fix: polish player controls and remove fake track stats

internal/library/service.go

@@ -40,6 +40,8 @@ type Track struct {
 	FilePath     string `json:"filePath"`
 	ContentType  string `json:"contentType"`
 	CoverArtID   string `json:"coverArtId"`
+	PlayCount    int    `json:"playCount"`
+	LastPlayedAt string `json:"lastPlayedAt"`
 }
 
 type HomePayload struct {
@@ -491,6 +493,60 @@ func (s *Service) RecordPlayEvent(ctx context.Context, userID, trackID, eventTyp
 	return nil
 }
 
+func (s *Service) PopulateTrackStats(ctx context.Context, userID string, tracks []Track) ([]Track, error) {
+	if userID == "" || len(tracks) == 0 {
+		return tracks, nil
+	}
+
+	placeholders := make([]string, 0, len(tracks))
+	args := make([]any, 0, len(tracks)+1)
+	args = append(args, userID)
+	for _, track := range tracks {
+		placeholders = append(placeholders, "?")
+		args = append(args, track.ID)
+	}
+
+	query := fmt.Sprintf(
+		`SELECT track_id, COUNT(*) AS play_count, COALESCE(MAX(played_at), '')
+		 FROM play_history
+		 WHERE user_id = ? AND track_id IN (%s)
+		 GROUP BY track_id`,
+		strings.Join(placeholders, ","),
+	)
+
+	rows, err := s.db.QueryContext(ctx, query, args...)
+	if err != nil {
+		return nil, fmt.Errorf("query track stats: %w", err)
+	}
+	defer rows.Close()
+
+	type stats struct {
+		playCount    int
+		lastPlayedAt string
+	}
+	byTrackID := map[string]stats{}
+	for rows.Next() {
+		var trackID string
+		var item stats
+		if err := rows.Scan(&trackID, &item.playCount, &item.lastPlayedAt); err != nil {
+			return nil, fmt.Errorf("scan track stats: %w", err)
+		}
+		byTrackID[trackID] = item
+	}
+	if err := rows.Err(); err != nil {
+		return nil, fmt.Errorf("iterate track stats: %w", err)
+	}
+
+	for index := range tracks {
+		if item, ok := byTrackID[tracks[index].ID]; ok {
+			tracks[index].PlayCount = item.playCount
+			tracks[index].LastPlayedAt = item.lastPlayedAt
+		}
+	}
+
+	return tracks, nil
+}
+
 func (s *Service) albumsByArtistID(ctx context.Context, artistID string) ([]Album, error) {
 	rows, err := s.db.QueryContext(
 		ctx,