linkTokenAddress

_oracleAddress

_fee

owner

approved

tokenId

Approval

operator

ApprovalForAll

ChainlinkCancelled

ChainlinkFulfilled

ChainlinkRequested

requestId

uriOwner

OracleResult

previousOwner

newOwner

OwnershipTransferred

from

Transfer

URIUpdate

approve

balanceOf

uriOwnerBytes

fulfill

getApproved

isApprovedForAll

mint

name

oracleAddress

ownerOf

renounceOwnership

requestData

minter

fulfilled

safeTransferFrom

data

setApprovalForAll

interfaceId

supportsInterface

symbol

tokenURI

totalSupply

transferFrom

transferOwnership

updateURI

withdrawLink

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.7;

import "@openzeppelin/contracts/token/ERC721/ERC721.sol";
import "@openzeppelin/contracts/token/ERC721/extensions/ERC721URIStorage.sol";
import "@openzeppelin/contracts/access/Ownable.sol";
import "@openzeppelin/contracts/utils/Counters.sol";
import "@chainlink/contracts/src/v0.8/ChainlinkClient.sol";

contract LagrangeChainlinkDataConsumer is
    ERC721,
    ERC721URIStorage,
    ChainlinkClient,
    Ownable
{
    using Chainlink for Chainlink.Request;
    using Counters for Counters.Counter;
    Counters.Counter private _tokenIdCounter;

    bytes32 private jobId;
    uint256 private fee;
    address public oracleAddress;

    struct RequestData {
        address minter;
        string uri;
        bool fulfilled;
    }

    mapping(bytes32 => RequestData) public requestData;

    event OracleResult(bytes32 indexed requestId, address uriOwner);
    event URIUpdate(uint tokenId, string uri);

    constructor(
        address linkTokenAddress,
        address _oracleAddress,
        uint _fee
    ) ERC721("Lagrange Data", "LDNFT") {
        setChainlinkToken(linkTokenAddress);
        setChainlinkOracle(_oracleAddress);
        oracleAddress = _oracleAddress;
        jobId = '7da2702f37fd48e5b1b9a5715e3509b6';
        fee = _fee; // 0,1 * 10**18 (Varies by network and job)
    }

    function bytesToAddress(bytes memory b) private pure returns (address addr) {
        assembly {
        addr := mload(add(b,20))
        }
    }

    // sends chainlink request
    // and the token gets minted (if api returns true) in the fulfill function
    // args[0] msg.sender
    // args[1] metadata uri
    // TODO: args is string array because sendRequests takes args array
    // TODO: mint should take (cid), create a array of cid and msg.sender
    function mint(string memory uri) public returns (bytes32 requestId) {
        Chainlink.Request memory req = buildChainlinkRequest(
            jobId,
            address(this),
            this.fulfill.selector
        );

        req.add("get", uri);
        req.add("path", "owner");


        bytes32 assignedReqID = sendChainlinkRequest(req, fee);
        requestData[assignedReqID] = RequestData(msg.sender, uri, false);

        return assignedReqID;
    }

    function fulfill(
        bytes32 requestId,
        bytes memory uriOwnerBytes
    ) public recordChainlinkFulfillment(requestId) {
        // if the response is true (meaning the minter is the owner of the dataset)
        // then mint the nft to the user
        address uriOwner = bytesToAddress(uriOwnerBytes);
        if (uriOwner == requestData[requestId].minter) {
            _tokenIdCounter.increment();
            uint256 tokenId = _tokenIdCounter.current();

            _safeMint(requestData[requestId].minter, tokenId);
            _setTokenURI(tokenId, requestData[requestId].uri);
        }

        // update requestData information
        requestData[requestId].fulfilled = true;

        emit OracleResult(requestId, uriOwner);
    }

    // The following functions are overrides required by Solidity.

    function _burn(
        uint256 tokenId
    ) internal override(ERC721, ERC721URIStorage) {
        super._burn(tokenId);
    }

    function updateURI(uint tokenId, string memory uri) public {
        require(ownerOf(tokenId) == msg.sender, "caller is not owner");
        _setTokenURI(tokenId, uri);

        emit URIUpdate(tokenId, uri);
    }

    function tokenURI(
        uint256 tokenId
    ) public view override(ERC721, ERC721URIStorage) returns (string memory) {
        //require(uriAccess[msg.sender][tokenId], "caller does not have access");
        return super.tokenURI(tokenId);
    }

    function totalSupply() public view returns (uint) {
        return _tokenIdCounter.current();
    }

    function withdrawLink() public onlyOwner {
        LinkTokenInterface link = LinkTokenInterface(chainlinkTokenAddress());
        require(
            link.transfer(msg.sender, link.balanceOf(address(this))),
            "Unable to transfer"
        );
    }

}


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

import "./Chainlink.sol";
import "./interfaces/ENSInterface.sol";
import "./interfaces/LinkTokenInterface.sol";
import "./interfaces/ChainlinkRequestInterface.sol";
import "./interfaces/OperatorInterface.sol";
import "./interfaces/PointerInterface.sol";
import {ENSResolver as ENSResolver_Chainlink} from "./vendor/ENSResolver.sol";

/**
 * @title The ChainlinkClient contract
 * @notice Contract writers can inherit this contract in order to create requests for the
 * Chainlink network
 */
abstract contract ChainlinkClient {
  using Chainlink for Chainlink.Request;

  uint256 internal constant LINK_DIVISIBILITY = 10**18;
  uint256 private constant AMOUNT_OVERRIDE = 0;
  address private constant SENDER_OVERRIDE = address(0);
  uint256 private constant ORACLE_ARGS_VERSION = 1;
  uint256 private constant OPERATOR_ARGS_VERSION = 2;
  bytes32 private constant ENS_TOKEN_SUBNAME = keccak256("link");
  bytes32 private constant ENS_ORACLE_SUBNAME = keccak256("oracle");
  address private constant LINK_TOKEN_POINTER = 0xC89bD4E1632D3A43CB03AAAd5262cbe4038Bc571;

