Move Downloads out of Settings into a dynamic Library collection

Downloads is no longer a Settings sub-screen - it's now a pinned entry
at the top of Library > Playlists (Settings keeps only the Wi-Fi-only
and default-quality preference toggles, which govern how downloads
behave rather than being downloaded content itself).

The Downloads screen it opens is no longer a flat track list. It now
splits into two sections, both fully reactive to what's actually on
disk:

- Playlists: any playlist with at least one downloaded track. Tapping
  one opens the real PlaylistDetailScreen, not a special-cased view -
  this is a live filter over existing playlists, not a copy of their
  data.
- Tracks: downloaded tracks that aren't a member of any playlist. A
  track belonging to a playlist is never listed twice - that playlist
  already qualifies for the Playlists section by virtue of this same
  track being downloaded, so once it's shown there this list skips it.

New PlaylistDao.observeAllMemberships() (and
PlaylistRepository.observeTrackIdsByPlaylist()) exposes the full
playlist-to-track-id membership map in one reactive query, so working
out which playlists have a downloaded track doesn't require loading
every playlist's full track list. DownloadsViewModel combines that
with the existing downloaded-tracks and playlists flows to derive both
sections - no new database tables, this is a computed view over the
same Room state Phase 5 and Phase 6 already maintain.

Verified on-device: Settings no longer shows a Downloads row; the
Library tab shows the new pinned "Downloads" entry; added a
downloaded track to a test playlist and confirmed it moved from the
flat Tracks list into a Playlists entry with no duplication; confirmed
tapping that entry opens the actual playlist detail screen; deleted
the playlist and confirmed the track reactively reverted to the flat
Tracks list with no manual refresh.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

app/src/main/java/com/InfernalAquatics/deepwave/data/local/playlist/PlaylistDao.kt

@@ -13,6 +13,10 @@ data class PlaylistWithCount(
     val trackCount: Int,
 )
 
+/** One (playlist, track) membership row - the raw shape the Downloads collection needs to work
+ * out which playlists contain a downloaded track, without loading every playlist's full track list. */
+data class PlaylistTrackMembership(val playlistLocalId: String, val trackId: String)
+
 @Dao
 interface PlaylistDao {
     @Query(
@@ -51,6 +55,9 @@ interface PlaylistDao {
     @Query("SELECT * FROM playlist_tracks WHERE playlistLocalId = :localId ORDER BY position ASC")
     fun observeTracks(localId: String): Flow<List<PlaylistTrackEntity>>
 
+    @Query("SELECT playlistLocalId, trackId FROM playlist_tracks")
+    fun observeAllMemberships(): Flow<List<PlaylistTrackMembership>>
+
     @Query("SELECT * FROM playlist_tracks WHERE playlistLocalId = :localId ORDER BY position ASC")
     suspend fun getTracks(localId: String): List<PlaylistTrackEntity>
 

app/src/main/java/com/InfernalAquatics/deepwave/data/playlist/PlaylistRepository.kt

@@ -62,6 +62,12 @@ class PlaylistRepository @Inject constructor(
     fun observeTracks(localId: String): Flow<List<Song>> =
         playlistDao.observeTracks(localId).map { list -> list.map { it.toDomain() } }
 
+    /** playlistId -> the set of track ids it contains, for the Downloads collection to work out
+     * which playlists have a downloaded track without loading every playlist's full track list. */
+    fun observeTrackIdsByPlaylist(): Flow<Map<String, Set<String>>> =
+        playlistDao.observeAllMemberships()
+            .map { rows -> rows.groupBy({ it.playlistLocalId }, { it.trackId }).mapValues { it.value.toSet() } }
+
     suspend fun createPlaylist(name: String, initialTracks: List<Song> = emptyList()): String {
         val localId = UUID.randomUUID().toString()
         val now = System.currentTimeMillis()

