ETH Price: $1,770.16 (-1.95%)
Gas: 0.42 Gwei

Transaction Decoder

Block:
14193746 at Feb-12-2022 09:38:50 PM +UTC
Transaction Fee:
0.009496213255863152 ETH $16.81
Gas Used:
112,336 Gas / 84.534016307 Gwei

Account State Difference:

  Address   Before After State Difference Code
0x45eC819d...6c403a424
0x64e45f67...Da12876f9
0xCcB06319...49d367d6B
3.633225044543653624 Eth
Nonce: 211
3.623728831287790472 Eth
Nonce: 212
0.009496213255863152
(Ethermine)
933.15753931549012419 Eth933.15770781949012419 Eth0.000168504

Execution Trace

CryptoBearsClaim.claimBears( bullIds=[6956] )
  • MintableERC721.ownerOf( tokenId=6956 ) => ( 0xCcB063198c7Ad1F93e837F788Fc5ae749d367d6B )
  • CryptoBearsERC721.mintTo( amount=1, _to=0xCcB063198c7Ad1F93e837F788Fc5ae749d367d6B )
    File 1 of 3: CryptoBearsClaim
    // SPDX-License-Identifier: MIT
    // Developed by KG Technologies (https://kgtechnologies.io)
    pragma solidity 0.8.11;
    import "@openzeppelin/contracts/token/ERC721/IERC721.sol";
    import "@openzeppelin/contracts/access/Ownable.sol";
    import { MerkleProof } from "@openzeppelin/contracts/utils/cryptography/MerkleProof.sol";
    /**
     * @notice Represents NFT Smart Contract
     */
    contract ICryptoBearsERC721 {
        /** 
         * @dev ERC-721 INTERFACE 
         */
        function ownerOf(uint256 tokenId) public view virtual returns (address) {}
        /** 
         * @dev CUSTOM INTERFACE 
         */
        function mintTo(uint256 amount, address _to) external {}
        function maxMintPerTransaction() public returns (uint256) {}
    }
    /**
     * @title CryptoBearsClaim.
     *
     * @author KG Technologies (https://kgtechnologies.io).
     *
     * @notice This Smart Contract can be used to claim a Crypto Bear if one holds
     * a Crypto Bull
     *
     * @dev The primary mode of verifying permissioned actions is through Merkle Proofs
     * which are generated off-chain.
     */
    contract CryptoBearsClaim is Ownable {
        /** 
         * @notice The Smart Contract of the NFT being sold 
         * @dev ERC-721 Smart Contract 
         */
        ICryptoBearsERC721 public immutable nft;
        /**
         * @notice Crypto Bull Society NFT address
         */
        address public immutable bulls;
        /**
         * @dev CLAIMING
         */
        uint256 public claimStart = 1644692400;
        mapping(uint256 => uint256) public hasBullClaimed; // 0 = false | 1 = true
        
        /**
         * @dev Events
         */
        event ReceivedEther(address indexed sender, uint256 indexed amount);    
        event Claim(address indexed claimer, uint256 indexed amount);    
        event setClaimStartEvent(uint256 indexed time);
        event WithdrawAllEvent(address indexed to, uint256 amount);
        constructor(
            address _nftaddress
        ) Ownable() {
            nft = ICryptoBearsERC721(_nftaddress);
            bulls = 0x469823c7B84264D1BAfBcD6010e9cdf1cac305a3;
        }
     
        /**
         * @dev CLAIMING
         */
        /**
         * @notice Claim bears by providing your crypto bull Ids
         * @dev Mints amount of bears to sender as valid crypto bulls 
         * provided. Validity depends on ownership and not having claimed yet.
         *
         * @param bullIds. The tokenIds of the bulls.
         */
        function claimBears(uint256[] calldata bullIds) external {
            require(address(nft) != address(0), "BEARS NFT NOT SET");
            require(bulls != address(0), "BULLS NFT NOT SET");
            require(bullIds.length > 0, "NO IDS SUPPLIED");
            require(block.timestamp >= claimStart, "CANNOT CLAIM YET");
            /// @dev Check if sender is owner of all bulls and that they haven't claimed yet
            /// @dev Update claim status of each bull
            for (uint256 i = 0; i < bullIds.length; i++) {
                uint256 bullId = bullIds[i];
                require(IERC721( bulls ).ownerOf(bullId) == msg.sender, "NOT OWNER OF BULL");
                require(hasBullClaimed[bullId] == 0, "BULL HAS ALREADY CLAIMED BEAR");
                hasBullClaimed[bullId] = 1;
            }
            nft.mintTo(bullIds.length, msg.sender);
            emit Claim(msg.sender, bullIds.length);
        }
        /**
         * @notice View which of your bulls can still claim bears
         * @dev Given an array of bull ids returns a subset of ids that
         * can still claim a bear. Used off chain to provide input of claimBears method.
         *
         * @param bullIds. The tokenIds of the bulls.
         */
        function getNotClaimedBullsByIds(uint256[] calldata bullIds) external view returns (uint256[] memory) {
            require(bullIds.length > 0, "NO IDS SUPPLIED");
            uint256 length = bullIds.length;
            uint256[] memory notClaimedBulls = new uint256[](length);
            uint256 counter;
            /// @dev Check if sender is owner of all bulls and that they haven't claimed yet
            /// @dev Update claim status of each bull
            for (uint256 i = 0; i < bullIds.length; i++) {
                uint256 bullId = bullIds[i];
                //require(IERC721( bulls ).ownerOf(bullId) == owner, "NOT OWNER OF BULL");            
                if (hasBullClaimed[bullId] == 0) {
                    notClaimedBulls[counter] = bullId;
                    counter++;
                }
            }
            return notClaimedBulls;
        }
        /** 
         * @dev OWNER ONLY 
         */
        /**
         * @notice Change the startime for bulls to claim their bears;
         *
         * @param newStart. The new start time.
         */
        function setClaimStart(uint256 newStart) external onlyOwner {
            claimStart = newStart;
            emit setClaimStartEvent(newStart);
        }
        /**
         * @dev FINANCE
         */
        /**
         * @notice Allows owner to withdraw funds generated from sale.
         *
         * @param _to. The address to send the funds to.
         */
        function withdrawAll(address _to) external onlyOwner {
            require(_to != address(0), "CANNOT WITHDRAW TO ZERO ADDRESS");
            uint256 contractBalance = address(this).balance;
            require(contractBalance > 0, "NO ETHER TO WITHDRAW");
            
            payable(_to).transfer(contractBalance);
            emit WithdrawAllEvent(_to, contractBalance);
        }
        /**
         * @dev Fallback function for receiving Ether
         */
        receive() external payable {
            emit ReceivedEther(msg.sender, msg.value);
        }
    }// SPDX-License-Identifier: MIT
    // OpenZeppelin Contracts v4.4.1 (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`, checking first that contract recipients
         * are aware of the ERC721 protocol to prevent tokens from being forever locked.
         *
         * Requirements:
         *
         * - `from` cannot be the zero address.
         * - `to` cannot be the zero address.
         * - `tokenId` token must exist and be owned by `from`.
         * - If the caller is not `from`, it must be have been allowed to move this token by either {approve} or {setApprovalForAll}.
         * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
         *
         * Emits a {Transfer} event.
         */
        function safeTransferFrom(
            address from,
            address to,
            uint256 tokenId
        ) external;
        /**
         * @dev Transfers `tokenId` token from `from` to `to`.
         *
         * WARNING: Usage of this method is discouraged, use {safeTransferFrom} whenever possible.
         *
         * Requirements:
         *
         * - `from` cannot be the zero address.
         * - `to` cannot be the zero address.
         * - `tokenId` token must be owned by `from`.
         * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
         *
         * Emits a {Transfer} event.
         */
        function transferFrom(
            address from,
            address to,
            uint256 tokenId
        ) external;
        /**
         * @dev Gives permission to `to` to transfer `tokenId` token to another account.
         * The approval is cleared when the token is transferred.
         *
         * Only a single account can be approved at a time, so approving the zero address clears previous approvals.
         *
         * Requirements:
         *
         * - The caller must own the token or be an approved operator.
         * - `tokenId` must exist.
         *
         * Emits an {Approval} event.
         */
        function approve(address to, uint256 tokenId) external;
        /**
         * @dev Returns the account approved for `tokenId` token.
         *
         * Requirements:
         *
         * - `tokenId` must exist.
         */
        function getApproved(uint256 tokenId) external view returns (address operator);
        /**
         * @dev Approve or remove `operator` as an operator for the caller.
         * Operators can call {transferFrom} or {safeTransferFrom} for any token owned by the caller.
         *
         * Requirements:
         *
         * - The `operator` cannot be the caller.
         *
         * Emits an {ApprovalForAll} event.
         */
        function setApprovalForAll(address operator, bool _approved) external;
        /**
         * @dev Returns if the `operator` is allowed to manage all of the assets of `owner`.
         *
         * See {setApprovalForAll}
         */
        function isApprovedForAll(address owner, address operator) external view returns (bool);
        /**
         * @dev Safely transfers `tokenId` token from `from` to `to`.
         *
         * Requirements:
         *
         * - `from` cannot be the zero address.
         * - `to` cannot be the zero address.
         * - `tokenId` token must exist and be owned by `from`.
         * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
         * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
         *
         * Emits a {Transfer} event.
         */
        function safeTransferFrom(
            address from,
            address to,
            uint256 tokenId,
            bytes calldata data
        ) external;
    }
    // SPDX-License-Identifier: MIT
    // OpenZeppelin Contracts v4.4.1 (access/Ownable.sol)
    pragma solidity ^0.8.0;
    import "../utils/Context.sol";
    /**
     * @dev Contract module which provides a basic access control mechanism, where
     * there is an account (an owner) that can be granted exclusive access to
     * specific functions.
     *
     * By default, the owner account will be the one that deploys the contract. This
     * can later be changed with {transferOwnership}.
     *
     * This module is used through inheritance. It will make available the modifier
     * `onlyOwner`, which can be applied to your functions to restrict their use to
     * the owner.
     */
    abstract contract Ownable is Context {
        address private _owner;
        event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
        /**
         * @dev Initializes the contract setting the deployer as the initial owner.
         */
        constructor() {
            _transferOwnership(_msgSender());
        }
        /**
         * @dev Returns the address of the current owner.
         */
        function owner() public view virtual returns (address) {
            return _owner;
        }
        /**
         * @dev Throws if called by any account other than the owner.
         */
        modifier onlyOwner() {
            require(owner() == _msgSender(), "Ownable: caller is not the owner");
            _;
        }
        /**
         * @dev Leaves the contract without owner. It will not be possible to call
         * `onlyOwner` functions anymore. Can only be called by the current owner.
         *
         * NOTE: Renouncing ownership will leave the contract without an owner,
         * thereby removing any functionality that is only available to the owner.
         */
        function renounceOwnership() public virtual onlyOwner {
            _transferOwnership(address(0));
        }
        /**
         * @dev Transfers ownership of the contract to a new account (`newOwner`).
         * Can only be called by the current owner.
         */
        function transferOwnership(address newOwner) public virtual onlyOwner {
            require(newOwner != address(0), "Ownable: new owner is the zero address");
            _transferOwnership(newOwner);
        }
        /**
         * @dev Transfers ownership of the contract to a new account (`newOwner`).