  ENSInterface private s_ens;
  bytes32 private s_ensNode;
  LinkTokenInterface private s_link;
  OperatorInterface private s_oracle;
  uint256 private s_requestCount = 1;
  mapping(bytes32 => address) private s_pendingRequests;

  event ChainlinkRequested(bytes32 indexed id);
  event ChainlinkFulfilled(bytes32 indexed id);
  event ChainlinkCancelled(bytes32 indexed id);

  /**
   * @notice Creates a request that can hold additional parameters
   * @param specId The Job Specification ID that the request will be created for
   * @param callbackAddr address to operate the callback on
   * @param callbackFunctionSignature function signature to use for the callback
   * @return A Chainlink Request struct in memory
   */
  function buildChainlinkRequest(
    bytes32 specId,
    address callbackAddr,
    bytes4 callbackFunctionSignature
  ) internal pure returns (Chainlink.Request memory) {
    Chainlink.Request memory req;
    return req.initialize(specId, callbackAddr, callbackFunctionSignature);
  }

  /**
   * @notice Creates a request that can hold additional parameters
   * @param specId The Job Specification ID that the request will be created for
   * @param callbackFunctionSignature function signature to use for the callback
   * @return A Chainlink Request struct in memory
   */
  function buildOperatorRequest(bytes32 specId, bytes4 callbackFunctionSignature)
    internal
    view
    returns (Chainlink.Request memory)
  {
    Chainlink.Request memory req;
    return req.initialize(specId, address(this), callbackFunctionSignature);
  }

  /**
   * @notice Creates a Chainlink request to the stored oracle address
   * @dev Calls `chainlinkRequestTo` with the stored oracle address
   * @param req The initialized Chainlink Request
   * @param payment The amount of LINK to send for the request
   * @return requestId The request ID
   */
  function sendChainlinkRequest(Chainlink.Request memory req, uint256 payment) internal returns (bytes32) {
    return sendChainlinkRequestTo(address(s_oracle), req, payment);
  }

  /**
   * @notice Creates a Chainlink request to the specified oracle address
   * @dev Generates and stores a request ID, increments the local nonce, and uses `transferAndCall` to
   * send LINK which creates a request on the target oracle contract.
   * Emits ChainlinkRequested event.
   * @param oracleAddress The address of the oracle for the request
   * @param req The initialized Chainlink Request
   * @param payment The amount of LINK to send for the request
   * @return requestId The request ID
   */
  function sendChainlinkRequestTo(
    address oracleAddress,
    Chainlink.Request memory req,
    uint256 payment
  ) internal returns (bytes32 requestId) {
    uint256 nonce = s_requestCount;
    s_requestCount = nonce + 1;
    bytes memory encodedRequest = abi.encodeWithSelector(
      ChainlinkRequestInterface.oracleRequest.selector,
      SENDER_OVERRIDE, // Sender value - overridden by onTokenTransfer by the requesting contract's address
      AMOUNT_OVERRIDE, // Amount value - overridden by onTokenTransfer by the actual amount of LINK sent
      req.id,
      address(this),
      req.callbackFunctionId,
      nonce,
      ORACLE_ARGS_VERSION,
      req.buf.buf
    );
    return _rawRequest(oracleAddress, nonce, payment, encodedRequest);
  }

  /**
   * @notice Creates a Chainlink request to the stored oracle address
   * @dev This function supports multi-word response
   * @dev Calls `sendOperatorRequestTo` with the stored oracle address
   * @param req The initialized Chainlink Request
   * @param payment The amount of LINK to send for the request
   * @return requestId The request ID
   */
  function sendOperatorRequest(Chainlink.Request memory req, uint256 payment) internal returns (bytes32) {
    return sendOperatorRequestTo(address(s_oracle), req, payment);
  }

  /**
   * @notice Creates a Chainlink request to the specified oracle address
   * @dev This function supports multi-word response
   * @dev Generates and stores a request ID, increments the local nonce, and uses `transferAndCall` to
   * send LINK which creates a request on the target oracle contract.
   * Emits ChainlinkRequested event.
   * @param oracleAddress The address of the oracle for the request
   * @param req The initialized Chainlink Request
   * @param payment The amount of LINK to send for the request
   * @return requestId The request ID
   */
  function sendOperatorRequestTo(
    address oracleAddress,
    Chainlink.Request memory req,
    uint256 payment
  ) internal returns (bytes32 requestId) {
    uint256 nonce = s_requestCount;
    s_requestCount = nonce + 1;
    bytes memory encodedRequest = abi.encodeWithSelector(
      OperatorInterface.operatorRequest.selector,
      SENDER_OVERRIDE, // Sender value - overridden by onTokenTransfer by the requesting contract's address
      AMOUNT_OVERRIDE, // Amount value - overridden by onTokenTransfer by the actual amount of LINK sent
      req.id,
      req.callbackFunctionId,
      nonce,
      OPERATOR_ARGS_VERSION,
      req.buf.buf
    );
    return _rawRequest(oracleAddress, nonce, payment, encodedRequest);
  }

  /**
   * @notice Make a request to an oracle
   * @param oracleAddress The address of the oracle for the request
   * @param nonce used to generate the request ID
   * @param payment The amount of LINK to send for the request
   * @param encodedRequest data encoded for request type specific format
   * @return requestId The request ID
   */
  function _rawRequest(
    address oracleAddress,
    uint256 nonce,
    uint256 payment,
    bytes memory encodedRequest
  ) private returns (bytes32 requestId) {
    requestId = keccak256(abi.encodePacked(this, nonce));
    s_pendingRequests[requestId] = oracleAddress;
    emit ChainlinkRequested(requestId);
    require(s_link.transferAndCall(oracleAddress, payment, encodedRequest), "unable to transferAndCall to oracle");
  }

  /**
   * @notice Allows a request to be cancelled if it has not been fulfilled
   * @dev Requires keeping track of the expiration value emitted from the oracle contract.
   * Deletes the request from the `pendingRequests` mapping.
   * Emits ChainlinkCancelled event.
   * @param requestId The request ID
   * @param payment The amount of LINK sent for the request
   * @param callbackFunc The callback function specified for the request
   * @param expiration The time of the expiration for the request
   */
  function cancelChainlinkRequest(
    bytes32 requestId,
    uint256 payment,
    bytes4 callbackFunc,
    uint256 expiration
  ) internal {
    OperatorInterface requested = OperatorInterface(s_pendingRequests[requestId]);
    delete s_pendingRequests[requestId];
    emit ChainlinkCancelled(requestId);
    requested.cancelOracleRequest(requestId, payment, callbackFunc, expiration);
  }

