */
    function revokeRole(bytes32 role, address account) external;

    /**

     * @dev Revokes `role` from the calling account.

     *

     * Roles are often managed via {grantRole} and {revokeRole}: this function's

     * purpose is to provide a mechanism for accounts to lose their privileges

     * if they are compromised (such as when a trusted device is misplaced).

     *

     * If the calling account had been granted `role`, emits a {RoleRevoked}

     * event.

     *

     * Requirements:

     *

     * - the caller must be `account`.

     */
    function renounceRole(bytes32 role, address account) external;
}


// File @openzeppelin/contracts/access/IAccessControlEnumerable.sol@v4.7.3


// OpenZeppelin Contracts v4.4.1 (access/IAccessControlEnumerable.sol)

pragma solidity ^0.8.0;

/**

 * @dev External interface of AccessControlEnumerable declared to support ERC165 detection.

 */
interface IAccessControlEnumerable is IAccessControl {
    /**

     * @dev Returns one of the accounts that have `role`. `index` must be a

     * value between 0 and {getRoleMemberCount}, non-inclusive.

     *

     * Role bearers are not sorted in any particular way, and their ordering may

     * change at any point.

     *

     * WARNING: When using {getRoleMember} and {getRoleMemberCount}, make sure

     * you perform all queries on the same block. See the following

     * https://forum.openzeppelin.com/t/iterating-over-elements-on-enumerableset-in-openzeppelin-contracts/2296[forum post]

     * for more information.

     */
    function getRoleMember(bytes32 role, uint256 index) external view returns (address);

    /**

     * @dev Returns the number of accounts that have `role`. Can be used

     * together with {getRoleMember} to enumerate all bearers of a role.

     */
    function getRoleMemberCount(bytes32 role) external view returns (uint256);
}


// File @openzeppelin/contracts/utils/Context.sol@v4.7.3


// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)

pragma solidity ^0.8.0;

/**

 * @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;
    }
}


// File @openzeppelin/contracts/utils/Strings.sol@v4.7.3


// OpenZeppelin Contracts (last updated v4.7.0) (utils/Strings.sol)

pragma solidity ^0.8.0;

/**

 * @dev String operations.

 */
library Strings {
    bytes16 private constant _HEX_SYMBOLS = "0123456789abcdef";
    uint8 private constant _ADDRESS_LENGTH = 20;

    /**

     * @dev Converts a `uint256` to its ASCII `string` decimal representation.

     */
    function toString(uint256 value) internal pure returns (string memory) {
        // Inspired by OraclizeAPI's implementation - MIT licence
        // https://github.com/oraclize/ethereum-api/blob/b42146b063c7d6ee1358846c198246239e9360e8/oraclizeAPI_0.4.25.sol

        if (value == 0) {
            return "0";
        }
        uint256 temp = value;
        uint256 digits;
        while (temp != 0) {
            digits++;
            temp /= 10;
        }
        bytes memory buffer = new bytes(digits);
        while (value != 0) {
            digits -= 1;
            buffer[digits] = bytes1(uint8(48 + uint256(value % 10)));
            value /= 10;
        }
        return string(buffer);
    }

    /**

     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation.

     */
    function toHexString(uint256 value) internal pure returns (string memory) {
        if (value == 0) {
            return "0x00";
        }
        uint256 temp = value;
        uint256 length = 0;
        while (temp != 0) {
            length++;
            temp >>= 8;
        }
        return toHexString(value, length);
    }

    /**

     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation with fixed length.

     */
    function toHexString(uint256 value, uint256 length) internal pure returns (string memory) {
        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_SYMBOLS[value & 0xf];
            value >>= 4;
        }
        require(value == 0, "Strings: hex length insufficient");
        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);
    }
}


// File @openzeppelin/contracts/utils/introspection/IERC165.sol@v4.7.3


// OpenZeppelin Contracts v4.4.1 (utils/introspection/IERC165.sol)

pragma solidity ^0.8.0;

/**

 * @dev Interface of the ERC165 standard, as defined in the

 * https://eips.ethereum.org/EIPS/eip-165[EIP].

 *

 * 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[EIP 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/utils/introspection/ERC165.sol@v4.7.3


// OpenZeppelin Contracts v4.4.1 (utils/introspection/ERC165.sol)

pragma solidity ^0.8.0;

/**

 * @dev Implementation of the {IERC165} interface.

 *

 * Contracts that want to implement ERC165 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);

 * }

 * ```

 *

 * Alternatively, {ERC165Storage} provides an easier to use but more expensive implementation.

 */
abstract contract ERC165 is IERC165 {
    /**

     * @dev See {IERC165-supportsInterface}.

     */
    function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
        return interfaceId == type(IERC165).interfaceId;
    }
}


// File @openzeppelin/contracts/access/AccessControl.sol@v4.7.3


// OpenZeppelin Contracts (last updated v4.7.0) (access/AccessControl.sol)

pragma solidity ^0.8.0;




/**

 * @dev Contract module that allows children to implement role-based access

 * control mechanisms. This is a lightweight version that doesn't allow enumerating role

 * members except through off-chain means by accessing the contract event logs. Some

 * applications may benefit from on-chain enumerability, for those cases see

 * {AccessControlEnumerable}.

 *

 * Roles are referred to by their `bytes32` identifier. These should be exposed

 * in the external API and be unique. The best way to achieve this is by

 * using `public constant` hash digests:

 *

 * ```

 * bytes32 public constant MY_ROLE = keccak256("MY_ROLE");

 * ```

 *

 * Roles can be used to represent a set of permissions. To restrict access to a

 * function call, use {hasRole}:

 *

 * ```

 * function foo() public {

 *     require(hasRole(MY_ROLE, msg.sender));

 *     ...

