// File: @openzeppelin/contracts/access/AccessControl.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.8.0) (access/AccessControl.sol)

pragma solidity ^0.8.0;

import "./IAccessControl.sol";
import "../utils/Context.sol";
import "../utils/Strings.sol";
import "../utils/introspection/ERC165.sol";

/**
 * @dev Contract module that allows children to implement role-based access
 * control mechanisms. This is a lightweight version that doesn't allow enumerating role
 * members except through off-chain means by accessing the contract event logs. Some
 * applications may benefit from on-chain enumerability, for those cases see
 * {AccessControlEnumerable}.
 *
 * Roles are referred to by their `bytes32` identifier. These should be exposed
 * in the external API and be unique. The best way to achieve this is by
 * using `public constant` hash digests:
 *
 * ```
 * bytes32 public constant MY_ROLE = keccak256("MY_ROLE");
 * ```
 *
 * Roles can be used to represent a set of permissions. To restrict access to a
 * function call, use {hasRole}:
 *
 * ```
 * function foo() public {
 *     require(hasRole(MY_ROLE, msg.sender));
 *     ...
 * }
 * ```
 *
 * Roles can be granted and revoked dynamically via the {grantRole} and
 * {revokeRole} functions. Each role has an associated admin role, and only
 * accounts that have a role's admin role can call {grantRole} and {revokeRole}.
 *
 * By default, the admin role for all roles is `DEFAULT_ADMIN_ROLE`, which means
 * that only accounts with this role will be able to grant or revoke other
 * roles. More complex role relationships can be created by using
 * {_setRoleAdmin}.
 *
 * WARNING: The `DEFAULT_ADMIN_ROLE` is also its own admin: it has permission to
 * grant and revoke this role. Extra precautions should be taken to secure
 * accounts that have been granted it.
 */
abstract contract AccessControl is Context, IAccessControl, ERC165 {
    struct RoleData {
        mapping(address => bool) members;
        bytes32 adminRole;
    }

    mapping(bytes32 => RoleData) private _roles;

    bytes32 public constant DEFAULT_ADMIN_ROLE = 0x00;

    /**
     * @dev Modifier that checks that an account has a specific role. Reverts
     * with a standardized message including the required role.
     *
     * The format of the revert reason is given by the following regular expression:
     *
     *  /^AccessControl: account (0x[0-9a-f]{40}) is missing role (0x[0-9a-f]{64})$/
     *
     * _Available since v4.1._
     */
    modifier onlyRole(bytes32 role) {
        _checkRole(role);
        _;
    }

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

    /**
     * @dev Returns `true` if `account` has been granted `role`.
     */
    function hasRole(bytes32 role, address account) public view virtual override returns (bool) {
        return _roles[role].members[account];
    }

    /**
     * @dev Revert with a standard message if `_msgSender()` is missing `role`.
     * Overriding this function changes the behavior of the {onlyRole} modifier.
     *
     * Format of the revert message is described in {_checkRole}.
     *
     * _Available since v4.6._
     */
    function _checkRole(bytes32 role) internal view virtual {
        _checkRole(role, _msgSender());
    }

    /**
     * @dev Revert with a standard message if `account` is missing `role`.
     *
     * The format of the revert reason is given by the following regular expression:
     *
     *  /^AccessControl: account (0x[0-9a-f]{40}) is missing role (0x[0-9a-f]{64})$/
     */
    function _checkRole(bytes32 role, address account) internal view virtual {
        if (!hasRole(role, account)) {
            revert(
                string(
                    abi.encodePacked(
                        "AccessControl: account ",
                        Strings.toHexString(account),
                        " is missing role ",
                        Strings.toHexString(uint256(role), 32)
                    )
                )
            );
        }
    }

    /**
     * @dev Returns the admin role that controls `role`. See {grantRole} and
     * {revokeRole}.
     *
     * To change a role's admin, use {_setRoleAdmin}.
     */
    function getRoleAdmin(bytes32 role) public view virtual override returns (bytes32) {
        return _roles[role].adminRole;
    }

    /**
     * @dev Grants `role` to `account`.
     *
     * If `account` had not been already granted `role`, emits a {RoleGranted}
     * event.
     *
     * Requirements:
     *
     * - the caller must have ``role``'s admin role.
     *
     * May emit a {RoleGranted} event.
     */
    function grantRole(bytes32 role, address account) public virtual override onlyRole(getRoleAdmin(role)) {
        _grantRole(role, account);
    }

    /**
     * @dev Revokes `role` from `account`.
     *
     * If `account` had been granted `role`, emits a {RoleRevoked} event.
     *
     * Requirements:
     *
     * - the caller must have ``role``'s admin role.
     *
     * May emit a {RoleRevoked} event.
     */
    function revokeRole(bytes32 role, address account) public virtual override onlyRole(getRoleAdmin(role)) {
        _revokeRole(role, account);
    }

    /**
     * @dev Revokes `role` from the calling account.
     *
     * Roles are often managed via {grantRole} and {revokeRole}: this function's
     * purpose is to provide a mechanism for accounts to lose their privileges
     * if they are compromised (such as when a trusted device is misplaced).
     *
     * If the calling account had been revoked `role`, emits a {RoleRevoked}
     * event.
     *
     * Requirements:
     *
     * - the caller must be `account`.
     *
     * May emit a {RoleRevoked} event.
     */
    function renounceRole(bytes32 role, address account) public virtual override {
        require(account == _msgSender(), "AccessControl: can only renounce roles for self");

        _revokeRole(role, account);
    }

    /**
     * @dev Grants `role` to `account`.
     *
     * If `account` had not been already granted `role`, emits a {RoleGranted}
     * event. Note that unlike {grantRole}, this function doesn't perform any
     * checks on the calling account.
     *
     * May emit a {RoleGranted} event.
     *
     * [WARNING]
     * ====
     * This function should only be called from the constructor when setting
     * up the initial roles for the system.
     *
     * Using this function in any other way is effectively circumventing the admin
     * system imposed by {AccessControl}.
     * ====
     *
     * NOTE: This function is deprecated in favor of {_grantRole}.
     */
    function _setupRole(bytes32 role, address account) internal virtual {
        _grantRole(role, account);
    }

    /**
     * @dev Sets `adminRole` as ``role``'s admin role.
     *
     * Emits a {RoleAdminChanged} event.
     */
    function _setRoleAdmin(bytes32 role, bytes32 adminRole) internal virtual {
        bytes32 previousAdminRole = getRoleAdmin(role);
        _roles[role].adminRole = adminRole;
        emit RoleAdminChanged(role, previousAdminRole, adminRole);
    }

    /**
     * @dev Grants `role` to `account`.
     *
     * Internal function without access restriction.
     *
     * May emit a {RoleGranted} event.
     */
    function _grantRole(bytes32 role, address account) internal virtual {
        if (!hasRole(role, account)) {
            _roles[role].members[account] = true;
            emit RoleGranted(role, account, _msgSender());
        }
    }

    /**
     * @dev Revokes `role` from `account`.
     *
     * Internal function without access restriction.
     *
     * May emit a {RoleRevoked} event.
     */
    function _revokeRole(bytes32 role, address account) internal virtual {
        if (hasRole(role, account)) {
            _roles[role].members[account] = false;
            emit RoleRevoked(role, account, _msgSender());
        }
    }
}

// File: @openzeppelin/contracts/access/IAccessControl.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (access/IAccessControl.sol)

pragma solidity ^0.8.0;

/**
 * @dev External interface of AccessControl declared to support ERC165 detection.
 */
interface IAccessControl {
    /**
     * @dev Emitted when `newAdminRole` is set as ``role``'s admin role, replacing `previousAdminRole`
     *
     * `DEFAULT_ADMIN_ROLE` is the starting admin for all roles, despite
     * {RoleAdminChanged} not being emitted signaling this.
     *
     * _Available since v3.1._
     */
    event RoleAdminChanged(bytes32 indexed role, bytes32 indexed previousAdminRole, bytes32 indexed newAdminRole);

    /**
     * @dev Emitted when `account` is granted `role`.
     *
     * `sender` is the account that originated the contract call, an admin role
     * bearer except when using {AccessControl-_setupRole}.
     */
    event RoleGranted(bytes32 indexed role, address indexed account, address indexed sender);

    /**
     * @dev Emitted when `account` is revoked `role`.
     *
     * `sender` is the account that originated the contract call:
     *   - if using `revokeRole`, it is the admin role bearer
     *   - if using `renounceRole`, it is the role bearer (i.e. `account`)
     */
    event RoleRevoked(bytes32 indexed role, address indexed account, address indexed sender);

    /**
     * @dev Returns `true` if `account` has been granted `role`.
     */
    function hasRole(bytes32 role, address account) external view returns (bool);

    /**
     * @dev Returns the admin role that controls `role`. See {grantRole} and
     * {revokeRole}.
     *
     * To change a role's admin, use {AccessControl-_setRoleAdmin}.
     */
    function getRoleAdmin(bytes32 role) external view returns (bytes32);

    /**
     * @dev Grants `role` to `account`.
     *
     * If `account` had not been already granted `role`, emits a {RoleGranted}
     * event.
     *
     * Requirements:
     *
     * - the caller must have ``role``'s admin role.
     */
    function grantRole(bytes32 role, address account) external;

    /**
     * @dev Revokes `role` from `account`.
     *
     * If `account` had been granted `role`, emits a {RoleRevoked} event.
     *
     * Requirements:
     *
     * - the caller must have ``role``'s admin role.
     */
    function revokeRole(bytes32 role, address account) external;

    /**
     * @dev Revokes `role` from the calling account.
     *
     * Roles are often managed via {grantRole} and {revokeRole}: this function's
     * purpose is to provide a mechanism for accounts to lose their privileges
     * if they are compromised (such as when a trusted device is misplaced).
     *
     * If the calling account had been granted `role`, emits a {RoleRevoked}
     * event.
     *
     * Requirements:
     *
     * - the caller must be `account`.
     */
    function renounceRole(bytes32 role, address account) external;
}

// File: @openzeppelin/contracts/interfaces/IERC20.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (interfaces/IERC20.sol)

pragma solidity ^0.8.0;

import "../token/ERC20/IERC20.sol";

// File: @openzeppelin/contracts/interfaces/IERC721.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (interfaces/IERC721.sol)

pragma solidity ^0.8.0;

import "../token/ERC721/IERC721.sol";

// File: @openzeppelin/contracts/security/ReentrancyGuard.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.8.0) (security/ReentrancyGuard.sol)

pragma solidity ^0.8.0;

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

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

    uint256 private _status;

    constructor() {
        _status = _NOT_ENTERED;
    }

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

    function _nonReentrantBefore() private {
        // On the first call to nonReentrant, _status will be _NOT_ENTERED
        require(_status != _ENTERED, "ReentrancyGuard: reentrant call");

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

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

// File: @openzeppelin/contracts/token/ERC20/extensions/draft-IERC20Permit.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC20/extensions/draft-IERC20Permit.sol)

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 Permit extension allowing approvals to be made via signatures, as defined in
 * https://eips.ethereum.org/EIPS/eip-2612[EIP-2612].
 *
 * Adds the {permit} method, which can be used to change an account's ERC20 allowance (see {IERC20-allowance}) by
 * presenting a message signed by the account. By not relying on {IERC20-approve}, the token holder account doesn't
 * need to send a transaction, and thus is not required to hold Ether at all.
 */
interface IERC20Permit {
    /**
     * @dev Sets `value` as the allowance of `spender` over ``owner``'s tokens,
     * given ``owner``'s signed approval.
     *
     * IMPORTANT: The same issues {IERC20-approve} has related to transaction
     * ordering also apply here.
     *
     * Emits an {Approval} event.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     * - `deadline` must be a timestamp in the future.
     * - `v`, `r` and `s` must be a valid `secp256k1` signature from `owner`
     * over the EIP712-formatted function arguments.
     * - the signature must use ``owner``'s current nonce (see {nonces}).
     *
     * For more information on the signature format, see the
     * https://eips.ethereum.org/EIPS/eip-2612#specification[relevant EIP
     * section].
     */
    function permit(
        address owner,
        address spender,
        uint256 value,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external;

    /**
     * @dev Returns the current nonce for `owner`. This value must be
     * included whenever a signature is generated for {permit}.
     *
     * Every successful call to {permit} increases ``owner``'s nonce by one. This
     * prevents a signature from being used multiple times.
     */
    function nonces(address owner) external view returns (uint256);

    /**
     * @dev Returns the domain separator used in the encoding of the signature for {permit}, as defined by {EIP712}.
     */
    // solhint-disable-next-line func-name-mixedcase
    function DOMAIN_SEPARATOR() external view returns (bytes32);
}

// File: @openzeppelin/contracts/token/ERC20/IERC20.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.6.0) (token/ERC20/IERC20.sol)

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);

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

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

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

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

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

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

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

// File: @openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.8.0) (token/ERC20/utils/SafeERC20.sol)

pragma solidity ^0.8.0;

import "../IERC20.sol";
import "../extensions/draft-IERC20Permit.sol";
import "../../../utils/Address.sol";

/**
 * @title SafeERC20
 * @dev Wrappers around ERC20 operations that throw on failure (when the token
 * contract returns false). Tokens that return no value (and instead revert or
 * throw on failure) are also supported, non-reverting calls are assumed to be
 * successful.
 * To use this library you can add a `using SafeERC20 for IERC20;` statement to your contract,
 * which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
 */
library SafeERC20 {
    using Address for address;

    function safeTransfer(
        IERC20 token,
        address to,
        uint256 value
    ) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
    }

    function safeTransferFrom(
        IERC20 token,
        address from,
        address to,
        uint256 value
    ) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
    }