app/src/main/java/com/InfernalAquatics/deepwave/ui/downloads/DownloadsScreen.kt

@@ -5,6 +5,7 @@ import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.lazy.LazyColumn
+import androidx.compose.foundation.lazy.items
 import androidx.compose.foundation.lazy.itemsIndexed
 import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.automirrored.filled.ArrowBack
@@ -12,6 +13,7 @@ import androidx.compose.material.icons.filled.Delete
 import androidx.compose.material3.ExperimentalMaterial3Api
 import androidx.compose.material3.Icon
 import androidx.compose.material3.IconButton
+import androidx.compose.material3.ListItem
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.Scaffold
 import androidx.compose.material3.Text
@@ -21,6 +23,7 @@ import androidx.compose.runtime.collectAsState
 import androidx.compose.runtime.getValue
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
+import androidx.compose.ui.res.pluralStringResource
 import androidx.compose.ui.res.stringResource
 import androidx.compose.ui.tooling.preview.Preview
 import androidx.hilt.lifecycle.viewmodel.compose.hiltViewModel
@@ -28,6 +31,7 @@ import androidx.media3.common.util.UnstableApi
 import com.InfernalAquatics.deepwave.R
 import com.InfernalAquatics.deepwave.data.local.download.DownloadStatus
 import com.InfernalAquatics.deepwave.data.local.download.DownloadedTrackEntity
+import com.InfernalAquatics.deepwave.data.model.Playlist
 import com.InfernalAquatics.deepwave.data.network.coverArtUrl
 import com.InfernalAquatics.deepwave.ui.components.TrackRow
 import com.InfernalAquatics.deepwave.ui.theme.DeepwaveTheme
@@ -36,12 +40,14 @@ import com.InfernalAquatics.deepwave.ui.theme.DeepwaveTheme
 @Composable
 fun DownloadsScreen(
     onBack: () -> Unit,
+    onPlaylistClick: (String) -> Unit,
     viewModel: DownloadsViewModel = hiltViewModel(),
 ) {
     val uiState by viewModel.uiState.collectAsState()
     DownloadsContent(
         uiState = uiState,
         onBack = onBack,
+        onPlaylistClick = onPlaylistClick,
         onTrackClick = viewModel::playTrack,
         onRemove = viewModel::remove,
     )
@@ -52,6 +58,7 @@ fun DownloadsScreen(
 private fun DownloadsContent(
     uiState: DownloadsUiState,
     onBack: () -> Unit,
+    onPlaylistClick: (String) -> Unit,
     onTrackClick: (Int) -> Unit,
     onRemove: (String) -> Unit,
 ) {
@@ -67,22 +74,29 @@ private fun DownloadsContent(
             )
         },
     ) { innerPadding ->
-        if (uiState.tracks.isEmpty()) {
+        if (uiState.downloadedPlaylists.isEmpty() && uiState.looseTracks.isEmpty()) {
             Box(
-                modifier = Modifier
+                modifier = Modifier.fillMaxSize().padding(innerPadding),
-                    .fillMaxSize()
-                    .padding(innerPadding),
                 contentAlignment = Alignment.Center,
             ) {
                 Text(text = stringResource(R.string.downloads_empty), style = MaterialTheme.typography.bodyLarge)
             }
         } else {
-            LazyColumn(
+            LazyColumn(modifier = Modifier.fillMaxSize().padding(innerPadding)) {
-                modifier = Modifier
+                if (uiState.downloadedPlaylists.isNotEmpty()) {
-                    .fillMaxSize()
+                    item { SectionHeader(stringResource(R.string.downloads_section_playlists)) }
-                    .padding(innerPadding),
+                    items(uiState.downloadedPlaylists, key = { "playlist:${it.id}" }) { playlist ->
-            ) {
+                        TrackRow(
-                itemsIndexed(uiState.tracks, key = { _, track -> track.trackId }) { index, track ->
+                            title = playlist.name,
+                            subtitle = pluralStringResource(R.plurals.playlist_track_count, playlist.trackCount, playlist.trackCount),
+                            coverArtUrl = coverArtUrl(playlist.coverArtId),
+                            onClick = { onPlaylistClick(playlist.id) },
+                        )
+                    }
+                }
+                if (uiState.looseTracks.isNotEmpty()) {
+                    item { SectionHeader(stringResource(R.string.downloads_section_tracks)) }
+                    itemsIndexed(uiState.looseTracks, key = { _, track -> "track:${track.trackId}" }) { index, track ->
                         TrackRow(
                             title = track.title,
                             subtitle = track.artistName.orEmpty(),
@@ -99,8 +113,17 @@ private fun DownloadsContent(
             }
         }
     }
+}
 
