// SPDX-License-Identifier: MIT
abstract contract Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }
}

library Strings {
    bytes16 private constant _HEX_SYMBOLS = "0123456789abcdef";

    /**
     * @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);
    }
}

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
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize, which returns 0 for contracts in
        // construction, since the code is only stored at the end of the
        // constructor execution.

        uint256 size;
        assembly {
            size := extcodesize(account)
        }
        return size > 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

                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}

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);
}

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;

    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 make it call a
     * `private` function that does the actual work.
     */
    modifier nonReentrant() {
        // On the first call to nonReentrant, _notEntered will be true
        require(_status != _ENTERED, "ReentrancyGuard: reentrant call");

        // Any calls to nonReentrant after this point will fail
        _status = _ENTERED;

        _;

        // By storing the original value once again, a refund is triggered (see
        // https://eips.ethereum.org/EIPS/eip-2200)
        _status = _NOT_ENTERED;
    }
}

library AddressUpgradeable {
    /**
     * @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
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize, which returns 0 for contracts in
        // construction, since the code is only stored at the end of the
        // constructor execution.

        uint256 size;
        assembly {
            size := extcodesize(account)
        }
        return size > 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 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

                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}

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 `IERC721.onERC721Received.selector`.
     */
    function onERC721Received(
        address operator,
        address from,
        uint256 tokenId,
        bytes calldata data
    ) external returns (bytes4);
}

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;

        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;

        assembly {
            result := store
        }

        return result;
    }
}

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 () {
        address msgSender = _msgSender();
        _owner = msgSender;
        emit OwnershipTransferred(address(0), msgSender);
    }

    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view virtual returns (address) {
        return _owner;
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        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 {
        emit OwnershipTransferred(_owner, address(0));
        _owner = 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");
        emit OwnershipTransferred(_owner, newOwner);
        _owner = newOwner;
    }
}

interface ICreatorExtensionTokenURI is IERC165 {
    /**
     * Get the uri for a given creator/tokenId
     */
    function tokenURI(address creator, uint256 tokenId)
        external
        view
        returns (string memory);
}

interface IERC721CreatorExtensionApproveTransfer is IERC165 {
    /**
     * @dev Set whether or not the creator will check the extension for approval of token transfer
     */
    function setApproveTransfer(address creator, bool enabled) external;

    /**
     * @dev Called by creator contract to approve a transfer
     */
    function approveTransfer(
        address from,
        address to,
        uint256 tokenId
    ) external returns (bool);
}

library ERC165Checker {
    // As per the EIP-165 spec, no interface should ever match 0xffffffff
    bytes4 private constant _INTERFACE_ID_INVALID = 0xffffffff;

    /**
     * @dev Returns true if `account` supports the {IERC165} interface,
     */
    function supportsERC165(address account) internal view returns (bool) {
        // Any contract that implements ERC165 must explicitly indicate support of
        // InterfaceId_ERC165 and explicitly indicate non-support of InterfaceId_Invalid
        return
            _supportsERC165Interface(account, type(IERC165).interfaceId) &&
            !_supportsERC165Interface(account, _INTERFACE_ID_INVALID);
    }

    /**
     * @dev Returns true if `account` supports the interface defined by
     * `interfaceId`. Support for {IERC165} itself is queried automatically.
     *
     * See {IERC165-supportsInterface}.
     */
    function supportsInterface(address account, bytes4 interfaceId) internal view returns (bool) {
        // query support of both ERC165 as per the spec and support of _interfaceId
        return supportsERC165(account) && _supportsERC165Interface(account, interfaceId);
    }

    /**
     * @dev Returns a boolean array where each value corresponds to the
     * interfaces passed in and whether they're supported or not. This allows
     * you to batch check interfaces for a contract where your expectation
     * is that some interfaces may not be supported.
     *
     * See {IERC165-supportsInterface}.
     *
     * _Available since v3.4._
     */
    function getSupportedInterfaces(address account, bytes4[] memory interfaceIds)
        internal
        view
        returns (bool[] memory)
    {
        // an array of booleans corresponding to interfaceIds and whether they're supported or not
        bool[] memory interfaceIdsSupported = new bool[](interfaceIds.length);

        // query support of ERC165 itself
        if (supportsERC165(account)) {
            // query support of each interface in interfaceIds
            for (uint256 i = 0; i < interfaceIds.length; i++) {
                interfaceIdsSupported[i] = _supportsERC165Interface(account, interfaceIds[i]);
            }
        }

        return interfaceIdsSupported;
    }

    /**
     * @dev Returns true if `account` supports all the interfaces defined in
     * `interfaceIds`. Support for {IERC165} itself is queried automatically.
     *
     * Batch-querying can lead to gas savings by skipping repeated checks for
     * {IERC165} support.
     *
     * See {IERC165-supportsInterface}.
     */
    function supportsAllInterfaces(address account, bytes4[] memory interfaceIds) internal view returns (bool) {
        // query support of ERC165 itself
        if (!supportsERC165(account)) {
            return false;
        }

        // query support of each interface in _interfaceIds
        for (uint256 i = 0; i < interfaceIds.length; i++) {
            if (!_supportsERC165Interface(account, interfaceIds[i])) {
                return false;
            }
        }