    /**
     * @dev Deprecated. This function has issues similar to the ones found in
     * {IERC20-approve}, and its usage is discouraged.
     *
     * Whenever possible, use {safeIncreaseAllowance} and
     * {safeDecreaseAllowance} instead.
     */
    function safeApprove(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
        // safeApprove should only be called when setting an initial allowance,
        // or when resetting it to zero. To increase and decrease it, use
        // 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
        require(
            (value == 0) || (token.allowance(address(this), spender) == 0),
            "SafeERC20: approve from non-zero to non-zero allowance"
        );
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
    }

    function safeIncreaseAllowance(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
        uint256 newAllowance = token.allowance(address(this), spender) + value;
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
    }

    function safeDecreaseAllowance(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
        unchecked {
            uint256 oldAllowance = token.allowance(address(this), spender);
            require(oldAllowance >= value, "SafeERC20: decreased allowance below zero");
            uint256 newAllowance = oldAllowance - value;
            _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
        }
    }

    function safePermit(
        IERC20Permit token,
        address owner,
        address spender,
        uint256 value,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) internal {
        uint256 nonceBefore = token.nonces(owner);
        token.permit(owner, spender, value, deadline, v, r, s);
        uint256 nonceAfter = token.nonces(owner);
        require(nonceAfter == nonceBefore + 1, "SafeERC20: permit did not succeed");
    }

    /**
     * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
     * on the return value: the return value is optional (but if data is returned, it must not be false).
     * @param token The token targeted by the call.
     * @param data The call data (encoded using abi.encode or one of its variants).
     */
    function _callOptionalReturn(IERC20 token, bytes memory data) private {
        // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
        // we're implementing it ourselves. We use {Address-functionCall} to perform this call, which verifies that
        // the target address contains contract code and also asserts for success in the low-level call.

        bytes memory returndata = address(token).functionCall(data, "SafeERC20: low-level call failed");
        if (returndata.length > 0) {
            // Return data is optional
            require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
        }
    }
}

// File: @openzeppelin/contracts/token/ERC721/ERC721.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.8.2) (token/ERC721/ERC721.sol)

pragma solidity ^0.8.0;

import "./IERC721.sol";
import "./IERC721Receiver.sol";
import "./extensions/IERC721Metadata.sol";
import "../../utils/Address.sol";
import "../../utils/Context.sol";
import "../../utils/Strings.sol";
import "../../utils/introspection/ERC165.sol";

/**
 * @dev Implementation of https://eips.ethereum.org/EIPS/eip-721[ERC721] Non-Fungible Token Standard, including
 * the Metadata extension, but not including the Enumerable extension, which is available separately as
 * {ERC721Enumerable}.
 */
contract ERC721 is Context, ERC165, IERC721, IERC721Metadata {
    using Address for address;
    using Strings for uint256;

    // Token name
    string private _name;

    // Token symbol
    string private _symbol;

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

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

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

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

    /**
     * @dev Initializes the contract by setting a `name` and a `symbol` to the token collection.
     */
    constructor(string memory name_, string memory symbol_) {
        _name = name_;
        _symbol = symbol_;
    }

    /**
     * @dev See {IERC165-supportsInterface}.
     */
    function supportsInterface(bytes4 interfaceId) public view virtual override(ERC165, IERC165) returns (bool) {
        return
            interfaceId == type(IERC721).interfaceId ||
            interfaceId == type(IERC721Metadata).interfaceId ||
            super.supportsInterface(interfaceId);
    }

    /**
     * @dev See {IERC721-balanceOf}.
     */
    function balanceOf(address owner) public view virtual override returns (uint256) {
        require(owner != address(0), "ERC721: address zero is not a valid owner");
        return _balances[owner];
    }

    /**
     * @dev See {IERC721-ownerOf}.
     */
    function ownerOf(uint256 tokenId) public view virtual override returns (address) {
        address owner = _ownerOf(tokenId);
        require(owner != address(0), "ERC721: invalid token ID");
        return owner;
    }

    /**
     * @dev See {IERC721Metadata-name}.
     */
    function name() public view virtual override returns (string memory) {
        return _name;
    }

    /**
     * @dev See {IERC721Metadata-symbol}.
     */
    function symbol() public view virtual override returns (string memory) {
        return _symbol;
    }

    /**
     * @dev See {IERC721Metadata-tokenURI}.
     */
    function tokenURI(uint256 tokenId) public view virtual override returns (string memory) {
        _requireMinted(tokenId);

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

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

    /**
     * @dev See {IERC721-approve}.
     */
    function approve(address to, uint256 tokenId) public virtual override {
        address owner = ERC721.ownerOf(tokenId);
        require(to != owner, "ERC721: approval to current owner");

        require(
            _msgSender() == owner || isApprovedForAll(owner, _msgSender()),
            "ERC721: approve caller is not token owner or approved for all"
        );

        _approve(to, tokenId);
    }

    /**
     * @dev See {IERC721-getApproved}.
     */
    function getApproved(uint256 tokenId) public view virtual override returns (address) {
        _requireMinted(tokenId);

        return _tokenApprovals[tokenId];
    }

    /**
     * @dev See {IERC721-setApprovalForAll}.
     */
    function setApprovalForAll(address operator, bool approved) public virtual override {
        _setApprovalForAll(_msgSender(), operator, approved);
    }

    /**
     * @dev See {IERC721-isApprovedForAll}.
     */
    function isApprovedForAll(address owner, address operator) public view virtual override returns (bool) {
        return _operatorApprovals[owner][operator];
    }

    /**
     * @dev See {IERC721-transferFrom}.
     */
    function transferFrom(
        address from,
        address to,
        uint256 tokenId
    ) public virtual override {
        //solhint-disable-next-line max-line-length
        require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721: caller is not token owner or approved");

        _transfer(from, to, tokenId);
    }

    /**
     * @dev See {IERC721-safeTransferFrom}.
     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId
    ) public virtual override {
        safeTransferFrom(from, to, tokenId, "");
    }

    /**
     * @dev See {IERC721-safeTransferFrom}.
     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId,
        bytes memory data
    ) public virtual override {
        require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721: caller is not token owner or 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 the owner of the `tokenId`. Does NOT revert if token doesn't exist
     */
    function _ownerOf(uint256 tokenId) internal view virtual returns (address) {
        return _owners[tokenId];
    }

    /**
     * @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 _ownerOf(tokenId) != address(0);
    }

    /**
     * @dev Returns whether `spender` is allowed to manage `tokenId`.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     */
    function _isApprovedOrOwner(address spender, uint256 tokenId) internal view virtual returns (bool) {
        address owner = ERC721.ownerOf(tokenId);
        return (spender == owner || isApprovedForAll(owner, spender) || getApproved(tokenId) == spender);
    }

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

    /**
     * @dev Same as {xref-ERC721-_safeMint-address-uint256-}[`_safeMint`], with an additional `data` parameter which is
     * forwarded in {IERC721Receiver-onERC721Received} to contract recipients.
     */
    function _safeMint(
        address to,
        uint256 tokenId,
        bytes memory data
    ) internal virtual {
        _mint(to, tokenId);
        require(
            _checkOnERC721Received(address(0), to, tokenId, data),
            "ERC721: transfer to non ERC721Receiver implementer"
        );
    }

    /**
     * @dev Mints `tokenId` and transfers it to `to`.
     *
     * WARNING: Usage of this method is discouraged, use {_safeMint} whenever possible
     *
     * Requirements:
     *
     * - `tokenId` must not exist.
     * - `to` cannot be the zero address.
     *
     * Emits a {Transfer} event.
     */
    function _mint(address to, uint256 tokenId) internal virtual {
        require(to != address(0), "ERC721: mint to the zero address");
        require(!_exists(tokenId), "ERC721: token already minted");

        _beforeTokenTransfer(address(0), to, tokenId, 1);

        // Check that tokenId was not minted by `_beforeTokenTransfer` hook
        require(!_exists(tokenId), "ERC721: token already minted");

        unchecked {
            // Will not overflow unless all 2**256 token ids are minted to the same owner.
            // Given that tokens are minted one by one, it is impossible in practice that
            // this ever happens. Might change if we allow batch minting.
            // The ERC fails to describe this case.
            _balances[to] += 1;
        }

        _owners[tokenId] = to;

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

        _afterTokenTransfer(address(0), to, tokenId, 1);
    }

    /**
     * @dev Destroys `tokenId`.
     * The approval is cleared when the token is burned.
     * This is an internal function that does not check if the sender is authorized to operate on the token.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     *
     * Emits a {Transfer} event.
     */
    function _burn(uint256 tokenId) internal virtual {
        address owner = ERC721.ownerOf(tokenId);

        _beforeTokenTransfer(owner, address(0), tokenId, 1);

        // Update ownership in case tokenId was transferred by `_beforeTokenTransfer` hook
        owner = ERC721.ownerOf(tokenId);

        // Clear approvals
        delete _tokenApprovals[tokenId];

        unchecked {
            // Cannot overflow, as that would require more tokens to be burned/transferred
            // out than the owner initially received through minting and transferring in.
            _balances[owner] -= 1;
        }
        delete _owners[tokenId];

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

        _afterTokenTransfer(owner, address(0), tokenId, 1);
    }

    /**
     * @dev Transfers `tokenId` from `from` to `to`.
     *  As opposed to {transferFrom}, this imposes no restrictions on msg.sender.
     *
     * Requirements:
     *
     * - `to` cannot be the zero address.
     * - `tokenId` token must be owned by `from`.
     *
     * Emits a {Transfer} event.
     */
    function _transfer(
        address from,
        address to,
        uint256 tokenId
    ) internal virtual {
        require(ERC721.ownerOf(tokenId) == from, "ERC721: transfer from incorrect owner");
        require(to != address(0), "ERC721: transfer to the zero address");

        _beforeTokenTransfer(from, to, tokenId, 1);

        // Check that tokenId was not transferred by `_beforeTokenTransfer` hook
        require(ERC721.ownerOf(tokenId) == from, "ERC721: transfer from incorrect owner");

        // Clear approvals from the previous owner
        delete _tokenApprovals[tokenId];

        unchecked {
            // `_balances[from]` cannot overflow for the same reason as described in `_burn`:
            // `from`'s balance is the number of token held, which is at least one before the current
            // transfer.
            // `_balances[to]` could overflow in the conditions described in `_mint`. That would require
            // all 2**256 token ids to be minted, which in practice is impossible.
            _balances[from] -= 1;
            _balances[to] += 1;
        }
        _owners[tokenId] = to;

        emit Transfer(from, to, tokenId);

        _afterTokenTransfer(from, to, tokenId, 1);
    }

    /**
     * @dev Approve `to` to operate on `tokenId`
     *
     * Emits an {Approval} event.
     */
    function _approve(address to, uint256 tokenId) internal virtual {
        _tokenApprovals[tokenId] = to;
        emit Approval(ERC721.ownerOf(tokenId), to, tokenId);
    }

    /**
     * @dev Approve `operator` to operate on all of `owner` tokens
     *
     * Emits an {ApprovalForAll} event.
     */
    function _setApprovalForAll(
        address owner,
        address operator,
        bool approved
    ) internal virtual {
        require(owner != operator, "ERC721: approve to caller");
        _operatorApprovals[owner][operator] = approved;
        emit ApprovalForAll(owner, operator, approved);
    }

    /**
     * @dev Reverts if the `tokenId` has not been minted yet.
     */
    function _requireMinted(uint256 tokenId) internal view virtual {
        require(_exists(tokenId), "ERC721: invalid token ID");
    }

    /**
     * @dev Internal function to invoke {IERC721Receiver-onERC721Received} on a target address.
     * The call is not executed if the target address is not a contract.
     *
     * @param from address representing the previous owner of the given token ID
     * @param to target address that will receive the tokens
     * @param tokenId uint256 ID of the token to be transferred
     * @param data bytes optional data to send along with the call
     * @return bool whether the call correctly returned the expected magic value
     */
    function _checkOnERC721Received(
        address from,
        address to,
        uint256 tokenId,
        bytes memory data
    ) private returns (bool) {
        if (to.isContract()) {
            try IERC721Receiver(to).onERC721Received(_msgSender(), from, tokenId, data) returns (bytes4 retval) {
                return retval == IERC721Receiver.onERC721Received.selector;
            } catch (bytes memory reason) {
                if (reason.length == 0) {
                    revert("ERC721: transfer to non ERC721Receiver implementer");
                } else {
                    /// @solidity memory-safe-assembly
                    assembly {
                        revert(add(32, reason), mload(reason))
                    }
                }
            }
        } else {
            return true;
        }
    }

    /**
     * @dev Hook that is called before any token transfer. This includes minting and burning. If {ERC721Consecutive} is
     * used, the hook may be called as part of a consecutive (batch) mint, as indicated by `batchSize` greater than 1.
     *
     * Calling conditions:
     *
     * - When `from` and `to` are both non-zero, ``from``'s tokens will be transferred to `to`.
     * - When `from` is zero, the tokens will be minted for `to`.
     * - When `to` is zero, ``from``'s tokens will be burned.
     * - `from` and `to` are never both zero.
     * - `batchSize` is non-zero.
     *
     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     */
    function _beforeTokenTransfer(
        address from,
        address to,
        uint256 firstTokenId,
        uint256 batchSize
    ) internal virtual {}