 * }

 * ```

 *

 * Roles can be granted and revoked dynamically via the {grantRole} and

 * {revokeRole} functions. Each role has an associated admin role, and only

 * accounts that have a role's admin role can call {grantRole} and {revokeRole}.

 *

 * By default, the admin role for all roles is `DEFAULT_ADMIN_ROLE`, which means

 * that only accounts with this role will be able to grant or revoke other

 * roles. More complex role relationships can be created by using

 * {_setRoleAdmin}.

 *

 * WARNING: The `DEFAULT_ADMIN_ROLE` is also its own admin: it has permission to

 * grant and revoke this role. Extra precautions should be taken to secure

 * accounts that have been granted it.

 */
abstract contract AccessControl is Context, IAccessControl, ERC165 {
    struct RoleData {
        mapping(address => bool) members;
        bytes32 adminRole;
    }

    mapping(bytes32 => RoleData) private _roles;

    bytes32 public constant DEFAULT_ADMIN_ROLE = 0x00;

    /**

     * @dev Modifier that checks that an account has a specific role. Reverts

     * with a standardized message including the required role.

     *

     * The format of the revert reason is given by the following regular expression:

     *

     *  /^AccessControl: account (0x[0-9a-f]{40}) is missing role (0x[0-9a-f]{64})$/

     *

     * _Available since v4.1._

     */
    modifier onlyRole(bytes32 role) {
        _checkRole(role);
        _;
    }

    /**

     * @dev See {IERC165-supportsInterface}.

     */
    function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
        return interfaceId == type(IAccessControl).interfaceId || super.supportsInterface(interfaceId);
    }

    /**

     * @dev Returns `true` if `account` has been granted `role`.

     */
    function hasRole(bytes32 role, address account) public view virtual override returns (bool) {
        return _roles[role].members[account];
    }

    /**

     * @dev Revert with a standard message if `_msgSender()` is missing `role`.

     * Overriding this function changes the behavior of the {onlyRole} modifier.

     *

     * Format of the revert message is described in {_checkRole}.

     *

     * _Available since v4.6._

     */
    function _checkRole(bytes32 role) internal view virtual {
        _checkRole(role, _msgSender());
    }

    /**

     * @dev Revert with a standard message if `account` is missing `role`.

     *

     * The format of the revert reason is given by the following regular expression:

     *

     *  /^AccessControl: account (0x[0-9a-f]{40}) is missing role (0x[0-9a-f]{64})$/

     */
    function _checkRole(bytes32 role, address account) internal view virtual {
        if (!hasRole(role, account)) {
            revert(
                string(
                    abi.encodePacked(

                        "AccessControl: account ",

                        Strings.toHexString(uint160(account), 20),
                        " is missing role ",
                        Strings.toHexString(uint256(role), 32)
                    )
                )
            );
        }
    }

    /**

     * @dev Returns the admin role that controls `role`. See {grantRole} and

     * {revokeRole}.

     *

     * To change a role's admin, use {_setRoleAdmin}.

     */
    function getRoleAdmin(bytes32 role) public view virtual override returns (bytes32) {
        return _roles[role].adminRole;
    }

    /**

     * @dev Grants `role` to `account`.

     *

     * If `account` had not been already granted `role`, emits a {RoleGranted}

     * event.

     *

     * Requirements:

     *

     * - the caller must have ``role``'s admin role.

     *

     * May emit a {RoleGranted} event.

     */
    function grantRole(bytes32 role, address account) public virtual override onlyRole(getRoleAdmin(role)) {
        _grantRole(role, account);
    }

    /**

     * @dev Revokes `role` from `account`.

     *

     * If `account` had been granted `role`, emits a {RoleRevoked} event.

     *

     * Requirements:

     *

     * - the caller must have ``role``'s admin role.

     *

     * May emit a {RoleRevoked} event.

     */
    function revokeRole(bytes32 role, address account) public virtual override onlyRole(getRoleAdmin(role)) {
        _revokeRole(role, account);
    }

    /**

     * @dev Revokes `role` from the calling account.

     *

     * Roles are often managed via {grantRole} and {revokeRole}: this function's

     * purpose is to provide a mechanism for accounts to lose their privileges

     * if they are compromised (such as when a trusted device is misplaced).

     *

     * If the calling account had been revoked `role`, emits a {RoleRevoked}

     * event.

     *

     * Requirements:

     *

     * - the caller must be `account`.

     *

     * May emit a {RoleRevoked} event.

     */
    function renounceRole(bytes32 role, address account) public virtual override {
        require(account == _msgSender(), "AccessControl: can only renounce roles for self");

        _revokeRole(role, account);
    }

    /**

     * @dev Grants `role` to `account`.

     *

     * If `account` had not been already granted `role`, emits a {RoleGranted}

     * event. Note that unlike {grantRole}, this function doesn't perform any

     * checks on the calling account.

     *

     * May emit a {RoleGranted} event.

     *

     * [WARNING]

     * ====

     * This function should only be called from the constructor when setting

     * up the initial roles for the system.

     *

     * Using this function in any other way is effectively circumventing the admin

     * system imposed by {AccessControl}.

     * ====

     *

     * NOTE: This function is deprecated in favor of {_grantRole}.

     */
    function _setupRole(bytes32 role, address account) internal virtual {
        _grantRole(role, account);
    }

    /**

     * @dev Sets `adminRole` as ``role``'s admin role.

     *

     * Emits a {RoleAdminChanged} event.

     */
    function _setRoleAdmin(bytes32 role, bytes32 adminRole) internal virtual {
        bytes32 previousAdminRole = getRoleAdmin(role);
        _roles[role].adminRole = adminRole;
        emit RoleAdminChanged(role, previousAdminRole, adminRole);
    }

    /**

     * @dev Grants `role` to `account`.

     *

     * Internal function without access restriction.

     *

     * May emit a {RoleGranted} event.

     */
    function _grantRole(bytes32 role, address account) internal virtual {
        if (!hasRole(role, account)) {
            _roles[role].members[account] = true;
            emit RoleGranted(role, account, _msgSender());
        }
    }

    /**

     * @dev Revokes `role` from `account`.

     *

     * Internal function without access restriction.

     *

     * May emit a {RoleRevoked} event.

     */
    function _revokeRole(bytes32 role, address account) internal virtual {
        if (hasRole(role, account)) {
            _roles[role].members[account] = false;
            emit RoleRevoked(role, account, _msgSender());
        }
    }
}


// File @openzeppelin/contracts/utils/structs/EnumerableSet.sol@v4.7.3


// OpenZeppelin Contracts (last updated v4.7.0) (utils/structs/EnumerableSet.sol)

pragma solidity ^0.8.0;

/**

 * @dev Library for managing

 * https://en.wikipedia.org/wiki/Set_(abstract_data_type)[sets] of primitive

 * types.

 *

 * Sets have the following properties:

 *

 * - Elements are added, removed, and checked for existence in constant time

 * (O(1)).

 * - Elements are enumerated in O(n). No guarantees are made on the ordering.

 *

 * ```

 * contract Example {

 *     // Add the library methods

 *     using EnumerableSet for EnumerableSet.AddressSet;

 *

 *     // Declare a set state variable

 *     EnumerableSet.AddressSet private mySet;

