show the downloaded song count on a playlist offline

app/src/main/kotlin/com/subtracks/data/db/LibraryDao.kt

@@ -97,6 +97,17 @@ internal const val PLAYLISTS_FILTER =
         "WHERE playlist_search MATCH '\"' || replace(:search, '\"', '\"\"') || '\"')) " +
         "OR (length(:search) < 3 AND instr(lower(name), lower(:search)) > 0)) "
 
+// With the Downloaded filter on, count the songs that actually have a download so the number under
+// a playlist matches the songs its detail screen lists.
+internal const val PLAYLISTS_SELECT =
+    "SELECT playlists.sourceId, playlists.id, playlists.name, playlists.comment, playlists.coverArt, " +
+        "CASE WHEN :downloadedFilter = 1 THEN (" +
+        "SELECT COUNT(DISTINCT ps.songId) FROM playlist_songs ps " +
+        "JOIN song_downloads sd ON sd.sourceId = ps.sourceId AND sd.songId = ps.songId AND sd.status = 'Completed' " +
+        "WHERE ps.sourceId = playlists.sourceId AND ps.playlistId = playlists.id " +
+        ") ELSE playlists.songCount END AS songCount, " +
+        "playlists.created, playlists.changed, playlists.duration "
+
 internal const val PLAYLIST_ORDER_BY_NAME = "name COLLATE NOCASE, id"
 internal const val PLAYLIST_ORDER_BY_NAME_REVERSED = "name COLLATE NOCASE DESC, id DESC"
 internal const val PLAYLIST_ORDER_BY_ADDED = "created DESC, name COLLATE NOCASE, id"
@@ -364,42 +375,42 @@ interface LibraryDao {
         downloadedFilter: Int = 0,
     ): PagingSource<Int, Artist>
 
-    @Query("SELECT * $PLAYLISTS_FILTER ORDER BY $PLAYLIST_ORDER_BY_NAME")
+    @Query("$PLAYLISTS_SELECT $PLAYLISTS_FILTER ORDER BY $PLAYLIST_ORDER_BY_NAME")
     fun playlistsByName(
         sourceId: Long,
         search: String,
         downloadedFilter: Int = 0,
     ): PagingSource<Int, Playlist>
 
-    @Query("SELECT * $PLAYLISTS_FILTER ORDER BY $PLAYLIST_ORDER_BY_NAME_REVERSED")
+    @Query("$PLAYLISTS_SELECT $PLAYLISTS_FILTER ORDER BY $PLAYLIST_ORDER_BY_NAME_REVERSED")
     fun playlistsByNameReversed(
         sourceId: Long,
         search: String,
         downloadedFilter: Int = 0,
     ): PagingSource<Int, Playlist>
 
-    @Query("SELECT * $PLAYLISTS_FILTER ORDER BY $PLAYLIST_ORDER_BY_ADDED")
+    @Query("$PLAYLISTS_SELECT $PLAYLISTS_FILTER ORDER BY $PLAYLIST_ORDER_BY_ADDED")
     fun playlistsByAdded(
         sourceId: Long,
         search: String,
         downloadedFilter: Int = 0,
     ): PagingSource<Int, Playlist>
 
-    @Query("SELECT * $PLAYLISTS_FILTER ORDER BY $PLAYLIST_ORDER_BY_ADDED_REVERSED")
+    @Query("$PLAYLISTS_SELECT $PLAYLISTS_FILTER ORDER BY $PLAYLIST_ORDER_BY_ADDED_REVERSED")
     fun playlistsByAddedReversed(
         sourceId: Long,
         search: String,
         downloadedFilter: Int = 0,
     ): PagingSource<Int, Playlist>
 
-    @Query("SELECT * $PLAYLISTS_FILTER ORDER BY $PLAYLIST_ORDER_BY_UPDATED")
+    @Query("$PLAYLISTS_SELECT $PLAYLISTS_FILTER ORDER BY $PLAYLIST_ORDER_BY_UPDATED")
     fun playlistsByUpdated(
         sourceId: Long,
         search: String,
         downloadedFilter: Int = 0,
     ): PagingSource<Int, Playlist>
 
