fix(worker): smooth Qobuz download progress via streamrip byte hook

streamrip reports progress only per concurrent track, so Job.downloadProgress
came solely from the file-count poller — 0% until every track landed, then a
jump to 100%. Patch streamrip.media.track.get_progress_callback to aggregate
per-track byte deltas over an estimated album total (avg started-track size ×
len(album.tracks)) into one smooth, generally-climbing 0..1 fraction routed
through the pipeline's on_progress. Capped at 0.99; the pipeline sets 1.0 on
completion. No signature changes — track count read from the resolved album.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

worker/lyra_worker/adapters/_streamrip.py

@@ -34,6 +34,53 @@ def _run(coro):
     return _loop.run_until_complete(coro)
 
 
+class _ProgressAggregator:
+    """Turn streamrip's per-track byte callbacks into one album-level 0..1 fraction.
+
+    streamrip downloads an album's tracks concurrently and reports progress only per track
+    (a byte delta per chunk), so the file-count poller sees 0 complete files until they all
+    land at once — the 0%→100% jump. Summing downloaded bytes over an *estimated* album total
+    (average started-track size × track count) gives a smooth, generally-climbing fraction.
+    Track sizes are similar, so the estimate is stable once a track or two has started; capped
+    at 0.99 because the pipeline sets 1.0 once the whole download returns. All streamrip
+    coroutines run on one event loop on the calling thread, so no locking is needed."""
+
+    def __init__(self, track_count: int, on_progress: Callable[[float], None]):
+        self._n = track_count or 0
+        self._on_progress = on_progress
+        self._seen_total = 0   # summed byte-size of tracks that have started downloading
+        self._seen_count = 0   # number of tracks that have started
+        self._done_bytes = 0   # summed bytes downloaded across all started tracks
+
+    def start_track(self, total) -> None:
+        self._seen_total += max(int(total or 0), 0)
+        self._seen_count += 1
+
+    def advance(self, delta) -> None:
+        self._done_bytes += max(int(delta or 0), 0)
+        if self._seen_count == 0:
+            return
+        avg = self._seen_total / self._seen_count
+        n = self._n if self._n > 0 else self._seen_count
+        est_total = avg * n
+        if est_total > 0:
+            self._on_progress(min(self._done_bytes / est_total, 0.99))
+
+
+class _ProgressHandle:
+    """streamrip's `Track.download` uses `with get_progress_callback(...) as cb:`; `cb` must be
+    the per-chunk byte callback. This stand-in yields that callback and no-ops on exit."""
+
+    def __init__(self, update: Callable[[int], None]):
+        self.update = update
+
+    def __enter__(self):
+        return self.update
+
+    def __exit__(self, *_):
+        return False
+
+
 def _flatten_audio(dest: str) -> int:
     """streamrip writes into a nested `Artist - Album [...]/` subfolder. Move any audio
     files up into `dest`, remove the now-empty subfolders, and return the count of audio
@@ -136,6 +183,7 @@ class StreamripClient:
 
     async def _download(self, album_id: str, dest: str, on_progress: Callable[[float], None]) -> None:
         os.makedirs(dest, exist_ok=True)
+        import streamrip.media.track as _track_mod
         from streamrip.client import QobuzClient
         from streamrip.db import Database, Dummy
         from streamrip.media import PendingAlbum
@@ -153,7 +201,21 @@ class StreamripClient:
             album = await pending.resolve()
             if album is None:
                 raise RuntimeError(f"could not resolve Qobuz album {album_id}")
+            # Hook streamrip's per-track byte progress into a single album-level fraction so the
+            # Floor bar climbs smoothly instead of jumping 0→100. `Track.download` binds
+            # get_progress_callback at import, so patch it on the track module (not progress.py).
+            agg = _ProgressAggregator(len(getattr(album, "tracks", []) or []), on_progress)
+            _orig_cb = _track_mod.get_progress_callback
+
+            def _hook(_enabled, total, _desc):
+                agg.start_track(total)
+                return _ProgressHandle(agg.advance)
+
+            _track_mod.get_progress_callback = _hook
+            try:
                 await album.rip()
+            finally:
+                _track_mod.get_progress_callback = _orig_cb
             on_progress(1.0)
         finally:
             await client.session.close()

worker/tests/test_streamrip_progress.py

@@ -0,0 +1,41 @@
+from lyra_worker.adapters._streamrip import _ProgressAggregator
+
+
+def _record():
+    seen: list[float] = []
+    return seen, seen.append
+
+
+def test_equal_size_tracks_aggregate_monotonically_to_near_one():
+    # 4 tracks of 100 bytes each, all started up front (concurrency covers the album), then
+    # each downloaded in 25-byte chunks. Fraction must climb monotonically 0→~1.
+    seen, cb = _record()
+    agg = _ProgressAggregator(4, cb)
+    for _ in range(4):
+        agg.start_track(100)
+    for _ in range(16):  # 16 chunks * 25 bytes = 400 bytes = full album
+        agg.advance(25)
+
+    assert seen == sorted(seen)                 # monotonic non-decreasing
+    assert all(0.0 <= f <= 0.99 for f in seen)  # never negative, capped at 0.99
+    assert seen[-1] == 0.99                      # reaches the cap when all bytes are in
+    assert seen[len(seen) // 2] > 0.3           # genuinely climbs mid-download (no 0→100 jump)
+
+
+def test_estimate_uses_track_count_before_all_tracks_start():
+    # Only the first of 4 tracks has started; with a known track count the estimate already
+    # spans the whole album, so finishing track 1 reports ~1/4, not ~1/1.
+    seen, cb = _record()
+    agg = _ProgressAggregator(4, cb)
+    agg.start_track(100)
+    agg.advance(100)  # track 1 fully downloaded
+    assert abs(seen[-1] - 0.25) < 0.01
+
+
+def test_zero_or_missing_sizes_never_emit_and_never_divide_by_zero():
+    seen, cb = _record()
+    agg = _ProgressAggregator(0, cb)
+    agg.advance(50)          # no track started yet -> no emit
+    agg.start_track(0)       # a track with unknown size
+    agg.advance(50)          # est_total still 0 -> still no emit, no crash
+    assert seen == []