feat: implement folder and folder track sorting

app/lib/sortlib.py

@@ -0,0 +1,44 @@
+from itertools import groupby
+import os
+from pprint import pprint
+from app.lib.albumslib import sort_by_track_no
+from app.models.folder import Folder
+from app.models.track import Track
+from app.utils import flatten
+
+
+def sort_tracks(tracks: list[Track], key: str, reverse: bool = False):
+    """
+    Sorts a list of tracks by a key.
+    """
+    if key == "default":
+        return tracks
+
+    sortfunc = lambda x: getattr(x, key)
+
+    if key == "artists" or key == "albumartists":
+        sortfunc = lambda x: getattr(x, key)[0]["name"]
+
+    if key == "disc":
+        # INFO: Group tracks into albums, then sort them by disc number.
+        tracks = sorted(tracks, key=lambda x: x.album)
+        groups = groupby(tracks, lambda x: x.albumhash)
+
+        return flatten([sort_by_track_no(list(g)) for k, g in groups])
+
+    return sorted(tracks, key=sortfunc, reverse=reverse)
+
+
+def sort_folders(folders: list[Folder], key: str, reverse: bool = False):
+    """
+    Sorts a list of folders by a key.
+    """
+    if key == "default":
+        return folders
+
+    sortfunc = lambda x: getattr(x, key)
+
+    if key == "lastmod":
+        sortfunc = lambda x: os.path.getmtime(x.path)
+
+    return sorted(folders, key=sortfunc, reverse=reverse)