  /**
   * @notice the next request count to be used in generating a nonce
   * @dev starts at 1 in order to ensure consistent gas cost
   * @return returns the next request count to be used in a nonce
   */
  function getNextRequestCount() internal view returns (uint256) {
    return s_requestCount;
  }

  /**
   * @notice Sets the stored oracle address
   * @param oracleAddress The address of the oracle contract
   */
  function setChainlinkOracle(address oracleAddress) internal {
    s_oracle = OperatorInterface(oracleAddress);
  }

  /**
   * @notice Sets the LINK token address
   * @param linkAddress The address of the LINK token contract
   */
  function setChainlinkToken(address linkAddress) internal {
    s_link = LinkTokenInterface(linkAddress);
  }

  /**
   * @notice Sets the Chainlink token address for the public
   * network as given by the Pointer contract
   */
  function setPublicChainlinkToken() internal {
    setChainlinkToken(PointerInterface(LINK_TOKEN_POINTER).getAddress());
  }

  /**
   * @notice Retrieves the stored address of the LINK token
   * @return The address of the LINK token
   */
  function chainlinkTokenAddress() internal view returns (address) {
    return address(s_link);
  }

  /**
   * @notice Retrieves the stored address of the oracle contract
   * @return The address of the oracle contract
   */
  function chainlinkOracleAddress() internal view returns (address) {
    return address(s_oracle);
  }

  /**
   * @notice Allows for a request which was created on another contract to be fulfilled
   * on this contract
   * @param oracleAddress The address of the oracle contract that will fulfill the request
   * @param requestId The request ID used for the response
   */
  function addChainlinkExternalRequest(address oracleAddress, bytes32 requestId) internal notPendingRequest(requestId) {
    s_pendingRequests[requestId] = oracleAddress;
  }

  /**
   * @notice Sets the stored oracle and LINK token contracts with the addresses resolved by ENS
   * @dev Accounts for subnodes having different resolvers
   * @param ensAddress The address of the ENS contract
   * @param node The ENS node hash
   */
  function useChainlinkWithENS(address ensAddress, bytes32 node) internal {
    s_ens = ENSInterface(ensAddress);
    s_ensNode = node;
    bytes32 linkSubnode = keccak256(abi.encodePacked(s_ensNode, ENS_TOKEN_SUBNAME));
    ENSResolver_Chainlink resolver = ENSResolver_Chainlink(s_ens.resolver(linkSubnode));
    setChainlinkToken(resolver.addr(linkSubnode));
    updateChainlinkOracleWithENS();
  }

  /**
   * @notice Sets the stored oracle contract with the address resolved by ENS
   * @dev This may be called on its own as long as `useChainlinkWithENS` has been called previously
   */
  function updateChainlinkOracleWithENS() internal {
    bytes32 oracleSubnode = keccak256(abi.encodePacked(s_ensNode, ENS_ORACLE_SUBNAME));
    ENSResolver_Chainlink resolver = ENSResolver_Chainlink(s_ens.resolver(oracleSubnode));
    setChainlinkOracle(resolver.addr(oracleSubnode));
  }

  /**
   * @notice Ensures that the fulfillment is valid for this contract
   * @dev Use if the contract developer prefers methods instead of modifiers for validation
   * @param requestId The request ID for fulfillment
   */
  function validateChainlinkCallback(bytes32 requestId)
    internal
    recordChainlinkFulfillment(requestId)
  // solhint-disable-next-line no-empty-blocks
  {

  }

  /**
   * @dev Reverts if the sender is not the oracle of the request.
   * Emits ChainlinkFulfilled event.
   * @param requestId The request ID for fulfillment
   */
  modifier recordChainlinkFulfillment(bytes32 requestId) {
    require(msg.sender == s_pendingRequests[requestId], "Source must be the oracle of the request");
    delete s_pendingRequests[requestId];
    emit ChainlinkFulfilled(requestId);
    _;
  }

  /**
   * @dev Reverts if the request is already pending
   * @param requestId The request ID for fulfillment
   */
  modifier notPendingRequest(bytes32 requestId) {
    require(s_pendingRequests[requestId] == address(0), "Request is already pending");
    _;
  }
}


The ChainlinkClient contract

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

pragma solidity ^0.8.0;

/**
 * @title Counters
 * @author Matt Condon (@shrugs)
 * @dev Provides counters that can only be incremented, decremented or reset. This can be used e.g. to track the number
 * of elements in a mapping, issuing ERC721 ids, or counting request ids.
 *
 * Include with `using Counters for Counters.Counter;`
 */
library Counters {
    struct Counter {
        // This variable should never be directly accessed by users of the library: interactions must be restricted to
        // the library's function. As of Solidity v0.5.2, this cannot be enforced, though there is a proposal to add
        // this feature: see https://github.com/ethereum/solidity/issues/4637
        uint256 _value; // default: 0
    }

    function current(Counter storage counter) internal view returns (uint256) {
        return counter._value;
    }

    function increment(Counter storage counter) internal {
        unchecked {
            counter._value += 1;
        }
    }

    function decrement(Counter storage counter) internal {
        uint256 value = counter._value;
        require(value > 0, "Counter: decrement overflow");
        unchecked {
            counter._value = value - 1;
        }
    }

    function reset(Counter storage counter) internal {
        counter._value = 0;
    }
}


Counters

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.7.0) (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 Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        _checkOwner();
        _;
    }

    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view virtual returns (address) {
        return _owner;
    }

    /**
     * @dev Throws if the sender is not the owner.
     */
    function _checkOwner() internal view virtual {
        require(owner() == _msgSender(), "Ownable: caller is not the owner");
    }