 * }

 * ```

 *

 * As of v3.3.0, sets of type `bytes32` (`Bytes32Set`), `address` (`AddressSet`)

 * and `uint256` (`UintSet`) are supported.

 *

 * [WARNING]

 * ====

 *  Trying to delete such a structure from storage will likely result in data corruption, rendering the structure unusable.

 *  See https://github.com/ethereum/solidity/pull/11843[ethereum/solidity#11843] for more info.

 *

 *  In order to clean an EnumerableSet, you can either remove all elements one by one or create a fresh instance using an array of EnumerableSet.

 * ====

 */
library EnumerableSet {
    // To implement this library for multiple types with as little code
    // repetition as possible, we write it in terms of a generic Set type with
    // bytes32 values.
    // The Set implementation uses private functions, and user-facing
    // implementations (such as AddressSet) are just wrappers around the
    // underlying Set.
    // This means that we can only create new EnumerableSets for types that fit
    // in bytes32.

    struct Set {
        // Storage of set values
        bytes32[] _values;
        // Position of the value in the `values` array, plus 1 because index 0
        // means a value is not in the set.
        mapping(bytes32 => uint256) _indexes;
    }

    /**

     * @dev Add a value to a set. O(1).

     *

     * Returns true if the value was added to the set, that is if it was not

     * already present.

     */
    function _add(Set storage set, bytes32 value) private returns (bool) {
        if (!_contains(set, value)) {
            set._values.push(value);
            // The value is stored at length-1, but we add 1 to all indexes
            // and use 0 as a sentinel value
            set._indexes[value] = set._values.length;
            return true;
        } else {
            return false;
        }
    }

    /**

     * @dev Removes a value from a set. O(1).

     *

     * Returns true if the value was removed from the set, that is if it was

     * present.

     */
    function _remove(Set storage set, bytes32 value) private returns (bool) {
        // We read and store the value's index to prevent multiple reads from the same storage slot
        uint256 valueIndex = set._indexes[value];

        if (valueIndex != 0) {
            // Equivalent to contains(set, value)
            // To delete an element from the _values array in O(1), we swap the element to delete with the last one in
            // the array, and then remove the last element (sometimes called as 'swap and pop').
            // This modifies the order of the array, as noted in {at}.

            uint256 toDeleteIndex = valueIndex - 1;
            uint256 lastIndex = set._values.length - 1;

            if (lastIndex != toDeleteIndex) {
                bytes32 lastValue = set._values[lastIndex];

                // Move the last value to the index where the value to delete is
                set._values[toDeleteIndex] = lastValue;
                // Update the index for the moved value
                set._indexes[lastValue] = valueIndex; // Replace lastValue's index to valueIndex
            }

            // Delete the slot where the moved value was stored
            set._values.pop();

            // Delete the index for the deleted slot
            delete set._indexes[value];

            return true;
        } else {
            return false;
        }
    }

    /**

     * @dev Returns true if the value is in the set. O(1).

     */
    function _contains(Set storage set, bytes32 value) private view returns (bool) {
        return set._indexes[value] != 0;
    }

    /**

     * @dev Returns the number of values on the set. O(1).

     */
    function _length(Set storage set) private view returns (uint256) {
        return set._values.length;
    }

    /**

     * @dev Returns the value stored at position `index` in the set. O(1).

     *

     * Note that there are no guarantees on the ordering of values inside the

     * array, and it may change when more values are added or removed.

     *

     * Requirements:

     *

     * - `index` must be strictly less than {length}.

     */
    function _at(Set storage set, uint256 index) private view returns (bytes32) {
        return set._values[index];
    }

    /**

     * @dev Return the entire set in an array

     *

     * WARNING: This operation will copy the entire storage to memory, which can be quite expensive. This is designed

     * to mostly be used by view accessors that are queried without any gas fees. Developers should keep in mind that

     * this function has an unbounded cost, and using it as part of a state-changing function may render the function

     * uncallable if the set grows to a point where copying to memory consumes too much gas to fit in a block.

     */
    function _values(Set storage set) private view returns (bytes32[] memory) {
        return set._values;
    }

    // Bytes32Set

    struct Bytes32Set {
        Set _inner;
    }

    /**

     * @dev Add a value to a set. O(1).

     *

     * Returns true if the value was added to the set, that is if it was not

     * already present.

     */
    function add(Bytes32Set storage set, bytes32 value) internal returns (bool) {
        return _add(set._inner, value);
    }

    /**

     * @dev Removes a value from a set. O(1).

     *

     * Returns true if the value was removed from the set, that is if it was

     * present.

     */
    function remove(Bytes32Set storage set, bytes32 value) internal returns (bool) {
        return _remove(set._inner, value);
    }

    /**

     * @dev Returns true if the value is in the set. O(1).

     */
    function contains(Bytes32Set storage set, bytes32 value) internal view returns (bool) {
        return _contains(set._inner, value);
    }

    /**

     * @dev Returns the number of values in the set. O(1).

     */
    function length(Bytes32Set storage set) internal view returns (uint256) {
        return _length(set._inner);
    }

    /**

     * @dev Returns the value stored at position `index` in the set. O(1).

     *

     * Note that there are no guarantees on the ordering of values inside the

     * array, and it may change when more values are added or removed.

     *

     * Requirements:

     *

     * - `index` must be strictly less than {length}.

     */
    function at(Bytes32Set storage set, uint256 index) internal view returns (bytes32) {
        return _at(set._inner, index);
    }

    /**

     * @dev Return the entire set in an array

     *

     * WARNING: This operation will copy the entire storage to memory, which can be quite expensive. This is designed

     * to mostly be used by view accessors that are queried without any gas fees. Developers should keep in mind that

     * this function has an unbounded cost, and using it as part of a state-changing function may render the function

     * uncallable if the set grows to a point where copying to memory consumes too much gas to fit in a block.

     */
    function values(Bytes32Set storage set) internal view returns (bytes32[] memory) {
        return _values(set._inner);
    }

    // AddressSet

    struct AddressSet {
        Set _inner;
    }

    /**

     * @dev Add a value to a set. O(1).

     *

     * Returns true if the value was added to the set, that is if it was not

     * already present.

     */
    function add(AddressSet storage set, address value) internal returns (bool) {
        return _add(set._inner, bytes32(uint256(uint160(value))));
    }

    /**

     * @dev Removes a value from a set. O(1).