        // all interfaces supported
        return true;
    }

    /**
     * @notice Query if a contract implements an interface, does not check ERC165 support
     * @param account The address of the contract to query for support of an interface
     * @param interfaceId The interface identifier, as specified in ERC-165
     * @return true if the contract at account indicates support of the interface with
     * identifier interfaceId, false otherwise
     * @dev Assumes that account contains a contract that supports ERC165, otherwise
     * the behavior of this method is undefined. This precondition can be checked
     * with {supportsERC165}.
     * Interface identification is specified in ERC-165.
     */
    function _supportsERC165Interface(address account, bytes4 interfaceId) private view returns (bool) {
        bytes memory encodedParams = abi.encodeWithSelector(IERC165.supportsInterface.selector, interfaceId);
        (bool success, bytes memory result) = account.staticcall{gas: 30000}(encodedParams);
        if (result.length < 32) return false;
        return success && abi.decode(result, (bool));
    }
}

interface ICreatorCore is IERC165 {
    event ExtensionRegistered(
        address indexed extension,
        address indexed sender
    );
    event ExtensionUnregistered(
        address indexed extension,
        address indexed sender
    );
    event ExtensionBlacklisted(
        address indexed extension,
        address indexed sender
    );
    event MintPermissionsUpdated(
        address indexed extension,
        address indexed permissions,
        address indexed sender
    );
    event RoyaltiesUpdated(
        uint256 indexed tokenId,
        address payable[] receivers,
        uint256[] basisPoints
    );
    event DefaultRoyaltiesUpdated(
        address payable[] receivers,
        uint256[] basisPoints
    );
    event ExtensionRoyaltiesUpdated(
        address indexed extension,
        address payable[] receivers,
        uint256[] basisPoints
    );
    event ExtensionApproveTransferUpdated(
        address indexed extension,
        bool enabled
    );

    /**
     * @dev gets address of all extensions
     */
    function getExtensions() external view returns (address[] memory);

    /**
     * @dev add an extension.  Can only be called by contract owner or admin.
     * extension address must point to a contract implementing ICreatorExtension.
     * Returns True if newly added, False if already added.
     */
    function registerExtension(address extension, string calldata baseURI)
        external;

    /**
     * @dev add an extension.  Can only be called by contract owner or admin.
     * extension address must point to a contract implementing ICreatorExtension.
     * Returns True if newly added, False if already added.
     */
    function registerExtension(
        address extension,
        string calldata baseURI,
        bool baseURIIdentical
    ) external;

    /**
     * @dev add an extension.  Can only be called by contract owner or admin.
     * Returns True if removed, False if already removed.
     */
    function unregisterExtension(address extension) external;

    /**
     * @dev blacklist an extension.  Can only be called by contract owner or admin.
     * This function will destroy all ability to reference the metadata of any tokens created
     * by the specified extension. It will also unregister the extension if needed.
     * Returns True if removed, False if already removed.
     */
    function blacklistExtension(address extension) external;

    /**
     * @dev set the baseTokenURI of an extension.  Can only be called by extension.
     */
    function setBaseTokenURIExtension(string calldata uri) external;

    /**
     * @dev set the baseTokenURI of an extension.  Can only be called by extension.
     * For tokens with no uri configured, tokenURI will return "uri+tokenId"
     */
    function setBaseTokenURIExtension(string calldata uri, bool identical)
        external;

    /**
     * @dev set the common prefix of an extension.  Can only be called by extension.
     * If configured, and a token has a uri set, tokenURI will return "prefixURI+tokenURI"
     * Useful if you want to use ipfs/arweave
     */
    function setTokenURIPrefixExtension(string calldata prefix) external;

    /**
     * @dev set the tokenURI of a token extension.  Can only be called by extension that minted token.
     */
    function setTokenURIExtension(uint256 tokenId, string calldata uri)
        external;

    /**
     * @dev set the tokenURI of a token extension for multiple tokens.  Can only be called by extension that minted token.
     */
    function setTokenURIExtension(
        uint256[] memory tokenId,
        string[] calldata uri
    ) external;

    /**
     * @dev set the baseTokenURI for tokens with no extension.  Can only be called by owner/admin.
     * For tokens with no uri configured, tokenURI will return "uri+tokenId"
     */
    function setBaseTokenURI(string calldata uri) external;

    /**
     * @dev set the common prefix for tokens with no extension.  Can only be called by owner/admin.
     * If configured, and a token has a uri set, tokenURI will return "prefixURI+tokenURI"
     * Useful if you want to use ipfs/arweave
     */
    function setTokenURIPrefix(string calldata prefix) external;

    /**
     * @dev set the tokenURI of a token with no extension.  Can only be called by owner/admin.
     */
    function setTokenURI(uint256 tokenId, string calldata uri) external;

    /**
     * @dev set the tokenURI of multiple tokens with no extension.  Can only be called by owner/admin.
     */
    function setTokenURI(uint256[] memory tokenIds, string[] calldata uris)
        external;

    /**
     * @dev set a permissions contract for an extension.  Used to control minting.
     */
    function setMintPermissions(address extension, address permissions)
        external;

    /**
     * @dev Configure so transfers of tokens created by the caller (must be extension) gets approval
     * from the extension before transferring
     */
    function setApproveTransferExtension(bool enabled) external;

    /**
     * @dev get the extension of a given token
     */
    function tokenExtension(uint256 tokenId) external view returns (address);

    /**
     * @dev Set default royalties
     */
    function setRoyalties(
        address payable[] calldata receivers,
        uint256[] calldata basisPoints
    ) external;

    /**
     * @dev Set royalties of a token
     */
    function setRoyalties(
        uint256 tokenId,
        address payable[] calldata receivers,
        uint256[] calldata basisPoints
    ) external;

    /**
     * @dev Set royalties of an extension
     */
    function setRoyaltiesExtension(
        address extension,
        address payable[] calldata receivers,
        uint256[] calldata basisPoints
    ) external;

    /**
     * @dev Get royalites of a token.  Returns list of receivers and basisPoints
     */
    function getRoyalties(uint256 tokenId)
        external
        view
        returns (address payable[] memory, uint256[] memory);

