NovaNexHub.sol

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

import "@openzeppelin/contracts/token/ERC721/ERC721.sol";
import "@openzeppelin/contracts/token/ERC721/extensions/ERC721Enumerable.sol";
import "@openzeppelin/contracts/token/ERC721/extensions/ERC721URIStorage.sol";
import "@openzeppelin/contracts/utils/Counters.sol";


contract NovaNexHub is ERC721Enumerable{
  using Counters for Counters.Counter;

  Counters.Counter private _tokenIds;
  address public marketplace;

  struct Item {
    uint256 id;
    address creator;
    string uri;//metadata url
  }

  mapping(uint256 => Item) public Items; //id => Item

  constructor () ERC721("NovaNexHub", "NNH") {}

  function mint(string memory uri) public returns (uint256){
    _tokenIds.increment();
    uint256 newItemId = _tokenIds.current();
    _safeMint(msg.sender, newItemId);
    approve(marketplace, newItemId);

    Items[newItemId] = Item({
      id: newItemId, 
      creator: msg.sender,
      uri: uri
    });

    return newItemId;
  }

  function tokenURI(uint256 tokenId) public view override returns (string memory) {
    return Items[tokenId].uri;
  }

  function setMarketplace(address market) public {
    //require(msg.sender ==);
    marketplace = market;
  }

}