    /**
     * @dev Hook that is called after any token transfer. This includes minting and burning. If {ERC721Consecutive} is
     * used, the hook may be called as part of a consecutive (batch) mint, as indicated by `batchSize` greater than 1.
     *
     * Calling conditions:
     *
     * - When `from` and `to` are both non-zero, ``from``'s tokens were transferred to `to`.
     * - When `from` is zero, the tokens were minted for `to`.
     * - When `to` is zero, ``from``'s tokens were burned.
     * - `from` and `to` are never both zero.
     * - `batchSize` is non-zero.
     *
     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     */
    function _afterTokenTransfer(
        address from,
        address to,
        uint256 firstTokenId,
        uint256 batchSize
    ) internal virtual {}

    /**
     * @dev Unsafe write access to the balances, used by extensions that "mint" tokens using an {ownerOf} override.
     *
     * WARNING: Anyone calling this MUST ensure that the balances remain consistent with the ownership. The invariant
     * being that for any address `a` the value returned by `balanceOf(a)` must be equal to the number of tokens such
     * that `ownerOf(tokenId)` is `a`.
     */
    // solhint-disable-next-line func-name-mixedcase
    function __unsafe_increaseBalance(address account, uint256 amount) internal {
        _balances[account] += amount;
    }
}

// File: @openzeppelin/contracts/token/ERC721/extensions/ERC721Burnable.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.8.0) (token/ERC721/extensions/ERC721Burnable.sol)

pragma solidity ^0.8.0;

import "../ERC721.sol";
import "../../../utils/Context.sol";

/**
 * @title ERC721 Burnable Token
 * @dev ERC721 Token that can be burned (destroyed).
 */
abstract contract ERC721Burnable is Context, ERC721 {
    /**
     * @dev Burns `tokenId`. See {ERC721-_burn}.
     *
     * Requirements:
     *
     * - The caller must own `tokenId` or be an approved operator.
     */
    function burn(uint256 tokenId) public virtual {
        //solhint-disable-next-line max-line-length
        require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721: caller is not token owner or approved");
        _burn(tokenId);
    }
}

// File: @openzeppelin/contracts/token/ERC721/extensions/ERC721Enumerable.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.8.0) (token/ERC721/extensions/ERC721Enumerable.sol)

pragma solidity ^0.8.0;

import "../ERC721.sol";
import "./IERC721Enumerable.sol";

/**
 * @dev This implements an optional extension of {ERC721} defined in the EIP that adds
 * enumerability of all the token ids in the contract as well as all token ids owned by each
 * account.
 */
abstract contract ERC721Enumerable is ERC721, IERC721Enumerable {
    // Mapping from owner to list of owned token IDs
    mapping(address => mapping(uint256 => uint256)) private _ownedTokens;

    // Mapping from token ID to index of the owner tokens list
    mapping(uint256 => uint256) private _ownedTokensIndex;

    // Array with all token ids, used for enumeration
    uint256[] private _allTokens;

    // Mapping from token id to position in the allTokens array
    mapping(uint256 => uint256) private _allTokensIndex;

    /**
     * @dev See {IERC165-supportsInterface}.
     */
    function supportsInterface(bytes4 interfaceId) public view virtual override(IERC165, ERC721) returns (bool) {
        return interfaceId == type(IERC721Enumerable).interfaceId || super.supportsInterface(interfaceId);
    }

    /**
     * @dev See {IERC721Enumerable-tokenOfOwnerByIndex}.
     */
    function tokenOfOwnerByIndex(address owner, uint256 index) public view virtual override returns (uint256) {
        require(index < ERC721.balanceOf(owner), "ERC721Enumerable: owner index out of bounds");
        return _ownedTokens[owner][index];
    }

    /**
     * @dev See {IERC721Enumerable-totalSupply}.
     */
    function totalSupply() public view virtual override returns (uint256) {
        return _allTokens.length;
    }

    /**
     * @dev See {IERC721Enumerable-tokenByIndex}.
     */
    function tokenByIndex(uint256 index) public view virtual override returns (uint256) {
        require(index < ERC721Enumerable.totalSupply(), "ERC721Enumerable: global index out of bounds");
        return _allTokens[index];
    }

    /**
     * @dev See {ERC721-_beforeTokenTransfer}.
     */
    function _beforeTokenTransfer(
        address from,
        address to,
        uint256 firstTokenId,
        uint256 batchSize
    ) internal virtual override {
        super._beforeTokenTransfer(from, to, firstTokenId, batchSize);

        if (batchSize > 1) {
            // Will only trigger during construction. Batch transferring (minting) is not available afterwards.
            revert("ERC721Enumerable: consecutive transfers not supported");
        }

        uint256 tokenId = firstTokenId;

        if (from == address(0)) {
            _addTokenToAllTokensEnumeration(tokenId);
        } else if (from != to) {
            _removeTokenFromOwnerEnumeration(from, tokenId);
        }
        if (to == address(0)) {
            _removeTokenFromAllTokensEnumeration(tokenId);
        } else if (to != from) {
            _addTokenToOwnerEnumeration(to, tokenId);
        }
    }

    /**
     * @dev Private function to add a token to this extension's ownership-tracking data structures.
     * @param to address representing the new owner of the given token ID
     * @param tokenId uint256 ID of the token to be added to the tokens list of the given address
     */
    function _addTokenToOwnerEnumeration(address to, uint256 tokenId) private {
        uint256 length = ERC721.balanceOf(to);
        _ownedTokens[to][length] = tokenId;
        _ownedTokensIndex[tokenId] = length;
    }

    /**
     * @dev Private function to add a token to this extension's token tracking data structures.
     * @param tokenId uint256 ID of the token to be added to the tokens list
     */
    function _addTokenToAllTokensEnumeration(uint256 tokenId) private {
        _allTokensIndex[tokenId] = _allTokens.length;
        _allTokens.push(tokenId);
    }

    /**
     * @dev Private function to remove a token from this extension's ownership-tracking data structures. Note that
     * while the token is not assigned a new owner, the `_ownedTokensIndex` mapping is _not_ updated: this allows for
     * gas optimizations e.g. when performing a transfer operation (avoiding double writes).
     * This has O(1) time complexity, but alters the order of the _ownedTokens array.
     * @param from address representing the previous owner of the given token ID
     * @param tokenId uint256 ID of the token to be removed from the tokens list of the given address
     */
    function _removeTokenFromOwnerEnumeration(address from, uint256 tokenId) private {
        // To prevent a gap in from's tokens array, we store the last token in the index of the token to delete, and
        // then delete the last slot (swap and pop).

        uint256 lastTokenIndex = ERC721.balanceOf(from) - 1;
        uint256 tokenIndex = _ownedTokensIndex[tokenId];

        // When the token to delete is the last token, the swap operation is unnecessary
        if (tokenIndex != lastTokenIndex) {
            uint256 lastTokenId = _ownedTokens[from][lastTokenIndex];

            _ownedTokens[from][tokenIndex] = lastTokenId; // Move the last token to the slot of the to-delete token
            _ownedTokensIndex[lastTokenId] = tokenIndex; // Update the moved token's index
        }

        // This also deletes the contents at the last position of the array
        delete _ownedTokensIndex[tokenId];
        delete _ownedTokens[from][lastTokenIndex];
    }

    /**
     * @dev Private function to remove a token from this extension's token tracking data structures.
     * This has O(1) time complexity, but alters the order of the _allTokens array.
     * @param tokenId uint256 ID of the token to be removed from the tokens list
     */
    function _removeTokenFromAllTokensEnumeration(uint256 tokenId) private {
        // To prevent a gap in the tokens array, we store the last token in the index of the token to delete, and
        // then delete the last slot (swap and pop).

        uint256 lastTokenIndex = _allTokens.length - 1;
        uint256 tokenIndex = _allTokensIndex[tokenId];

        // When the token to delete is the last token, the swap operation is unnecessary. However, since this occurs so
        // rarely (when the last minted token is burnt) that we still do the swap here to avoid the gas cost of adding
        // an 'if' statement (like in _removeTokenFromOwnerEnumeration)
        uint256 lastTokenId = _allTokens[lastTokenIndex];

        _allTokens[tokenIndex] = lastTokenId; // Move the last token to the slot of the to-delete token
        _allTokensIndex[lastTokenId] = tokenIndex; // Update the moved token's index

        // This also deletes the contents at the last position of the array
        delete _allTokensIndex[tokenId];
        _allTokens.pop();
    }
}

// File: @openzeppelin/contracts/token/ERC721/extensions/IERC721Enumerable.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.5.0) (token/ERC721/extensions/IERC721Enumerable.sol)

pragma solidity ^0.8.0;

import "../IERC721.sol";

/**
 * @title ERC-721 Non-Fungible Token Standard, optional enumeration extension
 * @dev See https://eips.ethereum.org/EIPS/eip-721
 */
interface IERC721Enumerable is IERC721 {
    /**
     * @dev Returns the total amount of tokens stored by the contract.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns a token ID owned by `owner` at a given `index` of its token list.
     * Use along with {balanceOf} to enumerate all of ``owner``'s tokens.
     */
    function tokenOfOwnerByIndex(address owner, uint256 index) external view returns (uint256);

    /**
     * @dev Returns a token ID at a given `index` of all the tokens stored by the contract.
     * Use along with {totalSupply} to enumerate all tokens.
     */
    function tokenByIndex(uint256 index) external view returns (uint256);
}

// File: @openzeppelin/contracts/token/ERC721/extensions/IERC721Metadata.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC721/extensions/IERC721Metadata.sol)

pragma solidity ^0.8.0;

import "../IERC721.sol";

/**
 * @title ERC-721 Non-Fungible Token Standard, optional metadata extension
 * @dev See https://eips.ethereum.org/EIPS/eip-721
 */
interface IERC721Metadata is IERC721 {
    /**
     * @dev Returns the token collection name.
     */
    function name() external view returns (string memory);

    /**
     * @dev Returns the token collection symbol.
     */
    function symbol() external view returns (string memory);

    /**
     * @dev Returns the Uniform Resource Identifier (URI) for `tokenId` token.
     */
    function tokenURI(uint256 tokenId) external view returns (string memory);
}

// File: @openzeppelin/contracts/token/ERC721/IERC721.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.8.0) (token/ERC721/IERC721.sol)

pragma solidity ^0.8.0;

import "../../utils/introspection/IERC165.sol";

/**
 * @dev Required interface of an ERC721 compliant contract.
 */
interface IERC721 is IERC165 {
    /**
     * @dev Emitted when `tokenId` token is transferred from `from` to `to`.
     */
    event Transfer(address indexed from, address indexed to, uint256 indexed tokenId);

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

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

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

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

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

    /**
     * @dev Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients
     * are aware of the ERC721 protocol to prevent tokens from being forever locked.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must exist and be owned by `from`.
     * - If the caller is not `from`, it must have been allowed to move this token by either {approve} or {setApprovalForAll}.
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
     *
     * Emits a {Transfer} event.
     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId
    ) external;

    /**
     * @dev Transfers `tokenId` token from `from` to `to`.
     *
     * WARNING: Note that the caller is responsible to confirm that the recipient is capable of receiving ERC721
     * or else they may be permanently lost. Usage of {safeTransferFrom} prevents loss, though the caller must
     * understand this adds an external call which potentially creates a reentrancy vulnerability.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must be owned by `from`.
     * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(
        address from,
        address to,
        uint256 tokenId
    ) external;

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

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

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

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

// File: @openzeppelin/contracts/token/ERC721/IERC721Receiver.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.6.0) (token/ERC721/IERC721Receiver.sol)

pragma solidity ^0.8.0;

/**
 * @title ERC721 token receiver interface
 * @dev Interface for any contract that wants to support safeTransfers
 * from ERC721 asset contracts.
 */
interface IERC721Receiver {
    /**
     * @dev Whenever an {IERC721} `tokenId` token is transferred to this contract via {IERC721-safeTransferFrom}
     * by `operator` from `from`, this function is called.
     *
     * It must return its Solidity selector to confirm the token transfer.
     * If any other value is returned or the interface is not implemented by the recipient, the transfer will be reverted.
     *
     * The selector can be obtained in Solidity with `IERC721Receiver.onERC721Received.selector`.
     */
    function onERC721Received(
        address operator,
        address from,
        uint256 tokenId,
        bytes calldata data
    ) external returns (bytes4);
}

// File: @openzeppelin/contracts/utils/Address.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.8.0) (utils/Address.sol)

pragma solidity ^0.8.1;

/**
 * @dev Collection of functions related to the address type
 */
library Address {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * [IMPORTANT]
     * ====
     * It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     *
     * Among others, `isContract` will return false for the following
     * types of addresses:
     *
     *  - an externally-owned account
     *  - a contract in construction
     *  - an address where a contract will be created
     *  - an address where a contract lived, but was destroyed
     * ====
     *
     * [IMPORTANT]
     * ====
     * You shouldn't rely on `isContract` to protect against flash loan attacks!
     *
     * Preventing calls from contracts is highly discouraged. It breaks composability, breaks support for smart wallets
     * like Gnosis Safe, and does not provide security since it can be circumvented by calling from a contract
     * constructor.
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize/address.code.length, which returns 0
        // for contracts in construction, since the code is only stored at the end
        // of the constructor execution.

        return account.code.length > 0;
    }

    /**
     * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
     * `recipient`, forwarding all available gas and reverting on errors.
     *
     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
     * of certain opcodes, possibly making contracts go over the 2300 gas limit
     * imposed by `transfer`, making them unable to receive funds via
     * `transfer`. {sendValue} removes this limitation.
     *
     * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
     *
     * IMPORTANT: because control is transferred to `recipient`, care must be
     * taken to not create reentrancy vulnerabilities. Consider using
     * {ReentrancyGuard} or the
     * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");