     *

     * Returns true if the value was removed from the set, that is if it was

     * present.

     */
    function remove(AddressSet storage set, address value) internal returns (bool) {
        return _remove(set._inner, bytes32(uint256(uint160(value))));
    }

    /**

     * @dev Returns true if the value is in the set. O(1).

     */
    function contains(AddressSet storage set, address value) internal view returns (bool) {
        return _contains(set._inner, bytes32(uint256(uint160(value))));
    }

    /**

     * @dev Returns the number of values in the set. O(1).

     */
    function length(AddressSet storage set) internal view returns (uint256) {
        return _length(set._inner);
    }

    /**

     * @dev Returns the value stored at position `index` in the set. O(1).

     *

     * Note that there are no guarantees on the ordering of values inside the

     * array, and it may change when more values are added or removed.

     *

     * Requirements:

     *

     * - `index` must be strictly less than {length}.

     */
    function at(AddressSet storage set, uint256 index) internal view returns (address) {
        return address(uint160(uint256(_at(set._inner, index))));
    }

    /**

     * @dev Return the entire set in an array

     *

     * WARNING: This operation will copy the entire storage to memory, which can be quite expensive. This is designed

     * to mostly be used by view accessors that are queried without any gas fees. Developers should keep in mind that

     * this function has an unbounded cost, and using it as part of a state-changing function may render the function

     * uncallable if the set grows to a point where copying to memory consumes too much gas to fit in a block.

     */
    function values(AddressSet storage set) internal view returns (address[] memory) {
        bytes32[] memory store = _values(set._inner);
        address[] memory result;

        /// @solidity memory-safe-assembly
        assembly {
            result := store
        }

        return result;
    }

    // UintSet

    struct UintSet {
        Set _inner;
    }

    /**

     * @dev Add a value to a set. O(1).

     *

     * Returns true if the value was added to the set, that is if it was not

     * already present.

     */
    function add(UintSet storage set, uint256 value) internal returns (bool) {
        return _add(set._inner, bytes32(value));
    }

    /**

     * @dev Removes a value from a set. O(1).

     *

     * Returns true if the value was removed from the set, that is if it was

     * present.

     */
    function remove(UintSet storage set, uint256 value) internal returns (bool) {
        return _remove(set._inner, bytes32(value));
    }

    /**

     * @dev Returns true if the value is in the set. O(1).

     */
    function contains(UintSet storage set, uint256 value) internal view returns (bool) {
        return _contains(set._inner, bytes32(value));
    }

    /**

     * @dev Returns the number of values on the set. O(1).

     */
    function length(UintSet storage set) internal view returns (uint256) {
        return _length(set._inner);
    }

    /**

     * @dev Returns the value stored at position `index` in the set. O(1).

     *

     * Note that there are no guarantees on the ordering of values inside the

     * array, and it may change when more values are added or removed.

     *

     * Requirements:

     *

     * - `index` must be strictly less than {length}.

     */
    function at(UintSet storage set, uint256 index) internal view returns (uint256) {
        return uint256(_at(set._inner, index));
    }

    /**

     * @dev Return the entire set in an array

     *

     * WARNING: This operation will copy the entire storage to memory, which can be quite expensive. This is designed

     * to mostly be used by view accessors that are queried without any gas fees. Developers should keep in mind that

     * this function has an unbounded cost, and using it as part of a state-changing function may render the function

     * uncallable if the set grows to a point where copying to memory consumes too much gas to fit in a block.

     */
    function values(UintSet storage set) internal view returns (uint256[] memory) {
        bytes32[] memory store = _values(set._inner);
        uint256[] memory result;

        /// @solidity memory-safe-assembly
        assembly {
            result := store
        }

        return result;
    }
}


// File @openzeppelin/contracts/access/AccessControlEnumerable.sol@v4.7.3


// OpenZeppelin Contracts (last updated v4.5.0) (access/AccessControlEnumerable.sol)

pragma solidity ^0.8.0;



/**

 * @dev Extension of {AccessControl} that allows enumerating the members of each role.

 */
abstract contract AccessControlEnumerable is IAccessControlEnumerable, AccessControl {
    using EnumerableSet for EnumerableSet.AddressSet;

    mapping(bytes32 => EnumerableSet.AddressSet) private _roleMembers;

    /**

     * @dev See {IERC165-supportsInterface}.

     */
    function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
        return interfaceId == type(IAccessControlEnumerable).interfaceId || super.supportsInterface(interfaceId);
    }

    /**

     * @dev Returns one of the accounts that have `role`. `index` must be a

     * value between 0 and {getRoleMemberCount}, non-inclusive.

     *

     * Role bearers are not sorted in any particular way, and their ordering may

     * change at any point.

     *

     * WARNING: When using {getRoleMember} and {getRoleMemberCount}, make sure

     * you perform all queries on the same block. See the following

     * https://forum.openzeppelin.com/t/iterating-over-elements-on-enumerableset-in-openzeppelin-contracts/2296[forum post]

     * for more information.

     */
    function getRoleMember(bytes32 role, uint256 index) public view virtual override returns (address) {
        return _roleMembers[role].at(index);
    }

    /**

     * @dev Returns the number of accounts that have `role`. Can be used

     * together with {getRoleMember} to enumerate all bearers of a role.

     */
    function getRoleMemberCount(bytes32 role) public view virtual override returns (uint256) {
        return _roleMembers[role].length();
    }

    /**

     * @dev Overload {_grantRole} to track enumerable memberships

     */
    function _grantRole(bytes32 role, address account) internal virtual override {
        super._grantRole(role, account);
        _roleMembers[role].add(account);
    }

    /**

     * @dev Overload {_revokeRole} to track enumerable memberships

     */
    function _revokeRole(bytes32 role, address account) internal virtual override {
        super._revokeRole(role, account);
        _roleMembers[role].remove(account);
    }
}


// File @openzeppelin/contracts/access/Ownable.sol@v4.7.3


// OpenZeppelin Contracts (last updated v4.7.0) (access/Ownable.sol)

pragma solidity ^0.8.0;

/**

 * @dev Contract module which provides a basic access control mechanism, where

 * there is an account (an owner) that can be granted exclusive access to

 * specific functions.

 *

 * By default, the owner account will be the one that deploys the contract. 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;

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

    /**

     * @dev Initializes the contract setting the deployer as the initial owner.

     */
    constructor() {
        _transferOwnership(_msgSender());
    }

    /**

     * @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 {
