// File: contracts/zone/tlds/HipHop.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.2;

import "../ICANN.sol";

contract HipHopZone is ICANNZone {
  constructor()
    ICANNZone(
      ENS(0x00000000000C2E074eC69A0dFb2997BA6C7d2e1e),
      PublicResolver(0x4976fb03C32e5B8cfe2b6cCB31c09Ba78EBaBa41),
      0x2e4d0b92c040073a779a941f10fd3884f10b8995870e4059fa548aa532b4ff3e,
      ".hiphop",
      "HIPHOP",
      "ipfs://"
    )
  {}
}

// File: contracts/zone/ICANN.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.2;

import "./Standard.sol";
import "./../external/ENS.sol";
import "./../external/PublicResolver.sol";
import "@openzeppelin/contracts/utils/cryptography/ECDSA.sol";

contract ICANNZone is StandardZone {
  using ECDSA for bytes32;
  using Strings for uint256;

  event SetOperator(
    address indexed owner,
    bytes32 indexed namehash,
    address indexed operator,
    bool approved
  );

  event Assigned(bytes32 indexed namehash, address indexed owner);

  event Synced(bytes32 indexed namehash, address indexed owner);

  event ChildLockSet(bytes32 indexed namehash, bool locked);

  event LockSet(bytes32 indexed namehash, bool locked);

  ENS public ens;
  PublicResolver public resolver;

  mapping(address => mapping(bytes32 => mapping(address => bool)))
    private operators;

  struct Domain {
    bytes32 parent;
    bytes32 label;
    uint256 nonce;
    bool locked;
    bool childlock;
  }

  mapping(bytes32 => Domain) public domains;

  constructor(
    ENS _registry,
    PublicResolver _resolver,
    bytes32 _origin,
    string memory _name,
    string memory _symbol,
    string memory _baseURI
  ) StandardZone(msg.sender, _origin, _name, _symbol, _baseURI) {
    ens = _registry;
    resolver = _resolver;
  }

  modifier onlyOperator(bytes32 namehash) {
    require(isOperator(namehash, _msgSender()), "unauthorized");
    _;
  }

  modifier onlyParentOperator(bytes32 namehash) {
    if (namehash == getOrigin()) {
      require(isOperator(namehash, _msgSender()), "unauthorized");
    } else {
      bytes32 parent = domains[namehash].parent;
      require(isOperator(parent, _msgSender()), "unauthorized");
    }
    _;
  }

  modifier onlyZoneAdmin() {
    require(
      _isApprovedOrOwner(_msgSender(), uint256(getOrigin())),
      "must own zone"
    );
    _;
  }

  // register a new domain
  function register(
    address to,
    bytes32 parent,
    string memory label
  ) public virtual override returns (bytes32 namehash) {
    require(
      _isApprovedOrOwner(_msgSender(), uint256(parent)),
      "must own parent"
    );
    require(_isValidLabel(bytes(label)), "invalid label");

    bytes32 _label = keccak256(bytes(label));
    namehash = _register(to, parent, _label);

    domains[namehash].parent = parent;

    emit ResourceRegistered(parent, label);
  }

  function _register(
    address to,
    bytes32 parent,
    bytes32 label
  ) internal virtual returns (bytes32 namehash) {
    namehash = keccak256(abi.encodePacked(parent, label));

    domains[namehash] = Domain({
      parent: parent,
      label: label,
      nonce: 0,
      locked: false,
      childlock: false
    });

    _safeMint(to, uint256(namehash));
  }

  function _beforeTokenTransfer(
    address from,
    address to,
    uint256 tokenId
  ) internal virtual override {
    bytes32 namehash = bytes32(tokenId);
    require(
      from == address(0x0) || !isLocked(namehash),
      "transfer not allowed"
    );

    if (namehash != getOrigin()) {
      _bridge(to, namehash);
    }
  }

  function _bridge(address to, bytes32 namehash) internal virtual {
    bytes32 parent = domains[namehash].parent;
    bytes32 label = domains[namehash].label;
    require(parent != 0x0 && label != 0x0, "invalid namehash");

    _takeOwnership(parent);

    bytes32 subnode = ens.setSubnodeOwner(parent, label, address(this));

    resolver.setAddr(subnode, to);
    ens.setResolver(subnode, address(resolver));
    ens.setSubnodeOwner(parent, label, to);

    _resetOwnership(parent);
  }

  function _takeOwnership(bytes32 namehash) internal {
    if (namehash != getOrigin() && ens.owner(namehash) != address(this)) {
      _takeOwnership(domains[namehash].parent);
      ens.setSubnodeOwner(
        domains[namehash].parent,
        domains[namehash].label,
        address(this)
      );
    }
  }

  function _resetOwnership(bytes32 namehash) internal {
    if (namehash != getOrigin() && ens.owner(namehash) == address(this)) {
      ens.setOwner(namehash, ownerOf(uint256(namehash)));
      _resetOwnership(domains[namehash].parent);
    }
  }

  function assign(address[] memory to, bytes32[] memory namehashes)
    public
    onlyZoneAdmin
  {
    require(to.length == namehashes.length, "Mismatched arrays");
    for (uint256 i = 0; i < namehashes.length; i++) {
      _assign(to[i], namehashes[i]);
    }
  }

  function assignTo(address to, bytes32[] memory namehashes)
    public
    onlyZoneAdmin
  {
    for (uint256 i = 0; i < namehashes.length; i++) {
      _assign(to, namehashes[i]);
    }
  }