    /**
     * @dev Leaves the contract without owner. It will not be possible to call
     * `onlyOwner` functions anymore. Can only be called by the current owner.
     *
     * NOTE: Renouncing ownership will leave the contract without an owner,
     * thereby removing any functionality that is only available to the owner.
     */
    function renounceOwnership() public virtual onlyOwner {
        _transferOwnership(address(0));
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Can only be called by the current owner.
     */
    function transferOwnership(address newOwner) public virtual onlyOwner {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        _transferOwnership(newOwner);
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Internal function without access restriction.
     */
    function _transferOwnership(address newOwner) internal virtual {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}


// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.7.0) (token/ERC721/extensions/ERC721URIStorage.sol)

pragma solidity ^0.8.0;

import "../ERC721.sol";

/**
 * @dev ERC721 token with storage based token URI management.
 */
abstract contract ERC721URIStorage is ERC721 {
    using Strings for uint256;

    // Optional mapping for token URIs
    mapping(uint256 => string) private _tokenURIs;

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

        string memory _tokenURI = _tokenURIs[tokenId];
        string memory base = _baseURI();

        // If there is no base URI, return the token URI.
        if (bytes(base).length == 0) {
            return _tokenURI;
        }
        // If both are set, concatenate the baseURI and tokenURI (via abi.encodePacked).
        if (bytes(_tokenURI).length > 0) {
            return string(abi.encodePacked(base, _tokenURI));
        }

        return super.tokenURI(tokenId);
    }

    /**
     * @dev Sets `_tokenURI` as the tokenURI of `tokenId`.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     */
    function _setTokenURI(uint256 tokenId, string memory _tokenURI) internal virtual {
        require(_exists(tokenId), "ERC721URIStorage: URI set of nonexistent token");
        _tokenURIs[tokenId] = _tokenURI;
    }

    /**
     * @dev See {ERC721-_burn}. This override additionally checks to see if a
     * token-specific URI was set for the token, and if so, it deletes the token URI from
     * the storage mapping.
     */
    function _burn(uint256 tokenId) internal virtual override {
        super._burn(tokenId);

        if (bytes(_tokenURIs[tokenId]).length != 0) {
            delete _tokenURIs[tokenId];
        }
    }
}


name_

symbol_

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

pragma solidity ^0.8.0;

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

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

    // Token name
    string private _name;

    // Token symbol
    string private _symbol;

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

        _approve(to, tokenId);
    }

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

        return _tokenApprovals[tokenId];
    }

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

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

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

        _transfer(from, to, tokenId);
    }

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

    /**
     * @dev See {IERC721-safeTransferFrom}.
     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId,
        bytes memory data
    ) public virtual override {
        require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721: caller is not token owner or approved");
        _safeTransfer(from, to, tokenId, data);
    }

    /**
     * @dev Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients
     * are aware of the ERC721 protocol to prevent tokens from being forever locked.
     *
     * `data` is additional data, it has no specified format and it is sent in call to `to`.
     *
     * This internal function is equivalent to {safeTransferFrom}, and can be used to e.g.
     * implement alternative mechanisms to perform token transfer, such as signature-based.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must exist and be owned by `from`.
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
     *
     * Emits a {Transfer} event.
     */
    function _safeTransfer(
        address from,
        address to,
        uint256 tokenId,
        bytes memory data
    ) internal virtual {
        _transfer(from, to, tokenId);
        require(_checkOnERC721Received(from, to, tokenId, data), "ERC721: transfer to non ERC721Receiver implementer");
    }

    /**
     * @dev Returns the owner of the `tokenId`. Does NOT revert if token doesn't exist
     */
    function _ownerOf(uint256 tokenId) internal view virtual returns (address) {
        return _owners[tokenId];
    }

    /**
     * @dev Returns whether `tokenId` exists.
     *
     * Tokens can be managed by their owner or approved accounts via {approve} or {setApprovalForAll}.
     *
     * Tokens start existing when they are minted (`_mint`),
     * and stop existing when they are burned (`_burn`).
     */
    function _exists(uint256 tokenId) internal view virtual returns (bool) {
        return _ownerOf(tokenId) != address(0);
    }

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

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

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

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

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

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

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

        _owners[tokenId] = to;

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

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

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

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

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

        // Clear approvals
        delete _tokenApprovals[tokenId];

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

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

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

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

        _beforeTokenTransfer(from, to, tokenId, 1);

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

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

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

        emit Transfer(from, to, tokenId);

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

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

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

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

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

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

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

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


// 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 (last updated v4.8.0) (utils/Strings.sol)

pragma solidity ^0.8.0;

import "./math/Math.sol";

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

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

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

    /**
     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation with fixed length.
     */
    function toHexString(uint256 value, uint256 length) internal pure returns (string memory) {
        bytes memory buffer = new bytes(2 * length + 2);
        buffer[0] = "0";
        buffer[1] = "x";
        for (uint256 i = 2 * length + 1; i > 1; --i) {
            buffer[i] = _SYMBOLS[value & 0xf];
            value >>= 4;
        }
        require(value == 0, "Strings: hex length insufficient");
        return string(buffer);
    }

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


// 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 (last updated v4.8.0) (utils/Address.sol)

pragma solidity ^0.8.1;

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

        return account.code.length > 0;
    }

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

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

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

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
     * `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but also transferring `value` wei to `target`.
     *
     * Requirements:
     *
     * - the calling contract must have an ETH balance of at least `value`.
     * - the called Solidity function must be `payable`.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value
    ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
    }

    /**
     * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
     * with `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value,
        string memory errorMessage
    ) internal returns (bytes memory) {
        require(address(this).balance >= value, "Address: insufficient balance for call");
        (bool success, bytes memory returndata) = target.call{value: value}(data);
        return verifyCallResultFromTarget(target, success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
        return functionStaticCall(target, data, "Address: low-level static call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal view returns (bytes memory) {
        (bool success, bytes memory returndata) = target.staticcall(data);
        return verifyCallResultFromTarget(target, success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionDelegateCall(target, data, "Address: low-level delegate call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        (bool success, bytes memory returndata) = target.delegatecall(data);
        return verifyCallResultFromTarget(target, success, returndata, errorMessage);
    }

