detail: improve playlist presentation

Improve playlist presentation in the detail views, especially when
it is empty.

app/src/main/java/org/oxycblt/auxio/detail/DetailViewModel.kt

@@ -46,6 +46,8 @@ import org.oxycblt.auxio.util.*
  * [ViewModel] that manages the Song, Album, Artist, and Genre detail views. Keeps track of the
  * current item they are showing, sub-data to display, and configuration.
  *
+ * FIXME: Need to do direct item comparison in equality checks, or reset on navigation.
+ *
  * @author Alexander Capehart (OxygenCobalt)
  */
 @HiltViewModel
@@ -416,15 +418,16 @@ constructor(
 
     private fun refreshPlaylistList(playlist: Playlist, replace: Boolean = false) {
         logD("Refreshing playlist list")
+        var instructions: UpdateInstructions = UpdateInstructions.Diff
         val list = mutableListOf<Item>()
-        list.add(SortHeader(R.string.lbl_songs))
-        val instructions =
+
+        if (playlist.songs.isNotEmpty()) {
+            list.add(SortHeader(R.string.lbl_songs))
             if (replace) {
-                UpdateInstructions.Replace(list.size)
-            } else {
-                UpdateInstructions.Diff
+                instructions = UpdateInstructions.Replace(list.size)
             }
-        list.addAll(playlistSongSort.songs(playlist.songs))
+            list.addAll(playlistSongSort.songs(playlist.songs))
+        }
         _playlistInstructions.put(instructions)
         _playlistList.value = list
     }

app/src/main/java/org/oxycblt/auxio/detail/header/ArtistDetailHeaderAdapter.kt

@@ -65,6 +65,17 @@ private constructor(private val binding: ItemDetailHeaderBinding) :
         binding.detailType.text = binding.context.getString(R.string.lbl_artist)
         binding.detailName.text = artist.name.resolve(binding.context)
 
+        // Song and album counts map to the info
+        binding.detailInfo.text =
+            binding.context.getString(
+                R.string.fmt_two,
+                binding.context.getPlural(R.plurals.fmt_album_count, artist.albums.size),
+                if (artist.songs.isNotEmpty()) {
+                    binding.context.getPlural(R.plurals.fmt_song_count, artist.songs.size)
+                } else {
+                    binding.context.getString(R.string.def_song_count)
+                })
+
         if (artist.songs.isNotEmpty()) {
             // Information about the artist's genre(s) map to the sub-head text
             binding.detailSubhead.apply {
@@ -72,13 +83,6 @@ private constructor(private val binding: ItemDetailHeaderBinding) :
                 text = artist.genres.resolveNames(context)
             }
 
-            // Song and album counts map to the info
-            binding.detailInfo.text =
-                binding.context.getString(
-                    R.string.fmt_two,
-                    binding.context.getPlural(R.plurals.fmt_album_count, artist.albums.size),
-                    binding.context.getPlural(R.plurals.fmt_song_count, artist.songs.size))
-
             // In the case that this header used to he configured to have no songs,
             // we want to reset the visibility of all information that was hidden.
             binding.detailPlayButton.isVisible = true
@@ -88,10 +92,8 @@ private constructor(private val binding: ItemDetailHeaderBinding) :
             // ex. Play and Shuffle, Song Counts, and Genre Information.
             // Artists are always guaranteed to have albums however, so continue to show those.
             binding.detailSubhead.isVisible = false
-            binding.detailInfo.text =
-                binding.context.getPlural(R.plurals.fmt_album_count, artist.albums.size)
-            binding.detailPlayButton.isVisible = false
-            binding.detailShuffleButton.isVisible = false
+            binding.detailPlayButton.isEnabled = false
+            binding.detailShuffleButton.isEnabled = false
         }
 
         binding.detailPlayButton.setOnClickListener { listener.onPlay() }

app/src/main/java/org/oxycblt/auxio/detail/header/PlaylistDetailHeaderAdapter.kt

@@ -65,11 +65,26 @@ private constructor(private val binding: ItemDetailHeaderBinding) :
         binding.detailName.text = playlist.name.resolve(binding.context)
         // Nothing about a playlist is applicable to the sub-head text.
         binding.detailSubhead.isVisible = false
+
         // The song count of the playlist maps to the info text.
-        binding.detailInfo.text =
-            binding.context.getPlural(R.plurals.fmt_song_count, playlist.songs.size)
-        binding.detailPlayButton.setOnClickListener { listener.onPlay() }
-        binding.detailShuffleButton.setOnClickListener { listener.onShuffle() }
+        binding.detailInfo.apply {
+            isVisible = true
+            text =
+                if (playlist.songs.isNotEmpty()) {
+                    binding.context.getPlural(R.plurals.fmt_song_count, playlist.songs.size)
+                } else {
+                    binding.context.getString(R.string.def_song_count)
+                }
+        }
+
+        binding.detailPlayButton.apply {
+            isEnabled = playlist.songs.isNotEmpty()
+            setOnClickListener { listener.onPlay() }
+        }
+        binding.detailShuffleButton.apply {
+            isEnabled = playlist.songs.isNotEmpty()
+            setOnClickListener { listener.onShuffle() }
+        }
     }
 