        require(owner() == _msgSender(), "Ownable: caller is not the owner");
    }

    /**

     * @dev Leaves the contract without owner. It will not be possible to call

     * `onlyOwner` functions anymore. Can only be called by the current owner.

     *

     * NOTE: Renouncing ownership will leave the contract without an owner,

     * thereby removing 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 {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        _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/interfaces/IERC2981.sol@v4.7.3


// OpenZeppelin Contracts (last updated v4.6.0) (interfaces/IERC2981.sol)

pragma solidity ^0.8.0;

/**

 * @dev Interface for the NFT Royalty Standard.

 *

 * A standardized way to retrieve royalty payment information for non-fungible tokens (NFTs) to enable universal

 * support for royalty payments across all NFT marketplaces and ecosystem participants.

 *

 * _Available since v4.5._

 */
interface IERC2981 is IERC165 {
    /**

     * @dev Returns how much royalty is owed and to whom, based on a sale price that may be denominated in any unit of

     * exchange. The royalty amount is denominated and should be paid in that same unit of exchange.

     */
    function royaltyInfo(uint256 tokenId, uint256 salePrice)
        external
        view
        returns (address receiver, uint256 royaltyAmount);
}


// File @openzeppelin/contracts/token/common/ERC2981.sol@v4.7.3


// OpenZeppelin Contracts (last updated v4.7.0) (token/common/ERC2981.sol)

pragma solidity ^0.8.0;


/**

 * @dev Implementation of the NFT Royalty Standard, a standardized way to retrieve royalty payment information.

 *

 * Royalty information can be specified globally for all token ids via {_setDefaultRoyalty}, and/or individually for

 * specific token ids via {_setTokenRoyalty}. The latter takes precedence over the first.

 *

 * Royalty is specified as a fraction of sale price. {_feeDenominator} is overridable but defaults to 10000, meaning the

 * fee is specified in basis points by default.

 *

 * IMPORTANT: ERC-2981 only specifies a way to signal royalty information and does not enforce its payment. See

 * https://eips.ethereum.org/EIPS/eip-2981#optional-royalty-payments[Rationale] in the EIP. Marketplaces are expected to

 * voluntarily pay royalties together with sales, but note that this standard is not yet widely supported.

 *

 * _Available since v4.5._

 */
abstract contract ERC2981 is IERC2981, ERC165 {
    struct RoyaltyInfo {
        address receiver;
        uint96 royaltyFraction;
    }

    RoyaltyInfo private _defaultRoyaltyInfo;
    mapping(uint256 => RoyaltyInfo) private _tokenRoyaltyInfo;

    /**

     * @dev See {IERC165-supportsInterface}.

     */
    function supportsInterface(bytes4 interfaceId) public view virtual override(IERC165, ERC165) returns (bool) {
        return interfaceId == type(IERC2981).interfaceId || super.supportsInterface(interfaceId);
    }

    /**

     * @inheritdoc IERC2981

     */
    function royaltyInfo(uint256 _tokenId, uint256 _salePrice) public view virtual override returns (address, uint256) {
        RoyaltyInfo memory royalty = _tokenRoyaltyInfo[_tokenId];

        if (royalty.receiver == address(0)) {
            royalty = _defaultRoyaltyInfo;
        }

        uint256 royaltyAmount = (_salePrice * royalty.royaltyFraction) / _feeDenominator();

        return (royalty.receiver, royaltyAmount);
    }

    /**

     * @dev The denominator with which to interpret the fee set in {_setTokenRoyalty} and {_setDefaultRoyalty} as a

     * fraction of the sale price. Defaults to 10000 so fees are expressed in basis points, but may be customized by an

     * override.

     */
    function _feeDenominator() internal pure virtual returns (uint96) {
        return 10000;
    }

    /**

     * @dev Sets the royalty information that all ids in this contract will default to.

     *

     * Requirements:

     *

     * - `receiver` cannot be the zero address.

     * - `feeNumerator` cannot be greater than the fee denominator.

     */
    function _setDefaultRoyalty(address receiver, uint96 feeNumerator) internal virtual {
        require(feeNumerator <= _feeDenominator(), "ERC2981: royalty fee will exceed salePrice");
        require(receiver != address(0), "ERC2981: invalid receiver");

        _defaultRoyaltyInfo = RoyaltyInfo(receiver, feeNumerator);
    }

    /**

     * @dev Removes default royalty information.

     */
    function _deleteDefaultRoyalty() internal virtual {
        delete _defaultRoyaltyInfo;
    }

    /**

     * @dev Sets the royalty information for a specific token id, overriding the global default.

     *

     * Requirements:

     *

     * - `receiver` cannot be the zero address.

     * - `feeNumerator` cannot be greater than the fee denominator.

     */
    function _setTokenRoyalty(

        uint256 tokenId,

        address receiver,

        uint96 feeNumerator

    ) internal virtual {
        require(feeNumerator <= _feeDenominator(), "ERC2981: royalty fee will exceed salePrice");
        require(receiver != address(0), "ERC2981: Invalid parameters");

        _tokenRoyaltyInfo[tokenId] = RoyaltyInfo(receiver, feeNumerator);
    }

    /**

     * @dev Resets royalty information for the token id back to the global default.

     */
    function _resetTokenRoyalty(uint256 tokenId) internal virtual {
        delete _tokenRoyaltyInfo[tokenId];
    }
}


// File @openzeppelin/contracts/utils/Address.sol@v4.7.3


// OpenZeppelin Contracts (last updated v4.7.0) (utils/Address.sol)

pragma solidity ^0.8.1;

/**

 * @dev Collection of functions related to the address type

 */
library Address {
    /**

     * @dev Returns true if `account` is a contract.

     *

     * [IMPORTANT]

     * ====

     * It is unsafe to assume that an address for which this function returns

     * false is an externally-owned account (EOA) and not a contract.

     *

     * Among others, `isContract` will return false for the following

     * types of addresses:

     *

     *  - an externally-owned account

     *  - a contract in construction

     *  - an address where a contract will be created

     *  - an address where a contract lived, but was destroyed

     * ====

     *

     * [IMPORTANT]

     * ====

     * You shouldn't rely on `isContract` to protect against flash loan attacks!

     *

     * Preventing calls from contracts is highly discouraged. It breaks composability, breaks support for smart wallets

     * like Gnosis Safe, and does not provide security since it can be circumvented by calling from a contract

     * constructor.

     * ====

     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize/address.code.length, which returns 0
        // for contracts in construction, since the code is only stored at the end
        // of the constructor execution.

        return account.code.length > 0;
    }

    /**

     * @dev Replacement for Solidity's `transfer`: sends `amount` wei to

     * `recipient`, forwarding all available gas and reverting on errors.

     *

     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost

     * of certain opcodes, possibly making contracts go over the 2300 gas limit

     * imposed by `transfer`, making them unable to receive funds via

     * `transfer`. {sendValue} removes this limitation.

     *

     * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].

     *

     * IMPORTANT: because control is transferred to `recipient`, care must be

     * taken to not create reentrancy vulnerabilities. Consider using

