feat(enrichment): record status/errors and trust high-confidence AcoustID

Two related gaps surfaced from "uploaded a track, nothing changed / no status":

- A track could stay stuck on `pending` forever (an unexpected worker error
  rolled back the run without recording anything), and `failed` carried no
  reason. Add `tracks.metadata_error` + `tracks.enriched_at` (migration), stamp
  the outcome in apply_enrichment, add TrackRepository.mark_enrichment_failed,
  wrap enrich_task to persist crashes as `failed` in a fresh session, and emit a
  human-readable no-match reason. Expose metadata_error/enriched_at in TrackOut.

- The tag-first merge let junk embedded tags (e.g. "Music Track"/"Sound_13958")
  override even a 0.99-confidence AcoustID match. Add acoustid_trust_score
  (default 0.85): above it the acoustic identity wins for title/artist/album/
  year, tags are fallback; below it, tag-first as before.

Add a license-free real-file fixture (Scarlet Fire / Otis McDonald) whose junk
tags AcoustID overrides, with an always-on tag-reader test plus fpcalc/AcoustID/
network-gated identity + full-pipeline tests (skip on host, run in the container).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

tests/fixtures/README.md

@@ -0,0 +1,20 @@
+# Test fixtures
+
+## `scarlet_fire_otis_mcdonald.mp3`
+
+"Scarlet Fire" by **Otis McDonald** — a royalty-free / license-free track
+(YouTube Audio Library; distributed via Pro-Sound.org). Used as a real-world
+audio fixture for the enrichment pipeline.
+
+What makes it a good fixture: its **embedded ID3 tags are junk**
+(`title=Sound_13958`, `artist=Music Track`, `album=Музыка`, `genre=Hip Hop & Rap`)
+while AcoustID identifies it with very high confidence as *Scarlet Fire /
+Otis McDonald*. So it exercises both:
+
+- the offline tag reader (deterministic, always runs), and
+- the "trust a high-confidence AcoustID match over junk tags" path
+  (`acoustid_trust_score`), which only runs when `fpcalc` + an AcoustID API key
+  + network are available — see `tests/test_real_file_enrichment.py`.
+
+Because it's license-free, it may also seed a built-in demo track for fresh
+instances.

tests/test_import_service.py

@@ -52,6 +52,8 @@ class FakeTrackRepo:
             genre=None,
             year=None,
             metadata_status=str(kw["metadata_status"]),
+            metadata_error=None,
+            enriched_at=None,
             created_at=now,
             updated_at=now,
         )
@@ -133,6 +135,8 @@ async def test_dedup_skips_already_imported() -> None:
         genre=None,
         year=None,
         metadata_status="pending",
+        metadata_error=None,
+        enriched_at=None,
         created_at=now,
         updated_at=now,
     )

tests/test_metadata_service.py

@@ -39,6 +39,8 @@ def _track(*, metadata_status: str = "pending", title: str = "raw-stem") -> Trac
         genre=None,
         year=None,
         metadata_status=metadata_status,
+        metadata_error=None,
+        enriched_at=None,
         created_at=now,
         updated_at=now,
     )
@@ -251,6 +253,33 @@ async def test_nothing_found_marks_failed() -> None:
     assert applied is not None
     assert applied["artist_id"] == track.artist_id  # fallback kept
     assert applied["metadata_status"] == "failed"
+    # A failed run records a human-readable reason; here both id steps were
+    # available, so it's the generic "no match" message.
+    assert applied["metadata_error"] == "No metadata match found in tags or AcoustID."
+
+
+async def test_failed_reason_names_unavailable_fingerprinter() -> None:
+    track = _track()
+    service, tracks, _, _, _ = _service(track=track, tags=None, fp=None, fp_available=False)
+
+    result = await service.enrich(track.id)
+
+    assert result.status == "failed"
+    applied = tracks.applied
+    assert applied is not None
+    assert "fingerprinting" in str(applied["metadata_error"])
+
+
+async def test_successful_enrich_clears_error() -> None:
+    track = _track()
+    service, tracks, _, _, _ = _service(track=track, tags=AudioTags(artist="Pink Floyd"))
+
+    result = await service.enrich(track.id)
+
+    assert result.status == "enriched"
+    applied = tracks.applied
+    assert applied is not None
+    assert applied["metadata_error"] is None
 
 
 async def test_acoustid_path_fills_when_tags_absent() -> None:
@@ -281,13 +310,14 @@ async def test_acoustid_path_fills_when_tags_absent() -> None:
     assert "Daft Punk" in artists.created
 
