Improvements to Now Playing page, including artist backdrops (#1782)

## Description
This PR has updates the Now Playing page.

Now only the song's backdrops and the song's artists' backdrops will
show. First, if the song has any backdrops (probably pretty uncommon),
they will be shuffled and shown, then if the song's artists have
backdrop, those are shuffled and shown. The backdrop changes every 2
minutes unless there's <15s left in the song to prevent rapid changes.
Note: album backdrops and album artists not directly linked to the
specific song are not included.

If a song has a lyrics and the user is scrolling through them, if the
user doesn't scroll for 5 seconds, the focus leaves the lyrics and they
scroll to the current line if available.

Dev note: Both backdrop & lyric updates are refactored to use `Flow`s to
trigger lookups

### Related issues
Fixes #1170

### Testing
Emulator, I need to test it longer term

## Screenshots
N/A

## AI or LLM usage
None

app/src/main/java/com/github/damontecres/wholphin/ui/detail/music/LyricsContent.kt

@@ -121,7 +121,10 @@ fun LyricsContent(
                             ),
                         modifier =
                             Modifier
-                                .focusRequester(focusRequesters[index]),
+                                .focusRequester(focusRequesters[index])
+                                .onFocusChanged {
+                                    if (it.isFocused) onFocusLyrics.invoke(true)
+                                },
                     ) {
                         val text =
                             remember(lyric.text) { lyric.text.ifBlank { "                " } }

app/src/main/java/com/github/damontecres/wholphin/ui/detail/music/NowPlayingPage.kt

@@ -74,7 +74,9 @@ import com.github.damontecres.wholphin.ui.playback.overlay.BottomDialog
 import com.github.damontecres.wholphin.ui.playback.overlay.BottomDialogItem
 import com.github.damontecres.wholphin.ui.tryRequestFocus
 import com.github.damontecres.wholphin.util.LoadingState
+import kotlinx.coroutines.delay
 import org.jellyfin.sdk.model.extensions.ticks
+import java.util.Date
 import kotlin.time.Duration.Companion.seconds
 
 @OptIn(UnstableApi::class)
@@ -140,19 +142,22 @@ fun NowPlayingPage(
     var showViewOptionsDialog by remember { mutableStateOf(false) }
     var showContextMenu by remember { mutableStateOf<ContextMenu.ForQueue?>(null) }
 
-    var lyricsHaveFocus by remember { mutableStateOf(false) }
+    var lyricsFocused by remember { mutableStateOf<Date?>(null) }
 
     val focusRequester = remember { FocusRequester() }
     LaunchedEffect(Unit) { focusRequester.tryRequestFocus() }
     val lyricsFocusRequester = remember { FocusRequester() }
     val hasLyrics = musicPrefs.showLyrics && state.hasLyrics
 
-    LaunchedEffect(lyricsHaveFocus) {
-        if (lyricsHaveFocus) {
+    LaunchedEffect(lyricsFocused) {
+        if (lyricsFocused != null) {
             controllerViewState.hideControls()
         }
+        delay(5.seconds)
+        lyricsFocused = null
+        focusRequester.tryRequestFocus()
     }
-    BackHandler(lyricsHaveFocus) {
+    BackHandler(lyricsFocused != null) {
         focusRequester.tryRequestFocus()
     }
 
@@ -290,8 +295,10 @@ fun NowPlayingPage(
                     LyricsContent(
                         lyrics = state.lyrics,
                         currentLyricPosition = state.currentLyricIndex,
-                        lyricsHaveFocus = lyricsHaveFocus,
-                        onFocusLyrics = { lyricsHaveFocus = it },
+                        lyricsHaveFocus = lyricsFocused != null,
+                        onFocusLyrics = {
+                            lyricsFocused = Date()
+                        },
                         onClick = {
                             it.start
                                 ?.ticks

app/src/main/java/com/github/damontecres/wholphin/ui/detail/music/NowPlayingState.kt

@@ -1,6 +1,7 @@
 package com.github.damontecres.wholphin.ui.detail.music
 
 import androidx.compose.runtime.Stable
+import com.github.damontecres.wholphin.data.model.AudioItem
 import com.github.damontecres.wholphin.services.BackdropResult
 import com.github.damontecres.wholphin.services.MusicServiceState
 import org.jellyfin.sdk.model.api.LyricDto
@@ -8,6 +9,7 @@ import org.jellyfin.sdk.model.api.LyricDto
 @Stable
 data class NowPlayingState(
     val musicServiceState: MusicServiceState,
+    val currentMediaItem: AudioItem? = null,
     val lyrics: LyricDto? = null,
     val currentLyricIndex: Int? = null,
     val visualizerPermissions: Boolean = false,

app/src/main/java/com/github/damontecres/wholphin/ui/detail/music/NowPlayingViewModel.kt