    // Royalty support for various other standards
    function getFeeRecipients(uint256 tokenId)
        external
        view
        returns (address payable[] memory);

    function getFeeBps(uint256 tokenId)
        external
        view
        returns (uint256[] memory);

    function getFees(uint256 tokenId)
        external
        view
        returns (address payable[] memory, uint256[] memory);

    function royaltyInfo(uint256 tokenId, uint256 value)
        external
        view
        returns (address, uint256);
}

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`, 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 be 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 Returns the account approved for `tokenId` token.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     */
    function getApproved(uint256 tokenId) external view returns (address operator);

    /**
     * @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 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);

    /**
     * @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;
}

abstract contract ERC165 is IERC165 {
    /**
     * @dev See {IERC165-supportsInterface}.
     */
    function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
        return interfaceId == type(IERC165).interfaceId;
    }
}

interface IAdminControl is IERC165 {
    event AdminApproved(address indexed account, address indexed sender);
    event AdminRevoked(address indexed account, address indexed sender);

    /**
     * @dev gets address of all admins
     */
    function getAdmins() external view returns (address[] memory);

    /**
     * @dev add an admin.  Can only be called by contract owner.
     */
    function approveAdmin(address admin) external;

    /**
     * @dev remove an admin.  Can only be called by contract owner.
     */
    function revokeAdmin(address admin) external;

    /**
     * @dev checks whether or not given address is an admin
     * Returns True if they are
     */
    function isAdmin(address admin) external view returns (bool);
}

interface IERC721CreatorExtensionBurnable is IERC165 {
    /**
     * @dev callback handler for burn events
     */
    function onBurn(address owner, uint256 tokenId) external;
}

interface IERC721CreatorMintPermissions is IERC165 {
    /**
     * @dev get approval to mint
     */
    function approveMint(
        address extension,
        address to,
        uint256 tokenId
    ) external;
}

interface IERC721CreatorCore is ICreatorCore {

    /**
     * @dev mint a token with no extension. Can only be called by an admin.
     * Returns tokenId minted
     */
    function mintBase(address to) external returns (uint256);

    /**
     * @dev mint a token with no extension. Can only be called by an admin.
     * Returns tokenId minted
     */
    function mintBase(address to, string calldata uri) external returns (uint256);

    /**
     * @dev batch mint a token with no extension. Can only be called by an admin.
     * Returns tokenId minted
     */
    function mintBaseBatch(address to, uint16 count) external returns (uint256[] memory);

    /**
     * @dev batch mint a token with no extension. Can only be called by an admin.
     * Returns tokenId minted
     */
    function mintBaseBatch(address to, string[] calldata uris) external returns (uint256[] memory);

    /**
     * @dev mint a token. Can only be called by a registered extension.
     * Returns tokenId minted
     */
    function mintExtension(address to) external returns (uint256);

    /**
     * @dev mint a token. Can only be called by a registered extension.
     * Returns tokenId minted
     */
    function mintExtension(address to, string calldata uri) external returns (uint256);

    /**
     * @dev batch mint a token. Can only be called by a registered extension.
     * Returns tokenIds minted
     */
    function mintExtensionBatch(address to, uint16 count) external returns (uint256[] memory);

    /**
     * @dev batch mint a token. Can only be called by a registered extension.
     * Returns tokenId minted
     */
    function mintExtensionBatch(address to, string[] calldata uris) external returns (uint256[] memory);

    /**
     * @dev burn a token. Can only be called by token owner or approved address.
     * On burn, calls back to the registered extension's onBurn method
     */
    function burn(uint256 tokenId) external;

}
abstract contract AdminControl is Ownable, IAdminControl, ERC165 {
    using EnumerableSet for EnumerableSet.AddressSet;

    // Track registered admins
    EnumerableSet.AddressSet private _admins;

    /**
     * @dev See {IERC165-supportsInterface}.
     */
    function supportsInterface(bytes4 interfaceId)
        public
        view
        virtual
        override(ERC165, IERC165)
        returns (bool)
    {
        return
            interfaceId == type(IAdminControl).interfaceId ||
            super.supportsInterface(interfaceId);
    }

    /**
     * @dev Only allows approved admins to call the specified function
     */
    modifier adminRequired() {
        require(
            owner() == msg.sender || _admins.contains(msg.sender),
            "AdminControl: Must be owner or admin"
        );
        _;
    }

    /**
     * @dev See {IAdminControl-getAdmins}.
     */
    function getAdmins()
        external
        view
        override
        returns (address[] memory admins)
    {
        admins = new address[](_admins.length());
        for (uint256 i = 0; i < _admins.length(); i++) {
            admins[i] = _admins.at(i);
        }
        return admins;
    }

    /**
     * @dev See {IAdminControl-approveAdmin}.
     */
    function approveAdmin(address admin) external override onlyOwner {
        if (!_admins.contains(admin)) {
            emit AdminApproved(admin, msg.sender);
            _admins.add(admin);
        }
    }

    /**
     * @dev See {IAdminControl-revokeAdmin}.
     */
    function revokeAdmin(address admin) external override onlyOwner {
        if (_admins.contains(admin)) {
            emit AdminRevoked(admin, msg.sender);
            _admins.remove(admin);
        }
    }

    /**
     * @dev See {IAdminControl-isAdmin}.
     */
    function isAdmin(address admin) public view override returns (bool) {
        return (owner() == admin || _admins.contains(admin));
    }
}

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);
}

abstract contract CreatorCore is ReentrancyGuard, ICreatorCore, ERC165 {
    using Strings for uint256;
    using EnumerableSet for EnumerableSet.AddressSet;
    using AddressUpgradeable for address;

    uint256 _tokenCount = 0;

