add a song info dialog and show the encoding in the manager

The song context menus gain Info, which lists every field we hold for the song
and, when it is downloaded, the file's format, bitrate, sample rate, channels
and size read from the file itself. For the song currently playing it takes the
encoding from the media3 stream instead, so a transcoded stream reports what is
actually being played. The menu is shared, so this reaches the album, playlist,
now playing and queue menus at once.

The downloads manager shows the same format and bitrate beside the size on each
song row, read lazily for the rows on screen rather than for the whole tree.

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

@@ -104,7 +104,7 @@ interface DownloadDao {
     fun playlistStatuses(sourceId: Long): Flow<List<EntityDownloadStatus>>
 
     @Query(
-        "SELECT d.songId AS songId, s.title AS title, s.albumId AS albumId, al.name AS albumName, " +
+        "SELECT d.sourceId AS sourceId, d.songId AS songId, s.title AS title, s.albumId AS albumId, al.name AS albumName, " +
             "al.artistId AS artistId, ar.name AS artistName, d.status AS status, d.total AS size " +
             "FROM song_downloads d " +
             "JOIN songs s ON s.sourceId = d.sourceId AND s.id = d.songId " +

app/src/main/kotlin/com/subtracks/data/media/AudioEncodingReader.kt

@@ -0,0 +1,32 @@
+package com.subtracks.data.media
+
+import android.media.MediaExtractor
+import android.media.MediaFormat
+import com.subtracks.data.model.AudioEncoding
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.withContext
+import java.io.File
+
+suspend fun readAudioEncoding(file: File): AudioEncoding? =
+    withContext(Dispatchers.IO) {
+        runCatching {
+            val extractor = MediaExtractor()
+            try {
+                extractor.setDataSource(file.absolutePath)
+                if (extractor.trackCount == 0) return@runCatching null
+                val format = extractor.getTrackFormat(0)
+                AudioEncoding(
+                    mimeType = format.stringOrNull(MediaFormat.KEY_MIME),
+                    bitrate = format.intOrNull(MediaFormat.KEY_BIT_RATE),
+                    sampleRate = format.intOrNull(MediaFormat.KEY_SAMPLE_RATE),
+                    channels = format.intOrNull(MediaFormat.KEY_CHANNEL_COUNT),
+                )
+            } finally {
+                extractor.release()
+            }
+        }.getOrNull()
+    }
+
+private fun MediaFormat.stringOrNull(key: String): String? = if (containsKey(key)) getString(key) else null
+
+private fun MediaFormat.intOrNull(key: String): Int? = if (containsKey(key)) getInteger(key) else null

app/src/main/kotlin/com/subtracks/data/model/AudioEncoding.kt

@@ -0,0 +1,22 @@
+package com.subtracks.data.model
+
+data class AudioEncoding(
+    val mimeType: String?,
+    val bitrate: Int? = null,
+    val sampleRate: Int? = null,
+    val channels: Int? = null,
+) {
+    val format: String?
+        get() =
+            when (mimeType?.lowercase()) {
+                null -> null
+                "audio/mpeg" -> "MP3"
+                "audio/mp4", "audio/m4a", "audio/x-m4a", "audio/aac" -> "AAC"
+                "audio/flac", "audio/x-flac" -> "FLAC"
+                "audio/ogg" -> "Ogg"
+                "audio/opus" -> "Opus"
+                "audio/webm" -> "WebM"
+                "audio/wav", "audio/x-wav" -> "WAV"
+                else -> mimeType.substringAfterLast('/').uppercase()
+            }
+}

app/src/main/kotlin/com/subtracks/data/model/Download.kt

@@ -63,6 +63,7 @@ data class EntityDownloadStatus(
 
 data class DownloadedSong(
     val songId: String,
+    val sourceId: Long,
     val title: String,
     val albumId: String?,
     val albumName: String?,

app/src/main/kotlin/com/subtracks/data/repo/DownloadRepository.kt

@@ -93,12 +93,17 @@ class DownloadRepository(
         if (started) loaded.await()
     }
 