  function _assign(address to, bytes32 namehash) internal {
    if (_exists(uint256(namehash))) {
      address currentOwner = ownerOf(uint256(namehash));
      _transfer(currentOwner, to, uint256(namehash));
      emit Assigned(namehash, to);
    }
  }

  function sync(
    address to,
    bytes32 parent,
    string memory label,
    bytes memory signature,
    uint256 nonce
  ) public virtual {
    bytes32 _label = keccak256(bytes(label));
    bytes32 namehash = keccak256(abi.encodePacked(parent, _label));

    require(nonce > domains[namehash].nonce, "invalid nonce");

    bytes32 message = keccak256(abi.encodePacked(nonce, to, namehash));
    address operator = message.toEthSignedMessageHash().recover(signature);

    require(isOperator(parent, operator), "unauthorized");

    domains[namehash].nonce = nonce;
    _assign(to, namehash);

    emit Synced(namehash, to);
  }

  // zone settings
  function setOperator(
    bytes32 namehash,
    address operator,
    bool approved
  ) public virtual {
    require(
      _isApprovedOrOwner(_msgSender(), uint256(namehash)),
      "unauthorized"
    );
    address owner = ownerOf(uint256(namehash));
    operators[owner][namehash][operator] = approved;
    emit SetOperator(owner, namehash, operator, approved);
  }

  function isOperator(bytes32 namehash, address operator)
    public
    view
    returns (bool)
  {
    address owner = ownerOf(uint256(namehash));
    return owner == operator || operators[owner][namehash][operator];
  }

  function lock(bytes32 namehash, bool _lock)
    public
    onlyParentOperator(namehash)
  {
    domains[namehash].locked = _lock;
    emit LockSet(namehash, _lock);
  }

  function childlock(bytes32 namehash, bool _lock)
    public
    onlyParentOperator(namehash)
  {
    domains[namehash].childlock = _lock;
    emit ChildLockSet(namehash, _lock);
  }

  // Updated function to check if a domain is locked using recursion
  function isLocked(bytes32 namehash) public view returns (bool) {
    return domains[namehash].locked || isChildLocked(namehash);
  }

  function isChildLocked(bytes32 namehash) public view returns (bool) {
    if (namehash == getOrigin()) {
      return domains[namehash].childlock;
    } else {
      return
        domains[namehash].childlock || isChildLocked(domains[namehash].parent);
    }
  }

  // Add a function to read the parent of a domain
  function parentOf(bytes32 namehash) public view returns (bytes32) {
    return domains[namehash].parent;
  }

  // Add a function to read the label of a domain
  function labelOf(bytes32 namehash) public view returns (bytes32) {
    return domains[namehash].label;
  }

  // Add a function to read the nonce of a domain
  function nonceOf(bytes32 namehash) public view returns (uint256) {
    return domains[namehash].nonce;
  }

  function setTokenURI(uint256 tokenId, string memory _tokenURI)
    public
    onlyZoneAdmin
  {
    _setTokenURI(tokenId, _tokenURI);
  }

  function transferOriginTo(address to) public onlyZoneAdmin {
    ens.setOwner(getOrigin(), to);
  }
}

// File: contracts/zone/Standard.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.2;

import "./Base.sol";

contract StandardZone is BaseZone {
  string public baseURI;

  constructor(
    address admin,
    bytes32 origin,
    string memory name,
    string memory symbol,
    string memory baseTokenURI
  ) BaseZone(admin, origin, name, symbol) {
    _setBaseURI(baseTokenURI);
  }

  function setBaseURI(string memory base) public {
    require(
      _isApprovedOrOwner(_msgSender(), uint256(getOrigin())),
      "must own zone"
    );
    _setBaseURI(base);
  }

  // function contractURI() public view returns (string memory) {
  //   return tokenURI(uint256(getOrigin()));
  // }

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

  function _setBaseURI(string memory base) internal virtual {
    baseURI = base;
  }
}

// File: contracts/external/ENS.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.2;

interface ENS {

    // 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);

    // Logged when an operator is added or removed.
    event ApprovalForAll(address indexed owner, address indexed operator, bool approved);

    function setRecord(bytes32 node, address _owner, address _resolver, uint64 _ttl) external;
    function setSubnodeRecord(bytes32 node, bytes32 label, address _owner, address _resolver, uint64 _ttl) external;
    function setSubnodeOwner(bytes32 node, bytes32 label, address _owner) external returns(bytes32);
    function setResolver(bytes32 node, address _resolver) external;
    function setOwner(bytes32 node, address _owner) external;
    function setTTL(bytes32 node, uint64 _ttl) external;
    function setApprovalForAll(address operator, bool approved) 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);
    function recordExists(bytes32 node) external view returns (bool);
    function isApprovedForAll(address _owner, address operator) external view returns (bool);
}

// File: contracts/external/PublicResolver.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.2;

import "./ENS.sol";
import "./profiles/AddrResolver.sol";
import "./profiles/TextResolver.sol";

/**
 * A simple resolver anyone can use; only allows the owner of a node to set its
 * address.
 */
contract PublicResolver is AddrResolver, TextResolver {
  ENS ens;

  /**
    * A mapping of operators. An address that is authorised for an address
    * may make any changes to the name that the owner could, but may not update
    * the set of authorisations.
    * (owner, operator) => approved
    */
  mapping(address => mapping(address => bool)) private _operatorApprovals;

