implement backup and restore draft 1

+ add extra fields for backup in favorites and scrobble data
- not yet for the playlist tracks

app/lib/extras.py

@@ -0,0 +1,37 @@
+from typing import Any
+from app.store.albums import AlbumStore
+from app.store.artists import ArtistStore
+from app.store.tracks import TrackStore
+
+
+def get_extra_info(hash: str, type: str):
+    """
+    Generates extra info for a track, album or artist, which will be stored
+    in the database (in favorites, playlists and scrobble data) for backup and restore.
+
+    The extra info contains all the fields needed to reconstruct the itemhash. The track contains an additional filepath field which can be used to locate the file when restoring.
+    """
+    extra: dict[str, Any] = {}
+
+    if type == "track":
+        trackentry = TrackStore.trackhashmap.get(hash)
+        if trackentry is not None:
+            track = trackentry.get_best()
+
+            extra["filepath"] = track.filepath
+            extra["title"] = track.title
+            extra["artists"] = [a["name"] for a in track.artists]
+            extra["album"] = track.albumhash
+
+    elif type == "album":
+        album = AlbumStore.get_album_by_hash(hash)
+        if album is not None:
+            extra["albumartists"] = [a["name"] for a in album.albumartists]
+            extra["title"] = album.title
+
+    elif type == "artist":
+        artist = ArtistStore.get_artist_by_hash(hash)
+        if artist is not None:
+            extra["name"] = artist.name
+
+    return extra