     companion object {

app/src/main/java/org/oxycblt/auxio/list/recycler/ViewHolders.kt

@@ -157,15 +157,14 @@ class ArtistViewHolder private constructor(private val binding: ItemParentBindin
         binding.parentImage.bind(artist)
         binding.parentName.text = artist.name.resolve(binding.context)
         binding.parentInfo.text =
-            if (artist.songs.isNotEmpty()) {
-                binding.context.getString(
-                    R.string.fmt_two,
-                    binding.context.getPlural(R.plurals.fmt_album_count, artist.albums.size),
-                    binding.context.getPlural(R.plurals.fmt_song_count, artist.songs.size))
-            } else {
-                // Artist has no songs, only display an album count.
-                binding.context.getPlural(R.plurals.fmt_album_count, artist.albums.size)
-            }
+            binding.context.getString(
+                R.string.fmt_two,
+                binding.context.getPlural(R.plurals.fmt_album_count, artist.albums.size),
+                if (artist.songs.isNotEmpty()) {
+                    binding.context.getPlural(R.plurals.fmt_song_count, artist.songs.size)
+                } else {
+                    binding.context.getString(R.string.def_song_count)
+                })
     }
 
     override fun updatePlayingIndicator(isActive: Boolean, isPlaying: Boolean) {
@@ -275,7 +274,11 @@ class PlaylistViewHolder private constructor(private val binding: ItemParentBind
         binding.parentImage.bind(playlist)
         binding.parentName.text = playlist.name.resolve(binding.context)
         binding.parentInfo.text =
-            binding.context.getPlural(R.plurals.fmt_song_count, playlist.songs.size)
+            if (playlist.songs.isNotEmpty()) {
+                binding.context.getPlural(R.plurals.fmt_song_count, playlist.songs.size)
+            } else {
+                binding.context.getString(R.string.def_song_count)
+            }
     }
 
     override fun updatePlayingIndicator(isActive: Boolean, isPlaying: Boolean) {

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

@@ -326,6 +326,7 @@
     <string name="def_genre">Unknown genre</string>
     <string name="def_date">No date</string>
     <string name="def_track">No track</string>
+    <string name="def_song_count">No songs</string>
     <string name="def_playback">No music playing</string>
 
     <!-- Codec Namespace | Format names -->

app/src/test/java/org/oxycblt/auxio/music/FakeMusicRepository.kt

@@ -62,6 +62,10 @@ open class FakeMusicRepository : MusicRepository {
         throw NotImplementedError()
     }
 
+    override fun addToPlaylist(songs: List<Song>, playlist: Playlist) {
+        throw NotImplementedError()
+    }
+
     override fun requestIndex(withCache: Boolean) {
         throw NotImplementedError()
     }

app/src/test/java/org/oxycblt/auxio/music/MusicViewModelTest.kt

@@ -32,7 +32,7 @@ class MusicViewModelTest {
             TestMusicRepository().apply {
                 indexingState = IndexingState.Indexing(IndexingProgress.Indeterminate)
             }
-        val musicViewModel = MusicViewModel(indexer)
+        val musicViewModel = MusicViewModel(indexer, FakeMusicSettings())
         assertTrue(indexer.updateListener is MusicViewModel)
         assertTrue(indexer.indexingListener is MusicViewModel)
         assertEquals(
@@ -47,7 +47,7 @@ class MusicViewModelTest {
     @Test
     fun statistics() {
         val musicRepository = TestMusicRepository()
-        val musicViewModel = MusicViewModel(musicRepository)
+        val musicViewModel = MusicViewModel(musicRepository, FakeMusicSettings())
         assertEquals(null, musicViewModel.statistics.value)
         musicRepository.deviceLibrary = TestDeviceLibrary()
         assertEquals(
@@ -64,7 +64,7 @@ class MusicViewModelTest {
     @Test
     fun requests() {
         val indexer = TestMusicRepository()
-        val musicViewModel = MusicViewModel(indexer)
+        val musicViewModel = MusicViewModel(indexer, FakeMusicSettings())
         musicViewModel.refresh()
         musicViewModel.rescan()
         assertEquals(listOf(true, false), indexer.requests)