         * Internal function without access restriction.
         */
        function _transferOwnership(address newOwner) internal virtual {
            address oldOwner = _owner;
            _owner = newOwner;
            emit OwnershipTransferred(oldOwner, newOwner);
        }
    }
    // SPDX-License-Identifier: MIT
    // OpenZeppelin Contracts (last updated v4.5.0) (utils/cryptography/MerkleProof.sol)
    pragma solidity ^0.8.0;
    /**
     * @dev These functions deal with verification of Merkle Trees proofs.
     *
     * The proofs can be generated using the JavaScript library
     * https://github.com/miguelmota/merkletreejs[merkletreejs].
     * Note: the hashing algorithm should be keccak256 and pair sorting should be enabled.
     *
     * See `test/utils/cryptography/MerkleProof.test.js` for some examples.
     */
    library MerkleProof {
        /**
         * @dev Returns true if a `leaf` can be proved to be a part of a Merkle tree
         * defined by `root`. For this, a `proof` must be provided, containing
         * sibling hashes on the branch from the leaf to the root of the tree. Each
         * pair of leaves and each pair of pre-images are assumed to be sorted.
         */
        function verify(
            bytes32[] memory proof,
            bytes32 root,
            bytes32 leaf
        ) internal pure returns (bool) {
            return processProof(proof, leaf) == root;
        }
        /**
         * @dev Returns the rebuilt hash obtained by traversing a Merklee tree up
         * from `leaf` using `proof`. A `proof` is valid if and only if the rebuilt
         * hash matches the root of the tree. When processing the proof, the pairs
         * of leafs & pre-images are assumed to be sorted.
         *
         * _Available since v4.4._
         */
        function processProof(bytes32[] memory proof, bytes32 leaf) internal pure returns (bytes32) {
            bytes32 computedHash = leaf;
            for (uint256 i = 0; i < proof.length; i++) {
                bytes32 proofElement = proof[i];
                if (computedHash <= proofElement) {
                    // Hash(current computed hash + current element of the proof)
                    computedHash = _efficientHash(computedHash, proofElement);
                } else {
                    // Hash(current element of the proof + current computed hash)
                    computedHash = _efficientHash(proofElement, computedHash);
                }
            }
            return computedHash;
        }
        function _efficientHash(bytes32 a, bytes32 b) private pure returns (bytes32 value) {
            assembly {
                mstore(0x00, a)
                mstore(0x20, b)
                value := keccak256(0x00, 0x40)
            }
        }
    }
    // 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);
    }
    // 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 2 of 3: CryptoBearsERC721
    // SPDX-License-Identifier: MIT
    // Developed by KG Technologies (https://kgtechnologies.io)
    pragma solidity 0.8.11;
    /**
       _____ _______     _______ _______ ____    ____  ______          _____   _____ 
      / ____|  __ \\ \\   / /  __ \\__   __/ __ \\  |  _ \\|  ____|   /\\   |  __ \\ / ____|
     | |    | |__) \\ \\_/ /| |__) | | | | |  | | | |_) | |__     /  \\  | |__) | (___  
     | |    |  _  / \\   / |  ___/  | | | |  | | |  _ <|  __|   / /\\ \\ |  _  / \\___ \\ 
     | |____| | \\ \\  | |  | |      | | | |__| | | |_) | |____ / ____ \\| | \\ \\ ____) |
      \\_____|_|  \\_\\ |_|  |_|      |_|  \\____/  |____/|______/_/    \\_\\_|  \\_\\_____/ 
                                                                                                                                                                                                         
     */
    import "./lib/ERC721A.sol";
    import "@openzeppelin/contracts/access/AccessControl.sol";
    import "@openzeppelin/contracts/access/Ownable.sol";
    /**
     * @notice Represents opensea's proxy contract for delegated transactions
     */
    contract OwnableDelegateProxy {}
    /**
     * @notice Represents opensea's ProxyRegistry contract.
     * Used to find the opensea proxy contract of a user
     */
    contract ProxyRegistry {
        mapping(address => OwnableDelegateProxy) public proxies;
    }
    /**
     * @title CryptoBearsERC721.
     *
     * @author KG Technologies (https://kgtechnologies.io).
     *
     * @notice This smart contract can be used to represent an ERC-721 asset on the Ethereum network.
     * It supports delayed reveals, gas-efficient batch minting {ERC721A}, freezing of metadata
     * and role-based access control.
     *
     * @dev The ERC-721A standard developed by chiru-labs, is used as a basis for this contract.
     *
     */
    contract CryptoBearsERC721 is ERC721A, AccessControl, Ownable {
        using Strings for uint256;
        /** 
         * @dev NFT PLATFORM INTEGRATION 
         */
        address public openseaProxyRegistryAddress;
        /**
         * @dev METADATA
         */
        string public baseURIString = "https://cryptobullsociety.com/bears/metadata/";
        string public preRevealBaseURIString = "https://cryptobullsociety.com/bears/metadata/";
        string public extension = ".json";
        /**
         * @dev MINT SETTINGS 
         */
        uint256 public immutable maxMintPerTransaction = 500;
        /** 
         * @dev FREEZE 
         */
        bool public isFrozen = false;
        /** 
         * @dev REVEAL 
         */
        uint256 public revealDate = 1644606000 + 7 days;
        /** 
         * @dev ROLES 
         */
        bytes32 public constant MINTER_ROLE = keccak256("MINTER_ROLE");
        bytes32 public constant BURNER_ROLE = keccak256("BURNER_ROLE");
        /** 
         * @dev MODIFIERS 
         */
        modifier notFrozen() {
            require(!isFrozen, "CONTRACT FROZEN");
            _;
        }
        /** 
         * @dev EVENTS 
         */    
        event setBaseURIEvent(string indexed baseURI);
        event setPreRevealBaseURIEvent(string indexed preRevealBaseURI);
        event setRevealDateEvent(uint256 indexed revealDate);
        event setExtensionEvent(string indexed extension);
        event setOwnersExplicitEvent(uint256 indexed quantity);
        event ReceivedEther(address indexed sender, uint256 indexed amount);
        event WithdrawAllEvent(address indexed to, uint256 amount);
        constructor(
            address _openseaProxyRegistryAddress
        ) ERC721A("Crypto Bears", "CB", maxMintPerTransaction) Ownable() {
            _setupRole(MINTER_ROLE, msg.sender);
            _setupRole(BURNER_ROLE, msg.sender);
            _setupRole(DEFAULT_ADMIN_ROLE, msg.sender);
            openseaProxyRegistryAddress = _openseaProxyRegistryAddress;
        }
        /**
         * @dev MINTING 
         */
        /**
         * @notice Function to mint NFTs to a specified address. Only 
         * accessible by accounts with a role of MINTER_ROLE
         *
         * @param amount The amount of NFTs to be minted
         * @param _to The address to which the NFTs will be minted to
         */
        function mintTo(uint256 amount, address _to) external onlyRole(MINTER_ROLE) {
            _safeMint(_to, amount);
        }
        /** 
         * @dev VIEW ONLY
         */
        /**
         * @notice Function to get the URI for the metadata of a specific tokenId
         * @dev Return value is based on revealDate.
         *
         * @param tokenId. The tokenId which we want to know the URI of.
         * @return The URI of token tokenid
         */
        function tokenURI(uint256 tokenId) public view virtual override returns (string memory) {
            if (block.timestamp >= revealDate) {
                return string(abi.encodePacked(baseURIString, tokenId.toString(), extension));
            } else {
                return string(abi.encodePacked(preRevealBaseURIString, tokenId.toString(), extension));
            }        
        }
        /**
         * @dev See {IERC165-supportsInterface}.
         */
        function supportsInterface(bytes4 interfaceId) public view virtual override(AccessControl, ERC721A) returns (bool) {
            return
                interfaceId == type(IERC721).interfaceId ||
                interfaceId == type(IERC721Metadata).interfaceId ||
                interfaceId == type(IERC721Enumerable).interfaceId ||
                interfaceId == type(IAccessControl).interfaceId ||
                super.supportsInterface(interfaceId);
        }
        /**
         * @notice Override isApprovedForAll to whitelist user's OpenSea proxy account to enable gas-less listings.
         * @dev Used for integration with opensea's Wyvern exchange protocol.
         * See {IERC721-isApprovedForAll}.
         */
        function isApprovedForAll(address owner, address operator)
            override
            public
            view
            returns (bool)
        {
            // Create an instance of the ProxyRegistry contract from Opensea
            ProxyRegistry proxyRegistry = ProxyRegistry(openseaProxyRegistryAddress);
            // whitelist the ProxyContract of the owner of the NFT
            if (address(proxyRegistry.proxies(owner)) == operator) {
                return true;
            }
            if (openseaProxyRegistryAddress == operator) {
                return true;
            }
            return super.isApprovedForAll(owner, operator);
        }
        /**
         * @dev Override msgSender to allow for meta transactions on OpenSea.
         */
        function _msgSender()
            override
            internal
            view
            returns (address sender)
        {
            if (msg.sender == address(this)) {
                bytes memory array = msg.data;
                uint256 index = msg.data.length;
                assembly {
                    // Load the 32 bytes word from memory with the address on the lower 20 bytes, and mask those.
                    sender := and(
                        mload(add(array, index)),
                        0xffffffffffffffffffffffffffffffffffffffff
                    )
                }
            } else {
                sender = payable(msg.sender);
            }
            return sender;
        }
        /**
         * @dev OWNER  ONLY
         */
        /**
         * @notice Allow for changing of metadata URL.
         * @dev Can be turned off by freezing the contract.
         *
         * @param _newBaseURI. The new base URL for the metadata of the collection.
         */
        function setBaseURI(string memory _newBaseURI) external onlyOwner notFrozen {
            baseURIString = _newBaseURI;
            emit setBaseURIEvent(_newBaseURI);
        }
        /**
         * @notice Allow for changing of placeholder metadata URL.
         * @dev Can be turned off by freezing the contract.
         *
         * @param _newBaseURI. The new base URL for the placeholder metadata of the collection.
         */
        function setPreRevealBaseURI(string memory _newBaseURI) external onlyOwner notFrozen {
            preRevealBaseURIString = _newBaseURI;
            emit setPreRevealBaseURIEvent(_newBaseURI);
        }
        /**
         * @notice Allow for changing of the reveal date of the collection.
         * @dev Can be turned off by freezing the contract.
         *
         * @param _newRevealDate. The new reveal date for the collection.
         */
        function setRevealDate(uint256 _newRevealDate) external onlyOwner notFrozen {
            revealDate = _newRevealDate;
            emit setRevealDateEvent(_newRevealDate);
        }
        /**
         * @notice Allow for changing of the extension of the metadata files.
         * @dev Can be turned off by freezing the contract.
         *
         * @param _extension. The new extension.
         */
        function setExtension(string calldata _extension) external onlyOwner notFrozen {
            extension = _extension;
            emit setExtensionEvent(_extension);
        }
        /**
         * @notice Allow for explicitly setting of an NFT's owner.
         * @dev Can be used in the future to avoid expensive in contract ownerOf query.
         * See {ERC721A-_setOwnersExplicit}.