-    @Query("SELECT * $PLAYLISTS_FILTER ORDER BY $PLAYLIST_ORDER_BY_UPDATED_REVERSED")
+    @Query("$PLAYLISTS_SELECT $PLAYLISTS_FILTER ORDER BY $PLAYLIST_ORDER_BY_UPDATED_REVERSED")
     fun playlistsByUpdatedReversed(
         sourceId: Long,
         search: String,

app/src/main/kotlin/com/subtracks/ui/library/PlaylistDetailScreen.kt

@@ -51,6 +51,7 @@ fun PlaylistDetailRoute(
     val playlist by viewModel.playlist.collectAsStateWithLifecycle(initialValue = null)
     val downloads by viewModel.downloads.collectAsStateWithLifecycle()
     val downloadStatus by viewModel.downloadStatus.collectAsStateWithLifecycle()
+    val offline by viewModel.offline.collectAsStateWithLifecycle()
     val scope = rememberCoroutineScope()
     var pendingDelete by remember { mutableStateOf<Long?>(null) }
     val playback by playbackController.state.collectAsStateWithLifecycle()
@@ -81,6 +82,7 @@ fun PlaylistDetailRoute(
         artwork = rememberArtworkColors(viewModel.coverArt(playlist?.coverArt, true), THEME_TRANSITION_MS),
         downloads = downloads,
         downloadStatus = downloadStatus,
+        offline = offline,
         onDownloadAction = requestDownloadAction,
         onBack = onBack,
         onSongClick = viewModel::play,
@@ -111,6 +113,7 @@ fun PlaylistDetailScreen(
     artwork: ArtworkColors?,
     downloads: Map<String, SongDownload> = emptyMap(),
     downloadStatus: ListDownloadStatus = ListDownloadStatus(),
+    offline: Boolean = false,
     onDownloadAction: (BulkDownloadAction) -> Unit = {},
     onBack: () -> Unit,
     onSongClick: (Long) -> Unit,
@@ -130,7 +133,7 @@ fun PlaylistDetailScreen(
                 art = coverArt(playlist?.coverArt, false),
                 thumbnailRef = coverArt(playlist?.coverArt, true),
                 name = playlist?.name.orEmpty(),
-                subtitle = playlistSummary(playlist),
+                subtitle = playlistSummary(playlist, offline, downloadStatus.downloaded),
                 comment = playlist?.comment,
                 hasSongs = songs.itemCount > 0,
                 onPlay = onPlay,
@@ -168,10 +171,15 @@ fun PlaylistDetailScreen(
     )
 }
 
-private fun playlistSummary(playlist: Playlist?): String {
+private fun playlistSummary(
+    playlist: Playlist?,
+    offline: Boolean,
+    downloadedSongs: Long,
+): String {
     playlist ?: return ""
+    val songs = if (offline) downloadedSongs else playlist.songCount
     return listOfNotNull(
-        "${playlist.songCount} ${if (playlist.songCount == 1L) "song" else "songs"}",
+        "$songs ${if (songs == 1L) "song" else "songs"}",
         formatDuration(playlist.duration),
     ).joinToString(" $DOT ")
 }

app/src/main/kotlin/com/subtracks/ui/library/PlaylistDetailViewModel.kt

@@ -47,6 +47,8 @@ class PlaylistDetailViewModel(
     val downloads: StateFlow<Map<String, SongDownload>> =
         downloadRepository.states()
 
+    val offline: StateFlow<Boolean> = sourceRepository.offline
+
     val downloadStatus: StateFlow<ListDownloadStatus> =
         sourceId
             .flatMapLatest { downloadRepository.status(it, DownloadList.Playlist, playlistId) }

app/src/test/kotlin/com/subtracks/data/db/LibraryDaoTest.kt

@@ -419,6 +419,40 @@ class LibraryDaoTest {
             )
         }
 
+    @Test
+    fun downloadedFilterReportsTheDownloadedSongCountForPlaylists() =
+        runTest {
+            val sourceId = source()
+            val dao = db.libraryDao()
+            dao.upsertPlaylists(listOf(playlist(sourceId, "pl-1", "List", created = 0, changed = 0).copy(songCount = 5)))
+            dao.upsertSongs(
+                listOf(
+                    song(sourceId, "s1", "One", starred = null),
+                    song(sourceId, "s2", "Two", starred = null),
+                ),
+            )
+            dao.upsertPlaylistSongs(
+                listOf(
+                    PlaylistSong(sourceId, "pl-1", "s1", 0),
+                    PlaylistSong(sourceId, "pl-1", "s2", 1),
+                ),
+            )
+            db.downloadDao().upsert(SongDownload(sourceId, "s1", DownloadStatus.Completed))
+
+            val filtered = dao.playlistsByName(sourceId, "", downloadedFilter = 1).page()
+            assertEquals(1, filtered.size)
+            assertEquals(1L, filtered.first().songCount)
+
+            assertEquals(
+                5L,
+                dao
+                    .playlistsByName(sourceId, "")
+                    .page()
+                    .first { it.id == "pl-1" }
+                    .songCount,
+            )
+        }
+
     @Test
     fun searchMatchesInfixCaseInsensitivelyAndFallsBackToAScanBelowThreeCharacters() =
         runTest {