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

    /**
     * @dev Performs a Solidity function call using a low level `call`. A
     * plain `call` is an unsafe replacement for a function call: use this
     * function instead.
     *
     * If `target` reverts with a revert reason, it is bubbled up by this
     * function (like regular Solidity function calls).
     *
     * Returns the raw returned data. To convert to the expected return value,
     * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
     *
     * Requirements:
     *
     * - `target` must be a contract.
     * - calling `target` with `data` must not revert.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, "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");
        (bool success, bytes memory returndata) = target.call{value: value}(data);
        return verifyCallResultFromTarget(target, 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) {
        (bool success, bytes memory returndata) = target.staticcall(data);
        return verifyCallResultFromTarget(target, 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) {
        (bool success, bytes memory returndata) = target.delegatecall(data);
        return verifyCallResultFromTarget(target, success, returndata, errorMessage);
    }

    /**
     * @dev Tool to verify that a low level call to smart-contract was successful, and revert (either by bubbling
     * the revert reason or using the provided one) in case of unsuccessful call or if target was not a contract.
     *
     * _Available since v4.8._
     */
    function verifyCallResultFromTarget(
        address target,
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal view returns (bytes memory) {
        if (success) {
            if (returndata.length == 0) {
                // only check isContract if the call was successful and the return data is empty
                // otherwise we already know that it was a contract
                require(isContract(target), "Address: call to non-contract");
            }
            return returndata;
        } else {
            _revert(returndata, errorMessage);
        }
    }

    /**
     * @dev Tool to verify that a low level call was successful, and revert if it wasn't, either by bubbling the
     * revert reason or 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 {
            _revert(returndata, errorMessage);
        }
    }

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

// File: @openzeppelin/contracts/utils/Context.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)

pragma solidity ^0.8.0;

/**
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
abstract contract Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }
}

// File: @openzeppelin/contracts/utils/introspection/ERC165.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/introspection/ERC165.sol)

pragma solidity ^0.8.0;

import "./IERC165.sol";

/**
 * @dev Implementation of the {IERC165} interface.
 *
 * Contracts that want to implement ERC165 should inherit from this contract and override {supportsInterface} to check
 * for the additional interface id that will be supported. For example:
 *
 * ```solidity
 * function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
 *     return interfaceId == type(MyInterface).interfaceId || super.supportsInterface(interfaceId);
 * }
 * ```
 *
 * Alternatively, {ERC165Storage} provides an easier to use but more expensive implementation.
 */
abstract contract ERC165 is IERC165 {
    /**
     * @dev See {IERC165-supportsInterface}.
     */
    function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
        return interfaceId == type(IERC165).interfaceId;
    }
}

// File: @openzeppelin/contracts/utils/introspection/IERC165.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/introspection/IERC165.sol)

pragma solidity ^0.8.0;

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

// File: @openzeppelin/contracts/utils/math/Math.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.8.0) (utils/math/Math.sol)

pragma solidity ^0.8.0;

/**
 * @dev Standard math utilities missing in the Solidity language.
 */
library Math {
    enum Rounding {
        Down, // Toward negative infinity
        Up, // Toward infinity
        Zero // Toward zero
    }

    /**
     * @dev Returns the largest of two numbers.
     */
    function max(uint256 a, uint256 b) internal pure returns (uint256) {
        return a > b ? a : b;
    }

    /**
     * @dev Returns the smallest of two numbers.
     */
    function min(uint256 a, uint256 b) internal pure returns (uint256) {
        return a < b ? a : b;
    }

    /**
     * @dev Returns the average of two numbers. The result is rounded towards
     * zero.
     */
    function average(uint256 a, uint256 b) internal pure returns (uint256) {
        // (a + b) / 2 can overflow.
        return (a & b) + (a ^ b) / 2;
    }

    /**
     * @dev Returns the ceiling of the division of two numbers.
     *
     * This differs from standard division with `/` in that it rounds up instead
     * of rounding down.
     */
    function ceilDiv(uint256 a, uint256 b) internal pure returns (uint256) {
        // (a + b - 1) / b can overflow on addition, so we distribute.
        return a == 0 ? 0 : (a - 1) / b + 1;
    }

    /**
     * @notice Calculates floor(x * y / denominator) with full precision. Throws if result overflows a uint256 or denominator == 0
     * @dev Original credit to Remco Bloemen under MIT license (https://xn--2-umb.com/21/muldiv)
     * with further edits by Uniswap Labs also under MIT license.
     */
    function mulDiv(
        uint256 x,
        uint256 y,
        uint256 denominator
    ) internal pure returns (uint256 result) {
        unchecked {
            // 512-bit multiply [prod1 prod0] = x * y. Compute the product mod 2^256 and mod 2^256 - 1, then use
            // use the Chinese Remainder Theorem to reconstruct the 512 bit result. The result is stored in two 256
            // variables such that product = prod1 * 2^256 + prod0.
            uint256 prod0; // Least significant 256 bits of the product
            uint256 prod1; // Most significant 256 bits of the product
            assembly {
                let mm := mulmod(x, y, not(0))
                prod0 := mul(x, y)
                prod1 := sub(sub(mm, prod0), lt(mm, prod0))
            }

            // Handle non-overflow cases, 256 by 256 division.
            if (prod1 == 0) {
                return prod0 / denominator;
            }

            // Make sure the result is less than 2^256. Also prevents denominator == 0.
            require(denominator > prod1);

            ///////////////////////////////////////////////
            // 512 by 256 division.
            ///////////////////////////////////////////////

            // Make division exact by subtracting the remainder from [prod1 prod0].
            uint256 remainder;
            assembly {
                // Compute remainder using mulmod.
                remainder := mulmod(x, y, denominator)

                // Subtract 256 bit number from 512 bit number.
                prod1 := sub(prod1, gt(remainder, prod0))
                prod0 := sub(prod0, remainder)
            }

            // Factor powers of two out of denominator and compute largest power of two divisor of denominator. Always >= 1.
            // See https://cs.stackexchange.com/q/138556/92363.

            // Does not overflow because the denominator cannot be zero at this stage in the function.
            uint256 twos = denominator & (~denominator + 1);
            assembly {
                // Divide denominator by twos.
                denominator := div(denominator, twos)

                // Divide [prod1 prod0] by twos.
                prod0 := div(prod0, twos)

                // Flip twos such that it is 2^256 / twos. If twos is zero, then it becomes one.
                twos := add(div(sub(0, twos), twos), 1)
            }

            // Shift in bits from prod1 into prod0.
            prod0 |= prod1 * twos;

            // Invert denominator mod 2^256. Now that denominator is an odd number, it has an inverse modulo 2^256 such
            // that denominator * inv = 1 mod 2^256. Compute the inverse by starting with a seed that is correct for
            // four bits. That is, denominator * inv = 1 mod 2^4.
            uint256 inverse = (3 * denominator) ^ 2;

            // Use the Newton-Raphson iteration to improve the precision. Thanks to Hensel's lifting lemma, this also works
            // in modular arithmetic, doubling the correct bits in each step.
            inverse *= 2 - denominator * inverse; // inverse mod 2^8
            inverse *= 2 - denominator * inverse; // inverse mod 2^16
            inverse *= 2 - denominator * inverse; // inverse mod 2^32
            inverse *= 2 - denominator * inverse; // inverse mod 2^64
            inverse *= 2 - denominator * inverse; // inverse mod 2^128
            inverse *= 2 - denominator * inverse; // inverse mod 2^256

            // Because the division is now exact we can divide by multiplying with the modular inverse of denominator.
            // This will give us the correct result modulo 2^256. Since the preconditions guarantee that the outcome is
            // less than 2^256, this is the final result. We don't need to compute the high bits of the result and prod1
            // is no longer required.
            result = prod0 * inverse;
            return result;
        }
    }

    /**
     * @notice Calculates x * y / denominator with full precision, following the selected rounding direction.
     */
    function mulDiv(
        uint256 x,
        uint256 y,
        uint256 denominator,
        Rounding rounding
    ) internal pure returns (uint256) {
        uint256 result = mulDiv(x, y, denominator);
        if (rounding == Rounding.Up && mulmod(x, y, denominator) > 0) {
            result += 1;
        }
        return result;
    }

    /**
     * @dev Returns the square root of a number. If the number is not a perfect square, the value is rounded down.
     *
     * Inspired by Henry S. Warren, Jr.'s "Hacker's Delight" (Chapter 11).
     */
    function sqrt(uint256 a) internal pure returns (uint256) {
        if (a == 0) {
            return 0;
        }

        // For our first guess, we get the biggest power of 2 which is smaller than the square root of the target.
        //
        // We know that the "msb" (most significant bit) of our target number `a` is a power of 2 such that we have
        // `msb(a) <= a < 2*msb(a)`. This value can be written `msb(a)=2**k` with `k=log2(a)`.
        //
        // This can be rewritten `2**log2(a) <= a < 2**(log2(a) + 1)`
        // → `sqrt(2**k) <= sqrt(a) < sqrt(2**(k+1))`
        // → `2**(k/2) <= sqrt(a) < 2**((k+1)/2) <= 2**(k/2 + 1)`
        //
        // Consequently, `2**(log2(a) / 2)` is a good first approximation of `sqrt(a)` with at least 1 correct bit.
        uint256 result = 1 << (log2(a) >> 1);

        // At this point `result` is an estimation with one bit of precision. We know the true value is a uint128,
        // since it is the square root of a uint256. Newton's method converges quadratically (precision doubles at
        // every iteration). We thus need at most 7 iteration to turn our partial result with one bit of precision
        // into the expected uint128 result.
        unchecked {
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            return min(result, a / result);
        }
    }

    /**
     * @notice Calculates sqrt(a), following the selected rounding direction.
     */
    function sqrt(uint256 a, Rounding rounding) internal pure returns (uint256) {
        unchecked {
            uint256 result = sqrt(a);
            return result + (rounding == Rounding.Up && result * result < a ? 1 : 0);
        }
    }

    /**
     * @dev Return the log in base 2, rounded down, of a positive value.
     * Returns 0 if given 0.
     */
    function log2(uint256 value) internal pure returns (uint256) {
        uint256 result = 0;
        unchecked {
            if (value >> 128 > 0) {
                value >>= 128;
                result += 128;
            }
            if (value >> 64 > 0) {
                value >>= 64;
                result += 64;
            }
            if (value >> 32 > 0) {
                value >>= 32;
                result += 32;
            }
            if (value >> 16 > 0) {
                value >>= 16;
                result += 16;
            }
            if (value >> 8 > 0) {
                value >>= 8;
                result += 8;
            }
            if (value >> 4 > 0) {
                value >>= 4;
                result += 4;
            }
            if (value >> 2 > 0) {
                value >>= 2;
                result += 2;
            }
            if (value >> 1 > 0) {
                result += 1;
            }
        }
        return result;
    }

    /**
     * @dev Return the log in base 2, following the selected rounding direction, of a positive value.
     * Returns 0 if given 0.
     */
    function log2(uint256 value, Rounding rounding) internal pure returns (uint256) {
        unchecked {
            uint256 result = log2(value);
            return result + (rounding == Rounding.Up && 1 << result < value ? 1 : 0);
        }
    }

    /**
     * @dev Return the log in base 10, rounded down, of a positive value.
     * Returns 0 if given 0.
     */
    function log10(uint256 value) internal pure returns (uint256) {
        uint256 result = 0;
        unchecked {
            if (value >= 10**64) {
                value /= 10**64;
                result += 64;
            }
            if (value >= 10**32) {
                value /= 10**32;
                result += 32;
            }
            if (value >= 10**16) {
                value /= 10**16;
                result += 16;
            }
            if (value >= 10**8) {
                value /= 10**8;
                result += 8;
            }
            if (value >= 10**4) {
                value /= 10**4;
                result += 4;
            }
            if (value >= 10**2) {
                value /= 10**2;
                result += 2;
            }
            if (value >= 10**1) {
                result += 1;
            }
        }
        return result;
    }

    /**
     * @dev Return the log in base 10, following the selected rounding direction, of a positive value.
     * Returns 0 if given 0.
     */
    function log10(uint256 value, Rounding rounding) internal pure returns (uint256) {
        unchecked {
            uint256 result = log10(value);
            return result + (rounding == Rounding.Up && 10**result < value ? 1 : 0);
        }
    }

    /**
     * @dev Return the log in base 256, rounded down, of a positive value.
     * Returns 0 if given 0.
     *
     * Adding one to the result gives the number of pairs of hex symbols needed to represent `value` as a hex string.
     */
    function log256(uint256 value) internal pure returns (uint256) {
        uint256 result = 0;
        unchecked {
            if (value >> 128 > 0) {
                value >>= 128;
                result += 16;
            }
            if (value >> 64 > 0) {
                value >>= 64;
                result += 8;
            }
            if (value >> 32 > 0) {
                value >>= 32;
                result += 4;
            }
            if (value >> 16 > 0) {
                value >>= 16;
                result += 2;
            }
            if (value >> 8 > 0) {
                result += 1;
            }
        }
        return result;
    }

    /**
     * @dev Return the log in base 10, following the selected rounding direction, of a positive value.
     * Returns 0 if given 0.
     */
    function log256(uint256 value, Rounding rounding) internal pure returns (uint256) {
        unchecked {
            uint256 result = log256(value);
            return result + (rounding == Rounding.Up && 1 << (result * 8) < value ? 1 : 0);
        }
    }
}