         *
         * @param _quantity. The amount of NFT's to set the owner of explicitly.
         */
        function setOwnersExplicit(uint256 _quantity) external onlyOwner {
            _setOwnersExplicit(_quantity);
            emit setOwnersExplicitEvent(_quantity);
        }    
        
        /**
         * @notice Emit transfer event on NFT in case opensea missed minting event.
         *
         * @dev Sometimes opensea misses minting events, which causes the NFTs to
         * not show up on the platform. We can fix this by re-emitting the transfer 
         * event on the NFT.
         *
         * @param start. The NFT to start from.
         * @param end. The NFT to finish with.
         */
        function emitTransferEvent(uint256 start, uint256 end) external onlyOwner {
            require(start < end, "START CANNOT BE GREATED THAN OR EQUAL TO END");
            require(end <= totalSupply(), "CANNOT EMIT ABOVE TOTAL SUPPY");
            for (uint i = start; i < end; i++) {
                address owner = ownerOf(i);
                emit Transfer(owner, owner, i);
            }
        }
        /** 
         * @dev FINANCE 
         */
        /**
         * @notice Allows owner to withdraw funds.
         *
         * @param _to. The address to send the funds to.
         */
        function withdrawAll(address _to) external onlyOwner {
            require(_to != address(0), "CANNOT WITHDRAW TO ZERO ADDRESS");
            uint256 contractBalance = address(this).balance;
            require(contractBalance > 0, "NO ETHER TO WITHDRAW");
            payable(_to).transfer(contractBalance);
            emit WithdrawAllEvent(_to, contractBalance);
        }
        /**
         * @dev Fallback function for receiving Ether
         */
        receive() external payable {
            emit ReceivedEther(msg.sender, msg.value);
        }
    }// SPDX-License-Identifier: MIT
    // Creator: Chiru Labs
    pragma solidity ^0.8.0;
    import "@openzeppelin/contracts/token/ERC721/IERC721.sol";
    import "@openzeppelin/contracts/token/ERC721/IERC721Receiver.sol";
    import "@openzeppelin/contracts/token/ERC721/extensions/IERC721Metadata.sol";
    import "@openzeppelin/contracts/token/ERC721/extensions/IERC721Enumerable.sol";
    import "@openzeppelin/contracts/utils/Address.sol";
    import "@openzeppelin/contracts/utils/Context.sol";
    import "@openzeppelin/contracts/utils/Strings.sol";
    import "@openzeppelin/contracts/utils/introspection/ERC165.sol";
    /**
     * @dev Implementation of https://eips.ethereum.org/EIPS/eip-721[ERC721] Non-Fungible Token Standard, including
     * the Metadata and Enumerable extension. Built to optimize for lower gas during batch mints.
     *
     * Assumes serials are sequentially minted starting at 0 (e.g. 0, 1, 2, 3..).
     *
     * Does not support burning tokens to address(0).
     */
    contract ERC721A is Context, ERC165, IERC721, IERC721Metadata, IERC721Enumerable {
        using Address for address;
        using Strings for uint256;
        struct TokenOwnership {
            address addr;
            uint64 startTimestamp;
        }
        struct AddressData {
            uint128 balance;
            uint128 numberMinted;
        }
        uint256 private currentIndex = 1;
        uint256 internal immutable maxBatchSize;
        // Token name
        string private _name;
        // Token symbol
        string private _symbol;
        // Mapping from token ID to ownership details
        // An empty struct value does not necessarily mean the token is unowned. See ownershipOf implementation for details.
        mapping(uint256 => TokenOwnership) private _ownerships;
        // Mapping owner address to address data
        mapping(address => AddressData) private _addressData;
        // 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
         * `maxBatchSize` refers to how much a minter can mint at a time.
         */
        constructor(
            string memory name_,
            string memory symbol_,
            uint256 maxBatchSize_
        ) {
            require(maxBatchSize_ > 0, "ERC721A: max batch size must be nonzero");
            _name = name_;
            _symbol = symbol_;
            maxBatchSize = maxBatchSize_;
        }
        /**
         * @dev See {IERC721Enumerable-totalSupply}.
         */
        function totalSupply() public view override returns (uint256) {
            return currentIndex - 1;
        }
        /**
         * @dev See {IERC721Enumerable-tokenByIndex}.
         */
        function tokenByIndex(uint256 index) public view override returns (uint256) {
            require(index <= totalSupply(), "ERC721A: global index out of bounds");
            return index;
        }
        /**
         * @dev See {IERC721Enumerable-tokenOfOwnerByIndex}.
         * This read function is O(totalSupply). If calling from a separate contract, be sure to test gas first.
         * It may also degrade with extremely large collection sizes (e.g >> 10000), test for your use case.
         */
        function tokenOfOwnerByIndex(address owner, uint256 index) public view override returns (uint256) {
            require(index < balanceOf(owner), "ERC721A: owner index out of bounds");
            uint256 numMintedSoFar = totalSupply();
            uint256 tokenIdsIdx = 0;
            address currOwnershipAddr = address(0);
            for (uint256 i = 0; i <= numMintedSoFar; i++) {
                TokenOwnership memory ownership = _ownerships[i];
                if (ownership.addr != address(0)) {
                    currOwnershipAddr = ownership.addr;
                }
                if (currOwnershipAddr == owner) {
                    if (tokenIdsIdx == index) {
                        return i;
                    }
                    tokenIdsIdx++;
                }
            }
            revert("ERC721A: unable to get token of owner by index");
        }
        /**
         * @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 ||
                interfaceId == type(IERC721Enumerable).interfaceId ||
                super.supportsInterface(interfaceId);
        }
        /**
         * @dev See {IERC721-balanceOf}.
         */
        function balanceOf(address owner) public view override returns (uint256) {
            require(owner != address(0), "ERC721A: balance query for the zero address");
            return uint256(_addressData[owner].balance);
        }
        function _numberMinted(address owner) internal view returns (uint256) {
            require(owner != address(0), "ERC721A: number minted query for the zero address");
            return uint256(_addressData[owner].numberMinted);
        }
        function ownershipOf(uint256 tokenId) internal view returns (TokenOwnership memory) {
            require(_exists(tokenId), "ERC721A: owner query for nonexistent token");
            uint256 lowestTokenToCheck;
            if (tokenId >= maxBatchSize) {
                lowestTokenToCheck = tokenId - maxBatchSize + 1;
            }
            for (uint256 curr = tokenId; curr >= lowestTokenToCheck; curr--) {
                TokenOwnership memory ownership = _ownerships[curr];
                if (ownership.addr != address(0)) {
                    return ownership;
                }
            }
            revert("ERC721A: unable to determine the owner of token");
        }
        /**
         * @dev See {IERC721-ownerOf}.
         */
        function ownerOf(uint256 tokenId) public view override returns (address) {
            return ownershipOf(tokenId).addr;
        }
        /**
         * @dev See {IERC721Metadata-name}.
         */
        function name() public view virtual override returns (string memory) {
            return _name;
        }
        /**
         * @dev See {IERC721Metadata-symbol}.
         */
        function symbol() public view virtual override returns (string memory) {
            return _symbol;
        }
        /**
         * @dev See {IERC721Metadata-tokenURI}.
         */
        function tokenURI(uint256 tokenId) public view virtual override returns (string memory) {
            require(_exists(tokenId), "ERC721Metadata: URI query for nonexistent token");
            string memory baseURI = _baseURI();
            return bytes(baseURI).length > 0 ? string(abi.encodePacked(baseURI, tokenId.toString())) : "";
        }
        /**
         * @dev Base URI for computing {tokenURI}. If set, the resulting URI for each
         * token will be the concatenation of the `baseURI` and the `tokenId`. Empty
         * by default, can be overriden in child contracts.
         */
        function _baseURI() internal view virtual returns (string memory) {
            return "";
        }
        /**
         * @dev See {IERC721-approve}.
         */
        function approve(address to, uint256 tokenId) public override {
            address owner = ERC721A.ownerOf(tokenId);
            require(to != owner, "ERC721A: approval to current owner");
            require(
                _msgSender() == owner || isApprovedForAll(owner, _msgSender()),
                "ERC721A: approve caller is not owner nor approved for all"
            );
            _approve(to, tokenId, owner);
        }
        /**
         * @dev See {IERC721-getApproved}.
         */
        function getApproved(uint256 tokenId) public view override returns (address) {
            require(_exists(tokenId), "ERC721A: approved query for nonexistent token");
            return _tokenApprovals[tokenId];
        }
        /**
         * @dev See {IERC721-setApprovalForAll}.
         */
        function setApprovalForAll(address operator, bool approved) public override {
            require(operator != _msgSender(), "ERC721A: approve to caller");
            _operatorApprovals[_msgSender()][operator] = approved;
            emit ApprovalForAll(_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 override {
            _transfer(from, to, tokenId);
        }
        /**
         * @dev See {IERC721-safeTransferFrom}.
         */
        function safeTransferFrom(
            address from,
            address to,
            uint256 tokenId
        ) public override {
            safeTransferFrom(from, to, tokenId, "");
        }
        /**
         * @dev See {IERC721-safeTransferFrom}.
         */
        function safeTransferFrom(
            address from,
            address to,
            uint256 tokenId,
            bytes memory _data
        ) public override {
            _transfer(from, to, tokenId);
            require(
                _checkOnERC721Received(from, to, tokenId, _data),
                "ERC721A: transfer to non ERC721Receiver implementer"
            );
        }
        /**
         * @dev Returns whether `tokenId` exists.
         *
         * Tokens can be managed by their owner or approved accounts via {approve} or {setApprovalForAll}.
         *
         * Tokens start existing when they are minted (`_mint`),
         */
        function _exists(uint256 tokenId) internal view returns (bool) {
            return tokenId < currentIndex && tokenId > 0;
        }
        function _safeMint(address to, uint256 quantity) internal {
            _safeMint(to, quantity, "");
        }
        /**
         * @dev Mints `quantity` tokens and transfers them to `to`.
         *
         * Requirements:
         *
         * - `to` cannot be the zero address.
         * - `quantity` cannot be larger than the max batch size.
         *
         * Emits a {Transfer} event.
         */
        function _safeMint(
            address to,
            uint256 quantity,
            bytes memory _data
        ) internal {
            uint256 startTokenId = currentIndex;
            require(to != address(0), "ERC721A: mint to the zero address");
            // We know if the first token in the batch doesn't exist, the other ones don't as well, because of serial ordering.
            require(!_exists(startTokenId), "ERC721A: token already minted");
            require(quantity <= maxBatchSize, "ERC721A: quantity to mint too high");
            _beforeTokenTransfers(address(0), to, startTokenId, quantity);
            AddressData memory addressData = _addressData[to];
            _addressData[to] = AddressData(
                addressData.balance + uint128(quantity),
                addressData.numberMinted + uint128(quantity)
            );
            _ownerships[startTokenId] = TokenOwnership(to, uint64(block.timestamp));
            uint256 updatedIndex = startTokenId;
            for (uint256 i = 0; i < quantity; i++) {
                emit Transfer(address(0), to, updatedIndex);
                require(
                    _checkOnERC721Received(address(0), to, updatedIndex, _data),
                    "ERC721A: transfer to non ERC721Receiver implementer"
                );
                updatedIndex++;
            }
            currentIndex = updatedIndex;
            _afterTokenTransfers(address(0), to, startTokenId, quantity);
        }
        /**
         * @dev Transfers `tokenId` from `from` to `to`.
