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contracts...MedChainNFT.sol

//Contract based on [https://docs.openzeppelin.com/contracts/3.x/erc721](https://docs.openzeppelin.com/contracts/3.x/erc721)
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.7;

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

contract MedChainNFT is ERC721URIStorage, ERC721Enumerable, Ownable {
    using Counters for Counters.Counter;
    Counters.Counter public _tokenIds;
    address contractAddress;
    
    constructor(/*address marketplaceAddress*/) ERC721("MedChainNFT Token", "MCT") {
        /*contractAddress = marketplaceAddress;*/
    }
    
    // string memory tokenURI is a string that should resolve to a JSON document that describes the NFT's metadata.
    // An NFT's metadata is really what brings it to life, allowing it to have configurable properties, such as a name, description, image, and other attributes
    function createToken(address marketplaceAddress, string memory _tokenURI)
        public returns (uint256)
    {
        _tokenIds.increment();
        uint256 newItemId = _tokenIds.current();
        
        _mint(msg.sender, newItemId);
        _setTokenURI(newItemId, _tokenURI);
        setApprovalForAll(address(marketplaceAddress), true);

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

    function _burn(uint256 tokenId) 
        internal override(ERC721, ERC721URIStorage) 
    {
        super._burn(tokenId);
    }
    
    function supportsInterface(bytes4 interfaceId)
        public view override(ERC721, ERC721Enumerable)
        returns (bool)
    {
        return super.supportsInterface(interfaceId);
    }
    
    function tokenURI(uint256 tokenId)
        public view override(ERC721, ERC721URIStorage)
        returns (string memory)
    {
        return super.tokenURI(tokenId);
    }
    
}