  // Logged when an operator is added or removed.
  event ApprovalForAll(address indexed owner, address indexed operator, bool approved);

  constructor(ENS _ens){
    ens = _ens;
  }

  /**
    * @dev See {IERC1155-setApprovalForAll}.
    */
  function setApprovalForAll(address operator, bool approved) external{
    require(
      msg.sender != operator,
      "ERC1155: setting approval status for self"
    );

    _operatorApprovals[msg.sender][operator] = approved;
    emit ApprovalForAll(msg.sender, operator, approved);
  }

  function isAuthorised(bytes32 node) internal override view returns(bool) {
    address owner = ens.owner(node);
    return owner == msg.sender || isApprovedForAll(owner, msg.sender);
  }

  /**
    * @dev See {IERC1155-isApprovedForAll}.
    */
  function isApprovedForAll(address account, address operator) public view returns (bool){
    return _operatorApprovals[account][operator];
  }
}

// File: @openzeppelin/contracts/utils/cryptography/ECDSA.sol



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

pragma solidity ^0.8.0;

import "../Strings.sol";

/**
 * @dev Elliptic Curve Digital Signature Algorithm (ECDSA) operations.
 *
 * These functions can be used to verify that a message was signed by the holder
 * of the private keys of a given address.
 */
library ECDSA {
    enum RecoverError {
        NoError,
        InvalidSignature,
        InvalidSignatureLength,
        InvalidSignatureS,
        InvalidSignatureV
    }

    function _throwError(RecoverError error) private pure {
        if (error == RecoverError.NoError) {
            return; // no error: do nothing
        } else if (error == RecoverError.InvalidSignature) {
            revert("ECDSA: invalid signature");
        } else if (error == RecoverError.InvalidSignatureLength) {
            revert("ECDSA: invalid signature length");
        } else if (error == RecoverError.InvalidSignatureS) {
            revert("ECDSA: invalid signature 's' value");
        } else if (error == RecoverError.InvalidSignatureV) {
            revert("ECDSA: invalid signature 'v' value");
        }
    }

    /**
     * @dev Returns the address that signed a hashed message (`hash`) with
     * `signature` or error string. This address can then be used for verification purposes.
     *
     * The `ecrecover` EVM opcode allows for malleable (non-unique) signatures:
     * this function rejects them by requiring the `s` value to be in the lower
     * half order, and the `v` value to be either 27 or 28.
     *
     * IMPORTANT: `hash` _must_ be the result of a hash operation for the
     * verification to be secure: it is possible to craft signatures that
     * recover to arbitrary addresses for non-hashed data. A safe way to ensure
     * this is by receiving a hash of the original message (which may otherwise
     * be too long), and then calling {toEthSignedMessageHash} on it.
     *
     * Documentation for signature generation:
     * - with https://web3js.readthedocs.io/en/v1.3.4/web3-eth-accounts.html#sign[Web3.js]
     * - with https://docs.ethers.io/v5/api/signer/#Signer-signMessage[ethers]
     *
     * _Available since v4.3._
     */
    function tryRecover(bytes32 hash, bytes memory signature) internal pure returns (address, RecoverError) {
        // Check the signature length
        // - case 65: r,s,v signature (standard)
        // - case 64: r,vs signature (cf https://eips.ethereum.org/EIPS/eip-2098) _Available since v4.1._
        if (signature.length == 65) {
            bytes32 r;
            bytes32 s;
            uint8 v;
            // ecrecover takes the signature parameters, and the only way to get them
            // currently is to use assembly.
            assembly {
                r := mload(add(signature, 0x20))
                s := mload(add(signature, 0x40))
                v := byte(0, mload(add(signature, 0x60)))
            }
            return tryRecover(hash, v, r, s);
        } else if (signature.length == 64) {
            bytes32 r;
            bytes32 vs;
            // ecrecover takes the signature parameters, and the only way to get them
            // currently is to use assembly.
            assembly {
                r := mload(add(signature, 0x20))
                vs := mload(add(signature, 0x40))
            }
            return tryRecover(hash, r, vs);
        } else {
            return (address(0), RecoverError.InvalidSignatureLength);
        }
    }

    /**
     * @dev Returns the address that signed a hashed message (`hash`) with
     * `signature`. This address can then be used for verification purposes.
     *
     * The `ecrecover` EVM opcode allows for malleable (non-unique) signatures:
     * this function rejects them by requiring the `s` value to be in the lower
     * half order, and the `v` value to be either 27 or 28.
     *
     * IMPORTANT: `hash` _must_ be the result of a hash operation for the
     * verification to be secure: it is possible to craft signatures that
     * recover to arbitrary addresses for non-hashed data. A safe way to ensure
     * this is by receiving a hash of the original message (which may otherwise
     * be too long), and then calling {toEthSignedMessageHash} on it.
     */
    function recover(bytes32 hash, bytes memory signature) internal pure returns (address) {
        (address recovered, RecoverError error) = tryRecover(hash, signature);
        _throwError(error);
        return recovered;
    }

    /**
     * @dev Overload of {ECDSA-tryRecover} that receives the `r` and `vs` short-signature fields separately.
     *
     * See https://eips.ethereum.org/EIPS/eip-2098[EIP-2098 short signatures]
     *
     * _Available since v4.3._
     */
    function tryRecover(
        bytes32 hash,
        bytes32 r,
        bytes32 vs
    ) internal pure returns (address, RecoverError) {
        bytes32 s;
        uint8 v;
        assembly {
            s := and(vs, 0x7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff)
            v := add(shr(255, vs), 27)
        }
        return tryRecover(hash, v, r, s);
    }

