feat: a release catalogue from MusicBrainz; request search asks it directly (M502 #5519)

Minstrel keeps its own record of what artists have released, read from
MusicBrainz, so the wanted list, search and import no longer need Lidarr.

- internal/musicbrainz: searches (artists, release groups, recordings) and
  browses (an artist's release groups; a group's releases with track lists).
  One process-wide pacer at 1.1s, shared with tag enrichment, because
  MusicBrainz's limit is per address. A 503 throttle is retried.
- Migration 0080: mb_artists, mb_release_groups, mb_artist_release_groups
  (a collaboration belongs to each credited artist), mb_releases,
  mb_release_tracks.
- internal/catalogue: Discography and Releases serve the held copy and
  re-read it when older than 7 or 30 days. An unreachable MusicBrainz
  serves the stale copy, marked. An hourly pass re-reads due artists.
- Art for what isn't held comes through /api/catalogue/art from the
  enabled cover-art sources (Cover Art Archive by release group, then the
  name-based sources) and is kept on disk, so the browser never fetches a
  third-party host. A miss is a 404 and the card shows its icon.
- Request search moves from /api/lidarr/search to /api/catalogue/search,
  with the same response shape. Albums are release groups, and "in
  library" matches albums.release_group_mbid. A 10-minute cache absorbs
  search-as-you-type. Discover suggestions point at the art endpoint
  instead of looking up Lidarr.
- Android calls the new path and loads Discover art through ServerImage.
  Installed builds older than this one lose Discover search until they
  update (no compatibility path, rule 22).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

internal/api/catalogue_test.go

@@ -0,0 +1,253 @@
+package api
+
+import (
+	"context"
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"net/url"
+	"testing"
+	"time"
+
+	"github.com/go-chi/chi/v5"
+
+	"git.fabledsword.com/bvandeusen/minstrel/internal/catalogue"
+	"git.fabledsword.com/bvandeusen/minstrel/internal/coverart"
+	"git.fabledsword.com/bvandeusen/minstrel/internal/db/dbq"
+	"git.fabledsword.com/bvandeusen/minstrel/internal/dbtest"
+	"git.fabledsword.com/bvandeusen/minstrel/internal/musicbrainz"
+)
+
+const (
+	searchArtistMBID = "a74b1b7f-71a5-4011-9441-d0b5e4122711"
+	searchGroupMBID  = "b1392450-e666-3926-a536-22c65f834433"
+	searchRecMBID    = "c1a0e1b2-0000-4000-8000-000000000001"
+)
+
+// fakeMusicBrainz answers the three searches with one Radiohead result each,
+// or 503 when down is set.
+func fakeMusicBrainz(t *testing.T, down bool) *httptest.Server {
+	t.Helper()
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if down {
+			w.WriteHeader(http.StatusServiceUnavailable)
+			return
+		}
+		credit := `[{"name": "Radiohead", "artist": {"id": "` + searchArtistMBID + `"}}]`
+		group := `{"id": "` + searchGroupMBID + `", "title": "OK Computer", "primary-type": "Album",
+			"first-release-date": "1997-05-21", "artist-credit": ` + credit + `}`
+		switch r.URL.Path {
+		case "/artist":
+			_, _ = w.Write([]byte(`{"artists": [{"id": "` + searchArtistMBID + `", "name": "Radiohead", "type": "Group", "country": "GB"}]}`))
+		case "/release-group":
+			_, _ = w.Write([]byte(`{"release-groups": [` + group + `]}`))
+		case "/recording":
+			_, _ = w.Write([]byte(`{"recordings": [{"id": "` + searchRecMBID + `", "title": "Karma Police",
+				"artist-credit": ` + credit + `,
+				"releases": [{"id": "r1", "status": "Official", "release-group": ` + group + `}]}]}`))
+		default:
+			w.WriteHeader(http.StatusNotFound)
+		}
+	}))
+	t.Cleanup(srv.Close)
+	return srv
+}
+
+func catalogueHandlers(t *testing.T, down bool) *handlers {
+	t.Helper()
+	h, pool := testHandlers(t)
+	resetLidarrState(t, h)
+	mb := &musicbrainz.Client{BaseURL: fakeMusicBrainz(t, down).URL, Pace: &musicbrainz.Pacer{}, Retries: -1}
+	h.catalogue = catalogue.New(pool, mb, h.logger)
+	return h
+}
+
+func doCatalogueSearch(t *testing.T, h *handlers, q, kind string) *httptest.ResponseRecorder {
+	t.Helper()
+	req := httptest.NewRequest(http.MethodGet, "/api/catalogue/search?"+url.Values{"q": {q}, "kind": {kind}}.Encode(), nil)
+	w := httptest.NewRecorder()
