Optimize playlist cover generation

core/artwork/reader_playlist.go

@@ -8,13 +8,12 @@ import (
 	"image/draw"
 	"image/png"
 	"io"
-	"math/rand"
 	"time"
 
 	"github.com/disintegration/imaging"
+	"github.com/navidrome/navidrome/log"
 	"github.com/navidrome/navidrome/model"
 	"github.com/navidrome/navidrome/utils/slice"
-	"golang.org/x/exp/slices"
 )
 
 type playlistArtworkReader struct {
@@ -44,18 +43,16 @@ func (a *playlistArtworkReader) LastUpdated() time.Time {
 }
 
 func (a *playlistArtworkReader) Reader(ctx context.Context) (io.ReadCloser, string, error) {
-	var ff []sourceFunc
+	ff := []sourceFunc{
-	pl, err := a.a.ds.Playlist(ctx).GetWithTracks(a.pl.ID, false)
+		a.fromGeneratedTile(ctx),
-	if err == nil {
+		fromAlbumPlaceholder(),
-		ff = append(ff, a.fromGeneratedTile(ctx, pl.Tracks))
 	}
-	ff = append(ff, fromAlbumPlaceholder())
 	return selectImageReader(ctx, a.artID, ff...)
 }
 
-func (a *playlistArtworkReader) fromGeneratedTile(ctx context.Context, tracks model.PlaylistTracks) sourceFunc {
+func (a *playlistArtworkReader) fromGeneratedTile(ctx context.Context) sourceFunc {
 	return func() (io.ReadCloser, string, error) {
-		tiles, err := a.loadTiles(ctx, tracks)
+		tiles, err := a.loadTiles(ctx)
 		if err != nil {
 			return nil, "", err
 		}
@@ -64,19 +61,21 @@ func (a *playlistArtworkReader) fromGeneratedTile(ctx context.Context, tracks mo
 	}
 }
 
-func compactIDs(tracks model.PlaylistTracks) []model.ArtworkID {
+func toArtworkIDs(albumIDs []string) []model.ArtworkID {
-	slices.SortFunc(tracks, func(a, b model.PlaylistTrack) bool { return a.AlbumID < b.AlbumID })
+	return slice.Map(albumIDs, func(id string) model.ArtworkID {
-	tracks = slices.CompactFunc(tracks, func(a, b model.PlaylistTrack) bool { return a.AlbumID == b.AlbumID })
+		al := model.Album{ID: id}
-	ids := slice.Map(tracks, func(e model.PlaylistTrack) model.ArtworkID {
+		return al.CoverArtID()
-		return e.AlbumCoverArtID()
 	})
-	rand.Seed(time.Now().UnixNano())
-	rand.Shuffle(len(ids), func(i, j int) { ids[i], ids[j] = ids[j], ids[i] })
-	return ids
 }
 
-func (a *playlistArtworkReader) loadTiles(ctx context.Context, t model.PlaylistTracks) ([]image.Image, error) {
+func (a *playlistArtworkReader) loadTiles(ctx context.Context) ([]image.Image, error) {
-	ids := compactIDs(t)
+	tracksRepo := a.a.ds.Playlist(ctx).Tracks(a.pl.ID, false)
+	albumIds, err := tracksRepo.GetAlbumIDs(model.QueryOptions{Max: 4, Sort: "random()"})
+	if err != nil {
+		log.Error(ctx, "Error getting album IDs for playlist", "id", a.pl.ID, "name", a.pl.Name, err)
+		return nil, err
+	}
+	ids := toArtworkIDs(albumIds)
 
 	var tiles []image.Image
 	for len(tiles) < 4 {

core/playlists.go

@@ -205,7 +205,7 @@ func (s *playlists) Update(ctx context.Context, playlistID string,
 			pls.AddTracks(idsToAdd)
 		} else {
 			if len(idsToAdd) > 0 {
-				_, err = repo.Tracks(playlistID).Add(idsToAdd)
+				_, err = repo.Tracks(playlistID, true).Add(idsToAdd)
 				if err != nil {
 					return err
 				}
@@ -232,7 +232,7 @@ func (s *playlists) Update(ctx context.Context, playlistID string,
 		}
 		// Special case: The playlist is now empty
 		if len(idxToRemove) > 0 && len(pls.Tracks) == 0 {
-			if err = repo.Tracks(playlistID).DeleteAll(); err != nil {
+			if err = repo.Tracks(playlistID, true).DeleteAll(); err != nil {
 				return err
 			}
 		}