-private val sampleTracks = List(3) { index ->
+@Composable
+private fun SectionHeader(title: String) {
+    ListItem(headlineContent = { Text(title, style = MaterialTheme.typography.titleMedium) })
+}
+
+private val samplePlaylists = listOf(
+    Playlist(id = "1", name = "Riddim Favs", coverArtId = null, trackCount = 12, isSynced = true),
+)
+private val sampleTracks = List(2) { index ->
     DownloadedTrackEntity(
         trackId = "sample-$index",
         title = "Sample Track ${index + 1}",
@@ -120,7 +143,13 @@ private val sampleTracks = List(3) { index ->
 @Composable
 private fun DownloadsContentPreview() {
     DeepwaveTheme {
-        DownloadsContent(uiState = DownloadsUiState(tracks = sampleTracks), onBack = {}, onTrackClick = {}, onRemove = {})
+        DownloadsContent(
+            uiState = DownloadsUiState(downloadedPlaylists = samplePlaylists, looseTracks = sampleTracks),
+            onBack = {},
+            onPlaylistClick = {},
+            onTrackClick = {},
+            onRemove = {},
+        )
     }
 }
 
@@ -128,6 +157,6 @@ private fun DownloadsContentPreview() {
 @Composable
 private fun DownloadsContentEmptyPreview() {
     DeepwaveTheme {
-        DownloadsContent(uiState = DownloadsUiState(), onBack = {}, onTrackClick = {}, onRemove = {})
+        DownloadsContent(uiState = DownloadsUiState(), onBack = {}, onPlaylistClick = {}, onTrackClick = {}, onRemove = {})
     }
 }

app/src/main/java/com/InfernalAquatics/deepwave/ui/downloads/DownloadsViewModel.kt

@@ -6,31 +6,56 @@ import androidx.media3.common.util.UnstableApi
 import com.InfernalAquatics.deepwave.data.download.DownloadRepository
 import com.InfernalAquatics.deepwave.data.local.download.DownloadStatus
 import com.InfernalAquatics.deepwave.data.local.download.DownloadedTrackEntity
+import com.InfernalAquatics.deepwave.data.model.Playlist
+import com.InfernalAquatics.deepwave.data.playlist.PlaylistRepository
 import com.InfernalAquatics.deepwave.media.PlaybackController
 import com.InfernalAquatics.deepwave.media.toMediaItem
 import dagger.hilt.android.lifecycle.HiltViewModel
 import kotlinx.coroutines.flow.SharingStarted
 import kotlinx.coroutines.flow.StateFlow
-import kotlinx.coroutines.flow.map
+import kotlinx.coroutines.flow.combine
 import kotlinx.coroutines.flow.stateIn
 import kotlinx.coroutines.launch
 import javax.inject.Inject
 
-data class DownloadsUiState(val tracks: List<DownloadedTrackEntity> = emptyList())
+/**
+ * [downloadedPlaylists]: any playlist with at least one downloaded track. [looseTracks]:
+ * downloaded tracks that aren't a member of any playlist - a track belonging to a playlist is
+ * never listed twice, since that playlist already qualifies for [downloadedPlaylists] by virtue
+ * of this same track being downloaded.
+ */
+data class DownloadsUiState(
+    val downloadedPlaylists: List<Playlist> = emptyList(),
+    val looseTracks: List<DownloadedTrackEntity> = emptyList(),
+)
 
 @UnstableApi
 @HiltViewModel
 class DownloadsViewModel @Inject constructor(
     private val downloadRepository: DownloadRepository,
+    private val playlistRepository: PlaylistRepository,
     private val playbackController: PlaybackController,
 ) : ViewModel() {
 