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

    /**
     * @dev Tool to verify that a low level call was successful, and revert if it wasn't, either by bubbling the
     * revert reason or using the provided one.
     *
     * _Available since v4.3._
     */
    function verifyCallResult(
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal pure returns (bytes memory) {
        if (success) {
            return returndata;
        } else {
            _revert(returndata, errorMessage);
        }
    }

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


balance

_approved

// 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);
}


ERC-721 Non-Fungible Token Standard, optional metadata extension

onERC721Received

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

pragma solidity ^0.8.0;

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


ERC721 token receiver interface

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

pragma solidity ^0.8.0;

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

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

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

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

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

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

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

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

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

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

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

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

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


node

addr

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

abstract contract ENSResolver {
  function addr(bytes32 node) public view virtual returns (address);
}


getAddress

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

interface PointerInterface {
  function getAddress() external view returns (address);
}


payment

callbackFunctionId

expiration

cancelOracleRequest

receivers

amounts

distributeFunds

callbackAddress

fulfillOracleRequest

fulfillOracleRequest2

getAuthorizedSenders

getForwarder

isAuthorizedSender

sender

specId

nonce

dataVersion

operatorRequest

requestPrice

serviceAgreementID

oracleRequest

value

ownerTransferAndCall

success

senders

setAuthorizedSenders

recipient

amount

withdraw

withdrawable

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

import "./OracleInterface.sol";
import "./ChainlinkRequestInterface.sol";

interface OperatorInterface is OracleInterface, ChainlinkRequestInterface {
  function operatorRequest(
    address sender,
    uint256 payment,
    bytes32 specId,
    bytes4 callbackFunctionId,
    uint256 nonce,
    uint256 dataVersion,
    bytes calldata data
  ) external;

  function fulfillOracleRequest2(
    bytes32 requestId,
    uint256 payment,
    address callbackAddress,
    bytes4 callbackFunctionId,
    uint256 expiration,
    bytes calldata data
  ) external returns (bool);

  function ownerTransferAndCall(
    address to,
    uint256 value,
    bytes calldata data
  ) external returns (bool success);

  function distributeFunds(address payable[] calldata receivers, uint256[] calldata amounts) external payable;

  function getAuthorizedSenders() external returns (address[] memory);

  function setAuthorizedSenders(address[] calldata senders) external;

  function getForwarder() external returns (address);
}


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

interface ChainlinkRequestInterface {
  function oracleRequest(
    address sender,
    uint256 requestPrice,
    bytes32 serviceAgreementID,
    address callbackAddress,
    bytes4 callbackFunctionId,
    uint256 nonce,
    uint256 dataVersion,
    bytes calldata data
  ) external;

  function cancelOracleRequest(
    bytes32 requestId,
    uint256 payment,
    bytes4 callbackFunctionId,
    uint256 expiration
  ) external;
}


spender

allowance

remaining

decimals

decimalPlaces

addedValue

decreaseApproval

subtractedValue

increaseApproval

tokenName

tokenSymbol

totalTokensIssued

transfer

transferAndCall

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

interface LinkTokenInterface {
  function allowance(address owner, address spender) external view returns (uint256 remaining);

  function approve(address spender, uint256 value) external returns (bool success);

  function balanceOf(address owner) external view returns (uint256 balance);

  function decimals() external view returns (uint8 decimalPlaces);

  function decreaseApproval(address spender, uint256 addedValue) external returns (bool success);

  function increaseApproval(address spender, uint256 subtractedValue) external;

  function name() external view returns (string memory tokenName);

  function symbol() external view returns (string memory tokenSymbol);

  function totalSupply() external view returns (uint256 totalTokensIssued);

  function transfer(address to, uint256 value) external returns (bool success);

  function transferAndCall(
    address to,
    uint256 value,
    bytes calldata data
  ) external returns (bool success);

  function transferFrom(
    address from,
    address to,
    uint256 value
  ) external returns (bool success);
}


label

NewOwner

resolver

NewResolver

NewTTL

setOwner

setResolver

setSubnodeOwner

setTTL

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

interface ENSInterface {
  // Logged when the owner of a node assigns a new owner to a subnode.
  event NewOwner(bytes32 indexed node, bytes32 indexed label, address owner);

  // Logged when the owner of a node transfers ownership to a new account.
  event Transfer(bytes32 indexed node, address owner);

  // Logged when the resolver for a node changes.
  event NewResolver(bytes32 indexed node, address resolver);

  // Logged when the TTL of a node changes
  event NewTTL(bytes32 indexed node, uint64 ttl);

  function setSubnodeOwner(
    bytes32 node,
    bytes32 label,
    address owner
  ) external;

  function setResolver(bytes32 node, address resolver) external;

  function setOwner(bytes32 node, address owner) external;

  function setTTL(bytes32 node, uint64 ttl) external;

  function owner(bytes32 node) external view returns (address);

  function resolver(bytes32 node) external view returns (address);

  function ttl(bytes32 node) external view returns (uint64);
}


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

import {CBORChainlink} from "./vendor/CBORChainlink.sol";
import {BufferChainlink} from "./vendor/BufferChainlink.sol";

/**
 * @title Library for common Chainlink functions
 * @dev Uses imported CBOR library for encoding to buffer
 */
library Chainlink {
  uint256 internal constant defaultBufferSize = 256; // solhint-disable-line const-name-snakecase

  using CBORChainlink for BufferChainlink.buffer;

  struct Request {
    bytes32 id;
    address callbackAddress;
    bytes4 callbackFunctionId;
    uint256 nonce;
    BufferChainlink.buffer buf;
  }

  /**
   * @notice Initializes a Chainlink request
   * @dev Sets the ID, callback address, and callback function signature on the request
   * @param self The uninitialized request
   * @param jobId The Job Specification ID
   * @param callbackAddr The callback address
   * @param callbackFunc The callback function signature
   * @return The initialized request
   */
  function initialize(
    Request memory self,
    bytes32 jobId,
    address callbackAddr,
    bytes4 callbackFunc
  ) internal pure returns (Chainlink.Request memory) {
    BufferChainlink.init(self.buf, defaultBufferSize);
    self.id = jobId;
    self.callbackAddress = callbackAddr;
    self.callbackFunctionId = callbackFunc;
    return self;
  }