@@ -12,7 +12,6 @@ import androidx.media3.common.MediaItem
 import androidx.media3.common.Player
 import androidx.media3.common.util.UnstableApi
 import com.github.damontecres.wholphin.data.model.AudioItem
-import com.github.damontecres.wholphin.data.model.BaseItem
 import com.github.damontecres.wholphin.preferences.AppPreference
 import com.github.damontecres.wholphin.preferences.AppPreferences
 import com.github.damontecres.wholphin.preferences.updateMusicPreferences
@@ -23,40 +22,43 @@ import com.github.damontecres.wholphin.services.MusicService
 import com.github.damontecres.wholphin.services.NavigationManager
 import com.github.damontecres.wholphin.services.NowPlayingStatus
 import com.github.damontecres.wholphin.services.UserPreferencesService
+import com.github.damontecres.wholphin.ui.combinePair
 import com.github.damontecres.wholphin.ui.launchDefault
 import com.github.damontecres.wholphin.ui.main.settings.MoveDirection
 import com.github.damontecres.wholphin.ui.onMain
 import com.github.damontecres.wholphin.ui.playback.ControllerViewState
+import com.github.damontecres.wholphin.util.GetItemsRequestHandler
 import com.github.damontecres.wholphin.util.WholphinDispatchers
 import com.mayakapps.kache.InMemoryKache
 import dagger.assisted.AssistedFactory
 import dagger.assisted.AssistedInject
 import dagger.hilt.android.lifecycle.HiltViewModel
 import dagger.hilt.android.qualifiers.ApplicationContext
+import kotlinx.coroutines.CancellationException
 import kotlinx.coroutines.CoroutineScope
-import kotlinx.coroutines.Job
 import kotlinx.coroutines.delay
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.collectLatest
+import kotlinx.coroutines.flow.distinctUntilChanged
 import kotlinx.coroutines.flow.first
+import kotlinx.coroutines.flow.map
 import kotlinx.coroutines.flow.update
 import kotlinx.coroutines.isActive
 import kotlinx.coroutines.sync.Mutex
 import kotlinx.coroutines.sync.withLock
 import org.jellyfin.sdk.api.client.ApiClient
-import org.jellyfin.sdk.api.client.extensions.itemsApi
 import org.jellyfin.sdk.api.client.extensions.lyricsApi
 import org.jellyfin.sdk.api.client.extensions.userLibraryApi
-import org.jellyfin.sdk.model.api.BaseItemKind
+import org.jellyfin.sdk.model.api.BaseItemDto
 import org.jellyfin.sdk.model.api.ImageType
-import org.jellyfin.sdk.model.api.ItemSortBy
 import org.jellyfin.sdk.model.api.LyricDto
+import org.jellyfin.sdk.model.api.request.GetItemsRequest
 import org.jellyfin.sdk.model.extensions.ticks
 import timber.log.Timber
 import java.util.UUID
 import kotlin.time.Duration
 import kotlin.time.Duration.Companion.milliseconds
-import kotlin.time.Duration.Companion.seconds
+import kotlin.time.Duration.Companion.minutes
 
 @UnstableApi
 @HiltViewModel(assistedFactory = NowPlayingViewModel.Factory::class)
@@ -99,6 +101,9 @@ class NowPlayingViewModel
             }
 
         init {
+            state.update {
+                it.copy(currentMediaItem = player.currentMediaItem?.localConfiguration?.tag as? AudioItem)
+            }
             player.addListener(this)
             addCloseable {
                 player.removeListener(this)
@@ -126,62 +131,39 @@ class NowPlayingViewModel
                     }.join()
                 controllerViewState.pulseControls()
             }
-            viewModelScope.launchDefault {
-                backdropService.clearBackdrop()
-                updateBackdrop(getCurrent())
-            }
-            playbackLoop()
+            viewModelScope.launchDefault { backdropService.clearBackdrop() }
+            listenForBackdrop()
+            listenForLyrics()
         }
 
         fun reportInteraction() {
             controllerViewState.pulseControls()
         }
 
