Pulls the 284-line artist quality enhancement helper out of
`web_server.py` into a new `core/artists/` package. Flask route handler
split: route + request parsing stay in web_server.py, the body lifts to
a pure function returning `(payload_dict, http_status_code)`.
What `enhance_artist_quality` does:
1. Validate request: track_ids must be non-empty, artist must exist.
2. Build a `track_lookup` from `database.get_artist_full_detail` so each
selected track resolves with its album context.
3. Per track:
- Read current quality tier from the file extension.
- Build `matched_track_data` for the wishlist entry, in priority
order:
- Spotify direct lookup via stored `spotify_track_id` (preferred).
Uses raw API data when available; otherwise rebuilds the payload
and pulls album images via a follow-up `get_album` call.
- Spotify search fallback using matching_engine queries with
artist+title similarity scoring (album-type bonus for albums,
smaller bonus for EPs). Stops at first >= 0.9 confidence match.
- iTunes/fallback source search with the same scoring shape.
- Add to wishlist via `wishlist_service.add_spotify_track_to_wishlist`
with `source_type='enhance'` and a `source_context` carrying the
original file path, format tier, bitrate, original_tier, and
artist_name.
- Tally `enhanced_count` / `failed_count` / per-track failure reasons.
4. Return `{success, enhanced_count, failed_count, failed_tracks}` 200.
Dependencies injected via `ArtistQualityDeps` (7 fields) — spotify_client,
matching_engine, get_database, get_wishlist_service,
get_current_profile_id, get_quality_tier_from_extension,
get_metadata_fallback_client.
Diff vs original after `deps.X` → global X normalization is **1 line of
cosmetic drift** — the success return now uses an explicit `(payload, 200)`
tuple to keep all returns shape-consistent for the wrapper. Flask treats
`jsonify(x)` and `(jsonify(x), 200)` identically. 284 lines orig = 285
lines lifted, body otherwise byte-identical.
Tests: 10 new under tests/artists/test_quality.py covering input
validation (empty track_ids, artist not found), Spotify direct lookup
via raw_data, Spotify direct lookup with enhanced format requiring
album image rebuild, Spotify search fallback, iTunes/fallback source
match path, track-not-found and no-file-path failure modes, complete
no-match failure, and source_context payload assertions (enhance flag,
file path, format tier, bitrate, source_type).
Full suite: 1340 passing (was 1330). Ruff clean.
91978656a5