    // Track registered extensions data
    EnumerableSet.AddressSet internal _extensions;
    EnumerableSet.AddressSet internal _blacklistedExtensions;
    mapping(address => address) internal _extensionPermissions;
    mapping(address => bool) internal _extensionApproveTransfers;

    // For tracking which extension a token was minted by
    mapping(uint256 => address) internal _tokensExtension;

    // The baseURI for a given extension
    mapping(address => string) private _extensionBaseURI;
    mapping(address => bool) private _extensionBaseURIIdentical;

    // The prefix for any tokens with a uri configured
    mapping(address => string) private _extensionURIPrefix;

    // Mapping for individual token URIs
    mapping(uint256 => string) internal _tokenURIs;

    // Royalty configurations
    mapping(address => address payable[]) internal _extensionRoyaltyReceivers;
    mapping(address => uint256[]) internal _extensionRoyaltyBPS;
    mapping(uint256 => address payable[]) internal _tokenRoyaltyReceivers;
    mapping(uint256 => uint256[]) internal _tokenRoyaltyBPS;

    /**
     * External interface identifiers for royalties
     */

    /**
     *  @dev CreatorCore
     *
     *  bytes4(keccak256('getRoyalties(uint256)')) == 0xbb3bafd6
     *
     *  => 0xbb3bafd6 = 0xbb3bafd6
     */
    bytes4 private constant _INTERFACE_ID_ROYALTIES_CREATORCORE = 0xbb3bafd6;

    /**
     *  @dev Rarible: RoyaltiesV1
     *
     *  bytes4(keccak256('getFeeRecipients(uint256)')) == 0xb9c4d9fb
     *  bytes4(keccak256('getFeeBps(uint256)')) == 0x0ebd4c7f
     *
     *  => 0xb9c4d9fb ^ 0x0ebd4c7f = 0xb7799584
     */
    bytes4 private constant _INTERFACE_ID_ROYALTIES_RARIBLE = 0xb7799584;

    /**
     *  @dev Foundation
     *
     *  bytes4(keccak256('getFees(uint256)')) == 0xd5a06d4c
     *
     *  => 0xd5a06d4c = 0xd5a06d4c
     */
    bytes4 private constant _INTERFACE_ID_ROYALTIES_FOUNDATION = 0xd5a06d4c;

    /**
     *  @dev EIP-2981
     *
     * bytes4(keccak256("royaltyInfo(uint256,uint256)")) == 0x2a55205a
     *
     * => 0x2a55205a = 0x2a55205a
     */
    bytes4 private constant _INTERFACE_ID_ROYALTIES_EIP2981 = 0x2a55205a;

    /**
     * @dev See {IERC165-supportsInterface}.
     */
    function supportsInterface(bytes4 interfaceId)
        public
        view
        virtual
        override(ERC165, IERC165)
        returns (bool)
    {
        return
            interfaceId == type(ICreatorCore).interfaceId ||
            super.supportsInterface(interfaceId) ||
            interfaceId == _INTERFACE_ID_ROYALTIES_CREATORCORE ||
            interfaceId == _INTERFACE_ID_ROYALTIES_RARIBLE ||
            interfaceId == _INTERFACE_ID_ROYALTIES_FOUNDATION ||
            interfaceId == _INTERFACE_ID_ROYALTIES_EIP2981;
    }

    /**
     * @dev Only allows registered extensions to call the specified function
     */
    modifier extensionRequired() {
        require(
            _extensions.contains(msg.sender),
            "Must be registered extension"
        );
        _;
    }

    /**
     * @dev Only allows non-blacklisted extensions
     */
    modifier nonBlacklistRequired(address extension) {
        require(
            !_blacklistedExtensions.contains(extension),
            "Extension blacklisted"
        );
        _;
    }

    /**
     * @dev See {ICreatorCore-getExtensions}.
     */
    function getExtensions()
        external
        view
        override
        returns (address[] memory extensions)
    {
        extensions = new address[](_extensions.length());
        for (uint256 i = 0; i < _extensions.length(); i++) {
            extensions[i] = _extensions.at(i);
        }
        return extensions;
    }

    /**
     * @dev Register an extension
     */
    function _registerExtension(
        address extension,
        string calldata baseURI,
        bool baseURIIdentical
    ) internal {
        require(extension != address(this), "Creator: Invalid");
        require(
            extension.isContract(),
            "Creator: Extension must be a contract"
        );
        if (!_extensions.contains(extension)) {
            _extensionBaseURI[extension] = baseURI;
            _extensionBaseURIIdentical[extension] = baseURIIdentical;
            emit ExtensionRegistered(extension, msg.sender);
            _extensions.add(extension);
        }
    }

    /**
     * @dev Unregister an extension
     */
    function _unregisterExtension(address extension) internal {
        if (_extensions.contains(extension)) {
            emit ExtensionUnregistered(extension, msg.sender);
            _extensions.remove(extension);
        }
    }

    /**
     * @dev Blacklist an extension
     */
    function _blacklistExtension(address extension) internal {
        require(extension != address(this), "Cannot blacklist yourself");
        if (_extensions.contains(extension)) {
            emit ExtensionUnregistered(extension, msg.sender);
            _extensions.remove(extension);
        }
        if (!_blacklistedExtensions.contains(extension)) {
            emit ExtensionBlacklisted(extension, msg.sender);
            _blacklistedExtensions.add(extension);
        }
    }

    /**
     * @dev Set base token uri for an extension
     */
    function _setBaseTokenURIExtension(string calldata uri, bool identical)
        internal
    {
        _extensionBaseURI[msg.sender] = uri;
        _extensionBaseURIIdentical[msg.sender] = identical;
    }