-        private suspend fun getCurrent(): AudioItem? {
-            val mediaItem =
-                onMain {
-                    player.currentMediaItemIndex
-                        .takeIf { it in 0..<player.mediaItemCount }
-                        ?.let { player.getMediaItemAt(it) }
-                }
-            return mediaItem?.localConfiguration?.tag as? AudioItem
-        }
-
-        private fun playbackLoop() {
+        private fun listenForLyrics() {
             viewModelScope.launchDefault {
-                while (isActive) {
-                    val position = onMain { player.currentPosition }.milliseconds
-//                    Timber.v("playbackLoop: %s", position)
-                    getCurrent()?.let { audio ->
-//                        Timber.v("Got current %s", audio.id)
-                        if (audio.hasLyrics) {
-                            val lyrics =
-                                lyricCache.getOrPut(audio.id) {
-                                    // TODO remote lyrics?
-                                    api.lyricsApi.getLyrics(audio.id).content
-                                }
+                state.map { it.currentMediaItem }.distinctUntilChanged().collectLatest { audio ->
+                    if (audio != null && audio.hasLyrics) {
+                        val lyrics = fetchAndUpdateLyrics(audio)
+                        Timber.d("Got lyrics for %s: %s", audio.id, lyrics != null)
+                        while (lyrics != null && isActive) {
+                            val position = onMain { player.currentPosition }.milliseconds
+                            val offset = lyrics.metadata.offset?.ticks ?: Duration.ZERO
+                            val lyricPosition = offset + position
                             val lyricIndex =
-                                if (lyrics != null) {
-                                    val offset = lyrics.metadata.offset?.ticks ?: Duration.ZERO
-                                    val lyricPosition = offset + position
-                                    lyrics.lyrics
-                                        .indexOfLast {
-                                            it.start?.ticks?.let { lyricPosition >= it } == true
-                                        }.takeIf { it >= 0 }
-                                } else {
-                                    null
-                                }
-//                            Timber.v("lyricIndex=$lyricIndex")
+                                lyrics.lyrics
+                                    .indexOfLast {
+                                        it.start?.ticks?.let { lyricPosition >= it } == true
+                                    }.takeIf { it >= 0 }
                             state.update {
                                 it.copy(
                                     lyrics = lyrics,
                                     currentLyricIndex = lyricIndex,
                                 )
                             }
+                            delay(150.milliseconds)
                         }
                     }
-
-                    delay(150)
                 }
             }
         }
@@ -192,100 +174,114 @@ class NowPlayingViewModel
         ) {
             val audio = mediaItem?.localConfiguration?.tag as? AudioItem
             Timber.v("onMediaItemTransition to %s", audio?.id)
-            updateBackdrop(audio)
-            viewModelScope.launchDefault {
-                state.update {
-                    it.copy(
-                        lyrics = null,
-                        currentLyricIndex = null,
-                    )
-                }
-                audio?.let { audio ->
-                    if (audio.hasLyrics) {
-                        val lyrics =
-                            lyricCache.getOrPut(audio.id) {
-                                // TODO remote lyrics?
-                                api.lyricsApi.getLyrics(audio.id).content
-                            }
-                        Timber.d("Got lyrics for %s: %s", audio.id, lyrics != null)
-                        state.update {
-                            it.copy(
-                                lyrics = lyrics,
-                            )
-                        }
-                    }
-                }
+            state.update {
+                it.copy(
+                    currentMediaItem = audio,
+                    lyrics = null,
+                    currentLyricIndex = null,
+                )
             }
         }
 
-        private var backDropJob: Job? = null
-
-        private fun updateBackdrop(audio: AudioItem?) {
-            backDropJob?.cancel()
-            backDropJob =
-                viewModelScope.launchDefault {
-                    val showBackdrop =
-                        userPreferencesService
-                            .getCurrent()
-                            .appPreferences.musicPreferences.showBackdrop
-                    if (showBackdrop) {
-                        var backdropItem: BaseItem? = null
+        private suspend fun fetchAndUpdateLyrics(audio: AudioItem?): LyricDto? =
+            audio?.let { audio ->
+                if (audio.hasLyrics) {
+                    lyricCache.getOrPut(audio.id) {
+                        // TODO remote lyrics?
                         try {
-                            if (audio?.artistId != null) {
-                                api.userLibraryApi.getItem(audio.artistId).content.let {
-                                    if (it.backdropImageTags?.isNotEmpty() == true) {
-                                        backdropItem = BaseItem(it, false)
-                                    }
-                                }
-                            }
-                            if (backdropItem == null && audio?.albumId != null) {
-                                api.userLibraryApi.getItem(audio.albumId).content.let {
-                                    backdropItem =
-                                        getBackdropItemForAlbum(api, BaseItem(it, false))
-                                }
-                            }
-                            if (backdropItem != null) {
-                                doUpdateBackdrop(backdropItem)
-                            } else {
-                                doUpdateBackdropRandom()
-                            }
+                            api.lyricsApi.getLyrics(audio.id).content
+                        } catch (ex: CancellationException) {
+                            throw ex
                         } catch (ex: Exception) {
-                            Timber.e(ex, "Error fetching backdrop")
-                            doUpdateBackdropRandom()
+                            Timber.e(ex, "Error fetching lyrics for %s", audio.id)
+                            null
                         }
-                        delay(60.seconds)
-                        doUpdateBackdropRandom()
                     }
+                } else {
+                    null
                 }
-        }
+            }
 