// File: @openzeppelin/contracts/utils/Strings.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.8.0) (utils/Strings.sol)

pragma solidity ^0.8.0;

import "./math/Math.sol";

/**
 * @dev String operations.
 */
library Strings {
    bytes16 private constant _SYMBOLS = "0123456789abcdef";
    uint8 private constant _ADDRESS_LENGTH = 20;

    /**
     * @dev Converts a `uint256` to its ASCII `string` decimal representation.
     */
    function toString(uint256 value) internal pure returns (string memory) {
        unchecked {
            uint256 length = Math.log10(value) + 1;
            string memory buffer = new string(length);
            uint256 ptr;
            /// @solidity memory-safe-assembly
            assembly {
                ptr := add(buffer, add(32, length))
            }
            while (true) {
                ptr--;
                /// @solidity memory-safe-assembly
                assembly {
                    mstore8(ptr, byte(mod(value, 10), _SYMBOLS))
                }
                value /= 10;
                if (value == 0) break;
            }
            return buffer;
        }
    }

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

    /**
     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation with fixed length.
     */
    function toHexString(uint256 value, uint256 length) internal pure returns (string memory) {
        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] = _SYMBOLS[value & 0xf];
            value >>= 4;
        }
        require(value == 0, "Strings: hex length insufficient");
        return string(buffer);
    }

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

// File: contracts/DBXENFT.sol



pragma solidity ^0.8.0;

import "@openzeppelin/contracts/token/ERC721/extensions/ERC721Enumerable.sol";
import "@openzeppelin/contracts/token/ERC721/extensions/ERC721Burnable.sol";
import "@openzeppelin/contracts/access/AccessControl.sol";
import "@openzeppelin/contracts/security/ReentrancyGuard.sol";
import "operator-filter-registry/src/DefaultOperatorFilterer.sol";

contract DBXENFT is
    ERC721Enumerable,
    ERC721Burnable,
    AccessControl,
    ReentrancyGuard,
    DefaultOperatorFilterer
{
    using Strings for uint256;
    address public immutable factory;

    address public ADMIN_ADDRESS = 0x5A5D0AD85762979cAAe341274f0eba22dF8EcEdD;
    
    /**
     * @dev Prefix for tokens metadata URIs
     */
    string public baseURI;

    // Sufix for tokens metadata URIs
    string public baseExtension = ".json";

    constructor() ERC721("DBXEN NFT on Ethereum", "DBXENFT") {
        factory = msg.sender;
    }

    function mintDBXENFT(
        address _to
    ) external nonReentrant returns (uint256 tokenId) {
        require(msg.sender == factory, "DBXENFT: Only factory can mint");
         tokenId = totalSupply() +1;
        _safeMint(_to, tokenId);
        return tokenId;
    }

    /**
     * @dev Returns the current base URI.
     * @return The base URI of the contract.
     */
    function _baseURI() internal view virtual override returns (string memory) {
        return baseURI;
    }

    /**
     * @dev This function sets the base URI of the NFT contract.
     * @param uri The new base URI of the NFT contract.
     * @notice Only the contract owner can call this function.
     */
    function setBasedURI(string memory uri) external {
        require(msg.sender == ADMIN_ADDRESS,"DBXENFT: Only admin can set baseURI!");
        baseURI = uri;
    }

    /**
     * @dev Returns the token URI for the given token ID. Throws if the token ID does not exist
     * @param tokenId The token ID to retrieve the URI for
     * @notice Retrieve the URI for the given token ID
     * @return The token URI for the given token ID
     */
    function tokenURI(
        uint256 tokenId
    ) public view virtual override returns (string memory) {
        require(
            _exists(tokenId),
            "ERC721Metadata: URI query for nonexistent token"
        );

        string memory currentBaseURI = _baseURI();
        return
            bytes(currentBaseURI).length > 0
                ? string(
                    abi.encodePacked(
                        currentBaseURI,
                        tokenId.toString(),
                        baseExtension
                    )
                )
                : "";
    }

    /**
     * Changes the base extension for token metadata
     *
     * Access: only the admin account
     *
     * @param _newBaseExtension new value
     */
    function setBaseExtension(
        string memory _newBaseExtension
    ) public {
       require(msg.sender == ADMIN_ADDRESS, "DBXENFT: Only admin can set baseExtension!");
        baseExtension = _newBaseExtension;
    }

     /**
     * Changes admin address
     *
     * Access: only the addmin account
     *
     * @param _newAdminAddress new value
     */
    function setAdminAddress(
        address  _newAdminAddress
    ) public {
       require(msg.sender == ADMIN_ADDRESS, "DBXENFT: Only addmin can set new address!");
        ADMIN_ADDRESS = _newAdminAddress;
    }


    /**
     * Returns the complete metadata URI for the given tokenId.
     */
    function walletOfOwner(
        address _owner
    ) public view returns (uint256[] memory) {
        uint256 ownerTokenCount = balanceOf(_owner);
        uint256[] memory tokenIds = new uint256[](ownerTokenCount);
        for (uint256 i; i < ownerTokenCount; i++) {
            tokenIds[i] = tokenOfOwnerByIndex(_owner, i);
        }
        return tokenIds;
    }

    function _burn(uint256 tokenId) internal virtual override(ERC721) {
        super._burn(tokenId);
    }

    function _beforeTokenTransfer(
        address from,
        address to,
        uint256 firstTokenId,
        uint256 batchSize
    ) internal virtual override(ERC721, ERC721Enumerable) {
        super._beforeTokenTransfer(from, to, firstTokenId, batchSize);
    }

    function supportsInterface(
        bytes4 interfaceId
    ) public view virtual override(ERC721, ERC721Enumerable, AccessControl) returns (bool) {
        return super.supportsInterface(interfaceId);
    }

    // OVERRIDING ERC-721 IMPLEMENTATION TO ALLOW OPENSEA ROYALTIES ENFORCEMENT PROTOCOL

    function setApprovalForAll(
        address operator,
        bool approved
    ) public override(ERC721, IERC721) onlyAllowedOperatorApproval(operator) {
        super.setApprovalForAll(operator, approved);
    }

    function approve(
        address operator,
        uint256 tokenId
    ) public override(ERC721, IERC721) onlyAllowedOperatorApproval(operator) {
        super.approve(operator, tokenId);
    }

    function transferFrom(
        address from,
        address to,
        uint256 tokenId
    ) public override(ERC721, IERC721) onlyAllowedOperator(from) {
        super.transferFrom(from, to, tokenId);
    }

    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId
    ) public override(ERC721, IERC721) onlyAllowedOperator(from) {
        super.safeTransferFrom(from, to, tokenId);
    }

    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId,
        bytes memory data
    ) public override(ERC721, IERC721) onlyAllowedOperator(from) {
        super.safeTransferFrom(from, to, tokenId, data);
    }
}

// File: contracts/DBXeNFTFactory.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

import "@openzeppelin/contracts/security/ReentrancyGuard.sol";
import "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
import "@openzeppelin/contracts/interfaces/IERC20.sol";
import "@openzeppelin/contracts/utils/math/Math.sol";
import "./interfaces/IXENCrypto.sol";
import "./interfaces/IXENFT.sol";
import "./libs/MintInfo.sol";
import "./DBXENFT.sol";
import "./XENFTStorage.sol";

contract DBXeNFTFactory is ReentrancyGuard {
    using MintInfo for uint256;
    using SafeERC20 for IERC20;

    /**
     * XENFT Token contract.
     */
    IXENFT public immutable xenft;

    /**
     * DBXen Reward Token contract.
     */
    IERC20 public immutable dxn;

    /**
     * Xen Token contract.
     */
    IXENCrypto public immutable xenCrypto;

    /**
     * DBXeNFT Token contract.
     */
    DBXENFT public immutable dbxenft;

    /**
     * Address receiving 2.5% of protocol fees.
     */
    address public devAddress;

    /**
     * Index (0-based) of the current cycle.
     * 
     * Updated upon cycle setup that is triggered by contract interaction 
     * (account burn tokens, claims fees, claims rewards, stakes or unstakes).
     */
    uint256 public currentCycle;

    /**
     * Stores the index of the penultimate active cycle plus one.
     */
    uint256 public previousStartedCycle;

    /**
     * Helper variable to store the index of the last active cycle.
     */
    uint256 public currentStartedCycle;

    /**
     * Stores the index of the penultimate active cycle plus one.
     */
    uint256 public lastStartedCycle;

    /**
     * Power reward amount allocated for the current cycle.
     */
    uint256 public currentCycleReward;

    /**
     * Power reward amount allocated for the previous cycle.
     */
    uint256 public lastCycleReward;

    /**
     * Amount of seconds in a day.
     */
    uint256 public constant SECONDS_IN_DAY = 3_600 * 24;

    /**
     * Upper percentage limit that can be applied as penalty.
     */
    uint256 public constant MAX_PENALTY_PCT = 99;

    /**
     * Basis points representation of 100 percent.
     */
    uint256 public constant MAX_BPS = 10_000_000;

    /**
     * Helper constant used in calculating the fee for locking XENFT.
     */
    uint256 public constant BASE_XEN = 5_000_000_000;

    /**
     * Used to minimize division remainder when earned fees are calculated.
     */
    uint256 public constant SCALING_FACTOR = 1e40;

    /**
     * Length of a fee distribution cycle.
     * Initialized in constructor to 1 day.
     */
    uint256 public immutable i_periodDuration;

    /**
     * Contract creation timestamp.
     * Initialized in constructor.
     */
    uint256 public immutable i_initialTimestamp;

    /**
     * Pending power decrease applied at the start of the next active cycle.
     */
    uint256 public pendingStakeWithdrawal;

    /**
     * Pending fees added into the pool of the next active cycle.
     */
    uint256 public pendingFees;

    /**
     * Pending extra power from DXN staking added into the pool of the next active cycle.
     */
    uint256 public pendingPower;

    /**
     * The total amount of accrued fees per cycle.
     */
    mapping(uint256 => uint256) public cycleAccruedFees;

    /**
     * Total entry power(in est. Xen reward) in the given cycle.
     */
    mapping(uint256 => uint256) public totalEntryPowerPerCycle;

    /**
     * Updated when staking DXN - used in the calculation of
     * all the extra power that needs to be added to the total
     * power of DBXENFTs.
     */
    mapping(uint256 => uint256) public totalExtraEntryPower;

    /**
     * Entry power(in est. Xen reward) of the given DBXENFT.
     */
    mapping(uint256 => uint256) public dbxenftEntryPower;

    /**
     * Cycle in which the given DBXENFT was minted.
     */
    mapping(uint256 => uint256) public tokenEntryCycle;

    /**
     * Total entry power(in est. Xen reward) of all DBXENFTs
     * that staked during entry cycle.
     */
    mapping(uint256 => uint256) public dbxenftEntryPowerWithStake;

    /**
     * Power of DBXENFT counting towards the share of protocol fees.
     * Equal to base DBXENFT power + (base DBXENFT power * DXN staked) / 100;
     */ 
    mapping(uint256 => uint256) public dbxenftPower;

    /**
     * Base power of DBXENFT obtained from the share of
     * power reward of its entry cycle.
     */
    mapping(uint256 => uint256) public baseDBXeNFTPower;

    /**
     * Stores the sum of the total DBXENFT powers from all
     * the previous cycles + the current power reward of the given cycle.
     */
    mapping(uint256 => uint256) public summedCyclePowers;

     /**
     * Sum of previous total cycle accrued fees divided by total DBXENFT powers.
     */
    mapping(uint256 => uint256) public cycleFeesPerPowerSummed;

    /**
     * Total power rewards allocated per cycle.
     */
    mapping(uint256 => uint256) public rewardPerCycle;

    /**
     * Cycle in which a DBXENFT's staked DXN is locked and begins generating fees.
     */
    mapping(uint256 => uint256) public dbxenftFirstStake;

    /**
     * Same as dbxenftFirstStake, but stores the second stake separately 
     * in case DXN is staked for the DBXENFT in two consecutive active cycles.
     */
    mapping(uint256 => uint256) public dbxenftSecondStake;

    /**
     * DXN amount a DBXENFT has staked and is locked during given cycle.
     */
    mapping(uint256 => mapping(uint256 => uint256)) public dbxenftStakeCycle;

    /**
     * Pending staked DXN helper variable used for
     * updating DBXENFT with the corresponding power.
     */
    mapping(uint256 => uint256) public pendingDXN;

    /**
     * Amount of unclaimed fees of given DBXENFT since last stats update.
     */
    mapping(uint256 => uint256) public dbxenftAccruedFees;

    /**
     * Last cycle in which the total accrued fee amount of the DBXENFT was updated.
     */
    mapping(uint256 => uint256) public lastFeeUpdateCycle;

    /**
     * Last cycle in which the power of the DBXENFT was updated.
     */
    mapping(uint256 => uint256) public lastPowerUpdateCycle;

    /**
     * DXN amount a DBXENFT can currently withdraw.
     */
    mapping(uint256 => uint256) public dbxenftWithdrawableStake;

    /**
     * DBXENFT's locked XENFT.
     */
    mapping(uint256 => uint256) public dbxenftUnderlyingXENFT;

    /**
     * Contains the address of the storage contract holding the XENFT for given DBXENFT.
     */
    mapping(uint256 => XENFTStorage) public dbxenftUnderlyingStorage;