    /**
     * @dev Set token uri prefix for an extension
     */
    function _setTokenURIPrefixExtension(string calldata prefix) internal {
        _extensionURIPrefix[msg.sender] = prefix;
    }

    /**
     * @dev Set token uri for a token of an extension
     */
    function _setTokenURIExtension(uint256 tokenId, string calldata uri)
        internal
    {
        require(_tokensExtension[tokenId] == msg.sender, "Invalid token");
        _tokenURIs[tokenId] = uri;
    }

    /**
     * @dev Set base token uri for tokens with no extension
     */
    function _setBaseTokenURI(string memory uri) internal {
        _extensionBaseURI[address(this)] = uri;
    }

    /**
     * @dev Set token uri prefix for tokens with no extension
     */
    function _setTokenURIPrefix(string calldata prefix) internal {
        _extensionURIPrefix[address(this)] = prefix;
    }

    /**
     * @dev Set token uri for a token with no extension
     */
    function _setTokenURI(uint256 tokenId, string calldata uri) internal {
        require(_tokensExtension[tokenId] == address(this), "Invalid token");
        _tokenURIs[tokenId] = uri;
    }

    /**
     * @dev Retrieve a token's URI
     */
    function _tokenURI(uint256 tokenId) internal view returns (string memory) {
        address extension = _tokensExtension[tokenId];
        require(
            !_blacklistedExtensions.contains(extension),
            "Extension blacklisted"
        );

        if (bytes(_tokenURIs[tokenId]).length != 0) {
            if (bytes(_extensionURIPrefix[extension]).length != 0) {
                return
                    string(
                        abi.encodePacked(
                            _extensionURIPrefix[extension],
                            _tokenURIs[tokenId]
                        )
                    );
            }
            return _tokenURIs[tokenId];
        }

        if (
            ERC165Checker.supportsInterface(
                extension,
                type(ICreatorExtensionTokenURI).interfaceId
            )
        ) {
            return
                ICreatorExtensionTokenURI(extension).tokenURI(
                    address(this),
                    tokenId
                );
        }

        if (!_extensionBaseURIIdentical[extension]) {
            return
                string(
                    abi.encodePacked(
                        _extensionBaseURI[extension],
                        tokenId.toString()
                    )
                );
        } else {
            return _extensionBaseURI[extension];
        }
    }

    /**
     * Get token extension
     */
    function _tokenExtension(uint256 tokenId)
        internal
        view
        returns (address extension)
    {
        extension = _tokensExtension[tokenId];

        require(extension != address(this), "No extension for token");
        require(
            !_blacklistedExtensions.contains(extension),
            "Extension blacklisted"
        );

        return extension;
    }

    /**
     * Helper to get royalties for a token
     */
    function _getRoyalties(uint256 tokenId)
        internal
        view
        returns (address payable[] storage, uint256[] storage)
    {
        return (_getRoyaltyReceivers(tokenId), _getRoyaltyBPS(tokenId));
    }

    /**
     * Helper to get royalty receivers for a token
     */
    function _getRoyaltyReceivers(uint256 tokenId)
        internal
        view
        returns (address payable[] storage)
    {
        if (_tokenRoyaltyReceivers[tokenId].length > 0) {
            return _tokenRoyaltyReceivers[tokenId];
        } else if (
            _extensionRoyaltyReceivers[_tokensExtension[tokenId]].length > 0
        ) {
            return _extensionRoyaltyReceivers[_tokensExtension[tokenId]];
        }
        return _extensionRoyaltyReceivers[address(this)];
    }

    /**
     * Helper to get royalty basis points for a token
     */
    function _getRoyaltyBPS(uint256 tokenId)
        internal
        view
        returns (uint256[] storage)
    {
        if (_tokenRoyaltyBPS[tokenId].length > 0) {
            return _tokenRoyaltyBPS[tokenId];
        } else if (_extensionRoyaltyBPS[_tokensExtension[tokenId]].length > 0) {
            return _extensionRoyaltyBPS[_tokensExtension[tokenId]];
        }
        return _extensionRoyaltyBPS[address(this)];
    }

    function _getRoyaltyInfo(uint256 tokenId, uint256 value)
        internal
        view
        returns (address receiver, uint256 amount)
    {
        address payable[] storage receivers = _getRoyaltyReceivers(tokenId);
        require(receivers.length <= 1, "More than 1 royalty receiver");

        if (receivers.length == 0) {
            return (address(this), 0);
        }
        return (receivers[0], (_getRoyaltyBPS(tokenId)[0] * value) / 10000);
    }

    /**
     * Set royalties for a token
     */
    function _setRoyalties(
        uint256 tokenId,
        address payable[] calldata receivers,
        uint256[] calldata basisPoints
    ) internal {
        require(receivers.length == basisPoints.length, "Invalid input");
        uint256 totalBasisPoints;
        for (uint256 i = 0; i < basisPoints.length; i++) {
            totalBasisPoints += basisPoints[i];
        }
        require(totalBasisPoints < 10000, "Invalid total royalties");
        _tokenRoyaltyReceivers[tokenId] = receivers;
        _tokenRoyaltyBPS[tokenId] = basisPoints;
        emit RoyaltiesUpdated(tokenId, receivers, basisPoints);
    }

    /**
     * Set royalties for all tokens of an extension
     */
    function _setRoyaltiesExtension(
        address extension,
        address payable[] calldata receivers,
        uint256[] calldata basisPoints
    ) internal {
        require(receivers.length == basisPoints.length, "Invalid input");
        uint256 totalBasisPoints;
        for (uint256 i = 0; i < basisPoints.length; i++) {
            totalBasisPoints += basisPoints[i];
        }
        require(totalBasisPoints < 10000, "Invalid total royalties");
        _extensionRoyaltyReceivers[extension] = receivers;
        _extensionRoyaltyBPS[extension] = basisPoints;
        if (extension == address(this)) {
            emit DefaultRoyaltiesUpdated(receivers, basisPoints);
        } else {
            emit ExtensionRoyaltiesUpdated(extension, receivers, basisPoints);
        }
    }
}