    /**
     * @dev Overload of {ECDSA-recover} that receives the `r and `vs` short-signature fields separately.
     *
     * _Available since v4.2._
     */
    function recover(
        bytes32 hash,
        bytes32 r,
        bytes32 vs
    ) internal pure returns (address) {
        (address recovered, RecoverError error) = tryRecover(hash, r, vs);
        _throwError(error);
        return recovered;
    }

    /**
     * @dev Overload of {ECDSA-tryRecover} that receives the `v`,
     * `r` and `s` signature fields separately.
     *
     * _Available since v4.3._
     */
    function tryRecover(
        bytes32 hash,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) internal pure returns (address, RecoverError) {
        // EIP-2 still allows signature malleability for ecrecover(). Remove this possibility and make the signature
        // unique. Appendix F in the Ethereum Yellow paper (https://ethereum.github.io/yellowpaper/paper.pdf), defines
        // the valid range for s in (301): 0 < s < secp256k1n ÷ 2 + 1, and for v in (302): v ∈ {27, 28}. Most
        // signatures from current libraries generate a unique signature with an s-value in the lower half order.
        //
        // If your library generates malleable signatures, such as s-values in the upper range, calculate a new s-value
        // with 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEBAAEDCE6AF48A03BBFD25E8CD0364141 - s1 and flip v from 27 to 28 or
        // vice versa. If your library also generates signatures with 0/1 for v instead 27/28, add 27 to v to accept
        // these malleable signatures as well.
        if (uint256(s) > 0x7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF5D576E7357A4501DDFE92F46681B20A0) {
            return (address(0), RecoverError.InvalidSignatureS);
        }
        if (v != 27 && v != 28) {
            return (address(0), RecoverError.InvalidSignatureV);
        }

        // If the signature is valid (and not malleable), return the signer address
        address signer = ecrecover(hash, v, r, s);
        if (signer == address(0)) {
            return (address(0), RecoverError.InvalidSignature);
        }

        return (signer, RecoverError.NoError);
    }

    /**
     * @dev Overload of {ECDSA-recover} that receives the `v`,
     * `r` and `s` signature fields separately.
     */
    function recover(
        bytes32 hash,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) internal pure returns (address) {
        (address recovered, RecoverError error) = tryRecover(hash, v, r, s);
        _throwError(error);
        return recovered;
    }

    /**
     * @dev Returns an Ethereum Signed Message, created from a `hash`. This
     * produces hash corresponding to the one signed with the
     * https://eth.wiki/json-rpc/API#eth_sign[`eth_sign`]
     * JSON-RPC method as part of EIP-191.
     *
     * See {recover}.
     */
    function toEthSignedMessageHash(bytes32 hash) internal pure returns (bytes32) {
        // 32 is the length in bytes of hash,
        // enforced by the type signature above
        return keccak256(abi.encodePacked("\x19Ethereum Signed Message:\n32", hash));
    }

    /**
     * @dev Returns an Ethereum Signed Message, created from `s`. This
     * produces hash corresponding to the one signed with the
     * https://eth.wiki/json-rpc/API#eth_sign[`eth_sign`]
     * JSON-RPC method as part of EIP-191.
     *
     * See {recover}.
     */
    function toEthSignedMessageHash(bytes memory s) internal pure returns (bytes32) {
        return keccak256(abi.encodePacked("\x19Ethereum Signed Message:\n", Strings.toString(s.length), s));
    }

    /**
     * @dev Returns an Ethereum Signed Typed Data, created from a
     * `domainSeparator` and a `structHash`. This produces hash corresponding
     * to the one signed with the
     * https://eips.ethereum.org/EIPS/eip-712[`eth_signTypedData`]
     * JSON-RPC method as part of EIP-712.
     *
     * See {recover}.
     */
    function toTypedDataHash(bytes32 domainSeparator, bytes32 structHash) internal pure returns (bytes32) {
        return keccak256(abi.encodePacked("\x19\x01", domainSeparator, structHash));
    }
}

// File: contracts/zone/Base.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.2;

import "./Interface.sol";
import "../common/StandardNFT.sol";

import "@openzeppelin/contracts/utils/math/SafeMath.sol";

contract BaseZone is ZoneInterface, StandardNFT {
  using SafeMath for uint256;

  bytes32 private _origin;

  constructor(
    address admin,
    bytes32 origin,
    string memory name,
    string memory symbol
  ) ERC721(name, symbol) EIP712MetaTransaction(name) {
    _origin = origin;
    _safeMint(admin, uint256(origin));
    emit ZoneCreated(origin, name, symbol);
  }

  function getOrigin() public view override returns (bytes32) {
    return _origin;
  }

  function owner() public view virtual override returns (address) {
    return ownerOf(uint256(_origin));
  }

  modifier onlyOwner() {
    require(owner() == _msgSender(), "Ownable: caller is not the owner");
    _;
  }

  function exists(bytes32 namehash)
    external
    view
    virtual
    override
    returns (bool)
  {
    return _exists(uint256(namehash));
  }

  function register(
    address to,
    bytes32 parent,
    string memory label
  ) public virtual override returns (bytes32 namehash) {
    require(
      _isApprovedOrOwner(_msgSender(), uint256(parent)),
      "must own parent"
    );
    require(_isValidLabel(bytes(label)), "invalid label");

    namehash = keccak256(abi.encodePacked(parent, keccak256(bytes(label))));
    _safeMint(to, uint256(namehash));

    emit ResourceRegistered(parent, label);
  }

  function _isValidLabel(bytes memory label)
    internal
    view
    virtual
    returns (bool valid)
  {
    require(label.length > 0, "must include a label");

    valid = true;

    for (uint256 i = 0; i < label.length; i++) {
      uint8 char = uint8(label[i]);
      valid =
        valid &&
        (char == 45 ||
          (char >= 48 && char <= 57) ||
          (char >= 97 && char <= 122));
    }
  }

  function _msgSender()
    internal
    view
    virtual
    override
    returns (address sender)
  {
    return EIP712MetaTransaction.msgSender();
  }
}

