add genre clean

server/db/migrations.go

@@ -14,8 +14,11 @@ func migrateInitSchema() gormigrate.Migration {
 		ID: "202002192100",
 		Migrate: func(tx *gorm.DB) error {
 			return tx.AutoMigrate(
-				Artist{},
+				Genre{},
+				TrackGenre{},
+				AlbumGenre{},
 				Track{},
+				Artist{},
 				User{},
 				Setting{},
 				Play{},
@@ -170,6 +173,10 @@ func migrateMultiGenre() gormigrate.Migration {
 				TrackGenre{},
 				AlbumGenre{},
 			)
+			if err := step.Error; err != nil {
+				return fmt.Errorf("step auto migrate: %w", err)
+			}
+
 			var genreCount int
 			tx.
 				Model(Genre{}).
@@ -178,9 +185,6 @@ func migrateMultiGenre() gormigrate.Migration {
 				return nil
 			}
 
-			if err := step.Error; err != nil {
-				return fmt.Errorf("step auto migrate: %w", err)
-			}
 			step = tx.Exec(`
 				INSERT INTO track_genres (track_id, genre_id)
 					SELECT id, tag_genre_id
@@ -188,10 +192,10 @@ func migrateMultiGenre() gormigrate.Migration {
 					WHERE tag_genre_id IS NOT NULL;
 				UPDATE tracks SET tag_genre_id=NULL;
 			`)
-
 			if err := step.Error; err != nil {
 				return fmt.Errorf("step migrate track genres: %w", err)
 			}
+
 			step = tx.Exec(`
 				INSERT INTO album_genres (album_id, genre_id)
 					SELECT id, tag_genre_id

server/db/model.go

@@ -126,7 +126,7 @@ func (t *Track) RelPath() string {
 }
 
 func (t *Track) GenreStrings() []string {
-	var strs []string
+	strs := make([]string, 0, len(t.Genres))
 	for _, genre := range t.Genres {
 		strs = append(strs, genre.Name)
 	}
@@ -197,7 +197,7 @@ func (a *Album) IndexRightPath() string {
 }
 
 func (a *Album) GenreStrings() []string {
-	var strs []string
+	strs := make([]string, 0, len(a.Genres))
 	for _, genre := range a.Genres {
 		strs = append(strs, genre.Name)
 	}

server/scanner/scanner.go

@@ -145,6 +145,28 @@ func (s *Scanner) cleanArtists() (int, error) {
 	return int(q.RowsAffected), q.Error
 }
 
+func (s *Scanner) cleanGenres() (int, error) {
+	subTrack := s.db.
+		Select("genres.id").
+		Model(&db.Genre{}).
+		Joins("JOIN track_genres ON track_genres.genre_id=genres.id").
+		Joins("LEFT JOIN tracks ON tracks.id=track_genres.track_id").
+		Where("tracks.id IS NULL").
+		SubQuery()
+	subAlbum := s.db.
+		Select("genres.id").
+		Model(&db.Genre{}).
+		Joins("JOIN album_genres ON album_genres.genre_id=genres.id").
+		Joins("LEFT JOIN albums ON albums.id=album_genres.album_id").
+		Where("albums.id IS NULL").
+		SubQuery()
+	q := s.db.
+		Where("genres.id IN ?", subTrack).
+		Or("genres.id IN ?", subAlbum).
+		Delete(&db.Genre{})
+	return int(q.RowsAffected), q.Error
+}
+
 // ## begin entries
 // ## begin entries
 // ## begin entries
@@ -199,6 +221,7 @@ func (s *Scanner) Start(opts ScanOptions) error {
 		{name: "tracks", f: s.cleanTracks},
 		{name: "folders", f: s.cleanFolders},
 		{name: "artists", f: s.cleanArtists},
+		{name: "genres", f: s.cleanGenres},
 	}
 	for _, clean := range cleanFuncs {
 		start = time.Now()