-    val uiState: StateFlow<DownloadsUiState> = downloadRepository.downloadedTracks()
+    val uiState: StateFlow<DownloadsUiState> = combine(
-        .map { tracks -> DownloadsUiState(tracks.filter { it.status == DownloadStatus.COMPLETE }) }
+        downloadRepository.downloadedTracks(),
-        .stateIn(viewModelScope, SharingStarted.WhileSubscribed(5_000), DownloadsUiState())
+        playlistRepository.observePlaylists(),
+        playlistRepository.observeTrackIdsByPlaylist(),
+    ) { tracks, playlists, trackIdsByPlaylist ->
+        val downloaded = tracks.filter { it.status == DownloadStatus.COMPLETE }
+        val downloadedIds = downloaded.map { it.trackId }.toSet()
+
+        val downloadedPlaylists = playlists.filter { playlist ->
+            trackIdsByPlaylist[playlist.id].orEmpty().any { it in downloadedIds }
+        }
+        val trackIdsInAnyPlaylist = trackIdsByPlaylist.values.flatten().toSet()
+        val looseTracks = downloaded.filter { it.trackId !in trackIdsInAnyPlaylist }
+
+        DownloadsUiState(downloadedPlaylists, looseTracks)
+    }.stateIn(viewModelScope, SharingStarted.WhileSubscribed(5_000), DownloadsUiState())
 
     fun playTrack(index: Int) {
-        val tracks = uiState.value.tracks
+        val tracks = uiState.value.looseTracks
         if (index !in tracks.indices) return
         viewModelScope.launch {
             playbackController.ensureConnected()

app/src/main/java/com/InfernalAquatics/deepwave/ui/library/LibraryScreen.kt

@@ -31,6 +31,7 @@ private enum class LibrarySection(val labelRes: Int) {
 fun LibraryScreen(
     onArtistClick: (String) -> Unit,
     onPlaylistClick: (String) -> Unit,
+    onOpenDownloads: () -> Unit,
     modifier: Modifier = Modifier,
 ) {
     var section by remember { mutableStateOf(LibrarySection.Playlists) }
@@ -47,7 +48,11 @@ fun LibraryScreen(
             }
         }
         when (section) {
-            LibrarySection.Playlists -> PlaylistsScreen(onPlaylistClick = onPlaylistClick, modifier = Modifier.weight(1f))
+            LibrarySection.Playlists -> PlaylistsScreen(
+                onPlaylistClick = onPlaylistClick,
+                onOpenDownloads = onOpenDownloads,
+                modifier = Modifier.weight(1f),
+            )
             LibrarySection.Artists -> ArtistsScreen(onArtistClick = onArtistClick, modifier = Modifier.weight(1f))
         }
     }
@@ -57,6 +62,6 @@ fun LibraryScreen(
 @Composable
 private fun LibraryScreenPreview() {
     DeepwaveTheme {
-        LibraryScreen(onArtistClick = {}, onPlaylistClick = {})
+        LibraryScreen(onArtistClick = {}, onPlaylistClick = {}, onOpenDownloads = {})
     }
 }

app/src/main/java/com/InfernalAquatics/deepwave/ui/navigation/DeepwaveNavHost.kt

@@ -95,6 +95,7 @@ fun DeepwaveNavHost(
                             onOpenArtist = { artistId -> navController.navigate(Route.ArtistDetail(artistId)) },
                             onOpenAlbum = { albumId -> navController.navigate(Route.AlbumDetail(albumId)) },
                             onOpenPlaylist = { playlistId -> navController.navigate(Route.PlaylistDetail(playlistId)) },
+                            onOpenDownloads = { navController.navigate(Route.Downloads) },
                         )
                     }
                     composable<Route.Settings> {
@@ -105,11 +106,13 @@ fun DeepwaveNavHost(
                                     popUpTo<Route.Main> { inclusive = true }
                                 }
                             },
-                            onOpenDownloads = { navController.navigate(Route.Downloads) },
                         )
                     }
                     composable<Route.Downloads> {
-                        DownloadsScreen(onBack = { navController.popBackStack() })
+                        DownloadsScreen(
+                            onBack = { navController.popBackStack() },
+                            onPlaylistClick = { playlistId -> navController.navigate(Route.PlaylistDetail(playlistId)) },
+                        )
                     }
                     composable<Route.ArtistDetail> {
                         ArtistDetailScreen(

app/src/main/java/com/InfernalAquatics/deepwave/ui/navigation/MainScreen.kt

@@ -41,6 +41,7 @@ fun MainScreen(
     onOpenArtist: (String) -> Unit,
     onOpenAlbum: (String) -> Unit,
     onOpenPlaylist: (String) -> Unit,
+    onOpenDownloads: () -> Unit,
 ) {
     var selectedTab by remember { mutableStateOf(BottomTab.Home) }
 
