GenArt721Core.sol

pragma solidity ^0.5.0;


function tokenURI(uint256 _tokenId) external
          view onlyValidTokenId(_tokenId) returns (string memory) {
    // if staticIpfsImageLink is present,
    // then return "{projectBaseIpfsURI}/{staticIpfsImageLink}"
    if (bytes(staticIpfsImageLink[_tokenId]).length > 0) {
        return Strings.strConcat(
          projects[tokenIdToProjectId[_tokenId]].projectBaseIpfsURI,
          staticIpfsImageLink[_tokenId]);
    }

    // if project is not dynamic and useIpfs is true,
    // then return "{projectBaseIpfsURI}/{ipfsHash}"
    if (!projects[tokenIdToProjectId[_tokenId]].dynamic
        && projects[tokenIdToProjectId[_tokenId]].useIpfs) {
        return Strings.strConcat(
          projects[tokenIdToProjectId[_tokenId]].projectBaseIpfsURI,
          projects[tokenIdToProjectId[_tokenId]].ipfsHash);
    }

    // else return "{projectBaseURI}/{_tokenId}"
    return Strings.strConcat(
      projects[tokenIdToProjectId[_tokenId]].projectBaseURI, 
      Strings.uint2str(_tokenId));
}