+	h.handleCatalogueSearch(w, req)
+	return w
+}
+
+func decodeResults(t *testing.T, w *httptest.ResponseRecorder) []catalogueSearchResult {
+	t.Helper()
+	if w.Code != http.StatusOK {
+		t.Fatalf("status = %d, body = %s", w.Code, w.Body.String())
+	}
+	var out []catalogueSearchResult
+	if err := json.Unmarshal(w.Body.Bytes(), &out); err != nil {
+		t.Fatalf("decode: %v; body = %s", err, w.Body.String())
+	}
+	return out
+}
+
+func errorCode(t *testing.T, w *httptest.ResponseRecorder) string {
+	t.Helper()
+	var resp struct {
+		Error struct {
+			Code string `json:"code"`
+		} `json:"error"`
+	}
+	if err := json.Unmarshal(w.Body.Bytes(), &resp); err != nil {
+		t.Fatalf("decode: %v; body = %s", err, w.Body.String())
+	}
+	return resp.Error.Code
+}
+
+func TestCatalogueSearch_RefusesABadKindOrNoQuery(t *testing.T) {
+	h := catalogueHandlers(t, false)
+	if w := doCatalogueSearch(t, h, "x", "playlist"); w.Code != http.StatusBadRequest || errorCode(t, w) != "bad_kind" {
+		t.Errorf("bad kind: %d %s", w.Code, w.Body.String())
+	}
+	if w := doCatalogueSearch(t, h, "  ", "artist"); w.Code != http.StatusBadRequest || errorCode(t, w) != "missing_query" {
+		t.Errorf("no query: %d %s", w.Code, w.Body.String())
+	}
+}
+
+func TestCatalogueSearch_EachKindAsksMusicBrainz(t *testing.T) {
+	h := catalogueHandlers(t, false)
+
+	artists := decodeResults(t, doCatalogueSearch(t, h, "radiohead", "artist"))
+	if len(artists) != 1 || artists[0].MBID != searchArtistMBID || artists[0].SecondaryText != "Group · GB" {
+		t.Fatalf("artists = %+v", artists)
+	}
+	if artists[0].ImageURL != "/api/catalogue/art/artist/"+searchArtistMBID+"?name=Radiohead" {
+		t.Errorf("artist art = %q: it must be Minstrel's own endpoint", artists[0].ImageURL)
+	}
+
+	albums := decodeResults(t, doCatalogueSearch(t, h, "ok computer", "album"))
+	if len(albums) != 1 || albums[0].MBID != searchGroupMBID || albums[0].ArtistMBID != searchArtistMBID ||
+		albums[0].SecondaryText != "Radiohead · 1997 · Album" {
+		t.Fatalf("albums = %+v", albums)
+	}
+
+	tracks := decodeResults(t, doCatalogueSearch(t, h, "karma police", "track"))
+	if len(tracks) != 1 || tracks[0].AlbumMBID != searchGroupMBID || tracks[0].ArtistMBID != searchArtistMBID ||
+		tracks[0].SecondaryText != "OK Computer · Radiohead" {
+		t.Fatalf("tracks = %+v", tracks)
+	}
+}
+
+func TestCatalogueSearch_MarksWhatIsHeldAndWhatIsRequested(t *testing.T) {
+	h := catalogueHandlers(t, false)
+	ctx := context.Background()
+	q := dbq.New(h.pool)
+
+	artistMBID := searchArtistMBID
+	artist, err := q.UpsertArtist(ctx, dbq.UpsertArtistParams{Name: dbtest.TestUserPrefix + "Radiohead", SortName: "Radiohead", Mbid: &artistMBID})
+	if err != nil {
+		t.Fatal(err)
+	}
+	// The album is held under a release id; its release group is what matches.
+	if _, err := h.pool.Exec(ctx,
+		`INSERT INTO albums (title, sort_title, artist_id, mbid, release_group_mbid) VALUES ('OK Computer', 'OK Computer', $1, 'some-release-id', $2)`,
+		artist.ID, searchGroupMBID); err != nil {
+		t.Fatal(err)
+	}
+	if got := decodeResults(t, doCatalogueSearch(t, h, "radiohead", "artist")); !got[0].InLibrary {
+		t.Error("the artist is held")
+	}
+	if got := decodeResults(t, doCatalogueSearch(t, h, "ok computer", "album")); !got[0].InLibrary {
+		t.Error("the album is held, matched by release group")
+	}
+
+	user := seedUser(t, h.pool, "requester", "pw", false)
+	track := searchRecMBID
+	if _, err := q.CreateLidarrRequest(ctx, dbq.CreateLidarrRequestParams{
+		UserID: user.ID, Kind: dbq.LidarrRequestKindTrack, LidarrArtistMbid: searchArtistMBID,
+		LidarrTrackMbid: &track, ArtistName: "Radiohead",
+	}); err != nil {
+		t.Fatal(err)
+	}
+	got := decodeResults(t, doCatalogueSearch(t, h, "karma police", "track"))
+	if got[0].InLibrary || !got[0].Requested {
+		t.Errorf("track = %+v, want requested and not held", got[0])
+	}
+}
+
+func TestCatalogueSearch_UnreachableMusicBrainzIs503(t *testing.T) {
+	h := catalogueHandlers(t, true)
+	w := doCatalogueSearch(t, h, "radiohead", "artist")
+	if w.Code != http.StatusServiceUnavailable || errorCode(t, w) != "musicbrainz_unreachable" {
+		t.Fatalf("status %d, body %s", w.Code, w.Body.String())
+	}
+}
+
+// artSource is an artist-art source with one image.