     * {ReentrancyGuard} or the

     * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].

     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");

        (bool success, ) = recipient.call{value: amount}("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }

    /**

     * @dev Performs a Solidity function call using a low level `call`. A

     * plain `call` is an unsafe replacement for a function call: use this

     * function instead.

     *

     * If `target` reverts with a revert reason, it is bubbled up by this

     * function (like regular Solidity function calls).

     *

     * Returns the raw returned data. To convert to the expected return value,

     * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].

     *

     * Requirements:

     *

     * - `target` must be a contract.

     * - calling `target` with `data` must not revert.

     *

     * _Available since v3.1._

     */
    function functionCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionCall(target, data, "Address: low-level call failed");
    }

    /**

     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with

     * `errorMessage` as a fallback revert reason when `target` reverts.

     *

     * _Available since v3.1._

     */
    function functionCall(

        address target,

        bytes memory data,

        string memory errorMessage

    ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, errorMessage);
    }

    /**

     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],

     * but also transferring `value` wei to `target`.

     *

     * Requirements:

     *

     * - the calling contract must have an ETH balance of at least `value`.

     * - the called Solidity function must be `payable`.

     *

     * _Available since v3.1._

     */
    function functionCallWithValue(

        address target,

        bytes memory data,

        uint256 value

    ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
    }

    /**

     * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but

     * with `errorMessage` as a fallback revert reason when `target` reverts.

     *

     * _Available since v3.1._

     */
    function functionCallWithValue(

        address target,

        bytes memory data,

        uint256 value,

        string memory errorMessage

    ) internal returns (bytes memory) {
        require(address(this).balance >= value, "Address: insufficient balance for call");
        require(isContract(target), "Address: call to non-contract");

        (bool success, bytes memory returndata) = target.call{value: value}(data);
        return verifyCallResult(success, returndata, errorMessage);
    }

    /**

     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],

     * but performing a static call.

     *

     * _Available since v3.3._

     */
    function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
        return functionStaticCall(target, data, "Address: low-level static call failed");
    }

    /**

     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],

     * but performing a static call.

     *

     * _Available since v3.3._

     */
    function functionStaticCall(

        address target,

        bytes memory data,

        string memory errorMessage

    ) internal view returns (bytes memory) {
        require(isContract(target), "Address: static call to non-contract");

        (bool success, bytes memory returndata) = target.staticcall(data);
        return verifyCallResult(success, returndata, errorMessage);
    }

    /**

     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],

     * but performing a delegate call.

     *

     * _Available since v3.4._

     */
    function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionDelegateCall(target, data, "Address: low-level delegate call failed");
    }

    /**

     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],

     * but performing a delegate call.

     *

     * _Available since v3.4._

     */
    function functionDelegateCall(

        address target,

        bytes memory data,

        string memory errorMessage

    ) internal returns (bytes memory) {
        require(isContract(target), "Address: delegate call to non-contract");

        (bool success, bytes memory returndata) = target.delegatecall(data);
        return verifyCallResult(success, returndata, errorMessage);
    }

    /**

     * @dev Tool to verifies that a low level call was successful, and revert if it wasn't, either by bubbling the

     * revert reason using the provided one.

     *

     * _Available since v4.3._

     */
    function verifyCallResult(

        bool success,

        bytes memory returndata,

        string memory errorMessage

    ) internal pure returns (bytes memory) {
        if (success) {
            return returndata;
        } else {
            // Look for revert reason and bubble it up if present
            if (returndata.length > 0) {
                // The easiest way to bubble the revert reason is using memory via assembly
                /// @solidity memory-safe-assembly
                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}


// File @openzeppelin/contracts/token/ERC721/IERC721.sol@v4.7.3


// OpenZeppelin Contracts (last updated v4.7.0) (token/ERC721/IERC721.sol)

pragma solidity ^0.8.0;

/**

 * @dev Required interface of an ERC721 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 ERC721 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: Usage of this method is discouraged, use {safeTransferFrom} whenever possible.

     *

     * 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 caller.

     *

     * 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@v4.7.3


// OpenZeppelin Contracts (last updated v4.6.0) (token/ERC721/IERC721Receiver.sol)

pragma solidity ^0.8.0;

/**

 * @title ERC721 token receiver interface

 * @dev Interface for any contract that wants to support safeTransfers

 * from ERC721 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/extensions/IERC721Metadata.sol@v4.7.3


// OpenZeppelin Contracts v4.4.1 (token/ERC721/extensions/IERC721Metadata.sol)

pragma solidity ^0.8.0;

/**

 * @title ERC-721 Non-Fungible Token Standard, optional metadata extension

 * @dev See https://eips.ethereum.org/EIPS/eip-721

 */
interface IERC721Metadata is IERC721 {
    /**

     * @dev Returns the token collection name.

     */
    function name() external view returns (string memory);

    /**

     * @dev Returns the token collection symbol.

     */
    function symbol() external view returns (string memory);

    /**

     * @dev Returns the Uniform Resource Identifier (URI) for `tokenId` token.

     */
    function tokenURI(uint256 tokenId) external view returns (string memory);
}


// File @openzeppelin/contracts/token/ERC721/ERC721.sol@v4.7.3


// OpenZeppelin Contracts (last updated v4.7.0) (token/ERC721/ERC721.sol)

pragma solidity ^0.8.0;







/**

 * @dev Implementation of https://eips.ethereum.org/EIPS/eip-721[ERC721] Non-Fungible Token Standard, including

 * the Metadata extension, but not including the Enumerable extension, which is available separately as

 * {ERC721Enumerable}.

 */
contract ERC721 is Context, ERC165, IERC721, IERC721Metadata {
    using Address for address;
    using Strings for uint256;

    // Token name
    string private _name;

    // Token symbol
    string private _symbol;

    // Mapping from token ID to owner address
    mapping(uint256 => address) private _owners;

    // Mapping owner address to token count