  /**
   * @notice Sets the data for the buffer without encoding CBOR on-chain
   * @dev CBOR can be closed with curly-brackets {} or they can be left off
   * @param self The initialized request
   * @param data The CBOR data
   */
  function setBuffer(Request memory self, bytes memory data) internal pure {
    BufferChainlink.init(self.buf, data.length);
    BufferChainlink.append(self.buf, data);
  }

  /**
   * @notice Adds a string value to the request with a given key name
   * @param self The initialized request
   * @param key The name of the key
   * @param value The string value to add
   */
  function add(
    Request memory self,
    string memory key,
    string memory value
  ) internal pure {
    self.buf.encodeString(key);
    self.buf.encodeString(value);
  }

  /**
   * @notice Adds a bytes value to the request with a given key name
   * @param self The initialized request
   * @param key The name of the key
   * @param value The bytes value to add
   */
  function addBytes(
    Request memory self,
    string memory key,
    bytes memory value
  ) internal pure {
    self.buf.encodeString(key);
    self.buf.encodeBytes(value);
  }

  /**
   * @notice Adds a int256 value to the request with a given key name
   * @param self The initialized request
   * @param key The name of the key
   * @param value The int256 value to add
   */
  function addInt(
    Request memory self,
    string memory key,
    int256 value
  ) internal pure {
    self.buf.encodeString(key);
    self.buf.encodeInt(value);
  }

  /**
   * @notice Adds a uint256 value to the request with a given key name
   * @param self The initialized request
   * @param key The name of the key
   * @param value The uint256 value to add
   */
  function addUint(
    Request memory self,
    string memory key,
    uint256 value
  ) internal pure {
    self.buf.encodeString(key);
    self.buf.encodeUInt(value);
  }

  /**
   * @notice Adds an array of strings to the request with a given key name
   * @param self The initialized request
   * @param key The name of the key
   * @param values The array of string values to add
   */
  function addStringArray(
    Request memory self,
    string memory key,
    string[] memory values
  ) internal pure {
    self.buf.encodeString(key);
    self.buf.startArray();
    for (uint256 i = 0; i < values.length; i++) {
      self.buf.encodeString(values[i]);
    }
    self.buf.endSequence();
  }
}


Library for common Chainlink functions

// 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 (last updated v4.8.0) (utils/math/Math.sol)

pragma solidity ^0.8.0;

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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


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

interface OracleInterface {
  function fulfillOracleRequest(
    bytes32 requestId,
    uint256 payment,
    address callbackAddress,
    bytes4 callbackFunctionId,
    uint256 expiration,
    bytes32 data
  ) external returns (bool);

  function isAuthorizedSender(address node) external view returns (bool);

  function withdraw(address recipient, uint256 amount) external;

  function withdrawable() external view returns (uint256);
}


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

/**
 * @dev A library for working with mutable byte buffers in Solidity.
 *
 * Byte buffers are mutable and expandable, and provide a variety of primitives
 * for writing to them. At any time you can fetch a bytes object containing the
 * current contents of the buffer. The bytes object should not be stored between
 * operations, as it may change due to resizing of the buffer.
 */
library BufferChainlink {
  /**
   * @dev Represents a mutable buffer. Buffers have a current value (buf) and
   *      a capacity. The capacity may be longer than the current value, in
   *      which case it can be extended without the need to allocate more memory.
   */
  struct buffer {
    bytes buf;
    uint256 capacity;
  }

  /**
   * @dev Initializes a buffer with an initial capacity.
   * @param buf The buffer to initialize.
   * @param capacity The number of bytes of space to allocate the buffer.
   * @return The buffer, for chaining.
   */
  function init(buffer memory buf, uint256 capacity) internal pure returns (buffer memory) {
    if (capacity % 32 != 0) {
      capacity += 32 - (capacity % 32);
    }
    // Allocate space for the buffer data
    buf.capacity = capacity;
    assembly {
      let ptr := mload(0x40)
      mstore(buf, ptr)
      mstore(ptr, 0)
      mstore(0x40, add(32, add(ptr, capacity)))
    }
    return buf;
  }

  /**
   * @dev Initializes a new buffer from an existing bytes object.
   *      Changes to the buffer may mutate the original value.
   * @param b The bytes object to initialize the buffer with.
   * @return A new buffer.
   */
  function fromBytes(bytes memory b) internal pure returns (buffer memory) {
    buffer memory buf;
    buf.buf = b;
    buf.capacity = b.length;
    return buf;
  }

  function resize(buffer memory buf, uint256 capacity) private pure {
    bytes memory oldbuf = buf.buf;
    init(buf, capacity);
    append(buf, oldbuf);
  }

  function max(uint256 a, uint256 b) private pure returns (uint256) {
    if (a > b) {
      return a;
    }
    return b;
  }

  /**
   * @dev Sets buffer length to 0.
   * @param buf The buffer to truncate.
   * @return The original buffer, for chaining..
   */
  function truncate(buffer memory buf) internal pure returns (buffer memory) {
    assembly {
      let bufptr := mload(buf)
      mstore(bufptr, 0)
    }
    return buf;
  }

  /**
   * @dev Writes a byte string to a buffer. Resizes if doing so would exceed
   *      the capacity of the buffer.
   * @param buf The buffer to append to.
   * @param off The start offset to write to.
   * @param data The data to append.
   * @param len The number of bytes to copy.
   * @return The original buffer, for chaining.
   */
  function write(
    buffer memory buf,
    uint256 off,
    bytes memory data,
    uint256 len
  ) internal pure returns (buffer memory) {
    require(len <= data.length);

    if (off + len > buf.capacity) {
      resize(buf, max(buf.capacity, len + off) * 2);
    }

    uint256 dest;
    uint256 src;
    assembly {
      // Memory address of the buffer data
      let bufptr := mload(buf)
      // Length of existing buffer data
      let buflen := mload(bufptr)
      // Start address = buffer address + offset + sizeof(buffer length)
      dest := add(add(bufptr, 32), off)
      // Update buffer length if we're extending it
      if gt(add(len, off), buflen) {
        mstore(bufptr, add(len, off))
      }
      src := add(data, 32)
    }

