feat(api): GET /api/albums/{id}/cover with sidecar fallback

internal/api/media_test.go

@@ -1,7 +1,11 @@
 package api
 
 import (
+	"bytes"
 	"context"
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
 	"os"
 	"path/filepath"
 	"testing"
@@ -147,3 +151,139 @@ func fetchAlbum(t *testing.T, pool *pgxpool.Pool, id pgtype.UUID) dbq.Album {
 	}
 	return a
 }
+
+func TestHandleGetCover_SidecarHappyPath(t *testing.T) {
+	h, pool := testHandlers(t)
+	truncateLibrary(t, pool)
+	artist := seedArtist(t, pool, "A")
+	album := seedAlbum(t, pool, artist.ID, "X", 0)
+
+	_, dir := seedTrackWithFile(t, pool, album.ID, artist.ID, "t", []byte("audio"), "mp3")
+	coverBytes := []byte{0xFF, 0xD8, 0xFF, 0xE0, 0x01, 0x02, 0x03} // small JPEG-ish payload
+	if err := os.WriteFile(filepath.Join(dir, "cover.jpg"), coverBytes, 0o644); err != nil {
+		t.Fatal(err)
+	}
+
+	req := httptest.NewRequest(http.MethodGet, "/api/albums/"+uuidToString(album.ID)+"/cover", nil)
+	w := httptest.NewRecorder()
+	newLibraryRouter(h).ServeHTTP(w, req)
+
+	if w.Code != http.StatusOK {
+		t.Fatalf("status = %d body = %s", w.Code, w.Body.String())
+	}
+	if ct := w.Header().Get("Content-Type"); ct != "image/jpeg" {
+		t.Errorf("Content-Type = %q", ct)
+	}
+	if !bytes.Equal(w.Body.Bytes(), coverBytes) {
+		t.Errorf("body = %x, want %x", w.Body.Bytes(), coverBytes)
+	}
+}
+
+func TestHandleGetCover_ExplicitPathHappyPath(t *testing.T) {
+	h, pool := testHandlers(t)
+	truncateLibrary(t, pool)
+	artist := seedArtist(t, pool, "A")
+	album := seedAlbum(t, pool, artist.ID, "X", 0)
+
+	dir := t.TempDir()
+	explicit := filepath.Join(dir, "art.png")
+	pngBytes := []byte{0x89, 0x50, 0x4E, 0x47, 0x0D, 0x0A, 0x1A, 0x0A} // PNG magic
+	if err := os.WriteFile(explicit, pngBytes, 0o644); err != nil {
+		t.Fatal(err)
+	}
+	if _, err := pool.Exec(context.Background(),
+		`UPDATE albums SET cover_art_path = $1 WHERE id = $2`, explicit, album.ID); err != nil {
+		t.Fatal(err)
+	}
+
+	req := httptest.NewRequest(http.MethodGet, "/api/albums/"+uuidToString(album.ID)+"/cover", nil)
+	w := httptest.NewRecorder()
+	newLibraryRouter(h).ServeHTTP(w, req)
+
+	if w.Code != http.StatusOK {
+		t.Fatalf("status = %d body = %s", w.Code, w.Body.String())
+	}
+	if ct := w.Header().Get("Content-Type"); ct != "image/png" {
+		t.Errorf("Content-Type = %q", ct)
+	}
+	if !bytes.Equal(w.Body.Bytes(), pngBytes) {
+		t.Errorf("body mismatch")
+	}
+}
+
+func TestHandleGetCover_ExplicitMissingFallsThroughToSidecar(t *testing.T) {
+	h, pool := testHandlers(t)
+	truncateLibrary(t, pool)
+	artist := seedArtist(t, pool, "A")
+	album := seedAlbum(t, pool, artist.ID, "X", 0)
+
+	_, dir := seedTrackWithFile(t, pool, album.ID, artist.ID, "t", []byte("audio"), "mp3")
+	sidecarBytes := []byte("sidecar")
+	if err := os.WriteFile(filepath.Join(dir, "cover.jpg"), sidecarBytes, 0o644); err != nil {
+		t.Fatal(err)
+	}
+	if _, err := pool.Exec(context.Background(),
+		`UPDATE albums SET cover_art_path = $1 WHERE id = $2`,
+		filepath.Join(dir, "does-not-exist.jpg"), album.ID); err != nil {
+		t.Fatal(err)
+	}
+
+	req := httptest.NewRequest(http.MethodGet, "/api/albums/"+uuidToString(album.ID)+"/cover", nil)
+	w := httptest.NewRecorder()
+	newLibraryRouter(h).ServeHTTP(w, req)
+
+	if w.Code != http.StatusOK {
+		t.Fatalf("status = %d", w.Code)
+	}
+	if !bytes.Equal(w.Body.Bytes(), sidecarBytes) {
+		t.Errorf("body = %q, want %q", w.Body.Bytes(), sidecarBytes)
+	}
+}
+
+func TestHandleGetCover_NoArt(t *testing.T) {
+	h, pool := testHandlers(t)
+	truncateLibrary(t, pool)
+	artist := seedArtist(t, pool, "A")
+	album := seedAlbum(t, pool, artist.ID, "X", 0)
+	seedTrack(t, pool, album.ID, artist.ID, "t", 1, 1000) // synthetic path, no sidecar
+
+	req := httptest.NewRequest(http.MethodGet, "/api/albums/"+uuidToString(album.ID)+"/cover", nil)
+	w := httptest.NewRecorder()
+	newLibraryRouter(h).ServeHTTP(w, req)
+
+	if w.Code != http.StatusNotFound {
+		t.Fatalf("status = %d", w.Code)
+	}
+	var body errorBody
+	_ = json.Unmarshal(w.Body.Bytes(), &body)
+	if body.Error.Code != "not_found" || body.Error.Message != "cover not found" {
+		t.Errorf("error body = %+v", body)
+	}
+}
+
+func TestHandleGetCover_BadUUID(t *testing.T) {
+	h, _ := testHandlers(t)
+	req := httptest.NewRequest(http.MethodGet, "/api/albums/not-a-uuid/cover", nil)
+	w := httptest.NewRecorder()
+	newLibraryRouter(h).ServeHTTP(w, req)
+	if w.Code != http.StatusBadRequest {
+		t.Errorf("status = %d, want 400", w.Code)
+	}
+}
+
+func TestHandleGetCover_UnknownAlbum(t *testing.T) {
+	h, pool := testHandlers(t)
+	truncateLibrary(t, pool)
+	req := httptest.NewRequest(http.MethodGet,
+		"/api/albums/00000000-0000-0000-0000-000000000001/cover", nil)
+	w := httptest.NewRecorder()
+	newLibraryRouter(h).ServeHTTP(w, req)
+	if w.Code != http.StatusNotFound {
+		t.Fatalf("status = %d", w.Code)
+	}
+	var body errorBody
+	_ = json.Unmarshal(w.Body.Bytes(), &body)
+	if body.Error.Message != "album not found" {
+		t.Errorf("message = %q, want \"album not found\"", body.Error.Message)
+	}
+}