         *
         * 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
        ) private {
            TokenOwnership memory prevOwnership = ownershipOf(tokenId);
            bool isApprovedOrOwner = (_msgSender() == prevOwnership.addr ||
                getApproved(tokenId) == _msgSender() ||
                isApprovedForAll(prevOwnership.addr, _msgSender()));
            require(isApprovedOrOwner, "ERC721A: transfer caller is not owner nor approved");
            require(prevOwnership.addr == from, "ERC721A: transfer from incorrect owner");
            require(to != address(0), "ERC721A: transfer to the zero address");
            _beforeTokenTransfers(from, to, tokenId, 1);
            // Clear approvals from the previous owner
            _approve(address(0), tokenId, prevOwnership.addr);
            _addressData[from].balance -= 1;
            _addressData[to].balance += 1;
            _ownerships[tokenId] = TokenOwnership(to, uint64(block.timestamp));
            // If the ownership slot of tokenId+1 is not explicitly set, that means the transfer initiator owns it.
            // Set the slot of tokenId+1 explicitly in storage to maintain correctness for ownerOf(tokenId+1) calls.
            uint256 nextTokenId = tokenId + 1;
            if (_ownerships[nextTokenId].addr == address(0)) {
                if (_exists(nextTokenId)) {
                    _ownerships[nextTokenId] = TokenOwnership(prevOwnership.addr, prevOwnership.startTimestamp);
                }
            }
            emit Transfer(from, to, tokenId);
            _afterTokenTransfers(from, to, tokenId, 1);
        }
        /**
         * @dev Approve `to` to operate on `tokenId`
         *
         * Emits a {Approval} event.
         */
        function _approve(
            address to,
            uint256 tokenId,
            address owner
        ) private {
            _tokenApprovals[tokenId] = to;
            emit Approval(owner, to, tokenId);
        }
        uint256 public nextOwnerToExplicitlySet = 0;
        /**
         * @dev Explicitly set `owners` to eliminate loops in future calls of ownerOf().
         */
        function _setOwnersExplicit(uint256 quantity) internal {
            uint256 oldNextOwnerToSet = nextOwnerToExplicitlySet;
            require(quantity > 0, "quantity must be nonzero");
            uint256 endIndex = oldNextOwnerToSet + quantity - 1;
            if (endIndex > currentIndex - 1) {
                endIndex = currentIndex - 1;
            }
            // We know if the last one in the group exists, all in the group exist, due to serial ordering.
            require(_exists(endIndex), "not enough minted yet for this cleanup");
            for (uint256 i = oldNextOwnerToSet; i <= endIndex; i++) {
                if (_ownerships[i].addr == address(0)) {
                    TokenOwnership memory ownership = ownershipOf(i);
                    _ownerships[i] = TokenOwnership(ownership.addr, ownership.startTimestamp);
                }
            }
            nextOwnerToExplicitlySet = endIndex + 1;
        }
        /**
         * @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(to).onERC721Received.selector;
                } catch (bytes memory reason) {
                    if (reason.length == 0) {
                        revert("ERC721A: transfer to non ERC721Receiver implementer");
                    } else {
                        assembly {
                            revert(add(32, reason), mload(reason))
                        }
                    }
                }
            } else {
                return true;
            }
        }
        /**
         * @dev Hook that is called before a set of serially-ordered token ids are about to be transferred. This includes minting.
         *
         * startTokenId - the first token id to be transferred
         * quantity - the amount to be transferred
         *
         * Calling conditions:
         *
         * - When `from` and `to` are both non-zero, ``from``'s `tokenId` will be
         * transferred to `to`.
         * - When `from` is zero, `tokenId` will be minted for `to`.
         */
        function _beforeTokenTransfers(
            address from,
            address to,
            uint256 startTokenId,
            uint256 quantity
        ) internal virtual {}
        /**
         * @dev Hook that is called after a set of serially-ordered token ids have been transferred. This includes
         * minting.
         *
         * startTokenId - the first token id to be transferred
         * quantity - the amount to be transferred
         *
         * Calling conditions:
         *
         * - when `from` and `to` are both non-zero.
         * - `from` and `to` are never both zero.
         */
        function _afterTokenTransfers(
            address from,
            address to,
            uint256 startTokenId,
            uint256 quantity
        ) internal virtual {}
    }// SPDX-License-Identifier: MIT
    // OpenZeppelin Contracts (last updated v4.5.0) (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})$/
         *
         * _Available since v4.1._
         */
        modifier onlyRole(bytes32 role) {
            _checkRole(role, _msgSender());
            _;
        }
        /**
         * @dev See {IERC165-supportsInterface}.
         */
        function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
            return interfaceId == type(IAccessControl).interfaceId || super.supportsInterface(interfaceId);
        }
        /**
         * @dev Returns `true` if `account` has been granted `role`.
         */
        function hasRole(bytes32 role, address account) public view virtual override returns (bool) {
            return _roles[role].members[account];
        }
        /**
         * @dev Revert with a standard message if `account` is missing `role`.
         *
         * The format of the revert reason is given by the following regular expression:
         *
         *  /^AccessControl: account (0x[0-9a-f]{40}) is missing role (0x[0-9a-f]{64})$/
         */
        function _checkRole(bytes32 role, address account) internal view virtual {
            if (!hasRole(role, account)) {
                revert(
                    string(
                        abi.encodePacked(
                            "AccessControl: account ",
                            Strings.toHexString(uint160(account), 20),
                            " is missing role ",
                            Strings.toHexString(uint256(role), 32)
                        )
                    )
                );
            }
        }
        /**
         * @dev Returns the admin role that controls `role`. See {grantRole} and
         * {revokeRole}.
         *
         * To change a role's admin, use {_setRoleAdmin}.
         */
        function getRoleAdmin(bytes32 role) public view virtual override returns (bytes32) {
            return _roles[role].adminRole;
        }
        /**
         * @dev Grants `role` to `account`.
         *
         * If `account` had not been already granted `role`, emits a {RoleGranted}
         * event.
         *
         * Requirements:
         *
         * - the caller must have ``role``'s admin role.
         */
        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.
         */
        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`.
         */
        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.
         *
         * [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.
         */
        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.
         */
        function _revokeRole(bytes32 role, address account) internal virtual {
            if (hasRole(role, account)) {
                _roles[role].members[account] = false;
                emit RoleRevoked(role, account, _msgSender());
            }
        }
    }
    // SPDX-License-Identifier: MIT
    // OpenZeppelin Contracts v4.4.1 (access/Ownable.sol)
    pragma solidity ^0.8.0;
    import "../utils/Context.sol";
    /**
     * @dev Contract module which provides a basic access control mechanism, where
     * there is an account (an owner) that can be granted exclusive access to
     * specific functions.
     *
     * By default, the owner account will be the one that deploys the contract. This
     * can later be changed with {transferOwnership}.
     *
     * This module is used through inheritance. It will make available the modifier
     * `onlyOwner`, which can be applied to your functions to restrict their use to
     * the owner.
     */
    abstract contract Ownable is Context {
        address private _owner;
        event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
        /**
         * @dev Initializes the contract setting the deployer as the initial owner.
         */
        constructor() {
            _transferOwnership(_msgSender());
        }
        /**
         * @dev Returns the address of the current owner.
         */
        function owner() public view virtual returns (address) {
            return _owner;
        }
        /**
         * @dev Throws if called by any account other than the owner.
         */
        modifier onlyOwner() {
            require(owner() == _msgSender(), "Ownable: caller is not the owner");
            _;
        }
        /**
         * @dev Leaves the contract without owner. It will not be possible to call
         * `onlyOwner` functions anymore. Can only be called by the current owner.
         *
         * NOTE: Renouncing ownership will leave the contract without an owner,
         * thereby removing any functionality that is only available to the owner.
         */
        function renounceOwnership() public virtual onlyOwner {
            _transferOwnership(address(0));
        }
        /**
         * @dev Transfers ownership of the contract to a new account (`newOwner`).
         * Can only be called by the current owner.
         */
        function transferOwnership(address newOwner) public virtual onlyOwner {
            require(newOwner != address(0), "Ownable: new owner is the zero address");
            _transferOwnership(newOwner);
        }
        /**
         * @dev Transfers ownership of the contract to a new account (`newOwner`).
         * Internal function without access restriction.
         */
        function _transferOwnership(address newOwner) internal virtual {
            address oldOwner = _owner;
            _owner = newOwner;
            emit OwnershipTransferred(oldOwner, newOwner);
        }
    }
    // SPDX-License-Identifier: MIT
    // OpenZeppelin Contracts v4.4.1 (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`, checking first that contract recipients
         * are aware of the ERC721 protocol to prevent tokens from being forever locked.
         *
         * Requirements:
         *
         * - `from` cannot be the zero address.
         * - `to` cannot be the zero address.
         * - `tokenId` token must exist and be owned by `from`.
         * - If the caller is not `from`, it must be have been allowed to move this token by either {approve} or {setApprovalForAll}.
         * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
         *
         * Emits a {Transfer} event.
         */
        function safeTransferFrom(
            address from,
            address to,
            uint256 tokenId
        ) external;
        /**
         * @dev Transfers `tokenId` token from `from` to `to`.
         *
         * WARNING: Usage of this method is discouraged, use {safeTransferFrom} whenever possible.
         *
         * Requirements:
         *
         * - `from` cannot be the zero address.
         * - `to` cannot be the zero address.
         * - `tokenId` token must be owned by `from`.
         * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
         *
         * Emits a {Transfer} event.
         */
        function transferFrom(
            address from,
            address to,
            uint256 tokenId
        ) external;
        /**
         * @dev Gives permission to `to` to transfer `tokenId` token to another account.
         * The approval is cleared when the token is transferred.
         *
         * Only a single account can be approved at a time, so approving the zero address clears previous approvals.
         *
         * Requirements:
         *
         * - The caller must own the token or be an approved operator.
         * - `tokenId` must exist.
         *
         * Emits an {Approval} event.
         */
        function approve(address to, uint256 tokenId) external;
        /**
         * @dev Returns the account approved for `tokenId` token.
         *
         * Requirements:
         *
         * - `tokenId` must exist.
         */
        function getApproved(uint256 tokenId) external view returns (address operator);
        /**
         * @dev Approve or remove `operator` as an operator for the caller.
         * Operators can call {transferFrom} or {safeTransferFrom} for any token owned by the caller.
         *
         * Requirements:
         *
         * - The `operator` cannot be the caller.
         *
         * Emits an {ApprovalForAll} event.
         */
        function setApprovalForAll(address operator, bool _approved) external;
        /**
         * @dev Returns if the `operator` is allowed to manage all of the assets of `owner`.
         *
         * See {setApprovalForAll}
         */
        function isApprovedForAll(address owner, address operator) external view returns (bool);
        /**
         * @dev Safely transfers `tokenId` token from `from` to `to`.
         *
         * Requirements:
         *
         * - `from` cannot be the zero address.
         * - `to` cannot be the zero address.