-        private suspend fun doUpdateBackdropRandom() {
-            val randomArtist =
-                api.itemsApi
-                    .getItems(
-                        recursive = true,
-                        imageTypes = listOf(ImageType.BACKDROP),
-                        includeItemTypes = listOf(BaseItemKind.MUSIC_ARTIST),
-                        sortBy = listOf(ItemSortBy.RANDOM),
-                        limit = 1,
-                    ).content.items
-                    .firstOrNull()
-            if (randomArtist != null) {
-                doUpdateBackdrop(BaseItem(randomArtist))
-            } else {
-                clearBackdrop()
+        private fun listenForBackdrop() {
+            viewModelScope.launchDefault {
+                userPreferencesService.flow
+                    .map { it.appPreferences.musicPreferences.showBackdrop }
+                    .combinePair(state.map { it.currentMediaItem })
+                    .distinctUntilChanged()
+                    .collectLatest { (showBackdrop, audio) ->
+                        if (showBackdrop && audio != null) {
+                            try {
+                                val song =
+                                    api.userLibraryApi
+                                        .getItem(audio.id)
+                                        .content
+                                val songBackdrops = song.backdropImageUrls()
+
+                                val artistIds = song.artistItems.orEmpty().map { it.id }
+                                val artists =
+                                    GetItemsRequestHandler
+                                        .execute(
+                                            api,
+                                            GetItemsRequest(
+                                                ids = artistIds,
+                                                imageTypes = listOf(ImageType.BACKDROP),
+                                                limit = 50,
+                                                enableImages = true,
+                                                enableImageTypes = listOf(ImageType.BACKDROP),
+                                            ),
+                                        ).content.items
+                                val artistBackdrops =
+                                    artists.flatMap { artist -> artist.backdropImageUrls() }
+
+                                val list = songBackdrops.shuffled() + artistBackdrops.shuffled()
+                                Timber.v("Got %s backdrops for %s", list.size, song.id)
+                                if (list.isNotEmpty()) {
+                                    val urls = generateSequence { list }.flatten()
+                                    urls.forEach {
+                                        val (position, duration) = onMain { player.currentPosition to player.duration }
+                                        if (duration - position >= 15_000 || state.value.backdropResult == BackdropResult.NONE) {
+                                            // Only change if there's backdrop currently, or at 15 seconds left to prevent quick changes
+                                            doUpdateBackdrop(audio.id, it)
+                                            delay(2.minutes)
+                                        }
+                                    }
+                                } else {
+                                    clearBackdrop()
+                                }
+                            } catch (ex: CancellationException) {
+                                throw ex
+                            } catch (ex: Exception) {
+                                Timber.e(ex, "Error fetching backdrops for %s", audio.id)
+                                clearBackdrop()
+                            }
+                        } else {
+                            clearBackdrop()
+                        }
+                    }
             }
         }
 
-        private suspend fun doUpdateBackdrop(item: BaseItem) {
-            val imageUrl = imageUrlService.getItemImageUrl(item, ImageType.BACKDROP)
+        private fun BaseItemDto.backdropImageUrls() =
+            backdropImageTags?.sorted().orEmpty().mapIndexedNotNull { index, tag ->
+                imageUrlService.getItemImageUrl(
+                    itemId = id,
+                    imageType = ImageType.BACKDROP,
+                    tag = tag,
+                    imageIndex = index,
+                )
+            }
+
+        private suspend fun doUpdateBackdrop(
+            itemId: UUID,
+            imageUrl: String,
+        ) {
             val (primaryColor, secondaryColor, tertiaryColor) =
                 backdropService.extractColorsFromBackdrop(
                     imageUrl,
                 )
             val backdropResult =
                 BackdropResult(
-                    itemId = item.id.toString(),
+                    itemId = itemId.toString(),
                     imageUrl = imageUrl,
                     primaryColor = primaryColor,
                     secondaryColor = secondaryColor,
@@ -343,19 +339,9 @@ class NowPlayingViewModel
 
         fun updatePreferences(prefs: AppPreferences) {
             viewModelScope.launchDefault {
-                var backdropChanged = false
                 preferencesDataStore.updateData {
-                    backdropChanged =
-                        it.musicPreferences.showBackdrop != prefs.musicPreferences.showBackdrop
                     prefs
                 }
-                if (backdropChanged) {
-                    if (prefs.musicPreferences.showBackdrop) {
-                        updateBackdrop(getCurrent())
-                    } else {
-                        clearBackdrop()
-                    }
-                }
             }
         }