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: balance query for the zero address");
        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: owner query for nonexistent token");
        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) {
        require(_exists(tokenId), "ERC721Metadata: URI query for nonexistent token");

        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 overriden 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 owner nor approved for all"
        );

        _approve(to, tokenId);
    }

    /**
     * @dev See {IERC721-getApproved}.
     */
    function getApproved(uint256 tokenId) public view virtual override returns (address) {
        require(_exists(tokenId), "ERC721: approved query for nonexistent token");

        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: transfer caller is not 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: transfer caller is not 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) {
        require(_exists(tokenId), "ERC721: operator query for nonexistent token");
        address owner = ERC721.ownerOf(tokenId);
        return (spender == owner || getApproved(tokenId) == spender || isApprovedForAll(owner, 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);
    }

    /**
     * @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);
    }

    /**
     * @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 of token that is not own");
        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);
    }

    /**
     * @dev Approve `to` to operate on `tokenId`
     *
     * Emits a {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 a {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 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 {
                    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 {}
}

abstract contract ERC721CreatorCore is CreatorCore, IERC721CreatorCore {
    using EnumerableSet for EnumerableSet.AddressSet;

    /**
     * @dev See {IERC165-supportsInterface}.
     */
    function supportsInterface(bytes4 interfaceId)
        public
        view
        virtual
        override(CreatorCore, IERC165)
        returns (bool)
    {
        return
            interfaceId == type(IERC721CreatorCore).interfaceId ||
            super.supportsInterface(interfaceId);
    }

    /**
     * @dev See {ICreatorCore-setApproveTransferExtension}.
     */
    function setApproveTransferExtension(bool enabled)
        external
        override
        extensionRequired
    {
        require(
            !enabled ||
                ERC165Checker.supportsInterface(
                    msg.sender,
                    type(IERC721CreatorExtensionApproveTransfer).interfaceId
                ),
            "Extension must implement IERC721CreatorExtensionApproveTransfer"
        );
        if (_extensionApproveTransfers[msg.sender] != enabled) {
            _extensionApproveTransfers[msg.sender] = enabled;
            emit ExtensionApproveTransferUpdated(msg.sender, enabled);
        }
    }

    /**
     * @dev Set mint permissions for an extension
     */
    function _setMintPermissions(address extension, address permissions)
        internal
    {
        require(
            _extensions.contains(extension),
            "CreatorCore: Invalid extension"
        );
        require(
            permissions == address(0x0) ||
                ERC165Checker.supportsInterface(
                    permissions,
                    type(IERC721CreatorMintPermissions).interfaceId
                ),
            "Invalid address"
        );
        if (_extensionPermissions[extension] != permissions) {
            _extensionPermissions[extension] = permissions;
            emit MintPermissionsUpdated(extension, permissions, msg.sender);
        }
    }

    /**
     * Check if an extension can mint
     */
    function _checkMintPermissions(address to, uint256 tokenId) internal {
        if (_extensionPermissions[msg.sender] != address(0x0)) {
            IERC721CreatorMintPermissions(_extensionPermissions[msg.sender])
                .approveMint(msg.sender, to, tokenId);
        }
    }

    /**
     * Override for post mint actions
     */
    function _postMintBase(address, uint256) internal virtual {}

    /**
     * Override for post mint actions
     */
    function _postMintExtension(address, uint256) internal virtual {}

    /**
     * Post-burning callback and metadata cleanup
     */
    function _postBurn(address owner, uint256 tokenId) internal virtual {
        // Callback to originating extension if needed
        if (_tokensExtension[tokenId] != address(this)) {
            if (
                ERC165Checker.supportsInterface(
                    _tokensExtension[tokenId],
                    type(IERC721CreatorExtensionBurnable).interfaceId
                )
            ) {
                IERC721CreatorExtensionBurnable(_tokensExtension[tokenId])
                    .onBurn(owner, tokenId);
            }
        }
        // Clear metadata (if any)
        if (bytes(_tokenURIs[tokenId]).length != 0) {
            delete _tokenURIs[tokenId];
        }
        // Delete token origin extension tracking
        delete _tokensExtension[tokenId];
    }

    /**
     * Approve a transfer
     */
    function _approveTransfer(
        address from,
        address to,
        uint256 tokenId
    ) internal {
        if (_extensionApproveTransfers[_tokensExtension[tokenId]]) {
            require(
                IERC721CreatorExtensionApproveTransfer(
                    _tokensExtension[tokenId]
                ).approveTransfer(from, to, tokenId),
                "ERC721Creator: Extension approval failure"
            );
        }
    }
}

contract ERC721Creator is AdminControl, ERC721, ERC721CreatorCore {
    constructor(string memory _name, string memory _symbol)
        ERC721(_name, _symbol)
    {}

    /**
     * @dev See {IERC165-supportsInterface}.
     */
    function supportsInterface(bytes4 interfaceId)
        public
        view
        virtual
        override(ERC721, ERC721CreatorCore, AdminControl)
        returns (bool)
    {
        return
            ERC721CreatorCore.supportsInterface(interfaceId) ||
            ERC721.supportsInterface(interfaceId) ||
            AdminControl.supportsInterface(interfaceId);
    }

    function _beforeTokenTransfer(
        address from,
        address to,
        uint256 tokenId
    ) internal virtual override {
        _approveTransfer(from, to, tokenId);
    }