    // Copy word-length chunks while possible
    for (; len >= 32; len -= 32) {
      assembly {
        mstore(dest, mload(src))
      }
      dest += 32;
      src += 32;
    }

    // Copy remaining bytes
    unchecked {
      uint256 mask = (256**(32 - len)) - 1;
      assembly {
        let srcpart := and(mload(src), not(mask))
        let destpart := and(mload(dest), mask)
        mstore(dest, or(destpart, srcpart))
      }
    }

    return buf;
  }

  /**
   * @dev Appends a byte string to a buffer. Resizes if doing so would exceed
   *      the capacity of the buffer.
   * @param buf The buffer to append to.
   * @param data The data to append.
   * @param len The number of bytes to copy.
   * @return The original buffer, for chaining.
   */
  function append(
    buffer memory buf,
    bytes memory data,
    uint256 len
  ) internal pure returns (buffer memory) {
    return write(buf, buf.buf.length, data, len);
  }

  /**
   * @dev Appends a byte string to a buffer. Resizes if doing so would exceed
   *      the capacity of the buffer.
   * @param buf The buffer to append to.
   * @param data The data to append.
   * @return The original buffer, for chaining.
   */
  function append(buffer memory buf, bytes memory data) internal pure returns (buffer memory) {
    return write(buf, buf.buf.length, data, data.length);
  }

  /**
   * @dev Writes a byte to the buffer. Resizes if doing so would exceed the
   *      capacity of the buffer.
   * @param buf The buffer to append to.
   * @param off The offset to write the byte at.
   * @param data The data to append.
   * @return The original buffer, for chaining.
   */
  function writeUint8(
    buffer memory buf,
    uint256 off,
    uint8 data
  ) internal pure returns (buffer memory) {
    if (off >= buf.capacity) {
      resize(buf, buf.capacity * 2);
    }

    assembly {
      // Memory address of the buffer data
      let bufptr := mload(buf)
      // Length of existing buffer data
      let buflen := mload(bufptr)
      // Address = buffer address + sizeof(buffer length) + off
      let dest := add(add(bufptr, off), 32)
      mstore8(dest, data)
      // Update buffer length if we extended it
      if eq(off, buflen) {
        mstore(bufptr, add(buflen, 1))
      }
    }
    return buf;
  }

  /**
   * @dev Appends a byte to the buffer. Resizes if doing so would exceed the
   *      capacity of the buffer.
   * @param buf The buffer to append to.
   * @param data The data to append.
   * @return The original buffer, for chaining.
   */
  function appendUint8(buffer memory buf, uint8 data) internal pure returns (buffer memory) {
    return writeUint8(buf, buf.buf.length, data);
  }

  /**
   * @dev Writes up to 32 bytes to the buffer. Resizes if doing so would
   *      exceed the capacity of the buffer.
   * @param buf The buffer to append to.
   * @param off The offset to write at.
   * @param data The data to append.
   * @param len The number of bytes to write (left-aligned).
   * @return The original buffer, for chaining.
   */
  function write(
    buffer memory buf,
    uint256 off,
    bytes32 data,
    uint256 len
  ) private pure returns (buffer memory) {
    if (len + off > buf.capacity) {
      resize(buf, (len + off) * 2);
    }

    unchecked {
      uint256 mask = (256**len) - 1;
      // Right-align data
      data = data >> (8 * (32 - len));
      assembly {
        // Memory address of the buffer data
        let bufptr := mload(buf)
        // Address = buffer address + sizeof(buffer length) + off + len
        let dest := add(add(bufptr, off), len)
        mstore(dest, or(and(mload(dest), not(mask)), data))
        // Update buffer length if we extended it
        if gt(add(off, len), mload(bufptr)) {
          mstore(bufptr, add(off, len))
        }
      }
    }
    return buf;
  }

  /**
   * @dev Writes a bytes20 to the buffer. Resizes if doing so would exceed the
   *      capacity of the buffer.
   * @param buf The buffer to append to.
   * @param off The offset to write at.
   * @param data The data to append.
   * @return The original buffer, for chaining.
   */
  function writeBytes20(
    buffer memory buf,
    uint256 off,
    bytes20 data
  ) internal pure returns (buffer memory) {
    return write(buf, off, bytes32(data), 20);
  }

  /**
   * @dev Appends a bytes20 to the buffer. Resizes if doing so would exceed
   *      the capacity of the buffer.
   * @param buf The buffer to append to.
   * @param data The data to append.
   * @return The original buffer, for chhaining.
   */
  function appendBytes20(buffer memory buf, bytes20 data) internal pure returns (buffer memory) {
    return write(buf, buf.buf.length, bytes32(data), 20);
  }

  /**
   * @dev Appends a bytes32 to the buffer. Resizes if doing so would exceed
   *      the capacity of the buffer.
   * @param buf The buffer to append to.
   * @param data The data to append.
   * @return The original buffer, for chaining.
   */
  function appendBytes32(buffer memory buf, bytes32 data) internal pure returns (buffer memory) {
    return write(buf, buf.buf.length, data, 32);
  }

  /**
   * @dev Writes an integer to the buffer. Resizes if doing so would exceed
   *      the capacity of the buffer.
   * @param buf The buffer to append to.
   * @param off The offset to write at.
   * @param data The data to append.
   * @param len The number of bytes to write (right-aligned).
   * @return The original buffer, for chaining.
   */
  function writeInt(
    buffer memory buf,
    uint256 off,
    uint256 data,
    uint256 len
  ) private pure returns (buffer memory) {
    if (len + off > buf.capacity) {
      resize(buf, (len + off) * 2);
    }

    uint256 mask = (256**len) - 1;
    assembly {
      // Memory address of the buffer data
      let bufptr := mload(buf)
      // Address = buffer address + off + sizeof(buffer length) + len
      let dest := add(add(bufptr, off), len)
      mstore(dest, or(and(mload(dest), not(mask)), data))
      // Update buffer length if we extended it
      if gt(add(off, len), mload(bufptr)) {
        mstore(bufptr, add(off, len))
      }
    }
    return buf;
  }