         * - `tokenId` token must exist and be owned by `from`.
         * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
         * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
         *
         * Emits a {Transfer} event.
         */
        function safeTransferFrom(
            address from,
            address to,
            uint256 tokenId,
            bytes calldata data
        ) external;
    }
    // SPDX-License-Identifier: MIT
    // OpenZeppelin Contracts v4.4.1 (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 `IERC721.onERC721Received.selector`.
         */
        function onERC721Received(
            address operator,
            address from,
            uint256 tokenId,
            bytes calldata data
        ) external returns (bytes4);
    }
    // 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);
    }
    // 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);
    }
    // SPDX-License-Identifier: MIT
    // OpenZeppelin Contracts (last updated v4.5.0) (utils/Address.sol)
    pragma solidity ^0.8.1;
    /**
     * @dev Collection of functions related to the address type
     */
    library Address {
        /**
         * @dev Returns true if `account` is a contract.
         *
         * [IMPORTANT]
         * ====
         * It is unsafe to assume that an address for which this function returns
         * false is an externally-owned account (EOA) and not a contract.
         *
         * Among others, `isContract` will return false for the following
         * types of addresses:
         *
         *  - an externally-owned account
         *  - a contract in construction
         *  - an address where a contract will be created
         *  - an address where a contract lived, but was destroyed
         * ====
         *
         * [IMPORTANT]
         * ====
         * You shouldn't rely on `isContract` to protect against flash loan attacks!
         *
         * Preventing calls from contracts is highly discouraged. It breaks composability, breaks support for smart wallets
         * like Gnosis Safe, and does not provide security since it can be circumvented by calling from a contract
         * constructor.
         * ====
         */
        function isContract(address account) internal view returns (bool) {
            // This method relies on extcodesize/address.code.length, which returns 0
            // for contracts in construction, since the code is only stored at the end
            // of the constructor execution.
            return account.code.length > 0;
        }
        /**
         * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
         * `recipient`, forwarding all available gas and reverting on errors.
         *
         * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
         * of certain opcodes, possibly making contracts go over the 2300 gas limit
         * imposed by `transfer`, making them unable to receive funds via
         * `transfer`. {sendValue} removes this limitation.
         *
         * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
         *
         * IMPORTANT: because control is transferred to `recipient`, care must be
         * taken to not create reentrancy vulnerabilities. Consider using
         * {ReentrancyGuard} or the
         * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
         */
        function sendValue(address payable recipient, uint256 amount) internal {
            require(address(this).balance >= amount, "Address: insufficient balance");
            (bool success, ) = recipient.call{value: amount}("");
            require(success, "Address: unable to send value, recipient may have reverted");
        }
        /**
         * @dev Performs a Solidity function call using a low level `call`. A
         * plain `call` is an unsafe replacement for a function call: use this
         * function instead.
         *
         * If `target` reverts with a revert reason, it is bubbled up by this
         * function (like regular Solidity function calls).
         *
         * Returns the raw returned data. To convert to the expected return value,
         * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
         *
         * Requirements:
         *
         * - `target` must be a contract.
         * - calling `target` with `data` must not revert.
         *
         * _Available since v3.1._
         */
        function functionCall(address target, bytes memory data) internal returns (bytes memory) {
            return functionCall(target, data, "Address: low-level call failed");
        }
        /**
         * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
         * `errorMessage` as a fallback revert reason when `target` reverts.
         *
         * _Available since v3.1._
         */
        function functionCall(
            address target,
            bytes memory data,
            string memory errorMessage
        ) internal returns (bytes memory) {
            return functionCallWithValue(target, data, 0, errorMessage);
        }
        /**
         * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
         * but also transferring `value` wei to `target`.
         *
         * Requirements:
         *
         * - the calling contract must have an ETH balance of at least `value`.
         * - the called Solidity function must be `payable`.
         *
         * _Available since v3.1._
         */
        function functionCallWithValue(
            address target,
            bytes memory data,
            uint256 value
        ) internal returns (bytes memory) {
            return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
        }
        /**
         * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
         * with `errorMessage` as a fallback revert reason when `target` reverts.
         *
         * _Available since v3.1._
         */
        function functionCallWithValue(
            address target,
            bytes memory data,
            uint256 value,
            string memory errorMessage
        ) internal returns (bytes memory) {
            require(address(this).balance >= value, "Address: insufficient balance for call");
            require(isContract(target), "Address: call to non-contract");
            (bool success, bytes memory returndata) = target.call{value: value}(data);
            return verifyCallResult(success, returndata, errorMessage);
        }
        /**
         * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
         * but performing a static call.
         *
         * _Available since v3.3._
         */
        function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
            return functionStaticCall(target, data, "Address: low-level static call failed");
        }
        /**
         * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
         * but performing a static call.
         *
         * _Available since v3.3._
         */
        function functionStaticCall(
            address target,
            bytes memory data,
            string memory errorMessage
        ) internal view returns (bytes memory) {
            require(isContract(target), "Address: static call to non-contract");
            (bool success, bytes memory returndata) = target.staticcall(data);
            return verifyCallResult(success, returndata, errorMessage);
        }
        /**
         * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
         * but performing a delegate call.
         *
         * _Available since v3.4._
         */
        function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
            return functionDelegateCall(target, data, "Address: low-level delegate call failed");
        }
        /**
         * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
         * but performing a delegate call.
         *
         * _Available since v3.4._
         */
        function functionDelegateCall(
            address target,
            bytes memory data,
            string memory errorMessage
        ) internal returns (bytes memory) {
            require(isContract(target), "Address: delegate call to non-contract");
            (bool success, bytes memory returndata) = target.delegatecall(data);
            return verifyCallResult(success, returndata, errorMessage);
        }
        /**
         * @dev Tool to verifies that a low level call was successful, and revert if it wasn't, either by bubbling the
         * revert reason using the provided one.
         *
         * _Available since v4.3._
         */
        function verifyCallResult(
            bool success,
            bytes memory returndata,
            string memory errorMessage
        ) internal pure returns (bytes memory) {
            if (success) {
                return returndata;
            } else {
                // Look for revert reason and bubble it up if present
                if (returndata.length > 0) {
                    // The easiest way to bubble the revert reason is using memory via assembly
                    assembly {
                        let returndata_size := mload(returndata)
                        revert(add(32, returndata), returndata_size)
                    }
                } else {
                    revert(errorMessage);
                }
            }
        }
    }
    // 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;
        }
    }
    // SPDX-License-Identifier: MIT
    // OpenZeppelin Contracts v4.4.1 (utils/Strings.sol)
    pragma solidity ^0.8.0;
    /**
     * @dev String operations.
     */
    library Strings {
        bytes16 private constant _HEX_SYMBOLS = "0123456789abcdef";
        /**
         * @dev Converts a `uint256` to its ASCII `string` decimal representation.
         */
        function toString(uint256 value) internal pure returns (string memory) {
            // Inspired by OraclizeAPI's implementation - MIT licence
            // https://github.com/oraclize/ethereum-api/blob/b42146b063c7d6ee1358846c198246239e9360e8/oraclizeAPI_0.4.25.sol
            if (value == 0) {
                return "0";
            }
            uint256 temp = value;
            uint256 digits;
            while (temp != 0) {
                digits++;
                temp /= 10;
            }
            bytes memory buffer = new bytes(digits);
            while (value != 0) {
                digits -= 1;
                buffer[digits] = bytes1(uint8(48 + uint256(value % 10)));
                value /= 10;
            }
            return string(buffer);
        }
        /**
         * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation.
         */
        function toHexString(uint256 value) internal pure returns (string memory) {
            if (value == 0) {
                return "0x00";
            }
            uint256 temp = value;
            uint256 length = 0;
            while (temp != 0) {
                length++;
                temp >>= 8;
            }
            return toHexString(value, length);
        }
        /**
         * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation with fixed length.
         */
        function toHexString(uint256 value, uint256 length) internal pure returns (string memory) {
            bytes memory buffer = new bytes(2 * length + 2);
            buffer[0] = "0";
            buffer[1] = "x";
            for (uint256 i = 2 * length + 1; i > 1; --i) {
                buffer[i] = _HEX_SYMBOLS[value & 0xf];
                value >>= 4;
            }
            require(value == 0, "Strings: hex length insufficient");
            return string(buffer);
        }
    }
    // 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;
        }
    }
    // 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);
    }
    // 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 3 of 3: MintableERC721
    // SPDX-License-Identifier: MIT
    pragma solidity 0.8.10;
    import "@openzeppelin/contracts/access/AccessControl.sol";
    import "@openzeppelin/contracts/access/Ownable.sol";
    import "@openzeppelin/contracts/token/ERC721/ERC721.sol";
    import "@openzeppelin/contracts/token/ERC721/IERC721Receiver.sol";
    import "@openzeppelin/contracts/token/ERC721/extensions/ERC721Enumerable.sol";
    import "@openzeppelin/contracts/utils/Strings.sol";
    import "@openzeppelin/contracts/utils/Address.sol";
    import "./interfaces/IMintableERC721.sol";
    contract MintableERC721 is ERC721, ERC721Enumerable, IMintableERC721, AccessControl, Ownable {
      using Address for address;
      using Strings for uint256;
      /**
    \t * @dev Smart contract unique identifier, a random number
    \t *
    \t * @dev Should be regenerated each time smart contact source code is changed
    \t *      and changes smart contract itself is to be redeployed
    \t *
    \t * @dev Generated using https://www.random.org/bytes/
    \t */
    \tuint256 public constant UID = 0xacc117b3ac718da27530715cb02078bcd68024f1f71535651f0c2b4231f0e399;
      bytes32 public constant MINTER_ROLE = keccak256("MINTER_ROLE");
      bytes32 public constant BURNER_ROLE = keccak256("BURNER_ROLE");
      bytes32 public constant URI_MANAGER_ROLE = keccak256("URI_MANAGER_ROLE");
      constructor(string memory _name, string memory _symbol) ERC721(_name, _symbol) {
        _setupRole(DEFAULT_ADMIN_ROLE, msg.sender);
        _setupRole(MINTER_ROLE, msg.sender);
        _setupRole(BURNER_ROLE, msg.sender);
        _setupRole(URI_MANAGER_ROLE, msg.sender);
      }
      string internal theBaseURI = "";
      function _baseURI() internal view virtual override returns (string memory) {
        return theBaseURI;
      }
      function tokenURI(uint256 tokenId) public view virtual override returns (string memory) {
        require(_exists(tokenId), "ERC721Metadata: URI query for nonexistent token");
        string memory baseURI = _baseURI();
        return bytes(baseURI).length > 0 ? string(abi.encodePacked(baseURI, tokenId.toString(), ".json")) : "";
      }
      /**
    \t * @dev Fired in setBaseURI()
    \t *
    \t * @param _by an address which executed update
    \t * @param _oldVal old _baseURI value
    \t * @param _newVal new _baseURI value
    \t */
      event BaseURIChanged(
        address _by,
        string _oldVal,
        string _newVal
      );
      /**
    \t * @dev Restricted access function which updates base URI used to construct
    \t *      ERC721Metadata.tokenURI
    \t *
    \t * @param _newBaseURI new base URI to set
    \t */
      function setBaseURI(string memory _newBaseURI) external onlyRole(URI_MANAGER_ROLE) {
        // Fire event
        emit BaseURIChanged(msg.sender, theBaseURI, _newBaseURI);
        // Update base uri
        theBaseURI = _newBaseURI;
      }
      /**
       * @inheritdoc IMintableERC721
       */
      function exists(uint256 _tokenId) external view returns(bool) {
        // Delegate to internal OpenZeppelin function
        return _exists(_tokenId);
      }
      /**
       * @dev Destroys `tokenId`.