    /**
     * @dev See {ICreatorCore-registerExtension}.
     */
    function registerExtension(address extension, string calldata baseURI)
        external
        override
        adminRequired
        nonBlacklistRequired(extension)
    {
        _registerExtension(extension, baseURI, false);
    }

    /**
     * @dev See {ICreatorCore-registerExtension}.
     */
    function registerExtension(
        address extension,
        string calldata baseURI,
        bool baseURIIdentical
    ) external override adminRequired nonBlacklistRequired(extension) {
        _registerExtension(extension, baseURI, baseURIIdentical);
    }

    /**
     * @dev See {ICreatorCore-unregisterExtension}.
     */
    function unregisterExtension(address extension)
        external
        override
        adminRequired
    {
        _unregisterExtension(extension);
    }

    /**
     * @dev See {ICreatorCore-blacklistExtension}.
     */
    function blacklistExtension(address extension)
        external
        override
        adminRequired
    {
        _blacklistExtension(extension);
    }

    /**
     * @dev See {ICreatorCore-setBaseTokenURIExtension}.
     */
    function setBaseTokenURIExtension(string calldata uri)
        external
        override
        extensionRequired
    {
        _setBaseTokenURIExtension(uri, false);
    }

    /**
     * @dev See {ICreatorCore-setBaseTokenURIExtension}.
     */
    function setBaseTokenURIExtension(string calldata uri, bool identical)
        external
        override
        extensionRequired
    {
        _setBaseTokenURIExtension(uri, identical);
    }

    /**
     * @dev See {ICreatorCore-setTokenURIPrefixExtension}.
     */
    function setTokenURIPrefixExtension(string calldata prefix)
        external
        override
        extensionRequired
    {
        _setTokenURIPrefixExtension(prefix);
    }

    /**
     * @dev See {ICreatorCore-setTokenURIExtension}.
     */
    function setTokenURIExtension(uint256 tokenId, string calldata uri)
        external
        override
        extensionRequired
    {
        _setTokenURIExtension(tokenId, uri);
    }

    /**
     * @dev See {ICreatorCore-setTokenURIExtension}.
     */
    function setTokenURIExtension(
        uint256[] memory tokenIds,
        string[] calldata uris
    ) external override extensionRequired {
        require(tokenIds.length == uris.length, "Invalid input");
        for (uint256 i = 0; i < tokenIds.length; i++) {
            _setTokenURIExtension(tokenIds[i], uris[i]);
        }
    }

    /**
     * @dev See {ICreatorCore-setBaseTokenURI}.
     */
    function setBaseTokenURI(string calldata uri)
        external
        override
        adminRequired
    {
        _setBaseTokenURI(uri);
    }

    /**
     * @dev See {ICreatorCore-setTokenURIPrefix}.
     */
    function setTokenURIPrefix(string calldata prefix)
        external
        override
        adminRequired
    {
        _setTokenURIPrefix(prefix);
    }

    /**
     * @dev See {ICreatorCore-setTokenURI}.
     */
    function setTokenURI(uint256 tokenId, string calldata uri)
        external
        override
        adminRequired
    {
        _setTokenURI(tokenId, uri);
    }

    /**
     * @dev See {ICreatorCore-setTokenURI}.
     */
    function setTokenURI(uint256[] memory tokenIds, string[] calldata uris)
        external
        override
        adminRequired
    {
        require(tokenIds.length == uris.length, "Invalid input");
        for (uint256 i = 0; i < tokenIds.length; i++) {
            _setTokenURI(tokenIds[i], uris[i]);
        }
    }

    /**
     * @dev See {ICreatorCore-setMintPermissions}.
     */
    function setMintPermissions(address extension, address permissions)
        external
        override
        adminRequired
    {
        _setMintPermissions(extension, permissions);
    }

    /**
     * @dev See {IERC721CreatorCore-mintBase}.
     */
    function mintBase(address to)
        public
        virtual
        override
        nonReentrant
        adminRequired
        returns (uint256)
    {
        return _mintBase(to, "");
    }

    /**
     * @dev See {IERC721CreatorCore-mintBase}.
     */
    function mintBase(address to, string calldata uri)
        public
        virtual
        override
        nonReentrant
        adminRequired
        returns (uint256)
    {
        return _mintBase(to, uri);
    }

    /**
     * @dev See {IERC721CreatorCore-mintBaseBatch}.
     */
    function mintBaseBatch(address to, uint16 count)
        public
        virtual
        override
        nonReentrant
        adminRequired
        returns (uint256[] memory tokenIds)
    {
        tokenIds = new uint256[](count);
        for (uint16 i = 0; i < count; i++) {
            tokenIds[i] = _mintBase(to, "");
        }
        return tokenIds;
    }

    /**
     * @dev See {IERC721CreatorCore-mintBaseBatch}.
     */
    function mintBaseBatch(address to, string[] calldata uris)
        public
        virtual
        override
        nonReentrant
        adminRequired
        returns (uint256[] memory tokenIds)
    {
        tokenIds = new uint256[](uris.length);
        for (uint256 i = 0; i < uris.length; i++) {
            tokenIds[i] = _mintBase(to, uris[i]);
        }
        return tokenIds;
    }

    /**
     * @dev Mint token with no extension
     */
    function _mintBase(address to, string memory uri)
        internal
        virtual
        returns (uint256 tokenId)
    {
        _tokenCount++;
        tokenId = _tokenCount;

        // Track the extension that minted the token
        _tokensExtension[tokenId] = address(this);

