ios: advance playback progress from server syncs

ios/QueueCube/Views/ContentView.swift

@@ -17,7 +17,6 @@ struct ContentView: View
         MainView(model: $model)
             .task(id: websocketRestartTrigger) { await watchWebsocket() }
             .task { await refresh([.nowPlaying, .playlist, .favorites]) }
-            .task { await pollPlaybackProgress() }
             .task { await watchForSettingsChanges() }
             .onChange(of: scenePhase) { oldPhase, newPhase in
                 handleScenePhaseChange(from: oldPhase, to: newPhase)
@@ -74,11 +73,13 @@ extension ContentView
                 model.nowPlayingViewModel.title = nowPlaying.playingItem?.title
                 model.nowPlayingViewModel.subtitle = nowPlaying.playingItem?.filename
                 
-                model.nowPlayingViewModel.isPlaying = !nowPlaying.isPaused
                 model.nowPlayingViewModel.volume = Double(nowPlaying.volume) / 100.0
-                model.nowPlayingViewModel.timePosition = nowPlaying.timePosition
+                model.nowPlayingViewModel.syncPlaybackPosition(
-                model.nowPlayingViewModel.duration = nowPlaying.duration
+                    nowPlaying.timePosition,
-                model.nowPlayingViewModel.isSeekable = nowPlaying.seekable ?? false
+                    duration: nowPlaying.duration,
+                    isPlaying: !nowPlaying.isPaused,
+                    isSeekable: nowPlaying.seekable ?? false
+                )
                 model.playlistModel.isPlaying = !nowPlaying.isPaused
                 model.favoritesModel.isPlaying = !nowPlaying.isPaused
             }
@@ -113,17 +114,6 @@ extension ContentView
         }
     }
 
-    private func pollPlaybackProgress() async {
-        while !Task.isCancelled {
-            try? await Task.sleep(for: .seconds(1.0))
-            guard !Task.isCancelled else { return }
-
-            if scenePhase == .active && model.nowPlayingViewModel.isPlaying {
-                await refresh(.nowPlaying)
-            }
-        }
-    }
-    
     private func watchWebsocket() async {
         guard let api = model.selectedServer?.api else { return }
 

ios/QueueCube/Views/NowPlayingMiniView.swift

@@ -61,12 +61,14 @@ struct NowPlayingMiniView: View {
             }
             .padding(EdgeInsets(top: 4.0, leading: 14.0, bottom: 4.0, trailing: 10.0))
 
-            if let progress = model.playbackProgress {
+            if model.playbackDuration != nil {
-                ProgressView(value: progress)
+                TimelineView(.periodic(from: .now, by: 1.0)) { context in
+                    ProgressView(value: model.playbackProgress(at: context.date) ?? 0.0)
                         .progressViewStyle(.linear)
                         .tint(.accentColor)
                 }
             }
+        }
         .background(
             containerShape
                 .fill(tapGestureState ? .ultraThinMaterial : .bar)

ios/QueueCube/Views/NowPlayingView.swift

@@ -33,6 +33,7 @@ class NowPlayingViewModel
 
     fileprivate var isSettingPlaybackPosition: Bool = false
     fileprivate var settingPlaybackPosition: Double = 0.0
+    private var playbackPositionSyncedAt = Date.now
 
     var playbackDuration: Double? {
         guard let duration, duration.isFinite, duration > 0 else { return nil }
@@ -40,14 +41,35 @@ class NowPlayingViewModel
     }
 
     var displayedPlaybackPosition: Double {
-        let position = isSettingPlaybackPosition ? settingPlaybackPosition : (timePosition ?? 0.0)
+        displayedPlaybackPosition(at: .now)
+    }
+
+    func displayedPlaybackPosition(at date: Date) -> Double {
+        var position = isSettingPlaybackPosition ? settingPlaybackPosition : (timePosition ?? 0.0)
+        if isPlaying && !isSettingPlaybackPosition {
+            position += max(date.timeIntervalSince(playbackPositionSyncedAt), 0.0)
+        }
+
         guard position.isFinite else { return 0.0 }
         return min(max(position, 0.0), playbackDuration ?? position)
     }
 
-    var playbackProgress: Double? {
+    func playbackProgress(at date: Date) -> Double? {
         guard let playbackDuration else { return nil }
-        return displayedPlaybackPosition / playbackDuration
+        return displayedPlaybackPosition(at: date) / playbackDuration
+    }
+
+    func syncPlaybackPosition(_ position: Double?, duration: Double?, isPlaying: Bool, isSeekable: Bool) {
+        timePosition = position
+        self.duration = duration
+        self.isPlaying = isPlaying
+        self.isSeekable = isSeekable
+        playbackPositionSyncedAt = .now
+    }
+
+    fileprivate func seekOptimistically(to position: Double) {
+        timePosition = position
+        playbackPositionSyncedAt = .now
     }
 }
 
@@ -87,22 +109,24 @@ struct NowPlayingView: View
                 Spacer(minLength: 20.0)
 
                 if let duration = model.playbackDuration {
+                    TimelineView(.periodic(from: .now, by: 1.0)) { context in
                         VStack(spacing: 2.0) {
                             Slider(
-                            value: playbackPositionBinding,
+                                value: playbackPositionBinding(at: context.date),
                                 in: 0.0...duration,
                                 onEditingChanged: playbackPositionEditingChanged
                             )
                             .disabled(!model.isSeekable || nothingQueued)
 
                             HStack {
-                            Text(formatTime(model.displayedPlaybackPosition))
+                                Text(formatTime(model.displayedPlaybackPosition(at: context.date)))
                                 Spacer()
                                 Text(formatTime(duration))
                             }
                             .font(.caption.monospacedDigit())
                             .foregroundStyle(.secondary)
                         }
+                    }
                     .padding(.horizontal, 4.0)
 
                     Spacer(minLength: 20.0)
@@ -170,9 +194,9 @@ struct NowPlayingView: View
         }
     }
 
-    private var playbackPositionBinding: Binding<Double> {
+    private func playbackPositionBinding(at date: Date) -> Binding<Double> {
         Binding(
-            get: { model.displayedPlaybackPosition },
+            get: { model.displayedPlaybackPosition(at: date) },
             set: { model.settingPlaybackPosition = $0 }
         )
     }
@@ -183,7 +207,7 @@ struct NowPlayingView: View
             model.isSettingPlaybackPosition = true
         } else if model.isSettingPlaybackPosition {
             let position = model.settingPlaybackPosition
-            model.timePosition = position
+            model.seekOptimistically(to: position)
             model.isSettingPlaybackPosition = false
             model.onSeek(model, position)
         }