// File: contracts/zone/Interface.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.2;

interface ZoneInterface {
  event ZoneCreated(bytes32 indexed origin, string name, string symbol);
  event ResourceRegistered(bytes32 indexed parent, string label);

  function getOrigin() external view returns (bytes32);

  function owner() external view returns (address);

  function exists(bytes32 namehash) external view returns (bool);

  function register(
    address to,
    bytes32 parent,
    string memory label
  ) external returns (bytes32 namehash);
}

// File: contracts/common/StandardNFT.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.2;

import "./ERC721HexURI.sol";
import "./EIP712MetaTransaction.sol";

import "@openzeppelin/contracts/utils/Strings.sol";
import "@openzeppelin/contracts/utils/math/Math.sol";
import "@openzeppelin/contracts/utils/math/SafeMath.sol";
import "@openzeppelin/contracts/token/ERC721/extensions/ERC721Burnable.sol";
import "@openzeppelin/contracts/token/ERC721/extensions/ERC721Enumerable.sol";
import "@openzeppelin/contracts/token/ERC721/extensions/ERC721URIStorage.sol";

abstract contract StandardNFT is
  ERC721HexURI,
  ERC721Burnable,
  ERC721Enumerable,
  ERC721URIStorage,
  EIP712MetaTransaction
{
  using Strings for uint256;
  using SafeMath for uint256;

  // Context Overrides
  function _msgSender() internal view virtual override returns (address sender) {
    return EIP712MetaTransaction.msgSender();
  }

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

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

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

  function tokenURI(uint256 tokenId)
    public view virtual override(ERC721, ERC721HexURI, ERC721URIStorage)
    returns (string memory)
  {
    return super.tokenURI(tokenId);
  }
}

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



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

pragma solidity ^0.8.0;

// CAUTION
// This version of SafeMath should only be used with Solidity 0.8 or later,
// because it relies on the compiler's built in overflow checks.

/**
 * @dev Wrappers over Solidity's arithmetic operations.
 *
 * NOTE: `SafeMath` is generally not needed starting with Solidity 0.8, since the compiler
 * now has built in overflow checking.
 */
library SafeMath {
    /**
     * @dev Returns the addition of two unsigned integers, with an overflow flag.
     *
     * _Available since v3.4._
     */
    function tryAdd(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            uint256 c = a + b;
            if (c < a) return (false, 0);
            return (true, c);
        }
    }

    /**
     * @dev Returns the substraction of two unsigned integers, with an overflow flag.
     *
     * _Available since v3.4._
     */
    function trySub(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            if (b > a) return (false, 0);
            return (true, a - b);
        }
    }

    /**
     * @dev Returns the multiplication of two unsigned integers, with an overflow flag.
     *
     * _Available since v3.4._
     */
    function tryMul(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
            // benefit is lost if 'b' is also tested.
            // See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
            if (a == 0) return (true, 0);
            uint256 c = a * b;
            if (c / a != b) return (false, 0);
            return (true, c);
        }
    }

    /**
     * @dev Returns the division of two unsigned integers, with a division by zero flag.
     *
     * _Available since v3.4._
     */
    function tryDiv(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            if (b == 0) return (false, 0);
            return (true, a / b);
        }
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers, with a division by zero flag.
     *
     * _Available since v3.4._
     */
    function tryMod(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            if (b == 0) return (false, 0);
            return (true, a % b);
        }
    }

    /**
     * @dev Returns the addition of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `+` operator.
     *
     * Requirements:
     *
     * - Addition cannot overflow.
     */
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        return a + b;
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        return a - b;
    }

    /**
     * @dev Returns the multiplication of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `*` operator.
     *
     * Requirements:
     *
     * - Multiplication cannot overflow.
     */
    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        return a * b;
    }

    /**
     * @dev Returns the integer division of two unsigned integers, reverting on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator.
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        return a / b;
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * reverting when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        return a % b;
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
     * overflow (when the result is negative).
     *
     * CAUTION: This function is deprecated because it requires allocating memory for the error
     * message unnecessarily. For custom revert reasons use {trySub}.
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    function sub(
        uint256 a,
        uint256 b,
        string memory errorMessage
    ) internal pure returns (uint256) {
        unchecked {
            require(b <= a, errorMessage);
            return a - b;
        }
    }

    /**
     * @dev Returns the integer division of two unsigned integers, reverting with custom message on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function div(
        uint256 a,
        uint256 b,
        string memory errorMessage
    ) internal pure returns (uint256) {
        unchecked {
            require(b > 0, errorMessage);
            return a / b;
        }
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * reverting with custom message when dividing by zero.
     *
     * CAUTION: This function is deprecated because it requires allocating memory for the error
     * message unnecessarily. For custom revert reasons use {tryMod}.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function mod(
        uint256 a,
        uint256 b,
        string memory errorMessage
    ) internal pure returns (uint256) {
        unchecked {
            require(b > 0, errorMessage);
            return a % b;
        }
    }
}