       * The approval is cleared when the token is burned.
       *
       * Requirements:
       *
       * - `tokenId` must exist.
       *
       * Emits a {Transfer} event.
       */
      function burn(uint256 _tokenId) public onlyRole(BURNER_ROLE) {
        // Delegate to internal OpenZeppelin burn function
        _burn(_tokenId);
      }
      /**
       * @inheritdoc IMintableERC721
       */
      function mint(address _to, uint256 _tokenId) public onlyRole(MINTER_ROLE) {
        // Delegate to internal OpenZeppelin function
        _mint(_to, _tokenId);
      }
      /**
       * @inheritdoc IMintableERC721
       */
      function mintBatch(address _to, uint256 _tokenId, uint256 _n) public onlyRole(MINTER_ROLE) {
        for(uint256 i = 0; i < _n; i++) {
          // Delegate to internal OpenZeppelin mint function
          _mint(_to, _tokenId + i);
        }
      }
      /**
       * @inheritdoc IMintableERC721
       */
      function safeMint(address _to, uint256 _tokenId, bytes memory _data) public onlyRole(MINTER_ROLE) {
        // Delegate to internal OpenZeppelin unsafe mint function
        _mint(_to, _tokenId);
        // If a contract, check if it can receive ERC721 tokens (safe to send)
        if(_to.isContract()) {
    \t\t  bytes4 response = IERC721Receiver(_to).onERC721Received(msg.sender, address(0), _tokenId, _data);
    \t\t  require(response == IERC721Receiver(_to).onERC721Received.selector, "Invalid onERC721Received response");
        }
      }
      /**
       * @inheritdoc IMintableERC721
       */
      function safeMint(address _to, uint256 _tokenId) public {
        // Delegate to internal safe mint function (includes permission check)
        safeMint(_to, _tokenId, "");
      }
      /**
       * @inheritdoc IMintableERC721
       */
      function safeMintBatch(address _to, uint256 _tokenId, uint256 _n, bytes memory _data) public {
        // Delegate to internal unsafe batch mint function (includes permission check)
        mintBatch(_to, _tokenId, _n);
        // If a contract, check if it can receive ERC721 tokens (safe to send)
        if(_to.isContract()) {
    \t\t  bytes4 response = IERC721Receiver(_to).onERC721Received(msg.sender, address(0), _tokenId, _data);
    \t\t  require(response == IERC721Receiver(_to).onERC721Received.selector, "Invalid onERC721Received response");
        }
      }
      /**
       * @inheritdoc IMintableERC721
       */
      function safeMintBatch(address _to, uint256 _tokenId, uint256 _n) external {
        // Delegate to internal safe batch mint function (includes permission check)
        safeMintBatch(_to, _tokenId, _n, "");
      }
      /**
       * @inheritdoc ERC721
       */
      function supportsInterface(bytes4 interfaceId) public view override(ERC721, ERC721Enumerable, AccessControl) returns (bool) {
        return interfaceId == type(IMintableERC721).interfaceId || super.supportsInterface(interfaceId);
      }
      /**
       * @inheritdoc ERC721
       */
      function _beforeTokenTransfer(address from, address to, uint256 tokenId) internal virtual override(ERC721, ERC721Enumerable) {
        super._beforeTokenTransfer(from, to, tokenId);
      }
    }
    // SPDX-License-Identifier: MIT
    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})$/
         *
         * _Available since v4.1._
         */
        modifier onlyRole(bytes32 role) {
            _checkRole(role, _msgSender());
            _;
        }
        /**
         * @dev See {IERC165-supportsInterface}.
         */
        function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
            return interfaceId == type(IAccessControl).interfaceId || super.supportsInterface(interfaceId);
        }
        /**
         * @dev Returns `true` if `account` has been granted `role`.
         */
        function hasRole(bytes32 role, address account) public view override returns (bool) {
            return _roles[role].members[account];
        }
        /**
         * @dev Revert with a standard message if `account` is missing `role`.
         *
         * The format of the revert reason is given by the following regular expression:
         *
         *  /^AccessControl: account (0x[0-9a-f]{40}) is missing role (0x[0-9a-f]{64})$/
         */
        function _checkRole(bytes32 role, address account) internal view {
            if (!hasRole(role, account)) {
                revert(
                    string(
                        abi.encodePacked(
                            "AccessControl: account ",
                            Strings.toHexString(uint160(account), 20),
                            " is missing role ",
                            Strings.toHexString(uint256(role), 32)
                        )
                    )
                );
            }
        }
        /**
         * @dev Returns the admin role that controls `role`. See {grantRole} and
         * {revokeRole}.
         *
         * To change a role's admin, use {_setRoleAdmin}.
         */
        function getRoleAdmin(bytes32 role) public view 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.
         */
        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.
         */
        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 granted `role`, emits a {RoleRevoked}
         * event.
         *
         * Requirements:
         *
         * - the caller must be `account`.
         */
        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.
         *
         * [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}.
         * ====
         */
        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);
        }
        function _grantRole(bytes32 role, address account) private {
            if (!hasRole(role, account)) {
                _roles[role].members[account] = true;
                emit RoleGranted(role, account, _msgSender());
            }
        }
        function _revokeRole(bytes32 role, address account) private {
            if (hasRole(role, account)) {
                _roles[role].members[account] = false;
                emit RoleRevoked(role, account, _msgSender());
            }
        }
    }
    // SPDX-License-Identifier: MIT
    pragma solidity ^0.8.0;
    import "../utils/Context.sol";
    /**
     * @dev Contract module which provides a basic access control mechanism, where
     * there is an account (an owner) that can be granted exclusive access to
     * specific functions.
     *
     * By default, the owner account will be the one that deploys the contract. This
     * can later be changed with {transferOwnership}.
     *
     * This module is used through inheritance. It will make available the modifier
     * `onlyOwner`, which can be applied to your functions to restrict their use to
     * the owner.
     */
    abstract contract Ownable is Context {
        address private _owner;
        event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
        /**
         * @dev Initializes the contract setting the deployer as the initial owner.
         */
        constructor() {
            _setOwner(_msgSender());
        }
        /**
         * @dev Returns the address of the current owner.
         */
        function owner() public view virtual returns (address) {
            return _owner;
        }
        /**
         * @dev Throws if called by any account other than the owner.
         */
        modifier onlyOwner() {
            require(owner() == _msgSender(), "Ownable: caller is not the owner");
            _;
        }
        /**
         * @dev Leaves the contract without owner. It will not be possible to call
         * `onlyOwner` functions anymore. Can only be called by the current owner.
         *
         * NOTE: Renouncing ownership will leave the contract without an owner,
         * thereby removing any functionality that is only available to the owner.
         */
        function renounceOwnership() public virtual onlyOwner {
            _setOwner(address(0));
        }
        /**
         * @dev Transfers ownership of the contract to a new account (`newOwner`).
         * Can only be called by the current owner.
         */
        function transferOwnership(address newOwner) public virtual onlyOwner {
            require(newOwner != address(0), "Ownable: new owner is the zero address");
            _setOwner(newOwner);
        }
        function _setOwner(address newOwner) private {
            address oldOwner = _owner;
            _owner = newOwner;
            emit OwnershipTransferred(oldOwner, newOwner);
        }
    }
    // SPDX-License-Identifier: MIT
    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: balance query for the zero address");
            return _balances[owner];
        }
        /**
         * @dev See {IERC721-ownerOf}.
         */
        function ownerOf(uint256 tokenId) public view virtual override returns (address) {
            address owner = _owners[tokenId];
            require(owner != address(0), "ERC721: owner query for nonexistent token");
            return owner;
        }
        /**
         * @dev See {IERC721Metadata-name}.
         */
        function name() public view virtual override returns (string memory) {
            return _name;
        }
        /**
         * @dev See {IERC721Metadata-symbol}.
         */
        function symbol() public view virtual override returns (string memory) {
            return _symbol;
        }
        /**
         * @dev See {IERC721Metadata-tokenURI}.
         */
        function tokenURI(uint256 tokenId) public view virtual override returns (string memory) {
            require(_exists(tokenId), "ERC721Metadata: URI query for nonexistent token");
            string memory baseURI = _baseURI();
            return bytes(baseURI).length > 0 ? string(abi.encodePacked(baseURI, tokenId.toString())) : "";
        }
        /**
         * @dev Base URI for computing {tokenURI}. If set, the resulting URI for each
         * token will be the concatenation of the `baseURI` and the `tokenId`. Empty
         * by default, can be overriden in child contracts.
         */
        function _baseURI() internal view virtual returns (string memory) {
            return "";
        }
        /**
         * @dev See {IERC721-approve}.
         */
        function approve(address to, uint256 tokenId) public virtual override {
            address owner = ERC721.ownerOf(tokenId);
            require(to != owner, "ERC721: approval to current owner");
            require(
                _msgSender() == owner || isApprovedForAll(owner, _msgSender()),
                "ERC721: approve caller is not owner nor approved for all"
            );
            _approve(to, tokenId);
        }
        /**
         * @dev See {IERC721-getApproved}.
         */
        function getApproved(uint256 tokenId) public view virtual override returns (address) {
            require(_exists(tokenId), "ERC721: approved query for nonexistent token");
            return _tokenApprovals[tokenId];
        }
        /**
         * @dev See {IERC721-setApprovalForAll}.
         */
        function setApprovalForAll(address operator, bool approved) public virtual override {
            require(operator != _msgSender(), "ERC721: approve to caller");
            _operatorApprovals[_msgSender()][operator] = approved;
            emit ApprovalForAll(_msgSender(), operator, approved);
        }
        /**
         * @dev See {IERC721-isApprovedForAll}.
         */
        function isApprovedForAll(address owner, address operator) public view virtual override returns (bool) {
            return _operatorApprovals[owner][operator];
        }
        /**
         * @dev See {IERC721-transferFrom}.
         */
        function transferFrom(
            address from,
            address to,
            uint256 tokenId
        ) public virtual override {
            //solhint-disable-next-line max-line-length
            require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721: transfer caller is not owner nor approved");
            _transfer(from, to, tokenId);
        }
        /**
         * @dev See {IERC721-safeTransferFrom}.
         */
        function safeTransferFrom(
            address from,
            address to,
            uint256 tokenId
        ) public virtual override {
            safeTransferFrom(from, to, tokenId, "");
        }
        /**
         * @dev See {IERC721-safeTransferFrom}.
         */
        function safeTransferFrom(
            address from,
            address to,
            uint256 tokenId,
            bytes memory _data
        ) public virtual override {
            require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721: transfer caller is not owner nor approved");
            _safeTransfer(from, to, tokenId, _data);
        }
        /**
         * @dev Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients
         * are aware of the ERC721 protocol to prevent tokens from being forever locked.