-    fun localUri(songId: String): String? =
+    fun localFile(songId: String): File? =
         statesFlow.value[songId]
             ?.takeIf { it.status == DownloadStatus.Completed }
-            ?.let { file(it.sourceId, it.songId) }
-            ?.takeIf { it.exists() }
-            ?.let { Uri.fromFile(it).toString() }
+            ?.let { localFile(it.sourceId, it.songId) }
+
+    fun localFile(
+        sourceId: Long,
+        songId: String,
+    ): File? = file(sourceId, songId).takeIf { it.exists() }
+
+    fun localUri(songId: String): String? = localFile(songId)?.let { Uri.fromFile(it).toString() }
 
     suspend fun download(
         sourceId: Long,

app/src/main/kotlin/com/subtracks/playback/Media3PlayerHandle.kt

@@ -3,12 +3,15 @@ package com.subtracks.playback
 import android.os.Bundle
 import android.util.Log
 import androidx.media3.common.C
+import androidx.media3.common.Format
 import androidx.media3.common.MediaItem
 import androidx.media3.common.MediaItem.ClippingConfiguration
 import androidx.media3.common.MediaMetadata
 import androidx.media3.common.PlaybackException
 import androidx.media3.common.Player
+import androidx.media3.common.util.UnstableApi
 import androidx.media3.session.MediaController
+import com.subtracks.data.model.AudioEncoding
 import com.subtracks.data.repo.DownloadRepository
 import com.subtracks.data.repo.SourceRepository
 
@@ -38,6 +41,24 @@ class Media3PlayerHandle(
 
     override val currentItem: QueueItem? get() = controller.currentMediaItem?.let(::toQueueItem)
 
+    @get:UnstableApi
+    override val audioEncoding: AudioEncoding?
+        get() =
+            controller.currentTracks.groups
+                .firstOrNull { it.type == C.TRACK_TYPE_AUDIO && it.isSelected }
+                ?.let { group ->
+                    (0 until group.length)
+                        .firstOrNull { group.isTrackSelected(it) }
+                        ?.let(group::getTrackFormat)
+                }?.let { format ->
+                    AudioEncoding(
+                        mimeType = format.sampleMimeType,
+                        bitrate = format.bitrate.takeIf { it != Format.NO_VALUE },
+                        sampleRate = format.sampleRate.takeIf { it != Format.NO_VALUE },
+                        channels = format.channelCount.takeIf { it != Format.NO_VALUE },
+                    )
+                }
+
     override fun setWindow(
         items: List<QueueItem>,
         startIndex: Int,

app/src/main/kotlin/com/subtracks/playback/PlaybackController.kt

@@ -1,5 +1,6 @@
 package com.subtracks.playback
 
+import com.subtracks.data.model.AudioEncoding
 import com.subtracks.data.model.CoverArtRef
 import com.subtracks.data.model.QueueEntry
 import com.subtracks.data.model.QueueKind
@@ -118,6 +119,8 @@ class PlaybackController(
     private val _positionMs = MutableStateFlow(0L)
     val positionMs: StateFlow<Long> = _positionMs
 
+    fun currentAudioEncoding(): AudioEncoding? = player?.audioEncoding
+
     private var player: PlayerHandle? = null
     private var connecting = false
     private var pendingPlay: PendingPlay? = null

app/src/main/kotlin/com/subtracks/playback/PlayerHandle.kt

@@ -1,5 +1,7 @@
 package com.subtracks.playback
 
+import com.subtracks.data.model.AudioEncoding
+
 interface PlayerHandle {
     val itemCount: Int
     val currentIndex: Int
@@ -12,6 +14,9 @@ interface PlayerHandle {
     val currentPositionMs: Long
     val currentItem: QueueItem?
 
+    /** The encoding of the audio now being rendered, when the player knows it. */
+    val audioEncoding: AudioEncoding? get() = null
+
     fun setWindow(
         items: List<QueueItem>,
         startIndex: Int,