@@ -67,7 +68,11 @@ fun MainScreen(
             when (selectedTab) {
                 BottomTab.Home -> HomeScreen(onAlbumClick = onOpenAlbum)
                 BottomTab.Search -> SearchScreen(onArtistClick = onOpenArtist, onAlbumClick = onOpenAlbum)
-                BottomTab.Library -> LibraryScreen(onArtistClick = onOpenArtist, onPlaylistClick = onOpenPlaylist)
+                BottomTab.Library -> LibraryScreen(
+                    onArtistClick = onOpenArtist,
+                    onPlaylistClick = onOpenPlaylist,
+                    onOpenDownloads = onOpenDownloads,
+                )
             }
         }
     }
@@ -78,6 +83,6 @@ fun MainScreen(
 @Composable
 private fun MainScreenPreview() {
     DeepwaveTheme {
-        MainScreen(onOpenSettings = {}, onOpenArtist = {}, onOpenAlbum = {}, onOpenPlaylist = {})
+        MainScreen(onOpenSettings = {}, onOpenArtist = {}, onOpenAlbum = {}, onOpenPlaylist = {}, onOpenDownloads = {})
     }
 }

app/src/main/java/com/InfernalAquatics/deepwave/ui/playlist/PlaylistsScreen.kt

@@ -7,6 +7,7 @@ import androidx.compose.foundation.lazy.LazyColumn
 import androidx.compose.foundation.lazy.items
 import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.filled.Add
+import androidx.compose.material.icons.filled.Download
 import androidx.compose.material3.Icon
 import androidx.compose.material3.ListItem
 import androidx.compose.material3.Text
@@ -27,6 +28,7 @@ import com.InfernalAquatics.deepwave.ui.theme.DeepwaveTheme
 @Composable
 fun PlaylistsScreen(
     onPlaylistClick: (String) -> Unit,
+    onOpenDownloads: () -> Unit,
     modifier: Modifier = Modifier,
     viewModel: PlaylistsViewModel = hiltViewModel(),
 ) {
@@ -34,6 +36,7 @@ fun PlaylistsScreen(
     PlaylistsContent(
         uiState = uiState,
         onPlaylistClick = onPlaylistClick,
+        onOpenDownloads = onOpenDownloads,
         onNewPlaylist = viewModel::openCreate,
         modifier = modifier,
     )
@@ -47,6 +50,7 @@ fun PlaylistsScreen(
 private fun PlaylistsContent(
     uiState: PlaylistsUiState,
     onPlaylistClick: (String) -> Unit,
+    onOpenDownloads: () -> Unit,
     onNewPlaylist: () -> Unit,
     modifier: Modifier = Modifier,
 ) {
@@ -58,6 +62,17 @@ private fun PlaylistsContent(
                 modifier = Modifier.clickable(onClick = onNewPlaylist),
             )
         }
+        item {
+            // Pinned, not a real Room playlist: its membership is computed live from what's
+            // actually on disk (see DownloadsViewModel), so it never drifts from reality and
+            // never syncs to the server - downloads are inherently per-device.
+            ListItem(
+                headlineContent = { Text(stringResource(R.string.downloads_title)) },
+                supportingContent = { Text(stringResource(R.string.downloads_subtitle)) },
+                leadingContent = { Icon(Icons.Filled.Download, contentDescription = null) },
+                modifier = Modifier.clickable(onClick = onOpenDownloads),
+            )
+        }
         if (uiState.playlists.isEmpty()) {
             item {
                 ListItem(headlineContent = { Text(stringResource(R.string.playlist_empty)) })
@@ -84,7 +99,12 @@ private val samplePlaylists = listOf(
 @Composable
 private fun PlaylistsContentPreview() {
     DeepwaveTheme {
-        PlaylistsContent(uiState = PlaylistsUiState(playlists = samplePlaylists), onPlaylistClick = {}, onNewPlaylist = {})
+        PlaylistsContent(
+            uiState = PlaylistsUiState(playlists = samplePlaylists),
+            onPlaylistClick = {},
+            onOpenDownloads = {},
+            onNewPlaylist = {},
+        )
     }
 }
 
