feat(sidebar): highlight currently-playing playlist

Sources/Kaset/Services/Player/PlayerService+PlaybackBoundaries.swift

@@ -91,6 +91,7 @@ extension PlayerService {
         if !preservesQueueContext {
             self.cancelDeferredQueueWork()
         }
+        self.sourcePlaylistId = nil
         self.logger.debug("Stopping playback")
         self.isStoppingPlayback = true
         self.shouldResumeAfterInterruption = false

Sources/Kaset/Services/Player/PlayerService+PlaybackControls.swift

@@ -90,6 +90,7 @@ extension PlayerService {
     func play(videoId: String, intent: MusicPlaybackIntent) async {
         guard self.acceptsMusicPlaybackIntent(intent) else { return }
         self.logger.debug("play() called with videoId: \(videoId)")
+        self.sourcePlaylistId = nil
         let acceptsPlaybackRequest = SingletonPlayerWebView.shared.acceptsPlaybackRequest(
             videoId: videoId,
             strategy: .standard
@@ -164,6 +165,7 @@ extension PlayerService {
     /// Plays a song.
     func play(song: Song) async {
         let intent = self.beginMusicPlaybackIntent()
+        self.sourcePlaylistId = nil
         await self.play(
             song: song,
             webLoadStrategy: .standard,
@@ -182,6 +184,7 @@ extension PlayerService {
         episode: ArtistEpisode? = nil
     ) async {
         let intent = self.beginMusicPlaybackIntent()
+        self.sourcePlaylistId = nil
         await self.play(
             song: song,
             webLoadStrategy: webLoadStrategy,

Sources/Kaset/Services/Player/PlayerService+Queue.swift

@@ -92,6 +92,7 @@ extension PlayerService {
     func playWithRadio(song: Song, intent: MusicPlaybackIntent) async {
         guard self.acceptsMusicPlaybackIntent(intent) else { return }
         self.logger.info("Playing with radio: \(song.title)")
+        self.sourcePlaylistId = nil
         self.clearForwardSkipNavigationStack()
         self.recordQueueStateForUndo()
         self.prepareForNewPlaybackContext()
@@ -137,6 +138,7 @@ extension PlayerService {
         guard self.acceptsMusicPlaybackIntent(intent) else { return }
         self.logger.info("Playing mix playlist: \(playlistId), startVideoId: \(startVideoId ?? "nil (random)")")
         let continuationRequiresAuth = self.authService?.hasPersonalAccount == true
+        self.sourcePlaylistId = nil
         self.clearForwardSkipNavigationStack()
 
         guard let client = self.ytMusicClient else {

Sources/Kaset/Services/Player/PlayerService.swift

@@ -123,6 +123,12 @@ final class PlayerService: NSObject, PlayerServiceProtocol {
         }
     }
 
+    /// The playlist ID the current track was played from, if any.
+    /// Set when playback starts from a playlist/album and cleared when a non-playlist
+    /// source (radio, mix, standalone track, or stop) takes over. The sidebar reads
+    /// this to highlight the originating pinned playlist row.
+    var sourcePlaylistId: String?
+
     @ObservationIgnored private var durationObservation: (videoId: String, duration: TimeInterval)?
     @ObservationIgnored var isApplyingPlaybackStateObservation = false
 

Sources/Kaset/Services/Player/PlaylistPlaybackActions.swift

@@ -20,6 +20,7 @@ enum PlaylistPlaybackActions {
         playerService: PlayerService
     ) -> Task<Void, Never> {
         let intent = playerService.beginMusicPlaybackIntent()
+        playerService.sourcePlaylistId = playlist.id
         return Task { @MainActor in
             do {
                 let response = try await client.getPlaylist(id: playlist.id)

Sources/Kaset/Services/Protocols.swift

@@ -442,6 +442,9 @@ protocol PlayerServiceProtocol: AnyObject, Sendable {
     /// Currently playing track.
     var currentTrack: Song? { get }
 
+    /// The playlist ID the current track was played from, if any.
+    var sourcePlaylistId: String? { get }
+
     /// Whether playback is active.
     var isPlaying: Bool { get }
 

Sources/Kaset/Views/PlaylistDetailView.swift

@@ -530,6 +530,7 @@ struct PlaylistDetailView: View {
         fallbackArtist: String?, fallbackAlbum: Album?
     ) {
         let intent = self.playerService.beginMusicPlaybackIntent()
+        self.playerService.sourcePlaylistId = self.viewModel.playlistDetail?.id
         Task { @MainActor in
             let willDeferLoad = self.viewModel.hasMore
             let loadGeneration = await self.playerService.playQueue(

Sources/Kaset/Views/SharedViews/KasetSidebarRow.swift

@@ -14,14 +14,15 @@ struct KasetSidebarRow: View {
     let title: String
     let systemImage: String
     let isSelected: Bool
+    var isNowPlayingSource: Bool = false
     let action: () -> Void
 
     var body: some View {
         Button(action: self.action) {
             Label {
                 Text(self.title)
                     .lineLimit(1)
-                    .foregroundStyle(.primary)
+                    .foregroundStyle(self.isNowPlayingSource ? PackageResourceLookup.brandAccent : .primary)
             } icon: {
                 Image(systemName: self.systemImage)
                     .foregroundStyle(PackageResourceLookup.brandAccent)

Sources/Kaset/Views/Sidebar.swift

@@ -204,7 +204,8 @@ struct Sidebar: View {
         KasetSidebarRow(
             title: item.title,
             systemImage: item.systemImage,
-            isSelected: self.currentSidebarSelection == .pinned(item)
+            isSelected: self.currentSidebarSelection == .pinned(item),
+            isNowPlayingSource: self.playerService.sourcePlaylistId == item.contentId
         ) {
             self.selectPinnedItem(item)
         }

Tests/KasetTests/Helpers/MockPlayerService.swift

@@ -5,6 +5,7 @@ import Foundation
 final class MockPlayerService: PlayerServiceProtocol {
     var state: PlayerService.PlaybackState = .idle
     var currentTrack: Song?
+    var sourcePlaylistId: String?
     var progress: TimeInterval = 0
     var duration: TimeInterval = 0
     var volume: Double = 1