Replace Track.artist and Track.extraArtists with Track.artists

[Lucki]

Ref: https://discord.com/channels/647373417091170314/1275405997736726609
Fix #1668

[nukeop]

Thanks for contributing this. Is it ready for review?

[Lucki]

Yes. Please let me know when you find something non-functional.

Edit: Found one - the MPRIS thing is showing unknown artist
Edit2: Another one - A discogs track without an artist but with extraartists, wanna use the album artist when no specific track artist is available.
Edit3: LastFM track search needs adjustments converting to internal

[nukeop]

NuclearMeta should be updated the same way. I'm afraid this is also going to need that:

• Scanned local library tracks will need to be migrated on first run
• Scanner will need to return data in this new format

[Lucki]

I adjusted the obvious bits, although blind (no manual testing).

As written in the Discord thread and as I have no usage experience with that part of the program, I think it's better you take this part.

[nukeop]

This function does the exact same thing as the one in playlists.ts and almost the same as the one in favorites.ts. The common parts of this logic should be extracted and can live in e.g. packages/app/app/actions/helpers.ts.

[Lucki]

Not quite. All three are slightly different:

Download[]: { track: Track }[]
Playlist[]: { tracks: Track[] }[]
Favorites: { tracks: Track[] }

I tried combining all into a generic function but wasn't successful with it.

Just for laughs

export interface TrackMember {
  track: Track;
}

export interface TracksMember {
  tracks: Track[];
}

export interface Favorites {
  albums: Album[];
  artists: Artist[];
  tracks: Track[];
}

function isTracksMember(config: TrackMember | TracksMember): config is TracksMember {
  return (config as TracksMember).tracks !== undefined;
}

function isTrackMember(config: TrackMember | TracksMember): config is TrackMember {
  return (config as TrackMember).track !== undefined;
}

function isTracksArrayMember(config: TrackMember | TracksMember | Favorites): config is Favorites {
  return (config as Favorites).tracks !== undefined && (config as Favorites).tracks instanceof Array;
}

function rewriteTrackArtists(track: Track) {
  // @ts-expect-error For backwards compatibility we're trying to parse an invalid field
  if (track.artists || !track.artist) {
    // New format already present, do nothing
    return;
  }

  // @ts-expect-error For backwards compatibility we're trying to parse an invalid field
  track.artists = _.isString(track.artist) ? [track.artist] : [track.artist.name];

  // @ts-expect-error For backwards compatibility we're trying to parse an invalid field
  track.artists = track.artists.concat(track.extraArtists?.map(artist));
}

/**
+* Helper function to read the old track format into the new format.
+*
+* `Track.artist` and `Track.extraArtists` are written into {@link Track.artists}
+*/
export function getFromStoreBackwardsCompatible<T extends Favorites | TrackMember[] | TracksMember[]>(configName: 'downloads' | 'favorites' | 'playlists'): T {
  let config: T = store.get(configName);

  if (config instanceof Array) {
    // Playlist[] || Download[]
    config = config.map((member: TrackMember | TracksMember) => {
      if (isTrackMember(member)) {
        // Download[]
        rewriteTrackArtists(member.track);
      } else if (isTracksMember(member)) {
        // Playlist[]
        member.tracks.forEach(track => {
          rewriteTrackArtists(track);
        });
      }
      return member;
    });
  } else if (isTracksArrayMember(config)) {
    // Favorites: { tracks: Track[] }
    config.tracks = config.tracks.map(track => {
      rewriteTrackArtists(track);
      return track;
    });
    config.albums = config.albums.map(album => {
      album.tracklist = album.tracklist?.map(track => {
        rewriteTrackArtists(track);
        return track;
      });
      return album;
    });
  }

  return config;
}

[nukeop]

This part can use the function that can be extracted from all getXBackwardsCompatible.

[Lucki]

As mentioned in the Discord thread, this is very strange.
I moved it in a separate helper function and then the tests start failing because the track is suddenly undefined.

[nukeop]

Instead of mutating by using forEach/push, you can use map and assign what map returns.

[nukeop]

This also applies to other places where forEach is used.

[Lucki]

Changed them all to use map now.
Aside from inside the helper functions there was only one single occurrence when reading from the DB.

[nukeop]

I'm still working on the track table refactor, after that I'll get back to this.