@@ -92,6 +112,6 @@ private fun PlaylistsContentPreview() {
 @Composable
 private fun PlaylistsContentEmptyPreview() {
     DeepwaveTheme {
-        PlaylistsContent(uiState = PlaylistsUiState(), onPlaylistClick = {}, onNewPlaylist = {})
+        PlaylistsContent(uiState = PlaylistsUiState(), onPlaylistClick = {}, onOpenDownloads = {}, onNewPlaylist = {})
     }
 }

app/src/main/java/com/InfernalAquatics/deepwave/ui/settings/SettingsScreen.kt

@@ -34,7 +34,6 @@ import com.InfernalAquatics.deepwave.ui.theme.DeepwaveTheme
 fun SettingsScreen(
     onBack: () -> Unit,
     onLoggedOut: () -> Unit,
-    onOpenDownloads: () -> Unit,
     viewModel: SettingsViewModel = hiltViewModel(),
 ) {
     val uiState by viewModel.uiState.collectAsState()
@@ -46,7 +45,6 @@ fun SettingsScreen(
         defaultBitrate = defaultBitrate,
         onBack = onBack,
         onLogOutClick = { viewModel.logout(onLoggedOut) },
-        onOpenDownloads = onOpenDownloads,
         onWifiOnlyChange = viewModel::setWifiOnly,
         onOpenDefaultQualityPicker = viewModel::openDefaultQualityPicker,
         onDismissDefaultQualityPicker = viewModel::dismissDefaultQualityPicker,
@@ -62,7 +60,6 @@ private fun SettingsContent(
     defaultBitrate: BitrateOption,
     onBack: () -> Unit,
     onLogOutClick: () -> Unit,
-    onOpenDownloads: () -> Unit,
     onWifiOnlyChange: (Boolean) -> Unit,
     onOpenDefaultQualityPicker: () -> Unit,
     onDismissDefaultQualityPicker: () -> Unit,
@@ -81,12 +78,6 @@ private fun SettingsContent(
         },
     ) { innerPadding ->
         Column(modifier = Modifier.fillMaxSize().padding(innerPadding)) {
-            ListItem(
-                headlineContent = { Text(stringResource(R.string.settings_downloads)) },
-                modifier = Modifier
-                    .fillMaxWidth()
-                    .clickable(onClick = onOpenDownloads),
-            )
             ListItem(
                 headlineContent = { Text(stringResource(R.string.settings_wifi_only_downloads)) },
                 trailingContent = { Switch(checked = wifiOnly, onCheckedChange = onWifiOnlyChange) },
@@ -124,7 +115,6 @@ private fun SettingsContentPreview() {
             defaultBitrate = BitrateOption.Normal,
             onBack = {},
             onLogOutClick = {},
-            onOpenDownloads = {},
             onWifiOnlyChange = {},
             onOpenDefaultQualityPicker = {},
             onDismissDefaultQualityPicker = {},

app/src/main/res/values/strings.xml

@@ -17,7 +17,6 @@
 
     <string name="settings_title">Settings</string>
     <string name="settings_log_out">Log out</string>
-    <string name="settings_downloads">Downloads</string>
     <string name="settings_wifi_only_downloads">Download over Wi-Fi only</string>
     <string name="settings_default_quality">Default download quality</string>
 
@@ -33,6 +32,9 @@
 
     <string name="downloads_title">Downloads</string>
     <string name="downloads_empty">No downloads yet</string>
+    <string name="downloads_subtitle">Available offline</string>
+    <string name="downloads_section_playlists">Playlists</string>
+    <string name="downloads_section_tracks">Tracks</string>
 
     <string name="player_nothing_playing">Nothing playing</string>
     <string name="player_play">Play</string>