    mapping(address => uint256) private _balances;

    // Mapping from token ID to approved address
    mapping(uint256 => address) private _tokenApprovals;

    // Mapping from owner to operator approvals
    mapping(address => mapping(address => bool)) private _operatorApprovals;

    /**

     * @dev Initializes the contract by setting a `name` and a `symbol` to the token collection.

     */
    constructor(string memory name_, string memory symbol_) {
        _name = name_;
        _symbol = symbol_;
    }

    /**

     * @dev See {IERC165-supportsInterface}.

     */
    function supportsInterface(bytes4 interfaceId) public view virtual override(ERC165, IERC165) returns (bool) {
        return
            interfaceId == type(IERC721).interfaceId ||

            interfaceId == type(IERC721Metadata).interfaceId ||

            super.supportsInterface(interfaceId);
    }

    /**

     * @dev See {IERC721-balanceOf}.

     */
    function balanceOf(address owner) public view virtual override returns (uint256) {
        require(owner != address(0), "ERC721: address zero is not a valid owner");
        return _balances[owner];
    }

    /**

     * @dev See {IERC721-ownerOf}.

     */
    function ownerOf(uint256 tokenId) public view virtual override returns (address) {
        address owner = _owners[tokenId];
        require(owner != address(0), "ERC721: invalid token ID");
        return owner;
    }

    /**

     * @dev See {IERC721Metadata-name}.

     */
    function name() public view virtual override returns (string memory) {
        return _name;
    }

    /**

     * @dev See {IERC721Metadata-symbol}.

     */
    function symbol() public view virtual override returns (string memory) {
        return _symbol;
    }

    /**

     * @dev See {IERC721Metadata-tokenURI}.

     */
    function tokenURI(uint256 tokenId) public view virtual override returns (string memory) {
        _requireMinted(tokenId);

        string memory baseURI = _baseURI();
        return bytes(baseURI).length > 0 ? string(abi.encodePacked(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 "";
    }

    /**

     * @dev See {IERC721-approve}.

     */
    function approve(address to, uint256 tokenId) public virtual override {
        address owner = ERC721.ownerOf(tokenId);
        require(to != owner, "ERC721: approval to current owner");

        require(
            _msgSender() == owner || isApprovedForAll(owner, _msgSender()),
            "ERC721: approve caller is not token owner nor approved for all"
        );

        _approve(to, tokenId);
    }

    /**

     * @dev See {IERC721-getApproved}.

     */
    function getApproved(uint256 tokenId) public view virtual override returns (address) {
        _requireMinted(tokenId);

        return _tokenApprovals[tokenId];
    }

    /**

     * @dev See {IERC721-setApprovalForAll}.

     */
    function setApprovalForAll(address operator, bool approved) public virtual override {
        _setApprovalForAll(_msgSender(), operator, approved);
    }

    /**

     * @dev See {IERC721-isApprovedForAll}.

     */
    function isApprovedForAll(address owner, address operator) public view virtual override returns (bool) {
        return _operatorApprovals[owner][operator];
    }

    /**

     * @dev See {IERC721-transferFrom}.

     */
    function transferFrom(

        address from,

        address to,

        uint256 tokenId

    ) public virtual override {
        //solhint-disable-next-line max-line-length
        require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721: caller is not token owner nor approved");

        _transfer(from, to, tokenId);
    }

    /**

     * @dev See {IERC721-safeTransferFrom}.

     */
    function safeTransferFrom(

        address from,

        address to,

        uint256 tokenId

    ) public virtual override {
        safeTransferFrom(from, to, tokenId, "");
    }

    /**

     * @dev See {IERC721-safeTransferFrom}.

     */
    function safeTransferFrom(

        address from,

        address to,

        uint256 tokenId,

        bytes memory data

    ) public virtual override {
        require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721: caller is not token owner nor approved");
        _safeTransfer(from, to, tokenId, data);
    }

    /**

     * @dev Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients

     * are aware of the ERC721 protocol 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 equivalent to {safeTransferFrom}, and can be used to e.g.

     * implement alternative mechanisms to perform token transfer, such as signature-based.

     *

     * Requirements:

     *

     * - `from` cannot be the zero address.

     * - `to` cannot be the zero address.

     * - `tokenId` token must exist and be owned by `from`.

     * - 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,

        bytes memory data

    ) internal virtual {
        _transfer(from, to, tokenId);
        require(_checkOnERC721Received(from, to, tokenId, data), "ERC721: transfer to non ERC721Receiver implementer");
    }

    /**

     * @dev Returns whether `tokenId` exists.

     *

     * Tokens can be managed by their owner or approved accounts via {approve} or {setApprovalForAll}.

     *

     * Tokens start existing when they are minted (`_mint`),

     * and stop existing when they are burned (`_burn`).

     */
    function _exists(uint256 tokenId) internal view virtual returns (bool) {
        return _owners[tokenId] != address(0);
    }

    /**

     * @dev Returns whether `spender` is allowed to manage `tokenId`.

     *

     * Requirements:

     *

     * - `tokenId` must exist.

     */
    function _isApprovedOrOwner(address spender, uint256 tokenId) internal view virtual returns (bool) {
        address owner = ERC721.ownerOf(tokenId);
        return (spender == owner || isApprovedForAll(owner, spender) || getApproved(tokenId) == spender);
    }

    /**

     * @dev Safely mints `tokenId` and transfers it to `to`.

     *

     * 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 virtual {
        _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);
        require(
            _checkOnERC721Received(address(0), to, tokenId, data),
            "ERC721: transfer to non ERC721Receiver implementer"
        );
    }

    /**

     * @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 virtual {
        require(to != address(0), "ERC721: mint to the zero address");
        require(!_exists(tokenId), "ERC721: token already minted");

        _beforeTokenTransfer(address(0), to, tokenId);

        _balances[to] += 1;
        _owners[tokenId] = to;

        emit Transfer(address(0), to, tokenId);

        _afterTokenTransfer(address(0), to, tokenId);
    }

    /**

     * @dev Destroys `tokenId`.

     * The approval is cleared when the token is burned.

     *

     * Requirements:

     *

     * - `tokenId` must exist.

     *

     * Emits a {Transfer} event.

     */
    function _burn(uint256 tokenId) internal virtual {
        address owner = ERC721.ownerOf(tokenId);

        _beforeTokenTransfer(owner, address(0), tokenId);

        // Clear approvals
        _approve(address(0), tokenId);

        _balances[owner] -= 1;
        delete _owners[tokenId];

        emit Transfer(owner, address(0), tokenId);

        _afterTokenTransfer(owner, address(0), 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 virtual {
        require(ERC721.ownerOf(tokenId) == from, "ERC721: transfer from incorrect owner");
        require(to != address(0), "ERC721: transfer to the zero address");