     /**
     * @dev Emitted when calling {mintDBXENFT} marking the new current `cycle`,
     * `calculatedCycleReward` and `summedCycleStakes`.
     */
    event NewCycleStarted(
        uint256 cycle,
        uint256 calculatedCycleReward,
        uint256 summedCyclePowers
    );

    /**
     * @dev Emitted when calling {mintDBXENFT} function by
     * `minter` in `cycle` which after paying `fee`amount native token
     * it's minted a DBXENFT with id `DBXENFTId` and
     * the XENFT with `XENFTID` gets locked.
     */
    event DBXeNFTMinted(
        uint256 indexed cycle,
        uint256 DBXENFTId,
        uint256 XENFTID,
        uint256 fee,
        address indexed minter
    );

    /**
     * @dev Emitted when `account` claims an amount of `fees` in native token
     * through {claimFees} in `cycle`.
     */
    event FeesClaimed(
        uint256 indexed cycle,
        uint256 indexed tokenId,
        uint256 fees,
        address indexed owner
    );

    /**
     * @dev Emitted when `owner` stakes `amount` DXN tokens through
     * {stake} on DBXENFT with `tokenId` in `cycle`.
     */
    event Staked(
        uint256 indexed cycle,
        uint256 indexed tokenId,
        uint256 amount,
        address indexed owner
    );

    /**
     * @dev Emitted when `owner` unstakes `amount` DXN tokens through
     * {unstake} on DBXENFT with `tokenId` in `cycle`.
     */
    event Unstaked(
        uint256 indexed cycle,
        uint256 indexed tokenId,
        uint256 amount,
        address indexed owner
    );

    /**
     * Emitted when `owner` of `dbxenftId` claims Xen
     * through {claimXen} from `xenftId`.
     */
    event XenRewardsClaimed(
        uint256 indexed cycle,
        uint256 dbxenftId,
        uint256 xenftId,
        address indexed owner
    );

    /**
     * @dev Used to check if the user owns a certain DBXENFT/XENFT.
     */
    modifier onlyNFTOwner(
        IERC721 tokenAddress,
        uint256 tokenId,
        address user
    ) {
        require(
            tokenAddress.ownerOf(tokenId) == user,
            "You do not own this NFT!"
        );
        _;
    }


    /**
     * @param xenftAddress XENFT contract address.
     * @param dbxAddress DXN contract address.
     * @param _xenCrypto Xen contract address.
     * @param _devAddress Dev address.
     */
    constructor(
        address dbxAddress,
        address xenftAddress,
        address _xenCrypto,
        address _devAddress
    ) {
        dxn = IERC20(dbxAddress);
        xenft = IXENFT(xenftAddress);
        xenCrypto = IXENCrypto(_xenCrypto);
        devAddress = _devAddress;
        i_periodDuration = 1 days;
        i_initialTimestamp = block.timestamp;
        dbxenft = new DBXENFT();
        currentCycleReward = 10000 * 1e18;
        summedCyclePowers[0] = 10000 * 1e18;
        rewardPerCycle[0] = 10000 * 1e18;
    }

    /**
     * @dev Locks an owned XENFT inside this contract and mints a DBXENFT.
     * Must pay a protocol fee based on the estimated Xen rewards
     * the XENFT yields at the time of locking. The estimated Xen
     * also determines the entry power that will provide the DBXENFT
     * a base power from the reward power pool split to all the
     * DBXENFTs created during the cycle.
     * If the XENFT is already redeemed, a DBXENFT that does not take
     * part in the auction of the cycle's reward power nor does it
     * start it is minted and is assigned the base power of 1.
     *
     * @param xenftId id of the XENFT to be locked.
     */
    function mintDBXENFT(
        uint256 xenftId
    ) external payable nonReentrant onlyNFTOwner(xenft, xenftId, msg.sender) {
        calculateCycle();
        updateCycleFeesPerStakeSummed();

        uint256 mintInfo = xenft.mintInfo(xenftId);

        bool redeemed = mintInfo.getRedeemed();

        uint256 fee;
        uint256 estimatedReward;
        if(redeemed) {
            fee = 1e15;
        } else {
            estimatedReward = _calculateUserMintReward(xenftId, mintInfo);

            fee = _calculateFee(
                estimatedReward,
                mintInfo.getMaturityTs(),
                mintInfo.getTerm()
            );
        }
        require(msg.value >= fee, "Payment less than fee");

        uint256 updatedFee = fee - calculateDevFee(fee);

        uint256 dbxenftId = dbxenft.mintDBXENFT(msg.sender);
        uint256 currentCycleMem = currentCycle;

        if(redeemed) {
            baseDBXeNFTPower[dbxenftId] = 1e18;
            dbxenftPower[dbxenftId] = 1e18;

            if(currentCycleMem != 0) {
                lastFeeUpdateCycle[dbxenftId] = lastStartedCycle + 1;
            }

            if(currentCycleMem == currentStartedCycle) {
                summedCyclePowers[currentCycleMem] += 1e18;
                cycleAccruedFees[currentCycleMem] = cycleAccruedFees[currentCycleMem] + updatedFee;

            } else {
                pendingPower += 1e18;
                pendingFees += updatedFee;
            }
        } else {
            setUpNewCycle();
            dbxenftEntryPower[dbxenftId] = estimatedReward;
            tokenEntryCycle[dbxenftId] = currentCycleMem;
            totalEntryPowerPerCycle[currentCycleMem] += estimatedReward;
            cycleAccruedFees[currentCycleMem] = cycleAccruedFees[currentCycleMem] + updatedFee;

            if(currentCycleMem != 0) {
                lastFeeUpdateCycle[dbxenftId] = lastStartedCycle + 1;
            }
        }
    
        dbxenftUnderlyingXENFT[dbxenftId] = xenftId;
       
        XENFTStorage dbxenftStorage = new XENFTStorage();
        dbxenftUnderlyingStorage[dbxenftId] = dbxenftStorage;

        xenft.transferFrom(msg.sender, address(dbxenftStorage), xenftId);
        sendViaCall(payable(msg.sender), msg.value - fee);
        sendViaCall(payable(devAddress), calculateDevFee(fee));

        emit DBXeNFTMinted(
            currentCycleMem,
            dbxenftId,
            xenftId,
            fee,
            msg.sender
        );
    }

    /**
     * @dev Calculates the protocol fee when staking 'dxnAmount' of DXN.
     *
     * @param dxnAmount amount of DXN to calculate protocol fee for.
     */
    function calcStakeFee(uint256 dxnAmount) internal pure returns(uint256 stakeFee){
        stakeFee = dxnAmount / 1000;
        require(stakeFee > 0, "DBXeNFT: stakeFee must be > 0");
    }

    /**
     * @dev Used for calculating extra entry power in order to find out
     * the extra total DBXENFT power of all the DBXENFTs that staked,
     * respectively when adding the extra power to an individual DBXENFT.
     *
     * @param power base/entry power to be multiplied upon.
     * @param dxnAmount amount of DXN to be multiplied with.
     */
    function calcExtraPower(uint256 power, uint256 dxnAmount) internal pure returns(uint256 calcPower){
        calcPower = Math.mulDiv(power, dxnAmount, 1e20);
    }

    /**
     * @dev Stake an amount of DXN for the given DBXENFT to give it extra power.
     * Must pay a protocol fee of 0.001 native coin for each DXN.
     * The corresponding DXN is locked until the end of the next cycle.
     *
     * @param amount amount of DXN to be staked.
     * @param tokenId DBXENFT id.
     */    
    function stake(uint256 amount, uint256 tokenId) external payable nonReentrant onlyNFTOwner(dbxenft, tokenId, msg.sender) {
        require(amount > 0, "DBXeNFT: amount is zero");
        calculateCycle();
        updateCycleFeesPerStakeSummed();
        updateDBXeNFT(tokenId);
        
        uint256 currentCycleMem = currentCycle;

        require(currentCycleMem == currentStartedCycle, "DBXeNFT: Only stake during active cycle");

        uint256 tokenEntryPowerMem = dbxenftEntryPower[tokenId];

        require(tokenEntryPowerMem != 0 || baseDBXeNFTPower[tokenId] != 0, "DBXeNFT does not exist");

        uint256 stakeFee = calcStakeFee(amount);
        require(msg.value >= stakeFee, "Value less than staking fee");
        uint256 devFee = calculateDevFee(stakeFee);
        uint256 updatedFee = stakeFee - devFee;

        cycleAccruedFees[currentCycleMem] += updatedFee;

        uint256 cycleToSet = currentCycleMem + 1;

        if (
            (cycleToSet != dbxenftFirstStake[tokenId] &&
                cycleToSet != dbxenftSecondStake[tokenId])
        ) {
            if (dbxenftFirstStake[tokenId] == 0) {
                dbxenftFirstStake[tokenId] = cycleToSet;
            } else if (dbxenftSecondStake[tokenId] == 0) {
                dbxenftSecondStake[tokenId] = cycleToSet;
            }
        }

        dbxenftStakeCycle[tokenId][cycleToSet] += amount;
        pendingDXN[tokenId] += amount;

        if(lastPowerUpdateCycle[tokenId] != currentCycle) {
            lastPowerUpdateCycle[tokenId] = currentCycle;
        }

        if(baseDBXeNFTPower[tokenId] == 0){
            uint256 extraPower = calcExtraPower(tokenEntryPowerMem, amount);
            dbxenftEntryPowerWithStake[currentCycleMem] += tokenEntryPowerMem;
            totalExtraEntryPower[currentCycleMem] += extraPower;
        } else {
            uint256 extraPower = calcExtraPower(baseDBXeNFTPower[tokenId], amount);
            pendingPower += extraPower;
        }

        dxn.safeTransferFrom(msg.sender, address(this), amount);
        sendViaCall(payable(msg.sender), msg.value - stakeFee);
        sendViaCall(payable(devAddress), devFee);
        emit Staked(
            currentCycleMem,
            tokenId,
            amount,
            msg.sender
        );
    }

    /**
     * @dev Unstake an amount of DXN for the given DBXENFT applying a power decrease
     * to the current cycle if it's an active one or beginning with the next active one.
     * Can only withdraw DXN that has completed the corresponding cycle lock-up.
     *
     * @param tokenId DBXENFT id.
     * @param amount amount of DXN to be unstaked.
     */ 
    function unstake(uint256 tokenId, uint256 amount) external nonReentrant onlyNFTOwner(dbxenft, tokenId, msg.sender) {
        require(amount > 0, "DBXeNFT: Amount is zero");
        calculateCycle();
        updateCycleFeesPerStakeSummed();
        updateDBXeNFT(tokenId);

        require(
            amount <= dbxenftWithdrawableStake[tokenId],
            "DBXeNFT: Amount greater than withdrawable stake"
        );

        uint256 powerDecrease = calcExtraPower(baseDBXeNFTPower[tokenId], amount);
        dbxenftWithdrawableStake[tokenId] -= amount;
        dbxenftPower[tokenId] -= powerDecrease;

        if (lastStartedCycle == currentStartedCycle) {
            pendingStakeWithdrawal += powerDecrease;
        } else {
            summedCyclePowers[currentCycle] -= powerDecrease;
        }

        dxn.safeTransfer(msg.sender, amount);
        emit Unstaked(
            currentCycle,
            tokenId,
            amount,
            msg.sender
        );
    }

    /**
     * @dev Transfers accrued fees of DBXENFT to its owner.
     *
     * @param tokenId DBXENFT id.
     */
    function claimFees(uint256 tokenId) external nonReentrant() onlyNFTOwner(dbxenft, tokenId, msg.sender){
        calculateCycle();
        updateCycleFeesPerStakeSummed();
        updateDBXeNFT(tokenId);

        uint256 fees = dbxenftAccruedFees[tokenId];
        require(fees > 0, "dbXENFT: amount is zero");
        dbxenftAccruedFees[tokenId] = 0;

        sendViaCall(payable(msg.sender), fees);
        emit FeesClaimed(
            currentCycle,
            tokenId,
            fees,
            msg.sender
        );
    }

    /**
     * @dev MaturityDays = Days since XENFT was minted - Days until XENFT can be claimed.
     *
     * @param term term attribute of XENFT
     * @param maturityTs maturity timestamp of XENFT
     */ 
    function calcMaturityDays(uint256 term, uint256 maturityTs) internal view returns(uint256 maturityDays) {
        uint256 daysTillClaim;
        uint256 daysSinceMinted;

        if(block.timestamp < maturityTs) {
            daysTillClaim = ((maturityTs - block.timestamp) / SECONDS_IN_DAY);
            daysSinceMinted = term - daysTillClaim;
        } else {
            daysTillClaim = 0;
            daysSinceMinted =
                ((term * SECONDS_IN_DAY + (block.timestamp - maturityTs))) /
                SECONDS_IN_DAY;
        }

        if (daysSinceMinted > daysTillClaim) {
            maturityDays = daysSinceMinted - daysTillClaim;
        }
    }
    