app/src/main/kotlin/com/subtracks/ui/AppRoot.kt

@@ -58,12 +58,15 @@ import androidx.navigation.compose.composable
 import androidx.navigation.compose.currentBackStackEntryAsState
 import androidx.navigation.compose.rememberNavController
 import androidx.navigation.navArgument
+import com.subtracks.data.model.Song
+import com.subtracks.data.repo.DownloadRepository
 import com.subtracks.data.repo.LibraryRepository
 import com.subtracks.data.repo.SourceRepository
 import com.subtracks.playback.PlaybackController
 import com.subtracks.ui.components.ContextMenuHost
 import com.subtracks.ui.components.ItemContextMenu
 import com.subtracks.ui.components.LoadingState
+import com.subtracks.ui.components.SongInfoDialog
 import com.subtracks.ui.components.statusBarScrim
 import com.subtracks.ui.downloads.DownloadsRoute
 import com.subtracks.ui.library.AlbumDetailRoute
@@ -175,7 +178,9 @@ private fun MainNavigation() {
     val tabBarVisible = currentRoute == Routes.LIBRARY
     val playbackController = koinInject<PlaybackController>()
     val libraryRepository = koinInject<LibraryRepository>()
+    val downloadRepository = koinInject<DownloadRepository>()
     val playback by playbackController.state.collectAsStateWithLifecycle()
+    val downloads by downloadRepository.states().collectAsStateWithLifecycle()
     var showingQueue by rememberSaveable { mutableStateOf(false) }
     var nowPlayingOpen by rememberSaveable { mutableStateOf(false) }
     var nowPlayingProgress by remember { mutableFloatStateOf(0f) }
@@ -184,6 +189,7 @@ private fun MainNavigation() {
     var settleJob by remember { mutableStateOf<Job?>(null) }
     val scope = rememberCoroutineScope()
     val contextMenuHost = remember { ContextMenuHost() }
+    var infoSong by remember { mutableStateOf<Song?>(null) }
 
     fun settleNowPlaying(open: Boolean) {
         if (open) {
@@ -502,7 +508,22 @@ private fun MainNavigation() {
             }
 
             contextMenuHost.target?.let { target ->
-                ItemContextMenu(target = target, actions = contextMenuHost.actions, onDismiss = { contextMenuHost.dismiss() })
+                ItemContextMenu(
+                    target = target,
+                    actions = contextMenuHost.actions,
+                    onDismiss = { contextMenuHost.dismiss() },
+                    onInfo = { infoSong = it },
+                )
+            }
+
+            infoSong?.let { song ->
+                SongInfoDialog(
+                    song = song,
+                    download = downloads[song.id],
+                    localFile = downloadRepository.localFile(song.id),
+                    streamEncoding = playbackController.currentAudioEncoding().takeIf { playback.item?.id == song.id },
+                    onDismiss = { infoSong = null },
+                )
             }
         }
     }

app/src/main/kotlin/com/subtracks/ui/components/ItemContextMenu.kt

@@ -17,6 +17,7 @@ import androidx.compose.material.icons.rounded.Album
 import androidx.compose.material.icons.rounded.Cancel
 import androidx.compose.material.icons.rounded.Delete
 import androidx.compose.material.icons.rounded.Download
+import androidx.compose.material.icons.rounded.Info
 import androidx.compose.material.icons.rounded.Person
 import androidx.compose.material.icons.rounded.SkipNext
 import androidx.compose.material.icons.rounded.Star
@@ -164,6 +165,7 @@ fun ItemContextMenu(
     target: MenuTarget,
     actions: ItemActions,
     onDismiss: () -> Unit,
+    onInfo: ((SongModel) -> Unit)? = null,
 ) {
     val sheetState = rememberModalBottomSheetState(skipPartiallyExpanded = true)
     val scope = rememberCoroutineScope()
@@ -219,6 +221,9 @@ fun ItemContextMenu(
                         }
                     }
                 }
+                onInfo?.let { info ->
+                    MenuItem(Icons.Rounded.Info, "Info") { dismiss { info(target.song) } }
+                }
             }
 