// File: contracts/common/ERC721HexURI.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.2;

import "@openzeppelin/contracts/utils/Strings.sol";
import "@openzeppelin/contracts/token/ERC721/ERC721.sol";

abstract contract ERC721HexURI is ERC721 {
  using Strings for uint256;

  function tokenURI(uint256 tokenId) public view virtual override returns (string memory) {
    string memory base = _baseURI();
    return bytes(base).length > 0 ? string(abi.encodePacked(base, tokenId.toHexString(32))) : "";
  }
}

// File: contracts/common/EIP712MetaTransaction.sol



//SPDX-License-Identifier: MIT
pragma solidity ^0.8.2;

import "./EIP712Base.sol";
import "@openzeppelin/contracts/utils/math/SafeMath.sol";

contract EIP712MetaTransaction is EIP712Base {
  using SafeMath for uint256;

  event MetaTransactionExecuted(address userAddress, address payable relayerAddress, bytes functionSignature);

  struct MetaTransaction {
    uint256 nonce;
    address from;
    bytes functionSignature;
  }

  bytes32 private constant META_TRANSACTION_TYPEHASH = keccak256(bytes("MetaTransaction(uint256 nonce,address from,bytes functionSignature)"));
  mapping(address => uint256) private nonces;

  constructor(string memory name) EIP712Base(name) {}

  function convertBytesToBytes4(
    bytes memory inBytes
  ) internal pure returns (bytes4 outBytes4) {
    if (inBytes.length == 0) {
      return 0x0;
    }

    assembly {
      outBytes4 := mload(add(inBytes, 32))
    }
  }

  function executeMetaTransaction(
    address userAddress,
    bytes memory functionSignature,
    bytes32 sigR,
    bytes32 sigS,
    uint8 sigV
  ) public payable returns(bytes memory) {
    bytes4 destinationFunctionSig = convertBytesToBytes4(functionSignature);
    require(destinationFunctionSig != msg.sig, "functionSignature can not be of executeMetaTransaction method");
    MetaTransaction memory metaTx = MetaTransaction({
      nonce: nonces[userAddress],
      from: userAddress,
      functionSignature: functionSignature
    });
    require(verify(userAddress, metaTx, sigR, sigS, sigV), "Signer and signature do not match");
    nonces[userAddress] = nonces[userAddress].add(1);
    // Append userAddress at the end to extract it from calling context
    (bool success, bytes memory returnData) = address(this).call(abi.encodePacked(functionSignature, userAddress));

    require(success, "Function call not successful");
    emit MetaTransactionExecuted(userAddress, payable(msg.sender), functionSignature);
    return returnData;
  }

  function hashMetaTransaction(MetaTransaction memory metaTx) internal pure returns (bytes32) {
    return keccak256(abi.encode(
      META_TRANSACTION_TYPEHASH,
      metaTx.nonce,
      metaTx.from,
      keccak256(metaTx.functionSignature)
    ));
  }

  function getNonce(address user) external view returns(uint256 nonce) {
    nonce = nonces[user];
  }

  function verify(address user, MetaTransaction memory metaTx, bytes32 sigR, bytes32 sigS, uint8 sigV) internal view returns (bool) {
    address signer = ecrecover(toTypedMessageHash(hashMetaTransaction(metaTx)), sigV, sigR, sigS);
    require(signer != address(0), "Invalid signature");
    return signer == user;
  }

  function msgSender() internal view returns(address sender) {
    if(msg.sender == address(this)) {
      bytes memory array = msg.data;
      uint256 index = msg.data.length;
      assembly {
        // Load the 32 bytes word from memory with the address on the lower 20 bytes, and mask those.
        sender := and(mload(add(array, index)), 0xffffffffffffffffffffffffffffffffffffffff)
      }
    } else {
      sender = msg.sender;
    }
    return sender;
  }
}

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



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

pragma solidity ^0.8.0;

/**
 * @dev String operations.
 */
library Strings {
    bytes16 private constant _HEX_SYMBOLS = "0123456789abcdef";

    /**
     * @dev Converts a `uint256` to its ASCII `string` decimal representation.
     */
    function toString(uint256 value) internal pure returns (string memory) {
        // Inspired by OraclizeAPI's implementation - MIT licence
        // https://github.com/oraclize/ethereum-api/blob/b42146b063c7d6ee1358846c198246239e9360e8/oraclizeAPI_0.4.25.sol

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

    /**
     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation.
     */
    function toHexString(uint256 value) internal pure returns (string memory) {
        if (value == 0) {
            return "0x00";
        }
        uint256 temp = value;
        uint256 length = 0;
        while (temp != 0) {
            length++;
            temp >>= 8;
        }
        return toHexString(value, length);
    }

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

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



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

pragma solidity ^0.8.0;

/**
 * @dev Standard math utilities missing in the Solidity language.
 */
library Math {
    /**
     * @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 / b + (a % b == 0 ? 0 : 1);
    }
}

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



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC721/extensions/ERC721Burnable.sol)

pragma solidity ^0.8.0;

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

/**
 * @title ERC721 Burnable Token
 * @dev ERC721 Token that can be irreversibly burned (destroyed).
 */
abstract contract ERC721Burnable is Context, ERC721 {
    /**
     * @dev Burns `tokenId`. See {ERC721-_burn}.
     *
     * Requirements:
     *
     * - The caller must own `tokenId` or be an approved operator.
     */
    function burn(uint256 tokenId) public virtual {
        //solhint-disable-next-line max-line-length
        require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721Burnable: caller is not owner nor approved");
        _burn(tokenId);
    }
}

