ui: show plural artists in song subtitles and info dialog

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

@@ -80,7 +80,7 @@ sealed interface MenuTarget {
     ) : MenuTarget {
         override val title: String get() = song.title
 
-        override val subtitle: String? get() = song.artist
+        override val subtitle: String? get() = song.artistSubtitle()
     }
 
     data class Album(

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

@@ -0,0 +1,15 @@
+package com.subtracks.ui.components
+
+import com.subtracks.data.model.Song
+
+private const val ARTIST_SEPARATOR = " \u00B7 "
+
+internal fun Song.artistSubtitle(): String? {
+    val names = artists.map { it.name }.filter { it.isNotBlank() }.distinct()
+    if (names.isEmpty()) return artist?.takeIf { it.isNotBlank() }
+    val primary = artist?.takeIf { it in names }
+    return buildList {
+        primary?.let(::add)
+        addAll(names.filterNot { it == primary })
+    }.joinToString(ARTIST_SEPARATOR)
+}

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

@@ -54,7 +54,7 @@ fun SongInfoDialog(
         text = {
             Column(verticalArrangement = Arrangement.spacedBy(6.dp)) {
                 InfoRow(stringResource(R.string.resources_sort_by_title), song.title)
-                InfoRow(stringResource(R.string.resources_filter_artist), song.artist)
+                InfoRow(stringResource(R.string.resources_filter_artist), song.artistSubtitle())
                 InfoRow(stringResource(R.string.resources_filter_album), song.album)
                 InfoRow(stringResource(R.string.info_duration), song.duration?.let(DateUtils::formatElapsedTime))
                 InfoRow(

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

@@ -61,6 +61,7 @@ import com.subtracks.data.model.DownloadStatus
 import com.subtracks.data.model.Song
 import com.subtracks.data.model.SongDownload
 import com.subtracks.ui.components.CoverArt
+import com.subtracks.ui.components.artistSubtitle
 
 private val TRACK_COLUMN_WIDTH = 24.dp
 private val TIME_COLUMN_WIDTH = 36.dp
@@ -146,7 +147,7 @@ fun SongRow(
         },
         supportingContent = {
             Text(
-                text = song.artist.orEmpty().ifEmpty { "\u00A0" },
+                text = song.artistSubtitle().orEmpty().ifEmpty { "\u00A0" },
                 color = if (isPlaying) MaterialTheme.colorScheme.primary else MaterialTheme.colorScheme.onSurfaceVariant,
                 maxLines = 1,
                 overflow = TextOverflow.Ellipsis,

app/src/test/kotlin/com/subtracks/ui/components/SongArtistDisplayTest.kt

@@ -0,0 +1,67 @@
+package com.subtracks.ui.components
+
+import androidx.activity.ComponentActivity
+import androidx.compose.ui.test.assertIsDisplayed
+import androidx.compose.ui.test.junit4.v2.createAndroidComposeRule
+import androidx.compose.ui.test.onNodeWithText
+import androidx.test.ext.junit.runners.AndroidJUnit4
+import com.subtracks.data.model.ArtistRef
+import com.subtracks.data.model.Song
+import com.subtracks.ui.library.SongRow
+import com.subtracks.ui.theme.SubtracksTheme
+import org.junit.Rule
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.robolectric.annotation.GraphicsMode
+
+@RunWith(AndroidJUnit4::class)
+@GraphicsMode(GraphicsMode.Mode.NATIVE)
+class SongArtistDisplayTest {
+    @get:Rule
+    val composeRule = createAndroidComposeRule<ComponentActivity>()
+
+    private val song =
+        Song(
+            sourceId = 1,
+            id = "s1",
+            albumId = "al1",
+            artistId = "ar2",
+            title = "Song",
+            album = "Album",
+            artist = "Two",
+            duration = 100,
+            track = 1,
+            disc = 1,
+            starred = null,
+            artists = listOf(ArtistRef("ar1", "One"), ArtistRef("ar2", "Two"), ArtistRef("ar3", "Three")),
+        )
+
+    @Test
+    fun aSongRowListsThePluralArtistsWithTheSingularArtistFirst() {
+        composeRule.setContent {
+            SubtracksTheme {
+                SongRow(song = song)
+            }
+        }
+
+        composeRule.onNodeWithText("Two · One · Three").assertIsDisplayed()
+    }
+
+    @Test
+    fun theInfoDialogListsThePluralArtistsWithTheSingularArtistFirst() {
+        composeRule.setContent {
+            SubtracksTheme {
+                SongInfoDialog(
+                    song = song,
+                    download = null,
+                    localFile = null,
+                    streamEncoding = null,
+                    onDismiss = {},
+                    genres = emptyList(),
+                )
+            }
+        }
+
+        composeRule.onNodeWithText("Two · One · Three").assertIsDisplayed()
+    }
+}

app/src/test/kotlin/com/subtracks/ui/library/SongArtistSubtitleTest.kt

@@ -0,0 +1,52 @@
+package com.subtracks.ui.library
+
+import com.subtracks.data.model.ArtistRef
+import com.subtracks.data.model.Song
+import com.subtracks.ui.components.artistSubtitle
+import org.junit.Assert.assertEquals
+import org.junit.Assert.assertNull
+import org.junit.Test
+
+class SongArtistSubtitleTest {
+    @Test
+    fun pluralArtistsAreJoinedWithDots() {
+        assertEquals("One · Two", song(artist = null, artists = listOf(ArtistRef("1", "One"), ArtistRef("2", "Two"))).artistSubtitle())
+    }
+
+    @Test
+    fun singularArtistIsListedFirstWhenItIsAlsoPlural() {
+        assertEquals(
+            "Two · One · Three",
+            song(artist = "Two", artists = listOf(ArtistRef("1", "One"), ArtistRef("2", "Two"), ArtistRef("3", "Three")))
+                .artistSubtitle(),
+        )
+    }
+
+    @Test
+    fun singularArtistIsUsedWhenNoPluralArtistsExist() {
+        assertEquals("One", song(artist = "One", artists = emptyList()).artistSubtitle())
+    }
+
+    @Test
+    fun noArtistGivesNoSubtitle() {
+        assertNull(song(artist = null, artists = emptyList()).artistSubtitle())
+    }
+
+    private fun song(
+        artist: String?,
+        artists: List<ArtistRef>,
+    ) = Song(
+        sourceId = 1,
+        id = "s1",
+        albumId = "al1",
+        artistId = "ar1",
+        title = "Song",
+        album = "Album",
+        artist = artist,
+        duration = 100,
+        track = 1,
+        disc = 1,
+        starred = null,
+        artists = artists,
+    )
+}