model/playlist.go

@@ -110,7 +110,7 @@ type PlaylistRepository interface {
 	GetAll(options ...QueryOptions) (Playlists, error)
 	FindByPath(path string) (*Playlist, error)
 	Delete(id string) error
-	Tracks(playlistId string) PlaylistTrackRepository
+	Tracks(playlistId string, refreshSmartPlaylist bool) PlaylistTrackRepository
 }
 
 type PlaylistTrack struct {
@@ -133,6 +133,7 @@ func (plt PlaylistTracks) MediaFiles() MediaFiles {
 type PlaylistTrackRepository interface {
 	ResourceRepository
 	GetAll(options ...QueryOptions) (PlaylistTracks, error)
+	GetAlbumIDs(options ...QueryOptions) ([]string, error)
 	Add(mediaFileIds []string) (int, error)
 	AddAlbums(albumIds []string) (int, error)
 	AddArtists(artistIds []string) (int, error)

persistence/playlist_track_repository.go

@@ -16,7 +16,7 @@ type playlistTrackRepository struct {
 	playlistRepo *playlistRepository
 }
 
-func (r *playlistRepository) Tracks(playlistId string) model.PlaylistTrackRepository {
+func (r *playlistRepository) Tracks(playlistId string, refreshSmartPlaylist bool) model.PlaylistTrackRepository {
 	p := &playlistTrackRepository{}
 	p.playlistRepo = r
 	p.playlistId = playlistId
@@ -30,7 +30,9 @@ func (r *playlistRepository) Tracks(playlistId string) model.PlaylistTrackReposi
 	if err != nil {
 		return nil
 	}
+	if refreshSmartPlaylist {
 		r.refreshSmartPlaylist(pls)
+	}
 	p.playlist = pls
 	return p
 }
@@ -70,6 +72,18 @@ func (r *playlistTrackRepository) GetAll(options ...model.QueryOptions) (model.P
 	return tracks, err
 }
 
+func (r *playlistTrackRepository) GetAlbumIDs(options ...model.QueryOptions) ([]string, error) {
+	sql := r.newSelect(options...).Columns("distinct mf.album_id").
+		Join("media_file mf on mf.id = media_file_id").
+		Where(Eq{"playlist_id": r.playlistId})
+	var ids []string
+	err := r.queryAll(sql, &ids)
+	if err != nil {
+		return nil, err
+	}
+	return ids, nil
+}
+
 func (r *playlistTrackRepository) ReadAll(options ...rest.QueryOptions) (interface{}, error) {
 	return r.GetAll(r.parseRestOptions(options...))
 }

server/nativeapi/playlists.go

@@ -25,7 +25,7 @@ func getPlaylist(ds model.DataStore) http.HandlerFunc {
 			constructor := func(ctx context.Context) rest.Repository {
 				plsRepo := ds.Playlist(ctx)
 				plsId := chi.URLParam(req, "playlistId")
-				return plsRepo.Tracks(plsId)
+				return plsRepo.Tracks(plsId, true)
 			}
 
 			handler(constructor).ServeHTTP(res, req)
@@ -77,7 +77,7 @@ func deleteFromPlaylist(ds model.DataStore) http.HandlerFunc {
 		playlistId := utils.ParamString(r, ":playlistId")
 		ids := r.URL.Query()["id"]
 		err := ds.WithTx(func(tx model.DataStore) error {
-			tracksRepo := tx.Playlist(r.Context()).Tracks(playlistId)
+			tracksRepo := tx.Playlist(r.Context()).Tracks(playlistId, true)
 			return tracksRepo.Delete(ids...)
 		})
 		if len(ids) == 1 && errors.Is(err, model.ErrNotFound) {
@@ -125,7 +125,7 @@ func addToPlaylist(ds model.DataStore) http.HandlerFunc {
 			http.Error(w, err.Error(), http.StatusBadRequest)
 			return
 		}
-		tracksRepo := ds.Playlist(r.Context()).Tracks(playlistId)
+		tracksRepo := ds.Playlist(r.Context()).Tracks(playlistId, true)
 		count, c := 0, 0
 		if c, err = tracksRepo.Add(payload.Ids); err != nil {
 			http.Error(w, err.Error(), http.StatusBadRequest)
@@ -179,7 +179,7 @@ func reorderItem(ds model.DataStore) http.HandlerFunc {
 			http.Error(w, err.Error(), http.StatusBadRequest)
 			return
 		}
-		tracksRepo := ds.Playlist(r.Context()).Tracks(playlistId)
+		tracksRepo := ds.Playlist(r.Context()).Tracks(playlistId, true)
 		err = tracksRepo.Reorder(id, newPos)
 		if errors.Is(err, rest.ErrPermissionDenied) {
 			http.Error(w, err.Error(), http.StatusForbidden)