         *
         * `_data` is additional data, it has no specified format and it is sent in call to `to`.
         *
         * This internal function is equivalent to {safeTransferFrom}, and can be used to e.g.
         * implement alternative mechanisms to perform token transfer, such as signature-based.
         *
         * Requirements:
         *
         * - `from` cannot be the zero address.
         * - `to` cannot be the zero address.
         * - `tokenId` token must exist and be owned by `from`.
         * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
         *
         * Emits a {Transfer} event.
         */
        function _safeTransfer(
            address from,
            address to,
            uint256 tokenId,
            bytes memory _data
        ) internal virtual {
            _transfer(from, to, tokenId);
            require(_checkOnERC721Received(from, to, tokenId, _data), "ERC721: transfer to non ERC721Receiver implementer");
        }
        /**
         * @dev Returns whether `tokenId` exists.
         *
         * Tokens can be managed by their owner or approved accounts via {approve} or {setApprovalForAll}.
         *
         * Tokens start existing when they are minted (`_mint`),
         * and stop existing when they are burned (`_burn`).
         */
        function _exists(uint256 tokenId) internal view virtual returns (bool) {
            return _owners[tokenId] != address(0);
        }
        /**
         * @dev Returns whether `spender` is allowed to manage `tokenId`.
         *
         * Requirements:
         *
         * - `tokenId` must exist.
         */
        function _isApprovedOrOwner(address spender, uint256 tokenId) internal view virtual returns (bool) {
            require(_exists(tokenId), "ERC721: operator query for nonexistent token");
            address owner = ERC721.ownerOf(tokenId);
            return (spender == owner || getApproved(tokenId) == spender || isApprovedForAll(owner, spender));
        }
        /**
         * @dev Safely mints `tokenId` and transfers it to `to`.
         *
         * Requirements:
         *
         * - `tokenId` must not exist.
         * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
         *
         * Emits a {Transfer} event.
         */
        function _safeMint(address to, uint256 tokenId) internal virtual {
            _safeMint(to, tokenId, "");
        }
        /**
         * @dev Same as {xref-ERC721-_safeMint-address-uint256-}[`_safeMint`], with an additional `data` parameter which is
         * forwarded in {IERC721Receiver-onERC721Received} to contract recipients.
         */
        function _safeMint(
            address to,
            uint256 tokenId,
            bytes memory _data
        ) internal virtual {
            _mint(to, tokenId);
            require(
                _checkOnERC721Received(address(0), to, tokenId, _data),
                "ERC721: transfer to non ERC721Receiver implementer"
            );
        }
        /**
         * @dev Mints `tokenId` and transfers it to `to`.
         *
         * WARNING: Usage of this method is discouraged, use {_safeMint} whenever possible
         *
         * Requirements:
         *
         * - `tokenId` must not exist.
         * - `to` cannot be the zero address.
         *
         * Emits a {Transfer} event.
         */
        function _mint(address to, uint256 tokenId) internal virtual {
            require(to != address(0), "ERC721: mint to the zero address");
            require(!_exists(tokenId), "ERC721: token already minted");
            _beforeTokenTransfer(address(0), to, tokenId);
            _balances[to] += 1;
            _owners[tokenId] = to;
            emit Transfer(address(0), to, tokenId);
        }
        /**
         * @dev Destroys `tokenId`.
         * The approval is cleared when the token is burned.
         *
         * Requirements:
         *
         * - `tokenId` must exist.
         *
         * Emits a {Transfer} event.
         */
        function _burn(uint256 tokenId) internal virtual {
            address owner = ERC721.ownerOf(tokenId);
            _beforeTokenTransfer(owner, address(0), tokenId);
            // Clear approvals
            _approve(address(0), tokenId);
            _balances[owner] -= 1;
            delete _owners[tokenId];
            emit Transfer(owner, address(0), tokenId);
        }
        /**
         * @dev Transfers `tokenId` from `from` to `to`.
         *  As opposed to {transferFrom}, this imposes no restrictions on msg.sender.
         *
         * Requirements:
         *
         * - `to` cannot be the zero address.
         * - `tokenId` token must be owned by `from`.
         *
         * Emits a {Transfer} event.
         */
        function _transfer(
            address from,
            address to,
            uint256 tokenId
        ) internal virtual {
            require(ERC721.ownerOf(tokenId) == from, "ERC721: transfer of token that is not own");
            require(to != address(0), "ERC721: transfer to the zero address");
            _beforeTokenTransfer(from, to, tokenId);
            // Clear approvals from the previous owner
            _approve(address(0), tokenId);
            _balances[from] -= 1;
            _balances[to] += 1;
            _owners[tokenId] = to;
            emit Transfer(from, to, tokenId);
        }
        /**
         * @dev Approve `to` to operate on `tokenId`
         *
         * Emits a {Approval} event.
         */
        function _approve(address to, uint256 tokenId) internal virtual {
            _tokenApprovals[tokenId] = to;
            emit Approval(ERC721.ownerOf(tokenId), to, tokenId);
        }
        /**
         * @dev Internal function to invoke {IERC721Receiver-onERC721Received} on a target address.
         * The call is not executed if the target address is not a contract.
         *
         * @param from address representing the previous owner of the given token ID
         * @param to target address that will receive the tokens
         * @param tokenId uint256 ID of the token to be transferred
         * @param _data bytes optional data to send along with the call
         * @return bool whether the call correctly returned the expected magic value
         */
        function _checkOnERC721Received(
            address from,
            address to,
            uint256 tokenId,
            bytes memory _data
        ) private returns (bool) {
            if (to.isContract()) {
                try IERC721Receiver(to).onERC721Received(_msgSender(), from, tokenId, _data) returns (bytes4 retval) {
                    return retval == IERC721Receiver.onERC721Received.selector;
                } catch (bytes memory reason) {
                    if (reason.length == 0) {
                        revert("ERC721: transfer to non ERC721Receiver implementer");
                    } else {
                        assembly {
                            revert(add(32, reason), mload(reason))
                        }
                    }
                }
            } else {
                return true;
            }
        }
        /**
         * @dev Hook that is called before any token transfer. This includes minting
         * and burning.
         *
         * Calling conditions:
         *
         * - When `from` and `to` are both non-zero, ``from``'s `tokenId` will be
         * transferred to `to`.
         * - When `from` is zero, `tokenId` will be minted for `to`.
         * - When `to` is zero, ``from``'s `tokenId` will be burned.
         * - `from` and `to` are never both zero.
         *
         * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
         */
        function _beforeTokenTransfer(
            address from,
            address to,
            uint256 tokenId
        ) internal virtual {}
    }
    // SPDX-License-Identifier: MIT
    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 `IERC721.onERC721Received.selector`.
         */
        function onERC721Received(
            address operator,
            address from,
            uint256 tokenId,
            bytes calldata data
        ) external returns (bytes4);
    }
    // SPDX-License-Identifier: MIT
    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 Hook that is called before any token transfer. This includes minting
         * and burning.
         *
         * Calling conditions:
         *
         * - When `from` and `to` are both non-zero, ``from``'s `tokenId` will be
         * transferred to `to`.
         * - When `from` is zero, `tokenId` will be minted for `to`.
         * - When `to` is zero, ``from``'s `tokenId` will be burned.
         * - `from` cannot be the zero address.
         * - `to` cannot be the zero address.
         *
         * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
         */
        function _beforeTokenTransfer(
            address from,
            address to,
            uint256 tokenId
        ) internal virtual override {
            super._beforeTokenTransfer(from, to, tokenId);
            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();
        }
    }
    // SPDX-License-Identifier: MIT
    pragma solidity ^0.8.0;
    /**
     * @dev String operations.
     */
    library Strings {
        bytes16 private constant _HEX_SYMBOLS = "0123456789abcdef";
        /**
         * @dev Converts a `uint256` to its ASCII `string` decimal representation.
         */
        function toString(uint256 value) internal pure returns (string memory) {
            // Inspired by OraclizeAPI's implementation - MIT licence
            // https://github.com/oraclize/ethereum-api/blob/b42146b063c7d6ee1358846c198246239e9360e8/oraclizeAPI_0.4.25.sol
            if (value == 0) {
                return "0";
            }
            uint256 temp = value;
            uint256 digits;
            while (temp != 0) {
                digits++;
                temp /= 10;
            }
            bytes memory buffer = new bytes(digits);
            while (value != 0) {
                digits -= 1;
                buffer[digits] = bytes1(uint8(48 + uint256(value % 10)));
                value /= 10;
            }
            return string(buffer);
        }
        /**
         * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation.
         */
        function toHexString(uint256 value) internal pure returns (string memory) {
            if (value == 0) {
                return "0x00";
            }
            uint256 temp = value;
            uint256 length = 0;
            while (temp != 0) {
                length++;
                temp >>= 8;
            }
            return toHexString(value, length);
        }
        /**
         * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation with fixed length.
         */
        function toHexString(uint256 value, uint256 length) internal pure returns (string memory) {
            bytes memory buffer = new bytes(2 * length + 2);
            buffer[0] = "0";
            buffer[1] = "x";
            for (uint256 i = 2 * length + 1; i > 1; --i) {
                buffer[i] = _HEX_SYMBOLS[value & 0xf];
                value >>= 4;
            }
            require(value == 0, "Strings: hex length insufficient");
            return string(buffer);
        }
    }
    // SPDX-License-Identifier: MIT
    pragma solidity ^0.8.0;
    /**
     * @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
         * ====
         */
        function isContract(address account) internal view returns (bool) {
            // This method relies on extcodesize, which returns 0 for contracts in
            // construction, since the code is only stored at the end of the
            // constructor execution.
            uint256 size;
            assembly {
                size := extcodesize(account)
            }
            return size > 0;
        }
        /**
         * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
         * `recipient`, forwarding all available gas and reverting on errors.
         *
         * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
         * of certain opcodes, possibly making contracts go over the 2300 gas limit
         * imposed by `transfer`, making them unable to receive funds via
         * `transfer`. {sendValue} removes this limitation.
         *
         * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
         *
         * IMPORTANT: because control is transferred to `recipient`, care must be
         * taken to not create reentrancy vulnerabilities. Consider using
         * {ReentrancyGuard} or the
         * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
         */
        function sendValue(address payable recipient, uint256 amount) internal {
            require(address(this).balance >= amount, "Address: insufficient balance");
            (bool success, ) = recipient.call{value: amount}("");
            require(success, "Address: unable to send value, recipient may have reverted");
        }
        /**
         * @dev Performs a Solidity function call using a low level `call`. A
         * plain `call` is an unsafe replacement for a function call: use this
         * function instead.
         *
         * If `target` reverts with a revert reason, it is bubbled up by this
         * function (like regular Solidity function calls).
         *
         * Returns the raw returned data. To convert to the expected return value,
         * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
         *
         * Requirements:
         *
         * - `target` must be a contract.
         * - calling `target` with `data` must not revert.
         *
         * _Available since v3.1._
         */
        function functionCall(address target, bytes memory data) internal returns (bytes memory) {
            return functionCall(target, data, "Address: low-level call failed");
        }
        /**
         * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
         * `errorMessage` as a fallback revert reason when `target` reverts.