        _safeMint(to, tokenId);

        if (bytes(uri).length > 0) {
            _tokenURIs[tokenId] = uri;
        }

        // Call post mint
        _postMintBase(to, tokenId);
        return tokenId;
    }

    /**
     * @dev See {IERC721CreatorCore-mintExtension}.
     */
    function mintExtension(address to)
        public
        virtual
        override
        nonReentrant
        extensionRequired
        returns (uint256)
    {
        return _mintExtension(to, "");
    }

    /**
     * @dev See {IERC721CreatorCore-mintExtension}.
     */
    function mintExtension(address to, string calldata uri)
        public
        virtual
        override
        nonReentrant
        extensionRequired
        returns (uint256)
    {
        return _mintExtension(to, uri);
    }

    /**
     * @dev See {IERC721CreatorCore-mintExtensionBatch}.
     */
    function mintExtensionBatch(address to, uint16 count)
        public
        virtual
        override
        nonReentrant
        extensionRequired
        returns (uint256[] memory tokenIds)
    {
        tokenIds = new uint256[](count);
        for (uint16 i = 0; i < count; i++) {
            tokenIds[i] = _mintExtension(to, "");
        }
        return tokenIds;
    }

    /**
     * @dev See {IERC721CreatorCore-mintExtensionBatch}.
     */
    function mintExtensionBatch(address to, string[] calldata uris)
        public
        virtual
        override
        nonReentrant
        extensionRequired
        returns (uint256[] memory tokenIds)
    {
        tokenIds = new uint256[](uris.length);
        for (uint256 i = 0; i < uris.length; i++) {
            tokenIds[i] = _mintExtension(to, uris[i]);
        }
    }

    /**
     * @dev Mint token via extension
     */
    function _mintExtension(address to, string memory uri)
        internal
        virtual
        returns (uint256 tokenId)
    {
        _tokenCount++;
        tokenId = _tokenCount;

        _checkMintPermissions(to, tokenId);

        // Track the extension that minted the token
        _tokensExtension[tokenId] = msg.sender;

        _safeMint(to, tokenId);

        if (bytes(uri).length > 0) {
            _tokenURIs[tokenId] = uri;
        }

        // Call post mint
        _postMintExtension(to, tokenId);
        return tokenId;
    }

    /**
     * @dev See {IERC721CreatorCore-tokenExtension}.
     */
    function tokenExtension(uint256 tokenId)
        public
        view
        virtual
        override
        returns (address)
    {
        require(_exists(tokenId), "Nonexistent token");
        return _tokenExtension(tokenId);
    }

    /**
     * @dev See {IERC721CreatorCore-burn}.
     */
    function burn(uint256 tokenId) public virtual override nonReentrant {
        require(
            _isApprovedOrOwner(msg.sender, tokenId),
            "Caller is not owner nor approved"
        );
        address owner = ownerOf(tokenId);
        _burn(tokenId);
        _postBurn(owner, tokenId);
    }

    /**
     * @dev See {ICreatorCore-setRoyalties}.
     */
    function setRoyalties(
        address payable[] calldata receivers,
        uint256[] calldata basisPoints
    ) external override adminRequired {
        _setRoyaltiesExtension(address(this), receivers, basisPoints);
    }

    /**
     * @dev See {ICreatorCore-setRoyalties}.
     */
    function setRoyalties(
        uint256 tokenId,
        address payable[] calldata receivers,
        uint256[] calldata basisPoints
    ) external override adminRequired {
        require(_exists(tokenId), "Nonexistent token");
        _setRoyalties(tokenId, receivers, basisPoints);
    }

    /**
     * @dev See {ICreatorCore-setRoyaltiesExtension}.
     */
    function setRoyaltiesExtension(
        address extension,
        address payable[] calldata receivers,
        uint256[] calldata basisPoints
    ) external override adminRequired {
        _setRoyaltiesExtension(extension, receivers, basisPoints);
    }

    /**
     * @dev {See ICreatorCore-getRoyalties}.
     */
    function getRoyalties(uint256 tokenId)
        external
        view
        virtual
        override
        returns (address payable[] memory, uint256[] memory)
    {
        require(_exists(tokenId), "Nonexistent token");
        return _getRoyalties(tokenId);
    }

    /**
     * @dev {See ICreatorCore-getFees}.
     */
    function getFees(uint256 tokenId)
        external
        view
        virtual
        override
        returns (address payable[] memory, uint256[] memory)
    {
        require(_exists(tokenId), "Nonexistent token");
        return _getRoyalties(tokenId);
    }

    /**
     * @dev {See ICreatorCore-getFeeRecipients}.
     */
    function getFeeRecipients(uint256 tokenId)
        external
        view
        virtual
        override
        returns (address payable[] memory)
    {
        require(_exists(tokenId), "Nonexistent token");
        return _getRoyaltyReceivers(tokenId);
    }

    /**
     * @dev {See ICreatorCore-getFeeBps}.
     */
    function getFeeBps(uint256 tokenId)
        external
        view
        virtual
        override
        returns (uint256[] memory)
    {
        require(_exists(tokenId), "Nonexistent token");
        return _getRoyaltyBPS(tokenId);
    }

    /**
     * @dev {See ICreatorCore-royaltyInfo}.
     */
    function royaltyInfo(uint256 tokenId, uint256 value)
        external
        view
        virtual
        override
        returns (address, uint256)
    {
        require(_exists(tokenId), "Nonexistent token");
        return _getRoyaltyInfo(tokenId, value);
    }

    /**
     * @dev See {IERC721Metadata-tokenURI}.
     */
    function tokenURI(uint256 tokenId)
        public
        view
        virtual
        override
        returns (string memory)
    {
        require(_exists(tokenId), "Nonexistent token");
        return _tokenURI(tokenId);
    }
}