  /**
   * @dev Appends a byte to the end of the buffer. Resizes if doing so would
   * exceed the capacity of the buffer.
   * @param buf The buffer to append to.
   * @param data The data to append.
   * @return The original buffer.
   */
  function appendInt(
    buffer memory buf,
    uint256 data,
    uint256 len
  ) internal pure returns (buffer memory) {
    return writeInt(buf, buf.buf.length, data, len);
  }
}


// SPDX-License-Identifier: MIT
pragma solidity >=0.4.19;

import {BufferChainlink} from "./BufferChainlink.sol";

library CBORChainlink {
  using BufferChainlink for BufferChainlink.buffer;

  uint8 private constant MAJOR_TYPE_INT = 0;
  uint8 private constant MAJOR_TYPE_NEGATIVE_INT = 1;
  uint8 private constant MAJOR_TYPE_BYTES = 2;
  uint8 private constant MAJOR_TYPE_STRING = 3;
  uint8 private constant MAJOR_TYPE_ARRAY = 4;
  uint8 private constant MAJOR_TYPE_MAP = 5;
  uint8 private constant MAJOR_TYPE_TAG = 6;
  uint8 private constant MAJOR_TYPE_CONTENT_FREE = 7;

  uint8 private constant TAG_TYPE_BIGNUM = 2;
  uint8 private constant TAG_TYPE_NEGATIVE_BIGNUM = 3;

  function encodeFixedNumeric(BufferChainlink.buffer memory buf, uint8 major, uint64 value) private pure {
    if(value <= 23) {
      buf.appendUint8(uint8((major << 5) | value));
    } else if (value <= 0xFF) {
      buf.appendUint8(uint8((major << 5) | 24));
      buf.appendInt(value, 1);
    } else if (value <= 0xFFFF) {
      buf.appendUint8(uint8((major << 5) | 25));
      buf.appendInt(value, 2);
    } else if (value <= 0xFFFFFFFF) {
      buf.appendUint8(uint8((major << 5) | 26));
      buf.appendInt(value, 4);
    } else {
      buf.appendUint8(uint8((major << 5) | 27));
      buf.appendInt(value, 8);
    }
  }

  function encodeIndefiniteLengthType(BufferChainlink.buffer memory buf, uint8 major) private pure {
    buf.appendUint8(uint8((major << 5) | 31));
  }

  function encodeUInt(BufferChainlink.buffer memory buf, uint value) internal pure {
    if(value > 0xFFFFFFFFFFFFFFFF) {
      encodeBigNum(buf, value);
    } else {
      encodeFixedNumeric(buf, MAJOR_TYPE_INT, uint64(value));
    }
  }

  function encodeInt(BufferChainlink.buffer memory buf, int value) internal pure {
    if(value < -0x10000000000000000) {
      encodeSignedBigNum(buf, value);
    } else if(value > 0xFFFFFFFFFFFFFFFF) {
      encodeBigNum(buf, uint(value));
    } else if(value >= 0) {
      encodeFixedNumeric(buf, MAJOR_TYPE_INT, uint64(uint256(value)));
    } else {
      encodeFixedNumeric(buf, MAJOR_TYPE_NEGATIVE_INT, uint64(uint256(-1 - value)));
    }
  }

  function encodeBytes(BufferChainlink.buffer memory buf, bytes memory value) internal pure {
    encodeFixedNumeric(buf, MAJOR_TYPE_BYTES, uint64(value.length));
    buf.append(value);
  }

  function encodeBigNum(BufferChainlink.buffer memory buf, uint value) internal pure {
    buf.appendUint8(uint8((MAJOR_TYPE_TAG << 5) | TAG_TYPE_BIGNUM));
    encodeBytes(buf, abi.encode(value));
  }

  function encodeSignedBigNum(BufferChainlink.buffer memory buf, int input) internal pure {
    buf.appendUint8(uint8((MAJOR_TYPE_TAG << 5) | TAG_TYPE_NEGATIVE_BIGNUM));
    encodeBytes(buf, abi.encode(uint256(-1 - input)));
  }

  function encodeString(BufferChainlink.buffer memory buf, string memory value) internal pure {
    encodeFixedNumeric(buf, MAJOR_TYPE_STRING, uint64(bytes(value).length));
    buf.append(bytes(value));
  }

  function startArray(BufferChainlink.buffer memory buf) internal pure {
    encodeIndefiniteLengthType(buf, MAJOR_TYPE_ARRAY);
  }

  function startMap(BufferChainlink.buffer memory buf) internal pure {
    encodeIndefiniteLengthType(buf, MAJOR_TYPE_MAP);
  }

  function endSequence(BufferChainlink.buffer memory buf) internal pure {
    encodeIndefiniteLengthType(buf, MAJOR_TYPE_CONTENT_FREE);
  }
}


This smart contract, LagrangeChainlinkDataConsumer, is an ERC721 non-fungible token (NFT) that integrates with Chainlink oracle services. It allows users to mint NFTs with a specified metadata URI if they are the owner of the dataset. The contract keeps track of request data and emits events for oracle results and URI updates. It also provides functions to update the token URI, view the total supply of tokens, and withdraw LINK tokens for the contract owner.

Lagrange NFT Data Oracle

This function burns (destroys) an ERC721 token with the given ID, using the overridden _burn function from ERC721URIStorage.
 (autogenerated documentation)

This function converts a byte array to an Ethereum address using assembly code to load the address from memory.
 (autogenerated documentation)

This function fulfills a Chainlink request by minting a new token and setting its URI if the requester is the minter.
 (autogenerated documentation)

This function mints a new token and assigns ownership based on the URI provided, using Chainlink to retrieve the owner information.
 (autogenerated documentation)

This function returns the URI (Uniform Resource Identifier) associated with a given token ID by calling the parent ERC721 and ERC721URIStorage contracts.
 (autogenerated documentation)

This function returns the total number of tokens that have been minted by using the current value of the _tokenIdCounter.
 (autogenerated documentation)

This function updates the URI of a token owned by the caller by setting a new URI and emitting an event.
 (autogenerated documentation)

This function withdraws all LINK tokens from the contract and transfers them to the contract owner's address.
 (autogenerated documentation)