    /**
     * @dev Given a DBXENFT, claim the Xen rewards of the underlying XENFT
     * and direct them to its owner. Not permitted during entry cycle of DBXENFT.
     * In doing so, the base power of the DBXENFT will become 1(unless it's already smaller)
     * and the DBXENFT total power is updated according to the new base power
     * and the existent DXN stake.
     *
     * @param tokenId DBXENFT id.
     */ 
    function claimXen(uint256 tokenId) external nonReentrant onlyNFTOwner(dbxenft, tokenId, msg.sender) {
        calculateCycle();
        updateCycleFeesPerStakeSummed();
        updateDBXeNFT(tokenId);

        uint256 xenftId = dbxenftUnderlyingXENFT[tokenId];
        uint256 mintInfo = xenft.mintInfo(xenftId);

        require(!mintInfo.getRedeemed(), "XENFT: Already redeemed");

        require(currentCycle != tokenEntryCycle[tokenId], "Can not claim during entry cycle");

        uint256 DBXenftPow = dbxenftPower[tokenId];
        uint256 baseDBXeNFTPow = baseDBXeNFTPower[tokenId];
        if(baseDBXeNFTPow > 1e18) {
            uint256 newPow = Math.mulDiv(DBXenftPow, 1e18, baseDBXeNFTPow);
            dbxenftPower[tokenId] = newPow;
            DBXenftPow -= newPow;
            baseDBXeNFTPower[tokenId] = 1e18;

            if (lastStartedCycle == currentStartedCycle) {
            pendingStakeWithdrawal += DBXenftPow;
            } else {
                summedCyclePowers[currentCycle] -= DBXenftPow;
            }
        }

        XENFTStorage xenftStorage = dbxenftUnderlyingStorage[tokenId];
        xenftStorage.claimXenFromStorage(address(xenft), msg.sender, xenftId);
        emit XenRewardsClaimed(
            currentCycle,
            tokenId, 
            xenftId,
            msg.sender
        );
    }

    /**
     * Allows the current dev address to set a new one.
     * 
     * @param newDevAddress new dev address to be set.
     */
    function setDevAddress(address newDevAddress) public {
        require(msg.sender == devAddress, "Only dev can change address");

        devAddress = newDevAddress;
    }

    /**
     * Calculated according to the following formula:
     * ProtocolFee = MAX( (Xen*MAX( 1-0.0011389 * MAX(MaturityDays,0) , 0.5) )/ BASE_XEN), MinCost).
     * Xen = Estimated Xen to be claimed.
     * BaseXen = The floor amount of Xen for 1 Native coin = 1_000_000_000.
     * MinCost = Minimum amount of Native coin to be paid for minting = 0.001 native coin.
     *
     * @param userReward estimated Xen reward.
     * @param term term attribute of XENFT
     * @param maturityTs maturity timestamp of XENFT
     */
    function _calculateFee(
        uint256 userReward,
        uint256 maturityTs,
        uint256 term
    ) private view returns (uint256 burnFee) {
        uint256 maturityDays = calcMaturityDays(term, maturityTs);
        uint256 maxDays = maturityDays;
        uint256 daysReduction = 11389 * maxDays;
        uint256 maxSubtrahend = Math.min(daysReduction, 5_000_000);
        uint256 difference = MAX_BPS - maxSubtrahend;
        uint256 maxPctReduction = Math.max(difference, 5_000_000);
        uint256 xenMulReduction = Math.mulDiv(userReward, maxPctReduction, MAX_BPS);
        burnFee = Math.max(1e15, xenMulReduction / BASE_XEN);
    }

    /**
     * @dev calculates withdrawal penalty of Xen rewards depending on lateness.
     *
     * @param secsLate second late since maturity timestamp of XENFT.
     */
    function _penalty(uint256 secsLate) private pure returns (uint256) {
        // =MIN(2^(daysLate+3)/window-1,99)
        uint256 daysLate = secsLate / SECONDS_IN_DAY;
        if (daysLate > 7 - 1) return MAX_PENALTY_PCT;
        uint256 penalty = (uint256(1) << (daysLate + 3)) / 7 - 1;
        return penalty < MAX_PENALTY_PCT ? penalty : MAX_PENALTY_PCT;
    }

    /**
     * @dev calculates net Xen Reward (adjusted for Penalty).
     */
    function _calculateMintReward(
        uint256 cRank,
        uint256 term,
        uint256 maturityTs,
        uint256 amplifier,
        uint256 eeaRate
    ) private view returns (uint256) {
        uint256 penalty;
        if (block.timestamp > maturityTs) {
            uint256 secsLate = block.timestamp - maturityTs;
            penalty = _penalty(secsLate);
        }
        uint256 rankDiff = xenCrypto.globalRank() - cRank;
        uint256 rankDelta = rankDiff > 2 ? rankDiff : 2;
        uint256 EAA = (1000 + eeaRate);
        uint256 reward = xenCrypto.getGrossReward(
            rankDelta,
            amplifier,
            term,
            EAA
        );
        return (reward * (100 - penalty)) / 100;
    }

    /**
     * @dev calculates the estimated total Xen reward of the XENFT.
     *
     * @param tokenId XENFT id.
     * @param mintInfo contains packed info about XENFT.
     */
    function _calculateUserMintReward(
        uint256 tokenId,
        uint256 mintInfo
    ) internal view returns (uint256 userMintReward) {
        uint256 vmuCount = xenft.vmuCount(tokenId);
        (
            uint256 term,
            uint256 maturityTs,
            uint256 rank,
            uint256 amp,
            uint256 eea,
            ,
            ,
            ,

        ) = mintInfo.decodeMintInfo();
        uint256 mintReward = _calculateMintReward(
            rank,
            term,
            maturityTs,
            amp,
            eea
        );
        return mintReward * vmuCount * 1 ether;
    }

    /**
     * @dev calculates 2.5% of the paid protocol fee to be attributed to dev.
     *
     * @param inputValue protocol fee from which the dev fee is deducted.
     */
    function calculateDevFee(uint256 inputValue) public pure returns (uint256) {
        uint256 percentage = Math.mulDiv(inputValue, 25, 1000);

        return percentage;
    }

    /**
     * @dev Updates the global helper variables related to fee distribution.
     */
    function updateCycleFeesPerStakeSummed() internal {
        if (currentCycle != currentStartedCycle) {
            previousStartedCycle = lastStartedCycle + 1;
            lastStartedCycle = currentStartedCycle;
        }

        if (
            currentCycle > lastStartedCycle &&
            cycleFeesPerPowerSummed[lastStartedCycle + 1] == 0
        ) {
            uint256 feePerStake =
                    (cycleAccruedFees[lastStartedCycle] * SCALING_FACTOR) /
                    summedCyclePowers[lastStartedCycle];

            cycleFeesPerPowerSummed[lastStartedCycle + 1] =
                cycleFeesPerPowerSummed[previousStartedCycle] +
                feePerStake;
        }
    }

    /**
     * @dev Set up the new active cycle calculating the new
     * reward power pool with an 1% increase. 
     * Introduce any pending fees in the cycle's fee pool.
     * Calculate the new total power of DBXENFTs based on
     * the ones that have staked DXN.
     * Apply pending power decrease to the total DBXENFT power.
     */
    function setUpNewCycle() internal {
        uint256 currentCycleMemory = currentCycle;
        if (rewardPerCycle[currentCycleMemory] == 0) {
            lastCycleReward = currentCycleReward;
            uint256 calculatedCycleReward = lastCycleReward +
                (lastCycleReward / 100);

            currentCycleReward = calculatedCycleReward;
            rewardPerCycle[currentCycleMemory] = calculatedCycleReward;

            if(pendingFees != 0) {
                cycleAccruedFees[currentCycleMemory] += pendingFees;
                pendingFees = 0;
            }

            uint256 lastStartedCycleMemory = lastStartedCycle;
            if(dbxenftEntryPowerWithStake[lastStartedCycleMemory] != 0) {
                uint256 extraPower = Math.mulDiv(totalExtraEntryPower[lastStartedCycleMemory],lastCycleReward,
                    totalEntryPowerPerCycle[lastStartedCycleMemory]);
                summedCyclePowers[currentCycleMemory] += extraPower;
            }

            if(pendingPower != 0) {
                summedCyclePowers[currentCycleMemory] += pendingPower;
                pendingPower = 0;
            }

            currentStartedCycle = currentCycleMemory;

            summedCyclePowers[currentCycleMemory] += summedCyclePowers[lastStartedCycleMemory] + calculatedCycleReward;

            if (pendingStakeWithdrawal != 0) {
                summedCyclePowers[
                    currentCycleMemory
                ] -= pendingStakeWithdrawal;
                pendingStakeWithdrawal = 0;
            }

            emit NewCycleStarted(
                currentCycle,
                calculatedCycleReward,
                summedCyclePowers[currentCycleMemory]
            );
        }
    }

    /**
     * Update DBXENFT stats:
     * Assign their respective base power if not yet set.
     * Calculate the new DBXENFT power if any new stake was made.
     * Calculate the new fees it has accumulated since last update.
     * Mark any stake that passed the lock-up cycle as withdrawable.
     *
     * @param tokenId DBXENFT id.
     */
    function updateDBXeNFT(uint256 tokenId) internal {
        uint256 entryCycle = tokenEntryCycle[tokenId];
        if(baseDBXeNFTPower[tokenId] == 0 && currentCycle > entryCycle) {
            baseDBXeNFTPower[tokenId] = Math.mulDiv(dbxenftEntryPower[tokenId],
                rewardPerCycle[entryCycle], totalEntryPowerPerCycle[entryCycle]);
            dbxenftPower[tokenId] += baseDBXeNFTPower[tokenId];
        }

        uint256 lastStartedCycleMem = lastStartedCycle;
        uint256 stakedDXN = pendingDXN[tokenId];
        uint256 extraPower;
        uint256 dbxenftPowerBeforeExtraPower = dbxenftPower[tokenId];
        if(currentCycle > lastPowerUpdateCycle[tokenId] && stakedDXN != 0) {
            extraPower = calcExtraPower(baseDBXeNFTPower[tokenId], stakedDXN);
            pendingDXN[tokenId] = 0;
            dbxenftPower[tokenId] += extraPower;
        }

        if (
            currentCycle > lastStartedCycleMem &&
            lastFeeUpdateCycle[tokenId] != lastStartedCycleMem + 1
        ) {
            
            dbxenftAccruedFees[tokenId] += (dbxenftPowerBeforeExtraPower
                    * (cycleFeesPerPowerSummed[lastStartedCycleMem + 1] - cycleFeesPerPowerSummed[lastFeeUpdateCycle[tokenId]])) / SCALING_FACTOR;

            if(stakedDXN != 0) {
                uint256 stakeCycle;

                if(dbxenftSecondStake[tokenId] != 0) {
                    stakeCycle = dbxenftSecondStake[tokenId];
                } else {
                    stakeCycle = dbxenftFirstStake[tokenId];
                }
                 
                if(lastStartedCycleMem >= stakeCycle) {
                        dbxenftAccruedFees[tokenId] += (extraPower 
                        * (cycleFeesPerPowerSummed[lastStartedCycleMem + 1] - 
                        cycleFeesPerPowerSummed[stakeCycle])) / SCALING_FACTOR;
                }
            }
            
            lastFeeUpdateCycle[tokenId] = lastStartedCycleMem + 1;
        }

        uint256 tokenFirstStakeMem = dbxenftFirstStake[tokenId];
        if (
            tokenFirstStakeMem != 0 &&
            currentCycle > tokenFirstStakeMem
        ) {
            uint256 unlockedFirstStake = dbxenftStakeCycle[tokenId][tokenFirstStakeMem];

            dbxenftWithdrawableStake[tokenId] += unlockedFirstStake;

            dbxenftStakeCycle[tokenId][tokenFirstStakeMem] = 0;
            dbxenftFirstStake[tokenId] = 0;

            uint256 tokenSecondStakeMem = dbxenftSecondStake[tokenId];
            if (tokenSecondStakeMem != 0) {
                if (currentCycle > tokenSecondStakeMem) {
                    uint256 unlockedSecondStake = dbxenftStakeCycle[tokenId][tokenSecondStakeMem];

                    dbxenftWithdrawableStake[tokenId] += unlockedSecondStake;

                    dbxenftStakeCycle[tokenId][tokenSecondStakeMem] = 0;
                    dbxenftSecondStake[tokenId] = 0;
                } else {
                    dbxenftFirstStake[tokenId] = tokenSecondStakeMem;
                    dbxenftSecondStake[tokenId] = 0;
                }
            }
        }
    }

    /**
     * @dev Returns the index of the cycle at the current block time.
     */
    function getCurrentCycle() public view returns (uint256) {
        return (block.timestamp - i_initialTimestamp) / i_periodDuration;
    }

    /**
     * @dev Updates the index of the cycle.
     */
    function calculateCycle() internal {
        uint256 calculatedCycle = getCurrentCycle();

        if (calculatedCycle > currentCycle) {
            currentCycle = calculatedCycle;
        }
    }

    /**
     * Recommended method to use to send native coins.
     *
     * @param to receiving address.
     * @param amount in wei.
     */
    function sendViaCall(address payable to, uint256 amount) internal {
        (bool sent, ) = to.call{value: amount}("");
        require(sent, "DBXen: failed to send amount");
    }
}
// File: contracts/interfaces/IXENCrypto.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.10;

interface IXENCrypto {
    function globalRank() external view returns (uint256);
    function getGrossReward(
        uint256 rankDelta,
        uint256 amplifier,
        uint256 term,
        uint256 EAA
        ) external view returns (uint256);
}
// File: contracts/interfaces/IXENFT.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.10;

import "@openzeppelin/contracts/interfaces/IERC721.sol";

interface IXENFT is IERC721{
    function vmuCount(uint256 tokenId) external view returns (uint256);

    function mintInfo(uint256 tokenId) external view returns (uint256);

    function bulkClaimMintReward(uint256 tokenId, address dest) external;
}
// File: contracts/interfaces/IXENFTMinimal.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.10;

interface IXENFTMinimal {
    function bulkClaimMintReward(uint256 tokenId, address dest) external;
}
// File: contracts/libs/MintInfo.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.10;

