SwappableMetadata.sol

contract OKPC is ERC721A {
  address public metadataAddress;

  function setMetadataAddress(address addr) external onlyOwner {
    if (addr == address(0)) revert InvalidAddress();
    metadataAddress = addr;
    emit MetadataAddressUpdated(addr);
  }

  function tokenURI(uint256 pcId) public view override returns (string memory) {
    if (!_exists(pcId)) revert OKPCNotFound();
    return IOKPCMetadata(metadataAddress).tokenURI(pcId);
  }
}