 
-async def test_tags_win_over_acoustid_for_overlapping_fields() -> None:
+async def test_tags_win_over_low_confidence_acoustid() -> None:
     track = _track()
     fp = Fingerprint(fingerprint="AQAA", duration_seconds=200)
     tags = AudioTags(title="Tagged Title", artist="Tagged Artist")
+    # Below the 0.85 trust threshold → keep tag-first.
     match = RecordingMatch(
         acoustid="aid",
-        score=0.9,
+        score=0.5,
         recording_mbid="mbid",
         title="AcoustID Title",
         artist="AcoustID Artist",
@@ -306,6 +336,36 @@ async def test_tags_win_over_acoustid_for_overlapping_fields() -> None:
     assert applied["musicbrainz_id"] == "mbid"
 
 
+async def test_high_confidence_acoustid_wins_over_junk_tags() -> None:
+    track = _track()
+    fp = Fingerprint(fingerprint="AQAA", duration_seconds=200)
+    # The real-world bug: junk embedded tags on a downloaded file vs a near-
+    # certain acoustic identification. The match must win for the identity.
+    tags = AudioTags(title="Sound_13958", artist="Music Track", album="Музыка")
+    match = RecordingMatch(
+        acoustid="aid",
+        score=0.98,
+        recording_mbid="mbid",
+        release_group_mbid="rg",
+        title="Scarlet Fire",
+        artist="Otis McDonald",
+        album="Scarlet Fire",
+    )
+    service, tracks, artists, albums, _acoustid = _service(
+        track=track, tags=tags, fp=fp, match=match
+    )
+
+    await service.enrich(track.id)
+
+    applied = tracks.applied
+    assert applied is not None
+    assert applied["title"] == "Scarlet Fire"
+    assert "Otis McDonald" in artists.created
+    assert "Music Track" not in artists.created
+    assert albums.created and albums.created[0][0] == "Scarlet Fire"
+    assert applied["metadata_status"] == "enriched"
+
+
 async def test_fingerprint_skipped_when_acoustid_unavailable() -> None:
     track = _track()
     fp = Fingerprint(fingerprint="AQAA", duration_seconds=200)
@@ -356,8 +416,10 @@ async def test_cover_extracted_from_embedded_art() -> None:
     extractor = FakeCoverExtractor(_PNG)
     provider = FakeCoverProvider(_JPG)
     service, albums, storage = _cover_service(
-        track=track, tags=AudioTags(album="The Wall", artist="PF"),
-        extractor=extractor, provider=provider,
+        track=track,
+        tags=AudioTags(album="The Wall", artist="PF"),
+        extractor=extractor,
+        provider=provider,
     )
 
     await service.enrich(track.id)
@@ -377,8 +439,12 @@ async def test_cover_falls_back_to_archive() -> None:
     match = RecordingMatch(acoustid="ac", score=1.0, release_group_mbid="rg-123", album="The Wall")
     fp = Fingerprint(fingerprint="AQAA", duration_seconds=200)
     service, albums, storage = _cover_service(
-        track=track, tags=AudioTags(album="The Wall", artist="PF"),
-        match=match, fp=fp, extractor=extractor, provider=provider,
+        track=track,
+        tags=AudioTags(album="The Wall", artist="PF"),
+        match=match,
+        fp=fp,
+        extractor=extractor,
+        provider=provider,
     )
 
     await service.enrich(track.id)
@@ -394,8 +460,10 @@ async def test_cover_not_fetched_without_release_group() -> None:
     track = _track()
     provider = FakeCoverProvider(_JPG)
     service, albums, _ = _cover_service(
-        track=track, tags=AudioTags(album="The Wall", artist="PF"),
-        extractor=FakeCoverExtractor(None), provider=provider,
+        track=track,
+        tags=AudioTags(album="The Wall", artist="PF"),
+        extractor=FakeCoverExtractor(None),
+        provider=provider,
     )
 