// mapping: NFT tokenId => MintInfo (used in tokenURI generation)
// MintInfo encoded as:
//      term (uint16)
//      | maturityTs (uint64)
//      | rank (uint128)
//      | amp (uint16)
//      | eaa (uint16)
//      | class (uint8):
//          [7] isApex
//          [6] isLimited
//          [0-5] powerGroupIdx
//      | redeemed (uint8)
library MintInfo {
    /**
        @dev helper to convert Bool to U256 type and make compiler happy
     */
    function toU256(bool x) internal pure returns (uint256 r) {
        assembly {
            r := x
        }
    }

    /**
        @dev encodes MintInfo record from its props
     */
    function encodeMintInfo(
        uint256 term,
        uint256 maturityTs,
        uint256 rank,
        uint256 amp,
        uint256 eaa,
        uint256 class_,
        bool redeemed
    ) public pure returns (uint256 info) {
        info = info | (toU256(redeemed) & 0xFF);
        info = info | ((class_ & 0xFF) << 8);
        info = info | ((eaa & 0xFFFF) << 16);
        info = info | ((amp & 0xFFFF) << 32);
        info = info | ((rank & 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF) << 48);
        info = info | ((maturityTs & 0xFFFFFFFFFFFFFFFF) << 176);
        info = info | ((term & 0xFFFF) << 240);
    }

    /**
        @dev decodes MintInfo record and extracts all of its props
     */
    function decodeMintInfo(uint256 info)
        public
        pure
        returns (
            uint256 term,
            uint256 maturityTs,
            uint256 rank,
            uint256 amp,
            uint256 eaa,
            uint256 class,
            bool apex,
            bool limited,
            bool redeemed
        )
    {
        term = uint16(info >> 240);
        maturityTs = uint64(info >> 176);
        rank = uint128(info >> 48);
        amp = uint16(info >> 32);
        eaa = uint16(info >> 16);
        class = uint8(info >> 8) & 0x3F;
        apex = (uint8(info >> 8) & 0x80) > 0;
        limited = (uint8(info >> 8) & 0x40) > 0;
        redeemed = uint8(info) == 1;
    }

    /**
        @dev extracts `term` prop from encoded MintInfo
     */
    function getTerm(uint256 info) public pure returns (uint256 term) {
        (term, , , , , , , , ) = decodeMintInfo(info);
    }

    /**
        @dev extracts `maturityTs` prop from encoded MintInfo
     */
    function getMaturityTs(uint256 info) public pure returns (uint256 maturityTs) {
        (, maturityTs, , , , , , , ) = decodeMintInfo(info);
    }

    /**
        @dev extracts `rank` prop from encoded MintInfo
     */
    function getRank(uint256 info) public pure returns (uint256 rank) {
        (, , rank, , , , , , ) = decodeMintInfo(info);
    }

    /**
        @dev extracts `AMP` prop from encoded MintInfo
     */
    function getAMP(uint256 info) public pure returns (uint256 amp) {
        (, , , amp, , , , , ) = decodeMintInfo(info);
    }

    /**
        @dev extracts `EAA` prop from encoded MintInfo
     */
    function getEAA(uint256 info) public pure returns (uint256 eaa) {
        (, , , , eaa, , , , ) = decodeMintInfo(info);
    }

    /**
        @dev extracts `redeemed` prop from encoded MintInfo
     */
    function getClass(uint256 info)
        public
        pure
        returns (
            uint256 class_,
            bool apex,
            bool limited
        )
    {
        (, , , , , class_, apex, limited, ) = decodeMintInfo(info);
    }

    /**
        @dev extracts `redeemed` prop from encoded MintInfo
     */
    function getRedeemed(uint256 info) public pure returns (bool redeemed) {
        (, , , , , , , , redeemed) = decodeMintInfo(info);
    }
}
// File: contracts/XENFTStorage.sol



pragma solidity ^0.8.19;
import "./interfaces/IXENFTMinimal.sol";

contract XENFTStorage {
    address factory;

    constructor(){
        factory = msg.sender;
    }

    function claimXenFromStorage(address xenft, address dest, uint256 tokenId) public {
        require(msg.sender == factory, "Caller is not factory");

        IXENFTMinimal(xenft).bulkClaimMintReward(tokenId, dest);
    }
}
// File: operator-filter-registry/src/DefaultOperatorFilterer.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.13;

import {OperatorFilterer} from "./OperatorFilterer.sol";
import {CANONICAL_CORI_SUBSCRIPTION} from "./lib/Constants.sol";
/**
 * @title  DefaultOperatorFilterer
 * @notice Inherits from OperatorFilterer and automatically subscribes to the default OpenSea subscription.
 * @dev    Please note that if your token contract does not provide an owner with EIP-173, it must provide
 *         administration methods on the contract itself to interact with the registry otherwise the subscription
 *         will be locked to the options set during construction.
 */

abstract contract DefaultOperatorFilterer is OperatorFilterer {
    /// @dev The constructor that is called when the contract is being deployed.
    constructor() OperatorFilterer(CANONICAL_CORI_SUBSCRIPTION, true) {}
}

// File: operator-filter-registry/src/IOperatorFilterRegistry.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.13;

interface IOperatorFilterRegistry {
    /**
     * @notice Returns true if operator is not filtered for a given token, either by address or codeHash. Also returns
     *         true if supplied registrant address is not registered.
     */
    function isOperatorAllowed(address registrant, address operator) external view returns (bool);

    /**
     * @notice Registers an address with the registry. May be called by address itself or by EIP-173 owner.
     */
    function register(address registrant) external;

    /**
     * @notice Registers an address with the registry and "subscribes" to another address's filtered operators and codeHashes.
     */
    function registerAndSubscribe(address registrant, address subscription) external;

    /**
     * @notice Registers an address with the registry and copies the filtered operators and codeHashes from another
     *         address without subscribing.
     */
    function registerAndCopyEntries(address registrant, address registrantToCopy) external;

    /**
     * @notice Unregisters an address with the registry and removes its subscription. May be called by address itself or by EIP-173 owner.
     *         Note that this does not remove any filtered addresses or codeHashes.
     *         Also note that any subscriptions to this registrant will still be active and follow the existing filtered addresses and codehashes.
     */
    function unregister(address addr) external;

    /**
     * @notice Update an operator address for a registered address - when filtered is true, the operator is filtered.
     */
    function updateOperator(address registrant, address operator, bool filtered) external;

    /**
     * @notice Update multiple operators for a registered address - when filtered is true, the operators will be filtered. Reverts on duplicates.
     */
    function updateOperators(address registrant, address[] calldata operators, bool filtered) external;

    /**
     * @notice Update a codeHash for a registered address - when filtered is true, the codeHash is filtered.
     */
    function updateCodeHash(address registrant, bytes32 codehash, bool filtered) external;

    /**
     * @notice Update multiple codeHashes for a registered address - when filtered is true, the codeHashes will be filtered. Reverts on duplicates.
     */
    function updateCodeHashes(address registrant, bytes32[] calldata codeHashes, bool filtered) external;

    /**
     * @notice Subscribe an address to another registrant's filtered operators and codeHashes. Will remove previous
     *         subscription if present.
     *         Note that accounts with subscriptions may go on to subscribe to other accounts - in this case,
     *         subscriptions will not be forwarded. Instead the former subscription's existing entries will still be
     *         used.
     */
    function subscribe(address registrant, address registrantToSubscribe) external;

    /**
     * @notice Unsubscribe an address from its current subscribed registrant, and optionally copy its filtered operators and codeHashes.
     */
    function unsubscribe(address registrant, bool copyExistingEntries) external;

    /**
     * @notice Get the subscription address of a given registrant, if any.
     */
    function subscriptionOf(address addr) external returns (address registrant);

    /**
     * @notice Get the set of addresses subscribed to a given registrant.
     *         Note that order is not guaranteed as updates are made.
     */
    function subscribers(address registrant) external returns (address[] memory);

    /**
     * @notice Get the subscriber at a given index in the set of addresses subscribed to a given registrant.
     *         Note that order is not guaranteed as updates are made.
     */
    function subscriberAt(address registrant, uint256 index) external returns (address);

    /**
     * @notice Copy filtered operators and codeHashes from a different registrantToCopy to addr.
     */
    function copyEntriesOf(address registrant, address registrantToCopy) external;

    /**
     * @notice Returns true if operator is filtered by a given address or its subscription.
     */
    function isOperatorFiltered(address registrant, address operator) external returns (bool);

    /**
     * @notice Returns true if the hash of an address's code is filtered by a given address or its subscription.
     */
    function isCodeHashOfFiltered(address registrant, address operatorWithCode) external returns (bool);

    /**
     * @notice Returns true if a codeHash is filtered by a given address or its subscription.
     */
    function isCodeHashFiltered(address registrant, bytes32 codeHash) external returns (bool);

    /**
     * @notice Returns a list of filtered operators for a given address or its subscription.
     */
    function filteredOperators(address addr) external returns (address[] memory);

    /**
     * @notice Returns the set of filtered codeHashes for a given address or its subscription.
     *         Note that order is not guaranteed as updates are made.
     */
    function filteredCodeHashes(address addr) external returns (bytes32[] memory);

    /**
     * @notice Returns the filtered operator at the given index of the set of filtered operators for a given address or
     *         its subscription.
     *         Note that order is not guaranteed as updates are made.
     */
    function filteredOperatorAt(address registrant, uint256 index) external returns (address);

    /**
     * @notice Returns the filtered codeHash at the given index of the list of filtered codeHashes for a given address or
     *         its subscription.
     *         Note that order is not guaranteed as updates are made.
     */
    function filteredCodeHashAt(address registrant, uint256 index) external returns (bytes32);

    /**
     * @notice Returns true if an address has registered
     */
    function isRegistered(address addr) external returns (bool);

    /**
     * @dev Convenience method to compute the code hash of an arbitrary contract
     */
    function codeHashOf(address addr) external returns (bytes32);
}

// File: operator-filter-registry/src/lib/Constants.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.13;

address constant CANONICAL_OPERATOR_FILTER_REGISTRY_ADDRESS = 0x000000000000AAeB6D7670E522A718067333cd4E;
address constant CANONICAL_CORI_SUBSCRIPTION = 0x3cc6CddA760b79bAfa08dF41ECFA224f810dCeB6;

// File: operator-filter-registry/src/OperatorFilterer.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.13;

import {IOperatorFilterRegistry} from "./IOperatorFilterRegistry.sol";
import {CANONICAL_OPERATOR_FILTER_REGISTRY_ADDRESS} from "./lib/Constants.sol";
/**
 * @title  OperatorFilterer
 * @notice Abstract contract whose constructor automatically registers and optionally subscribes to or copies another
 *         registrant's entries in the OperatorFilterRegistry.
 * @dev    This smart contract is meant to be inherited by token contracts so they can use the following:
 *         - `onlyAllowedOperator` modifier for `transferFrom` and `safeTransferFrom` methods.
 *         - `onlyAllowedOperatorApproval` modifier for `approve` and `setApprovalForAll` methods.
 *         Please note that if your token contract does not provide an owner with EIP-173, it must provide
 *         administration methods on the contract itself to interact with the registry otherwise the subscription
 *         will be locked to the options set during construction.
 */

abstract contract OperatorFilterer {
    /// @dev Emitted when an operator is not allowed.
    error OperatorNotAllowed(address operator);

    IOperatorFilterRegistry public constant OPERATOR_FILTER_REGISTRY =
        IOperatorFilterRegistry(CANONICAL_OPERATOR_FILTER_REGISTRY_ADDRESS);

    /// @dev The constructor that is called when the contract is being deployed.
    constructor(address subscriptionOrRegistrantToCopy, bool subscribe) {
        // If an inheriting token contract is deployed to a network without the registry deployed, the modifier
        // will not revert, but the contract will need to be registered with the registry once it is deployed in
        // order for the modifier to filter addresses.
        if (address(OPERATOR_FILTER_REGISTRY).code.length > 0) {
            if (subscribe) {
                OPERATOR_FILTER_REGISTRY.registerAndSubscribe(address(this), subscriptionOrRegistrantToCopy);
            } else {
                if (subscriptionOrRegistrantToCopy != address(0)) {
                    OPERATOR_FILTER_REGISTRY.registerAndCopyEntries(address(this), subscriptionOrRegistrantToCopy);
                } else {
                    OPERATOR_FILTER_REGISTRY.register(address(this));
                }
            }
        }
    }

    /**
     * @dev A helper function to check if an operator is allowed.
     */
    modifier onlyAllowedOperator(address from) virtual {
        // Allow spending tokens from addresses with balance
        // Note that this still allows listings and marketplaces with escrow to transfer tokens if transferred
        // from an EOA.
        if (from != msg.sender) {
            _checkFilterOperator(msg.sender);
        }
        _;
    }

    /**
     * @dev A helper function to check if an operator approval is allowed.
     */
    modifier onlyAllowedOperatorApproval(address operator) virtual {
        _checkFilterOperator(operator);
        _;
    }

    /**
     * @dev A helper function to check if an operator is allowed.
     */
    function _checkFilterOperator(address operator) internal view virtual {
        // Check registry code length to facilitate testing in environments without a deployed registry.
        if (address(OPERATOR_FILTER_REGISTRY).code.length > 0) {
            // under normal circumstances, this function will revert rather than return false, but inheriting contracts
            // may specify their own OperatorFilterRegistry implementations, which may behave differently
            if (!OPERATOR_FILTER_REGISTRY.isOperatorAllowed(address(this), operator)) {
                revert OperatorNotAllowed(operator);
            }
        }
    }
}