         *
         * _Available since v3.1._
         */
        function functionCall(
            address target,
            bytes memory data,
            string memory errorMessage
        ) internal returns (bytes memory) {
            return functionCallWithValue(target, data, 0, errorMessage);
        }
        /**
         * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
         * but also transferring `value` wei to `target`.
         *
         * Requirements:
         *
         * - the calling contract must have an ETH balance of at least `value`.
         * - the called Solidity function must be `payable`.
         *
         * _Available since v3.1._
         */
        function functionCallWithValue(
            address target,
            bytes memory data,
            uint256 value
        ) internal returns (bytes memory) {
            return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
        }
        /**
         * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
         * with `errorMessage` as a fallback revert reason when `target` reverts.
         *
         * _Available since v3.1._
         */
        function functionCallWithValue(
            address target,
            bytes memory data,
            uint256 value,
            string memory errorMessage
        ) internal returns (bytes memory) {
            require(address(this).balance >= value, "Address: insufficient balance for call");
            require(isContract(target), "Address: call to non-contract");
            (bool success, bytes memory returndata) = target.call{value: value}(data);
            return verifyCallResult(success, returndata, errorMessage);
        }
        /**
         * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
         * but performing a static call.
         *
         * _Available since v3.3._
         */
        function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
            return functionStaticCall(target, data, "Address: low-level static call failed");
        }
        /**
         * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
         * but performing a static call.
         *
         * _Available since v3.3._
         */
        function functionStaticCall(
            address target,
            bytes memory data,
            string memory errorMessage
        ) internal view returns (bytes memory) {
            require(isContract(target), "Address: static call to non-contract");
            (bool success, bytes memory returndata) = target.staticcall(data);
            return verifyCallResult(success, returndata, errorMessage);
        }
        /**
         * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
         * but performing a delegate call.
         *
         * _Available since v3.4._
         */
        function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
            return functionDelegateCall(target, data, "Address: low-level delegate call failed");
        }
        /**
         * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
         * but performing a delegate call.
         *
         * _Available since v3.4._
         */
        function functionDelegateCall(
            address target,
            bytes memory data,
            string memory errorMessage
        ) internal returns (bytes memory) {
            require(isContract(target), "Address: delegate call to non-contract");
            (bool success, bytes memory returndata) = target.delegatecall(data);
            return verifyCallResult(success, returndata, errorMessage);
        }
        /**
         * @dev Tool to verifies that a low level call was successful, and revert if it wasn't, either by bubbling the
         * revert reason using the provided one.
         *
         * _Available since v4.3._
         */
        function verifyCallResult(
            bool success,
            bytes memory returndata,
            string memory errorMessage
        ) internal pure returns (bytes memory) {
            if (success) {
                return returndata;
            } else {
                // Look for revert reason and bubble it up if present
                if (returndata.length > 0) {
                    // The easiest way to bubble the revert reason is using memory via assembly
                    assembly {
                        let returndata_size := mload(returndata)
                        revert(add(32, returndata), returndata_size)
                    }
                } else {
                    revert(errorMessage);
                }
            }
        }
    }
    // SPDX-License-Identifier: MIT
    pragma solidity 0.8.10;
    interface IMintableERC721 {
    \t/**
    \t * @notice Checks if specified token exists
    \t *
    \t * @dev Returns whether the specified token ID has an ownership
    \t *      information associated with it
    \t *
    \t * @param _tokenId ID of the token to query existence for
    \t * @return whether the token exists (true - exists, false - doesn't exist)
    \t */
    \tfunction exists(uint256 _tokenId) external view returns(bool);
    \t/**
    \t * @dev Creates new token with token ID specified
    \t *      and assigns an ownership `_to` for this token
    \t *
    \t * @dev Unsafe: doesn't execute `onERC721Received` on the receiver.
    \t *      Prefer the use of `saveMint` instead of `mint`.
    \t *
    \t * @dev Should have a restricted access handled by the implementation
    \t *
    \t * @param _to an address to mint token to
    \t * @param _tokenId ID of the token to mint
    \t */
    \tfunction mint(address _to, uint256 _tokenId) external;
    \t/**
    \t * @dev Creates new tokens starting with token ID specified
    \t *      and assigns an ownership `_to` for these tokens
    \t *
    \t * @dev Token IDs to be minted: [_tokenId, _tokenId + n)
    \t *
    \t * @dev n must be greater or equal 2: `n > 1`
    \t *
    \t * @dev Unsafe: doesn't execute `onERC721Received` on the receiver.
    \t *      Prefer the use of `saveMintBatch` instead of `mintBatch`.
    \t *
    \t * @dev Should have a restricted access handled by the implementation
    \t *
    \t * @param _to an address to mint tokens to
    \t * @param _tokenId ID of the first token to mint
    \t * @param n how many tokens to mint, sequentially increasing the _tokenId
    \t */
    \tfunction mintBatch(address _to, uint256 _tokenId, uint256 n) external;
    \t/**
    \t * @dev Creates new token with token ID specified
    \t *      and assigns an ownership `_to` for this token
    \t *
    \t * @dev Checks if `_to` is a smart contract (code size > 0). If so, it calls
    \t *      `onERC721Received` on `_to` and throws if the return value is not
    \t *      `bytes4(keccak256("onERC721Received(address,address,uint256,bytes)"))`.
    \t *
    \t * @dev Should have a restricted access handled by the implementation
    \t *
    \t * @param _to an address to mint token to
    \t * @param _tokenId ID of the token to mint
    \t */
    \tfunction safeMint(address _to, uint256 _tokenId) external;
    \t/**
    \t * @dev Creates new token with token ID specified
    \t *      and assigns an ownership `_to` for this token
    \t *
    \t * @dev Checks if `_to` is a smart contract (code size > 0). If so, it calls
    \t *      `onERC721Received` on `_to` and throws if the return value is not
    \t *      `bytes4(keccak256("onERC721Received(address,address,uint256,bytes)"))`.
    \t *
    \t * @dev Should have a restricted access handled by the implementation
    \t *
    \t * @param _to an address to mint token to
    \t * @param _tokenId ID of the token to mint
    \t * @param _data additional data with no specified format, sent in call to `_to`
    \t */
    \tfunction safeMint(address _to, uint256 _tokenId, bytes memory _data) external;
    \t/**
    \t * @dev Creates new tokens starting with token ID specified
    \t *      and assigns an ownership `_to` for these tokens
    \t *
    \t * @dev Token IDs to be minted: [_tokenId, _tokenId + n)
    \t *
    \t * @dev n must be greater or equal 2: `n > 1`
    \t *
    \t * @dev Checks if `_to` is a smart contract (code size > 0). If so, it calls
    \t *      `onERC721Received` on `_to` and throws if the return value is not
    \t *      `bytes4(keccak256("onERC721Received(address,address,uint256,bytes)"))`.
    \t *
    \t * @dev Should have a restricted access handled by the implementation
    \t *
    \t * @param _to an address to mint token to
    \t * @param _tokenId ID of the token to mint
    \t * @param n how many tokens to mint, sequentially increasing the _tokenId
    \t */
    \tfunction safeMintBatch(address _to, uint256 _tokenId, uint256 n) external;
    \t/**
    \t * @dev Creates new tokens starting with token ID specified
    \t *      and assigns an ownership `_to` for these tokens
    \t *
    \t * @dev Token IDs to be minted: [_tokenId, _tokenId + n)
    \t *
    \t * @dev n must be greater or equal 2: `n > 1`
    \t *
    \t * @dev Checks if `_to` is a smart contract (code size > 0). If so, it calls
    \t *      `onERC721Received` on `_to` and throws if the return value is not
    \t *      `bytes4(keccak256("onERC721Received(address,address,uint256,bytes)"))`.
    \t *
    \t * @dev Should have a restricted access handled by the implementation
    \t *
    \t * @param _to an address to mint token to
    \t * @param _tokenId ID of the token to mint
    \t * @param n how many tokens to mint, sequentially increasing the _tokenId
    \t * @param _data additional data with no specified format, sent in call to `_to`
    \t */
    \tfunction safeMintBatch(address _to, uint256 _tokenId, uint256 n, bytes memory _data) external;
    }
    // SPDX-License-Identifier: MIT
    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;
    }
    // SPDX-License-Identifier: MIT
    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;
        }
    }
    // SPDX-License-Identifier: MIT
    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;
        }
    }
    // SPDX-License-Identifier: MIT
    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);
    }
    // SPDX-License-Identifier: MIT
    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`, checking first that contract recipients
         * are aware of the ERC721 protocol to prevent tokens from being forever locked.
         *
         * Requirements:
         *
         * - `from` cannot be the zero address.
         * - `to` cannot be the zero address.
         * - `tokenId` token must exist and be owned by `from`.
         * - If the caller is not `from`, it must be have been allowed to move this token by either {approve} or {setApprovalForAll}.
         * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
         *
         * Emits a {Transfer} event.
         */
        function safeTransferFrom(
            address from,
            address to,
            uint256 tokenId
        ) external;
        /**
         * @dev Transfers `tokenId` token from `from` to `to`.
         *
         * WARNING: Usage of this method is discouraged, use {safeTransferFrom} whenever possible.
         *
         * Requirements:
         *
         * - `from` cannot be the zero address.
         * - `to` cannot be the zero address.
         * - `tokenId` token must be owned by `from`.
         * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
         *
         * Emits a {Transfer} event.
         */
        function transferFrom(
            address from,
            address to,
            uint256 tokenId
        ) external;
        /**
         * @dev Gives permission to `to` to transfer `tokenId` token to another account.
         * The approval is cleared when the token is transferred.
         *
         * Only a single account can be approved at a time, so approving the zero address clears previous approvals.
         *
         * Requirements:
         *
         * - The caller must own the token or be an approved operator.
         * - `tokenId` must exist.
         *
         * Emits an {Approval} event.
         */
        function approve(address to, uint256 tokenId) external;
        /**
         * @dev Returns the account approved for `tokenId` token.
         *
         * Requirements:
         *
         * - `tokenId` must exist.
         */
        function getApproved(uint256 tokenId) external view returns (address operator);
        /**
         * @dev Approve or remove `operator` as an operator for the caller.
         * Operators can call {transferFrom} or {safeTransferFrom} for any token owned by the caller.
         *
         * Requirements:
         *
         * - The `operator` cannot be the caller.
         *
         * Emits an {ApprovalForAll} event.
         */
        function setApprovalForAll(address operator, bool _approved) external;
        /**
         * @dev Returns if the `operator` is allowed to manage all of the assets of `owner`.
         *
         * See {setApprovalForAll}
         */
        function isApprovedForAll(address owner, address operator) external view returns (bool);
        /**
         * @dev Safely transfers `tokenId` token from `from` to `to`.
         *
         * Requirements:
         *
         * - `from` cannot be the zero address.
         * - `to` cannot be the zero address.
         * - `tokenId` token must exist and be owned by `from`.
         * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
         * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
         *
         * Emits a {Transfer} event.
         */
        function safeTransferFrom(
            address from,
            address to,
            uint256 tokenId,
            bytes calldata data
        ) external;
    }
    // SPDX-License-Identifier: MIT
    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);
    }
    // SPDX-License-Identifier: MIT
    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 tokenId);
        /**
         * @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);
    }