     await service.enrich(track.id)
@@ -408,8 +476,10 @@ async def test_existing_cover_is_not_overwritten() -> None:
     track = _track()
     extractor = FakeCoverExtractor(_PNG)
     service, albums, storage = _cover_service(
-        track=track, tags=AudioTags(album="The Wall", artist="PF"),
-        extractor=extractor, existing_cover="covers/old.jpg",
+        track=track,
+        tags=AudioTags(album="The Wall", artist="PF"),
+        extractor=extractor,
+        existing_cover="covers/old.jpg",
     )
 
     await service.enrich(track.id)

tests/test_real_file_enrichment.py

@@ -0,0 +1,206 @@
+"""Enrichment tests against a real audio file (``tests/fixtures/``).
+
+The fixture "Scarlet Fire" by Otis McDonald carries *junk* embedded tags
+(``Sound_13958`` / ``Music Track`` / ``Музыка``) yet is identified by AcoustID
+with ~0.99 confidence. That makes it the real-world reproduction of the
+"uploaded a track, got the wrong name/artist" bug: tag reading must be exact,
+and a high-confidence AcoustID match must override the junk tags.
+
+Two layers:
+- The tag-reader test is offline and deterministic — it always runs.
+- The AcoustID/identity tests need the ``fpcalc`` binary, an AcoustID API key,
+  and network. They *skip* (never fail) when those aren't present, honouring the
+  project rule that the suite never hard-requires network. They do run inside the
+  api/worker container (``make test-api``), which ships fpcalc + the key.
+"""
+
+import uuid
+from collections.abc import AsyncIterator
+from contextlib import asynccontextmanager
+from dataclasses import dataclass, field
+from datetime import UTC, datetime
+from pathlib import Path
+
+import pytest
+from app.application.metadata_service import MetadataEnrichmentService
+from app.core.config import get_settings
+from app.domain.entities.album import Album
+from app.domain.entities.track import Artist, Track
+from app.infrastructure.metadata.acoustid import AcoustIdHttpClient
+from app.infrastructure.metadata.fingerprint import FpcalcFingerprinter
+from app.infrastructure.metadata.tags import MutagenTagReader
+
+pytestmark = pytest.mark.asyncio
+
+FIXTURE = Path(__file__).parent / "fixtures" / "scarlet_fire_otis_mcdonald.mp3"
+
+_settings = get_settings()
+_fpcalc = FpcalcFingerprinter(_settings.fpcalc_path)
+
+# Gate for the network/identity tests — present in the container, absent in CI.
+requires_acoustid = pytest.mark.skipif(
+    not (_fpcalc.is_available() and _settings.acoustid_api_key is not None),
+    reason="needs the fpcalc binary + ACOUSTID_API_KEY (+ network)",
+)
+
+
+def _acoustid_client() -> AcoustIdHttpClient:
+    key = _settings.acoustid_api_key
+    return AcoustIdHttpClient(
+        api_key=key.get_secret_value() if key else None,
+        user_agent=_settings.musicbrainz_user_agent,
+        api_url=_settings.acoustid_api_url,
+    )
+
+
+# --- offline: tag reading on a real file -----------------------------------
+
+
+async def test_real_file_embedded_tags_are_read() -> None:
+    """The reader extracts the file's actual (junk) embedded tags verbatim —
+    proving real-file tag parsing works end to end, no network involved."""
+    assert FIXTURE.exists(), "fixture mp3 missing"
+    tags = await MutagenTagReader().read(FIXTURE)
+
+    assert tags is not None
+    assert tags.title == "Sound_13958"
+    assert tags.artist == "Music Track"
+    assert tags.album == "Музыка"
+    assert tags.genre == "Hip Hop & Rap"
+    assert tags.year == 2018
+    assert tags.duration_seconds == 143
+    assert tags.bitrate == 128
+
+
+# --- networked: AcoustID identifies the real recording ---------------------
+
+
+@requires_acoustid
+async def test_real_file_identified_by_acoustid() -> None:
+    """fpcalc → AcoustID identifies the real audio as Scarlet Fire / Otis
+    McDonald with high confidence (despite the junk tags)."""
+    fingerprint = await _fpcalc.calculate(FIXTURE)
+    if fingerprint is None:
+        pytest.skip("fpcalc produced no fingerprint")
