feat: real mutagen tagger and MusicBrainz tracklist

worker/lyra_worker/_musicbrainz.py

@@ -47,6 +47,7 @@ class MusicBrainzResolver:
 
         track_count = None
         total_duration_s = None
+        titles: tuple[str, ...] = ()
         rgid = rg.get("id")
         if rgid:
             rgfull = musicbrainzngs.get_release_group_by_id(rgid, includes=["releases"])
@@ -62,6 +63,7 @@ class MusicBrainzResolver:
                     track_count = len(tracks)
                     total_ms = sum(int((t.get("recording") or {}).get("length") or 0) for t in tracks)
                     total_duration_s = total_ms // 1000 if total_ms else None
+                    titles = tuple((t.get("recording") or {}).get("title", "") for t in tracks)
 
         return MBTarget(
             artist=canonical_artist,
@@ -69,4 +71,5 @@ class MusicBrainzResolver:
             track_count=track_count,
             total_duration_s=total_duration_s,
             year=year,
+            tracklist=titles,
         )

worker/lyra_worker/_mutagen.py

@@ -0,0 +1,48 @@
+import os
+
+from lyra_worker.library import safe_name
+
+_AUDIO_EXT = {".flac", ".mp3", ".m4a", ".opus", ".ogg", ".aac", ".wav"}
+
+
+def plan_track_names(names: list[str], tracklist: tuple[str, ...]) -> list[tuple[str, str, str, int]]:
+    """Map audio filenames -> (old_name, new_name, title, track_number).
+
+    Files are sorted; titles come from `tracklist` by position when available,
+    else the filename stem. Pure — no filesystem or tag I/O.
+    """
+    plan: list[tuple[str, str, str, int]] = []
+    audio = sorted(n for n in names if os.path.splitext(n)[1].lower() in _AUDIO_EXT)
+    for i, name in enumerate(audio):
+        ext = os.path.splitext(name)[1].lower()
+        title = tracklist[i] if i < len(tracklist) else os.path.splitext(name)[0]
+        new_name = f"{i + 1:02d} {safe_name(title)}{ext}"
+        plan.append((name, new_name, title, i + 1))
+    return plan
+
+
+class MutagenTagger:
+    """Real Tagger using mutagen (lazily imported). The tag-write is not unit-tested
+    offline (needs real audio); the naming logic (`plan_track_names`) is."""
+
+    def tag_album(self, album_dir: str, target) -> None:
+        import mutagen
+
+        names = os.listdir(album_dir)
+        for old_name, new_name, title, number in plan_track_names(names, target.tracklist):
+            path = os.path.join(album_dir, old_name)
+            audio = mutagen.File(path, easy=True)
+            if audio is None:  # unreadable/unsupported file — leave it untouched
+                continue
+            audio["artist"] = target.artist
+            audio["albumartist"] = target.artist
+            audio["album"] = target.album
+            audio["title"] = title
+            audio["tracknumber"] = str(number)
+            if target.year:
+                audio["date"] = str(target.year)
+            audio.save()
+
+            new_path = os.path.join(album_dir, new_name)
+            if os.path.abspath(new_path) != os.path.abspath(path) and not os.path.exists(new_path):
+                os.rename(path, new_path)