             is MenuTarget.Album -> {

app/src/main/kotlin/com/subtracks/ui/components/SongInfoDialog.kt

@@ -0,0 +1,100 @@
+package com.subtracks.ui.components
+
+import android.text.format.DateUtils
+import android.text.format.Formatter
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.padding
+import androidx.compose.material3.AlertDialog
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Text
+import androidx.compose.material3.TextButton
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.platform.LocalContext
+import androidx.compose.ui.unit.dp
+import com.subtracks.data.media.readAudioEncoding
+import com.subtracks.data.model.AudioEncoding
+import com.subtracks.data.model.DownloadStatus
+import com.subtracks.data.model.Song
+import com.subtracks.data.model.SongDownload
+import java.io.File
+
+@Composable
+fun SongInfoDialog(
+    song: Song,
+    download: SongDownload?,
+    localFile: File?,
+    streamEncoding: AudioEncoding?,
+    onDismiss: () -> Unit,
+) {
+    val context = LocalContext.current
+    var encoding by remember(song.id, localFile) { mutableStateOf<AudioEncoding?>(null) }
+    LaunchedEffect(song.id, localFile) {
+        encoding = localFile?.let { readAudioEncoding(it) }
+    }
+    val shown = if (download?.status == DownloadStatus.Completed) encoding else streamEncoding
+    AlertDialog(
+        onDismissRequest = onDismiss,
+        title = { Text("Info") },
+        text = {
+            Column(verticalArrangement = Arrangement.spacedBy(6.dp)) {
+                InfoRow("Title", song.title)
+                InfoRow("Artist", song.artist)
+                InfoRow("Album", song.album)
+                InfoRow("Duration", song.duration?.let(DateUtils::formatElapsedTime))
+                InfoRow("Track", song.track?.let { track -> song.disc?.let { "$it.$track" } ?: track.toString() })
+                InfoRow("Genre", song.genre)
+                InfoRow("Starred", if (song.starred != null) "Yes" else null)
+                if (download != null) {
+                    InfoRow("Download", downloadStatus(download.status))
+                    InfoRow("Size", localFile?.length()?.takeIf { it > 0 }?.let { Formatter.formatFileSize(context, it) })
+                    download.error?.let { InfoRow("Error", it) }
+                }
+                shown?.let { enc ->
+                    InfoRow("Format", enc.format)
+                    InfoRow("Bitrate", enc.bitrate?.takeIf { it > 0 }?.let { "${it / 1000} kbps" })
+                    InfoRow("Sample rate", enc.sampleRate?.takeIf { it > 0 }?.let { "$it Hz" })
+                    InfoRow("Channels", enc.channels?.takeIf { it > 0 }?.toString())
+                }
+            }
+        },
+        confirmButton = { TextButton(onClick = onDismiss) { Text("Close") } },
+    )
+}
+
+@Composable
+private fun InfoRow(
+    label: String,
+    value: String?,
+) {
+    if (value.isNullOrBlank()) return
+    Row(Modifier.fillMaxWidth().padding(vertical = 2.dp)) {
+        Text(
+            text = label,
+            style = MaterialTheme.typography.bodyMedium,
+            color = MaterialTheme.colorScheme.onSurfaceVariant,
+            modifier = Modifier.padding(end = 16.dp),
+        )
+        Text(
+            text = value,
+            style = MaterialTheme.typography.bodyMedium,
+            modifier = Modifier.weight(1f),
+        )
+    }
+}
+
+private fun downloadStatus(status: DownloadStatus): String =
+    when (status) {
+        DownloadStatus.Completed -> "Downloaded"
+        DownloadStatus.Queued -> "Queued"
+        DownloadStatus.Running -> "Downloading"
+        DownloadStatus.Failed -> "Failed"
+    }

app/src/main/kotlin/com/subtracks/ui/downloads/DownloadsScreen.kt

@@ -26,6 +26,7 @@ import androidx.compose.material3.Text
 import androidx.compose.material3.TextButton
 import androidx.compose.material3.TopAppBar
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
@@ -37,6 +38,7 @@ import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.text.style.TextOverflow
 import androidx.compose.ui.unit.dp
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
+import com.subtracks.data.model.AudioEncoding
 import com.subtracks.data.model.DownloadList
 import com.subtracks.data.model.DownloadStatus
 import com.subtracks.data.model.DownloadedSong
@@ -68,6 +70,7 @@ fun DownloadsRoute(
     var pending by remember { mutableStateOf<DownloadDeleteTarget?>(null) }
     DownloadsScreen(
         tree = tree,
+        loadEncoding = viewModel::encoding,
         onBack = onBack,
         onDelete = { target ->
             when (target) {
@@ -105,6 +108,7 @@ fun DownloadsRoute(
 @Composable
 fun DownloadsScreen(
     tree: DownloadTree,
+    loadEncoding: suspend (DownloadedSong) -> AudioEncoding?,
     onBack: () -> Unit,
     onDelete: (DownloadDeleteTarget) -> Unit,
     modifier: Modifier = Modifier,
@@ -177,7 +181,7 @@ fun DownloadsScreen(
                         }
                         if (albumKey in expanded) {
                             items(album.songs, key = { "$albumKey:${it.songId}" }) { song ->
-                                SongRow(song) { onDelete(DownloadDeleteTarget.Songs(listOf(song.songId))) }
+                                SongRow(song, loadEncoding) { onDelete(DownloadDeleteTarget.Songs(listOf(song.songId))) }
                             }
                         }
                     }
@@ -239,11 +243,16 @@ private fun NodeRow(
 @Composable
 private fun SongRow(
     song: DownloadedSong,
+    loadEncoding: suspend (DownloadedSong) -> AudioEncoding?,
     onDelete: () -> Unit,
 ) {
+    var encoding by remember(song.songId) { mutableStateOf<AudioEncoding?>(null) }
+    LaunchedEffect(song.songId, song.status) {
+        encoding = if (song.status == DownloadStatus.Completed) loadEncoding(song) else null
+    }
     ListItem(
         headlineContent = { Text(song.title, maxLines = 1, overflow = TextOverflow.Ellipsis) },
-        supportingContent = { Text(statusLabel(song), maxLines = 1, overflow = TextOverflow.Ellipsis) },
+        supportingContent = { Text(songSubtitle(song, encoding), maxLines = 1, overflow = TextOverflow.Ellipsis) },
         trailingContent = {
             IconButton(onClick = onDelete) {
                 Icon(Icons.Rounded.Delete, contentDescription = "Delete download")
@@ -255,13 +264,31 @@ private fun SongRow(
 }
 