+type artSource struct{ apiTestAlbumProvider }
+
+func (artSource) FetchArtistArt(_ context.Context, _ coverart.ArtistRef) ([]byte, []byte, error) {
+	return []byte("\x89PNG\r\n\x1a\nrest"), nil, nil
+}
+
+type fakeArtSources struct{ artists []coverart.ArtistArtProvider }
+
+func (s fakeArtSources) EnabledArtistProviders() []coverart.ArtistArtProvider { return s.artists }
+func (fakeArtSources) EnabledAlbumProviders() []coverart.AlbumCoverProvider   { return nil }
+
+func TestCatalogueArt_ServesTheImageOrAPlaceholder404(t *testing.T) {
+	h := &handlers{catalogueArt: catalogue.NewArt(t.TempDir(), fakeArtSources{artists: []coverart.ArtistArtProvider{&artSource{}}})}
+	r := chi.NewRouter()
+	r.Get("/api/catalogue/art/{kind}/{mbid}", h.handleCatalogueArt)
+
+	get := func(path string) *httptest.ResponseRecorder {
+		w := httptest.NewRecorder()
+		r.ServeHTTP(w, httptest.NewRequest(http.MethodGet, path, nil))
+		return w
+	}
+	if w := get("/api/catalogue/art/artist/" + searchArtistMBID + "?name=Radiohead"); w.Code != http.StatusOK || w.Header().Get("Content-Type") != "image/png" {
+		t.Errorf("artist: %d %q", w.Code, w.Header().Get("Content-Type"))
+	}
+	// No album source is enabled: a 404, which the page shows as its placeholder.
+	if w := get("/api/catalogue/art/release-group/" + searchGroupMBID); w.Code != http.StatusNotFound {
+		t.Errorf("release group with no source: %d", w.Code)
+	}
+	for _, bad := range []string{"/api/catalogue/art/artist/not-an-id", "/api/catalogue/art/label/" + searchArtistMBID} {
+		if w := get(bad); w.Code != http.StatusNotFound {
+			t.Errorf("%s: %d", bad, w.Code)
+		}
+	}
+}
+
+func TestSuggestionArt_PointsAtMinstrelsOwnEndpoint(t *testing.T) {
+	views := []suggestionView{{MBID: searchArtistMBID, Name: "Sigur Rós"}, {Name: "No MBID"}}
+	resolveSuggestionArt(views)
+	if views[0].ImageURL != "/api/catalogue/art/artist/"+searchArtistMBID+"?name=Sigur+R%C3%B3s" {
+		t.Errorf("image_url = %q", views[0].ImageURL)
+	}
+	if views[1].ImageURL != "" {
+		t.Errorf("no MBID, no image: %q", views[1].ImageURL)
+	}
+}
+
+func TestSearchCache_ReusesAnAnswerButNotTheFlags(t *testing.T) {
+	c := newSearchCache()
+	now := time.Now()
+	c.now = func() time.Time { return now }
+	asks := 0
+	ask := func(context.Context, string, string) ([]catalogueSearchResult, error) {
+		asks++
+		return []catalogueSearchResult{{MBID: "m"}}, nil
+	}
+	first, _ := c.get(context.Background(), "artist", "Radiohead", ask)
+	first[0].InLibrary = true // the handler sets flags on what it is given
+	again, _ := c.get(context.Background(), "artist", "radiohead", ask)
+	if asks != 1 {
+		t.Errorf("asks = %d: the same words in another case are the same search", asks)
+	}
+	if again[0].InLibrary {
+		t.Error("a flag set on one answer leaked into the cache")
+	}
+	if _, _ = c.get(context.Background(), "album", "radiohead", ask); asks != 2 {
+		t.Error("another kind is another search")
+	}
+	now = now.Add(catalogueSearchTTL + time.Second)
+	if _, _ = c.get(context.Background(), "artist", "radiohead", ask); asks != 3 {
+		t.Error("an old answer is asked again")
+	}
+	var none *searchCache
+	if _, _ = none.get(context.Background(), "artist", "x", ask); asks != 4 {
+		t.Error("a nil cache asks every time")
+	}
+}