feat(api): add GET /api/artists/{id}/tracks handler

Wires ListArtistTracksForUser (Task 3 SQL) to a new handler that returns
all quarantine-filtered tracks for an artist as a flat TrackRef list.
404 when the artist doesn't exist. Route registered in Mount().

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

internal/api/api.go

@@ -43,6 +43,7 @@ func Mount(r chi.Router, pool *pgxpool.Pool, logger *slog.Logger, events *playev
 
 			authed.Get("/artists", h.handleListArtists)
 			authed.Get("/artists/{id}", h.handleGetArtist)
+			authed.Get("/artists/{id}/tracks", h.handleGetArtistTracks)
 			authed.Get("/albums/{id}", h.handleGetAlbum)
 			authed.Get("/albums/{id}/cover", h.handleGetCover)
 			authed.Get("/tracks/{id}", h.handleGetTrack)

internal/api/library.go

@@ -143,6 +143,46 @@ func (h *handlers) handleGetArtist(w http.ResponseWriter, r *http.Request) {
 	writeJSON(w, http.StatusOK, detail)
 }
 
+// handleGetArtistTracks implements GET /api/artists/{id}/tracks. Returns
+// every track the artist has across albums (per-user-quarantine filtered)
+// as a flat list. Used by ArtistCard's play affordance, which shuffles
+// client-side. 404 when the artist doesn't exist.
+func (h *handlers) handleGetArtistTracks(w http.ResponseWriter, r *http.Request) {
+	id, ok := parseUUID(chi.URLParam(r, "id"))
+	if !ok {
+		writeErr(w, http.StatusBadRequest, "bad_request", "invalid artist id")
+		return
+	}
+	user, ok := auth.UserFromContext(r.Context())
+	if !ok {
+		writeErr(w, http.StatusUnauthorized, "unauthorized", "authentication required")
+		return
+	}
+	q := dbq.New(h.pool)
+	if _, err := q.GetArtistByID(r.Context(), id); err != nil {
+		if errors.Is(err, pgx.ErrNoRows) {
+			writeErr(w, http.StatusNotFound, "not_found", "artist not found")
+			return
+		}
+		h.logger.Error("api: get artist for tracks", "err", err)
+		writeErr(w, http.StatusInternalServerError, "server_error", "lookup failed")
+		return
+	}
+	rows, err := q.ListArtistTracksForUser(r.Context(), dbq.ListArtistTracksForUserParams{
+		ArtistID: id, UserID: user.ID,
+	})
+	if err != nil {
+		h.logger.Error("api: list artist tracks", "err", err)
+		writeErr(w, http.StatusInternalServerError, "server_error", "lookup failed")
+		return
+	}
+	out := make([]TrackRef, 0, len(rows))
+	for _, row := range rows {
+		out = append(out, trackRefFrom(row.Track, row.AlbumTitle, row.ArtistName))
+	}
+	writeJSON(w, http.StatusOK, out)
+}
+
 // handleListArtists implements GET /api/artists with two sort modes
 // (alpha|newest) and enveloped pagination. album_count per artist is
 // computed via an N+1 — acceptable at limit=200.

internal/api/library_test.go

@@ -1,6 +1,7 @@
 package api
 
 import (
+	"context"
 	"encoding/json"
 	"io"
 	"log/slog"
@@ -12,6 +13,7 @@ import (
 	"github.com/go-chi/chi/v5"
 
 	"git.fabledsword.com/bvandeusen/minstrel/internal/config"
+	"git.fabledsword.com/bvandeusen/minstrel/internal/db/dbq"
 	"git.fabledsword.com/bvandeusen/minstrel/internal/playevents"
 )
 