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



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC721/extensions/ERC721Enumerable.sol)

pragma solidity ^0.8.0;

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

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

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

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

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

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

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

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

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

    /**
     * @dev Hook that is called before any token transfer. This includes minting
     * and burning.
     *
     * Calling conditions:
     *
     * - When `from` and `to` are both non-zero, ``from``'s `tokenId` will be
     * transferred to `to`.
     * - When `from` is zero, `tokenId` will be minted for `to`.
     * - When `to` is zero, ``from``'s `tokenId` will be burned.
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     *
     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     */
    function _beforeTokenTransfer(
        address from,
        address to,
        uint256 tokenId
    ) internal virtual override {
        super._beforeTokenTransfer(from, to, tokenId);

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

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

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

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

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

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

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

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

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

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

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

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

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

// File: @openzeppelin/contracts/token/ERC721/extensions/ERC721URIStorage.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (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) {
        require(_exists(tokenId), "ERC721URIStorage: URI query for nonexistent token");

        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 Destroys `tokenId`.
     * The approval is cleared when the token is burned.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     *
     * Emits a {Transfer} event.
     */
    function _burn(uint256 tokenId) internal virtual override {
        super._burn(tokenId);

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

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



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (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: balance query for the zero address");
        return _balances[owner];
    }

    /**
     * @dev See {IERC721-ownerOf}.
     */
    function ownerOf(uint256 tokenId) public view virtual override returns (address) {
        address owner = _owners[tokenId];
        require(owner != address(0), "ERC721: owner query for nonexistent token");
        return owner;
    }

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

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

    /**
     * @dev See {IERC721Metadata-tokenURI}.
     */
    function tokenURI(uint256 tokenId) public view virtual override returns (string memory) {
        require(_exists(tokenId), "ERC721Metadata: URI query for nonexistent token");

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

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

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

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

        _approve(to, tokenId);
    }

    /**
     * @dev See {IERC721-getApproved}.
     */
    function getApproved(uint256 tokenId) public view virtual override returns (address) {
        require(_exists(tokenId), "ERC721: approved query for nonexistent token");

        return _tokenApprovals[tokenId];
    }

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

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

    /**
     * @dev See {IERC721-transferFrom}.
     */
    function transferFrom(
        address from,
        address to,
        uint256 tokenId
    ) public virtual override {
        //solhint-disable-next-line max-line-length
        require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721: transfer caller is not owner nor approved");

        _transfer(from, to, tokenId);
    }

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

    /**
     * @dev See {IERC721-safeTransferFrom}.
     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId,
        bytes memory _data
    ) public virtual override {
        require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721: transfer caller is not owner nor approved");
        _safeTransfer(from, to, tokenId, _data);
    }

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

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

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

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

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

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

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

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

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

    /**
     * @dev Destroys `tokenId`.
     * The approval is cleared when the token is burned.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     *
     * Emits a {Transfer} event.
     */
    function _burn(uint256 tokenId) internal virtual {
        address owner = ERC721.ownerOf(tokenId);

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

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

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

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

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

        _beforeTokenTransfer(from, to, tokenId);

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

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

        emit Transfer(from, to, tokenId);
    }

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

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

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

    /**
     * @dev Hook that is called before any token transfer. This includes minting
     * and burning.
     *
     * Calling conditions:
     *
     * - When `from` and `to` are both non-zero, ``from``'s `tokenId` will be
     * transferred to `to`.
     * - When `from` is zero, `tokenId` will be minted for `to`.
     * - When `to` is zero, ``from``'s `tokenId` will be burned.
     * - `from` and `to` are never both zero.
     *
     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     */
    function _beforeTokenTransfer(
        address from,
        address to,
        uint256 tokenId
    ) internal virtual {}
}

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



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC721/IERC721.sol)

pragma solidity ^0.8.0;

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

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

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

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

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

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

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

    /**
     * @dev Transfers `tokenId` token from `from` to `to`.
     *
     * WARNING: Usage of this method is discouraged, use {safeTransferFrom} whenever possible.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must be owned by `from`.
     * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(
        address from,
        address to,
        uint256 tokenId
    ) external;

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

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

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

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

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

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



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC721/IERC721Receiver.sol)

pragma solidity ^0.8.0;

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

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



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

pragma solidity ^0.8.0;

import "../IERC721.sol";

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

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

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

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



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

pragma solidity ^0.8.0;

/**
 * @dev Collection of functions related to the address type
 */
library Address {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * [IMPORTANT]
     * ====
     * It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     *
     * Among others, `isContract` will return false for the following
     * types of addresses:
     *
     *  - an externally-owned account
     *  - a contract in construction
     *  - an address where a contract will be created
     *  - an address where a contract lived, but was destroyed
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize, which returns 0 for contracts in
        // construction, since the code is only stored at the end of the
        // constructor execution.

        uint256 size;
        assembly {
            size := extcodesize(account)
        }
        return size > 0;
    }

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

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

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

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

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

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

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

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

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal view returns (bytes memory) {
        require(isContract(target), "Address: static call to non-contract");

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

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

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        require(isContract(target), "Address: delegate call to non-contract");

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

    /**
     * @dev Tool to verifies that a low level call was successful, and revert if it wasn't, either by bubbling the
     * revert reason using the provided one.
     *
     * _Available since v4.3._
     */
    function verifyCallResult(
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal pure returns (bytes memory) {
        if (success) {
            return returndata;
        } else {
            // Look for revert reason and bubble it up if present
            if (returndata.length > 0) {
                // The easiest way to bubble the revert reason is using memory via assembly