+
+    match = await _acoustid_client().lookup(fingerprint)
+    if match is None:
+        pytest.skip("AcoustID returned no match (network/rate limit?)")
+
+    assert match.score >= _settings.acoustid_trust_score
+    assert match.title == "Scarlet Fire"
+    assert match.artist == "Otis McDonald"
+    assert match.recording_mbid is not None
+
+
+@requires_acoustid
+async def test_real_file_enrichment_overrides_junk_tags() -> None:
+    """Full pipeline on the real file with the real tag-reader, fingerprinter
+    and AcoustID client: the high-confidence match wins over the junk embedded
+    tags, so the track is stored as Scarlet Fire / Otis McDonald."""
+    track = _pending_track()
+    tracks = _FakeTrackRepo(track)
+    artists = _FakeArtistRepo()
+    albums = _FakeAlbumRepo()
+
+    service = MetadataEnrichmentService(
+        tracks=tracks,  # type: ignore[arg-type]
+        artists=artists,  # type: ignore[arg-type]
+        albums=albums,  # type: ignore[arg-type]
+        storage=_FixtureStorage(),  # type: ignore[arg-type]
+        tag_reader=MutagenTagReader(),
+        fingerprinter=_fpcalc,
+        acoustid=_acoustid_client(),
+        acoustid_trust_score=_settings.acoustid_trust_score,
+    )
+
+    result = await service.enrich(track.id)
+    if result.status == "failed":
+        pytest.skip("AcoustID unavailable at run time (network/rate limit?)")
+
+    assert result.status == "enriched"
+    applied = tracks.applied
+    assert applied is not None
+    assert applied["title"] == "Scarlet Fire"
+    assert "Otis McDonald" in artists.created
+    assert "Music Track" not in artists.created
+    assert albums.created and albums.created[0][0] == "Scarlet Fire"
+
+
+# --- minimal in-memory adapters --------------------------------------------
+
+
+def _pending_track() -> Track:
+    now = datetime.now(UTC)
+    return Track(
+        id=uuid.uuid4(),
+        title="scarlet_fire_otis_mcdonald",  # the upload-time filename stem
+        artist_id=uuid.uuid4(),
+        album_id=None,
+        storage_uri="tracks/sf/scarlet.mp3",
+        file_format="mp3",
+        file_size=FIXTURE.stat().st_size,
+        source="upload",
+        source_id="sha-real",
+        duration_seconds=None,
+        genre=None,
+        year=None,
+        metadata_status="pending",
+        metadata_error=None,
+        enriched_at=None,
+        created_at=now,
+        updated_at=now,
+    )
+
+
+class _FixtureStorage:
+    @asynccontextmanager
+    async def as_local_path(self, _key: str) -> AsyncIterator[Path]:
+        yield FIXTURE
+
+
+class _FakeTrackRepo:
+    def __init__(self, track: Track) -> None:
+        self._track = track
+        self.applied: dict[str, object] | None = None
+
+    async def get_by_id(self, _track_id: uuid.UUID) -> Track:
+        return self._track
+
+    async def apply_enrichment(self, _track_id: uuid.UUID, **kw: object) -> Track:
+        self.applied = kw
+        return self._track
+
+
+@dataclass
+class _FakeArtistRepo:
+    created: list[str] = field(default_factory=list)
+
+    async def get_or_create(self, name: str) -> Artist:
+        self.created.append(name)
+        now = datetime.now(UTC)
+        return Artist(id=uuid.uuid4(), name=name, created_at=now, updated_at=now)
+
+
+@dataclass
+class _FakeAlbumRepo:
+    created: list[tuple[str, uuid.UUID]] = field(default_factory=list)
+
+    async def get_or_create(
+        self, *, title: str, artist_id: uuid.UUID, year: int | None, musicbrainz_id: str | None
+    ) -> Album:
+        self.created.append((title, artist_id))
+        now = datetime.now(UTC)
+        return Album(
+            id=uuid.uuid4(),
+            title=title,
+            artist_id=artist_id,
+            year=year,
+            cover_path=None,
+            musicbrainz_id=musicbrainz_id,
+            created_at=now,
+            updated_at=now,
+        )
+
+    async def set_cover_path(self, _album_id: uuid.UUID, _cover_path: str) -> None:
+        return None