@@ -465,3 +467,103 @@ func TestRoutesRegisteredInMount(t *testing.T) {
 		}
 	}
 }
+
+func TestGetArtistTracks_HappyPath(t *testing.T) {
+	h, pool := testHandlers(t)
+	user := seedUser(t, pool, "alice", "pw", false)
+	q := dbq.New(pool)
+	artist, _ := q.UpsertArtist(context.Background(), dbq.UpsertArtistParams{
+		Name: "ArtistA", SortName: "ArtistA",
+	})
+	album, _ := q.UpsertAlbum(context.Background(), dbq.UpsertAlbumParams{
+		Title: "AlbumA", SortTitle: "AlbumA", ArtistID: artist.ID,
+	})
+	_, _ = q.UpsertTrack(context.Background(), dbq.UpsertTrackParams{
+		Title: "T1", AlbumID: album.ID, ArtistID: artist.ID,
+		DurationMs: 1000, FilePath: "/tmp/m6a-T1.mp3",
+		FileSize: 1, FileFormat: "mp3",
+	})
+	_, _ = q.UpsertTrack(context.Background(), dbq.UpsertTrackParams{
+		Title: "T2", AlbumID: album.ID, ArtistID: artist.ID,
+		DurationMs: 1000, FilePath: "/tmp/m6a-T2.mp3",
+		FileSize: 1, FileFormat: "mp3",
+	})
+
+	r := chi.NewRouter()
+	r.Get("/api/artists/{id}/tracks", h.handleGetArtistTracks)
+	req := httptest.NewRequest(http.MethodGet, "/api/artists/"+uuidToString(artist.ID)+"/tracks", nil)
+	req = withUser(req, user)
+	w := httptest.NewRecorder()
+	r.ServeHTTP(w, req)
+
+	if w.Code != http.StatusOK {
+		t.Fatalf("status = %d, body = %s", w.Code, w.Body.String())
+	}
+	var got []TrackRef
+	if err := json.Unmarshal(w.Body.Bytes(), &got); err != nil {
+		t.Fatalf("decode: %v", err)
+	}
+	if len(got) != 2 {
+		t.Fatalf("len = %d, want 2", len(got))
+	}
+	if got[0].ArtistName != "ArtistA" || got[0].AlbumTitle != "AlbumA" {
+		t.Errorf("got = %+v", got[0])
+	}
+}
+
+func TestGetArtistTracks_HonorsQuarantine(t *testing.T) {
+	h, pool := testHandlers(t)
+	user := seedUser(t, pool, "alice", "pw", false)
+	q := dbq.New(pool)
+	artist, _ := q.UpsertArtist(context.Background(), dbq.UpsertArtistParams{
+		Name: "ArtistB", SortName: "ArtistB",
+	})
+	album, _ := q.UpsertAlbum(context.Background(), dbq.UpsertAlbumParams{
+		Title: "AlbumB", SortTitle: "AlbumB", ArtistID: artist.ID,
+	})
+	track, _ := q.UpsertTrack(context.Background(), dbq.UpsertTrackParams{
+		Title: "Q", AlbumID: album.ID, ArtistID: artist.ID,
+		DurationMs: 1000, FilePath: "/tmp/m6a-Q.mp3",
+		FileSize: 1, FileFormat: "mp3",
+	})
+	if _, err := pool.Exec(context.Background(),
+		`INSERT INTO lidarr_quarantine (user_id, track_id, reason) VALUES ($1, $2, 'bad_rip')`,
+		user.ID, track.ID,
+	); err != nil {
+		t.Fatalf("quarantine insert: %v", err)
+	}
+
+	r := chi.NewRouter()
+	r.Get("/api/artists/{id}/tracks", h.handleGetArtistTracks)
+	req := httptest.NewRequest(http.MethodGet, "/api/artists/"+uuidToString(artist.ID)+"/tracks", nil)
+	req = withUser(req, user)
+	w := httptest.NewRecorder()
+	r.ServeHTTP(w, req)
+
+	if w.Code != http.StatusOK {
+		t.Fatalf("status = %d", w.Code)
+	}
+	var got []TrackRef
+	_ = json.Unmarshal(w.Body.Bytes(), &got)
+	if len(got) != 0 {
+		t.Errorf("len = %d, want 0 (quarantined)", len(got))
+	}
+}
+
+func TestGetArtistTracks_NotFound(t *testing.T) {
+	h, pool := testHandlers(t)
+	user := seedUser(t, pool, "alice", "pw", false)
+
+	r := chi.NewRouter()
+	r.Get("/api/artists/{id}/tracks", h.handleGetArtistTracks)
+	// Random UUID — no such artist exists.
+	req := httptest.NewRequest(http.MethodGet, "/api/artists/00000000-0000-0000-0000-000000000000/tracks", nil)
+	req = withUser(req, user)
+	w := httptest.NewRecorder()
+	r.ServeHTTP(w, req)
+
+	if w.Code != http.StatusNotFound {
+		t.Errorf("status = %d, want 404", w.Code)
+	}
+	_ = pool
+}