                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}

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



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

pragma solidity ^0.8.0;

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

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

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



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

pragma solidity ^0.8.0;

import "./IERC165.sol";

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

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



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

pragma solidity ^0.8.0;

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

// File: contracts/common/EIP712Base.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.2;

contract EIP712Base {
  struct EIP712Domain {
    string name;
    string version;
    address verifyingContract;
    bytes32 salt;
  }

  bytes32 internal constant EIP712_DOMAIN_TYPEHASH = keccak256(bytes("EIP712Domain(string name,string version,address verifyingContract,bytes32 salt)"));

  bytes32 internal domainSeparator;

  constructor(string memory name) {
    domainSeparator = keccak256(abi.encode(
      EIP712_DOMAIN_TYPEHASH,
      keccak256(bytes(name)),
      keccak256(bytes("1")),
      address(this),
      bytes32(getChainID())
    ));
  }

  function getChainID() internal view returns (uint256 id) {
    assembly {
      id := chainid()
    }
  }

  function getDomainSeparator() private view returns(bytes32) {
    return domainSeparator;
  }

  /**
  * Accept message hash and returns hash message in EIP712 compatible form
  * So that it can be used to recover signer from signature signed using EIP712 formatted data
  * https://eips.ethereum.org/EIPS/eip-712
  * "\\x19" makes the encoding deterministic
  * "\\x01" is the version byte to make it compatible to EIP-191
  */
  function toTypedMessageHash(bytes32 messageHash) internal view returns(bytes32) {
    return keccak256(abi.encodePacked("\x19\x01", getDomainSeparator(), messageHash));
  }
}

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



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC721/extensions/IERC721Enumerable.sol)

pragma solidity ^0.8.0;

import "../IERC721.sol";

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

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

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

// File: contracts/external/profiles/AddrResolver.sol



// SPDX-License-Identifier: MIT
pragma solidity >=0.8.4;

import "../ResolverBase.sol";

interface IAddrResolver {
  event AddrChanged(bytes32 indexed node, address a);
  function addr(bytes32 node) external view returns (address payable);
}

interface IAddressResolver {
  event AddressChanged(bytes32 indexed node, uint coinType, bytes newAddress);
  function addr(bytes32 node, uint coinType) external view returns(bytes memory);
}

abstract contract AddrResolver is IAddrResolver, IAddressResolver, ResolverBase {
  uint constant private COIN_TYPE_ETH = 60;

  mapping(bytes32=>mapping(uint=>bytes)) _addresses;

  /**
    * Sets the address associated with an ENS node.
    * May only be called by the owner of that node in the ENS registry.
    * @param node The node to update.
    * @param a The address to set.
    */
  function setAddr(bytes32 node, address a) virtual external authorised(node) {
    setAddr(node, COIN_TYPE_ETH, addressToBytes(a));
  }

  /**
    * Returns the address associated with an ENS node.
    * @param node The ENS node to query.
    * @return The associated address.
    */
  function addr(bytes32 node) virtual override public view returns (address payable) {
    bytes memory a = addr(node, COIN_TYPE_ETH);
    if(a.length == 0) {
      return payable(0);
    }
    return bytesToAddress(a);
  }

  function setAddr(bytes32 node, uint coinType, bytes memory a) virtual public authorised(node) {
    emit AddressChanged(node, coinType, a);
    if(coinType == COIN_TYPE_ETH) {
      emit AddrChanged(node, bytesToAddress(a));
    }
    _addresses[node][coinType] = a;
  }

  function addr(bytes32 node, uint coinType) virtual override public view returns(bytes memory) {
    return _addresses[node][coinType];
  }

  function bytesToAddress(bytes memory b) internal pure returns(address payable a) {
    require(b.length == 20);
    assembly {
      a := div(mload(add(b, 32)), exp(256, 12))
    }
  }

  function addressToBytes(address a) internal pure returns(bytes memory b) {
    b = new bytes(20);
    assembly {
      mstore(add(b, 32), mul(a, exp(256, 12)))
    }
  }
}

// File: contracts/external/profiles/TextResolver.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.2;

import "../ResolverBase.sol";

interface ITextResolver {
  event TextChanged(bytes32 indexed node, string indexed indexedKey, string key);
  function text(bytes32 node, string calldata key) external view returns (string memory);
}

abstract contract TextResolver is ITextResolver, ResolverBase {
  mapping(bytes32=>mapping(string=>string)) texts;

  /**
    * Sets the text data associated with an ENS node and key.
    * May only be called by the owner of that node in the ENS registry.
    * @param node The node to update.
    * @param key The key to set.
    * @param value The text data value to set.
    */
  function setText(bytes32 node, string calldata key, string calldata value) virtual external authorised(node) {
    texts[node][key] = value;
    emit TextChanged(node, key, key);
  }

  /**
    * Returns the text data associated with an ENS node and key.
    * @param node The ENS node to query.
    * @param key The text data key to query.
    * @return The associated text data.
    */
  function text(bytes32 node, string calldata key) virtual override external view returns (string memory) {
    return texts[node][key];
  }
}

// File: contracts/external/ResolverBase.sol



// SPDX-License-Identifier: MIT
pragma solidity >=0.8.4;

abstract contract ResolverBase {
    function isAuthorised(bytes32 node) internal virtual view returns(bool);

    modifier authorised(bytes32 node) {
        require(isAuthorised(node));
        _;
    }
}