 @Composable
-private fun statusLabel(song: DownloadedSong): String {
+private fun songSubtitle(
+    song: DownloadedSong,
+    encoding: AudioEncoding?,
+): String {
     val size = size(song.size)
     return when (song.status) {
-        DownloadStatus.Completed -> size
-        DownloadStatus.Queued -> "Queued · $size"
-        DownloadStatus.Running -> "Downloading · $size"
-        DownloadStatus.Failed -> "Failed · $size"
+        DownloadStatus.Completed -> {
+            listOfNotNull(
+                encoding?.format,
+                encoding?.bitrate?.takeIf { it > 0 }?.let { "${it / 1000} kbps" },
+                size,
+            ).joinToString(" · ")
+        }
+
+        DownloadStatus.Queued -> {
+            "Queued · $size"
+        }
+
+        DownloadStatus.Running -> {
+            "Downloading · $size"
+        }
+
+        DownloadStatus.Failed -> {
+            "Failed · $size"
+        }
     }
 }
 

app/src/main/kotlin/com/subtracks/ui/downloads/DownloadsViewModel.kt

@@ -2,6 +2,8 @@ package com.subtracks.ui.downloads
 
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
+import com.subtracks.data.media.readAudioEncoding
+import com.subtracks.data.model.AudioEncoding
 import com.subtracks.data.model.DownloadList
 import com.subtracks.data.model.DownloadedSong
 import com.subtracks.data.repo.DownloadRepository
@@ -76,6 +78,9 @@ class DownloadsViewModel(
             playbackController.refreshMediaItems()
         }
     }
+
+    suspend fun encoding(song: DownloadedSong): AudioEncoding? =
+        downloadRepository.localFile(song.sourceId, song.songId)?.let { readAudioEncoding(it) }
 }
 
 internal fun buildTree(songs: List<DownloadedSong>): DownloadTree =

app/src/test/kotlin/com/subtracks/data/model/AudioEncodingTest.kt

@@ -0,0 +1,25 @@
+package com.subtracks.data.model
+
+import org.junit.Assert.assertEquals
+import org.junit.Assert.assertNull
+import org.junit.Test
+
+class AudioEncodingTest {
+    @Test
+    fun commonTypesGetReadableNames() {
+        assertEquals("MP3", AudioEncoding("audio/mpeg").format)
+        assertEquals("FLAC", AudioEncoding("audio/flac").format)
+        assertEquals("AAC", AudioEncoding("audio/mp4").format)
+        assertEquals("Opus", AudioEncoding("audio/opus").format)
+    }
+
+    @Test
+    fun anUnknownTypeFallsBackToItsSubtype() {
+        assertEquals("X-CUSTOM", AudioEncoding("audio/x-custom").format)
+    }
+
+    @Test
+    fun noTypeMeansNoFormat() {
+        assertNull(AudioEncoding(null).format)
+    }
+}

app/src/test/kotlin/com/subtracks/ui/downloads/DownloadTreeTest.kt

@@ -54,6 +54,7 @@ class DownloadTreeTest {
         size: Long,
     ) = DownloadedSong(
         songId = id,
+        sourceId = 1,
         title = title,
         albumId = albumId,
         albumName = albumName,