        _beforeTokenTransfer(from, to, tokenId);

        // Clear approvals from the previous owner
        _approve(address(0), tokenId);

        _balances[from] -= 1;
        _balances[to] += 1;
        _owners[tokenId] = to;

        emit Transfer(from, to, tokenId);

        _afterTokenTransfer(from, to, tokenId);
    }

    /**

     * @dev Approve `to` to operate on `tokenId`

     *

     * Emits an {Approval} event.

     */
    function _approve(address to, uint256 tokenId) internal virtual {
        _tokenApprovals[tokenId] = to;
        emit Approval(ERC721.ownerOf(tokenId), to, tokenId);
    }

    /**

     * @dev Approve `operator` to operate on all of `owner` tokens

     *

     * Emits an {ApprovalForAll} event.

     */
    function _setApprovalForAll(

        address owner,

        address operator,

        bool approved

    ) internal virtual {
        require(owner != operator, "ERC721: approve to caller");
        _operatorApprovals[owner][operator] = approved;
        emit ApprovalForAll(owner, operator, approved);
    }

    /**

     * @dev Reverts if the `tokenId` has not been minted yet.

     */
    function _requireMinted(uint256 tokenId) internal view virtual {
        require(_exists(tokenId), "ERC721: invalid token ID");
    }

    /**

     * @dev Internal function to invoke {IERC721Receiver-onERC721Received} on a target address.

     * The call is not executed if the target address is not a contract.

     *

     * @param from address representing the previous owner of the given token ID

     * @param to target address that will receive the tokens

     * @param tokenId uint256 ID of the token to be transferred

     * @param data bytes optional data to send along with the call

     * @return bool whether the call correctly returned the expected magic value

     */
    function _checkOnERC721Received(

        address from,

        address to,

        uint256 tokenId,

        bytes memory data

    ) private returns (bool) {
        if (to.isContract()) {
            try IERC721Receiver(to).onERC721Received(_msgSender(), from, tokenId, data) returns (bytes4 retval) {
                return retval == IERC721Receiver.onERC721Received.selector;
            } catch (bytes memory reason) {
                if (reason.length == 0) {
                    revert("ERC721: transfer to non ERC721Receiver implementer");
                } else {
                    /// @solidity memory-safe-assembly
                    assembly {
                        revert(add(32, reason), mload(reason))
                    }
                }
            }
        } else {
            return true;
        }
    }

    /**

     * @dev Hook that is called before any token transfer. This includes minting

     * and burning.

     *

     * Calling conditions:

     *

     * - When `from` and `to` are both non-zero, ``from``'s `tokenId` will be

     * transferred to `to`.

     * - When `from` is zero, `tokenId` will be minted for `to`.

     * - When `to` is zero, ``from``'s `tokenId` will be burned.

     * - `from` and `to` are never both zero.

     *

     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].

     */
    function _beforeTokenTransfer(

        address from,

        address to,

        uint256 tokenId

    ) internal virtual {}

    /**

     * @dev Hook that is called after any transfer of tokens. This includes

     * minting and burning.

     *

     * Calling conditions:

     *

     * - when `from` and `to` are both non-zero.

     * - `from` and `to` are never both zero.

     *

     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].

     */
    function _afterTokenTransfer(

        address from,

        address to,

        uint256 tokenId

    ) internal virtual {}
}


// File contracts/Murmuration.sol

// SPDX-License-Identifier: UNLICENSED
pragma solidity ^0.8.9;




/**

 * @notice This contract holds the NFTs of the Murmuration collection

 * @dev Sale is implemented in another contract. See {MurmurationSale}

 */
contract Murmuration is ERC721, ERC2981, Ownable, AccessControlEnumerable {
    //Admin role that will manage the minter role and the URI
    bytes32 public constant ADMIN_ROLE = keccak256("ADMIN_ROLE");
    //Minter role that will be allowed to mint
    bytes32 public constant MINTER_ROLE = keccak256("MINTER_ROLE");

    //There are 11 pieces of work in the Murmuration collection
    uint256 public constant MAX_SUPPLY = 11;

    //URI that will point to the metadatas
    string public baseURI;

    //Prevent further changes to metadatas
    bool public metadatasFrozen = false;

    constructor(address _baseRoyaltyReceiver) ERC721("Murmuration", "MURMURATION") {
        _setRoleAdmin(MINTER_ROLE, ADMIN_ROLE); //Admin role can grant and revoke minter role
        _grantRole(ADMIN_ROLE, msg.sender); //Make deployer Admin by default
        _setDefaultRoyalty(_baseRoyaltyReceiver, 700);
    }

    modifier onlyAdmin() {
        require(
            hasRole(ADMIN_ROLE, msg.sender),
            "You are not allowed to perform this action"
        );
        _;
    }

    modifier onlyMinter() {
        require(
            hasRole(MINTER_ROLE, msg.sender),
            "You are not allowed to perform this action"
        );
        _;
    }

    /**

     * @dev Transfers the admin role. Only callable by current admin.

     */
    function transferAdmin(address _to) public onlyAdmin {
        require(_to != address(0), "Can't lose adminship");
        _revokeRole(ADMIN_ROLE, msg.sender);
        _grantRole(ADMIN_ROLE, _to);
    }

    /**

     * @dev Changes the base uri that will hold the metadatas.

     * @param _newBaseURI The new uri

     */
    function setBaseURI(string calldata _newBaseURI) public onlyAdmin {
        require(!metadatasFrozen, "Metadatas are frozen");
        baseURI = _newBaseURI;
    }

    /**

     * @dev Freezes the metadatas of the contract, preventing any modifications to the NFT.

     */
    function freezeMetadatas() public onlyAdmin {
        metadatasFrozen = true;
    }

    /**

     * @dev Mints a token.

     * @param _to The address to mint the NFT to

     * @param _id The id of the token to mint

     */
    function mintTo(address _to, uint256 _id) public onlyMinter {
        //Check that the id to be minted is in range [1;MAX_SUPPLY].
        require(_id >= 1 && _id <=MAX_SUPPLY, "This NFT does not exist");
        //If id has already by minted, this will revert
        _mint(_to, _id);
    }

    /**

     * @dev Change the royalties for this collection.

     * @param _receiver The address that will receive the royalties

     * @param _feeNumerator The number of basis points. Example: _feeNumerator = 100 -> 1% royalties

     */
    function setDefaultRoyalty(address _receiver, uint96 _feeNumerator) public onlyAdmin{

        _setDefaultRoyalty(_receiver, _feeNumerator);

    }

    /**

     * @dev Overrides the _baseURI from ERC721 to use this contract's baseURI

     */
    function _baseURI() internal view override(ERC721) returns (string memory) {
        return baseURI;
    }

    /**

     * @dev See {IERC165-supportsInterface}.

     */
    function supportsInterface(bytes4 interfaceId)
        public
        view
        virtual
        override(ERC721, AccessControlEnumerable, ERC2981)
        returns (bool)
    {
        return super.supportsInterface(interfaceId);
    }

    /**

     * @dev Return the total supply of Murmuration. Used for display purposes.

     */
    function totalSupply() public pure returns(uint256){
        return 11;
    }
}