Improve suspend/resume on Windows

not sure if that actually fixes it fully since debugging app lifecycle doesn't work at all

Sources/Stylophone.Common/Services/AlbumArtService.cs

@@ -40,7 +40,6 @@ public void Initialize()
         {
             _queueCanceller?.Cancel();
             _queueCanceller = new CancellationTokenSource();
-
             var token = _queueCanceller.Token;
 
             _albumArtQueue = new Stack<AlbumViewModel>();
@@ -81,6 +80,11 @@ public void Initialize()
             }).ConfigureAwait(false);
         }
 
+        public void Stop()
+        {
+            _queueCanceller?.Cancel();
+        }
+
         /// <summary>
         /// Check if this file's album art is already stored in the internal Album Art cache.
         /// </summary>

Sources/Stylophone.Common/Services/MPDConnectionService.cs

@@ -77,13 +77,7 @@ public async Task InitializeAsync(bool withRetry = false)
             IsConnecting = true;
             CurrentStatus = BOGUS_STATUS; // Reset status
 
-            if (IsConnected)
-            {
-                IsConnected = false;
-                ConnectionChanged?.Invoke(this, new EventArgs());
-            }
-
-            ClearResources();
+            Disconnect();
 
             var cancelToken = _cancelConnect.Token;
 
@@ -106,23 +100,31 @@ public async Task InitializeAsync(bool withRetry = false)
                     _connectionRetryAttempter.Start();
                 }
             }
-
+            
             IsConnecting = false;
         }
 
-        private void ClearResources()
+        public void Disconnect()
         {
-            _idleConnection?.SendAsync(new NoIdleCommand());
-            _idleConnection?.DisconnectAsync();
-            _statusConnection?.DisconnectAsync();
+
+            if (IsConnected)
+            {
+                System.Diagnostics.Debug.WriteLine($"Terminating MPD connections");
+                IsConnected = false;
+                ConnectionChanged?.Invoke(this, new EventArgs());
+            }
+
+            // Stop the idle connection first
+            _cancelIdle?.Cancel();
 
             _connectionRetryAttempter?.Stop();
             _connectionRetryAttempter?.Dispose();
 
+            // Stop the status timer before killing the matching connection
             _statusUpdater?.Stop();
             _statusUpdater?.Dispose();
+            _statusConnection?.DisconnectAsync();
 
-            _cancelIdle?.Cancel();
             _cancelIdle = new CancellationTokenSource();
 
             _cancelConnect?.Cancel();
@@ -270,15 +272,25 @@ private void InitializeStatusUpdater(CancellationToken token = default)
 
                     try
                     {
+                        // Run the idleConnection in a wrapper task since MpcNET isn't fully async and will block here
+                        var idleChangesTask = Task.Run(async () => await _idleConnection.SendAsync(new IdleCommand("stored_playlist playlist player mixer output options update")));
+
+                        // Wait for the idle command to finish or for the token to be cancelled
+                        await Task.WhenAny(idleChangesTask, Task.Delay(-1, token));
+
                         if (token.IsCancellationRequested || _idleConnection == null || !_idleConnection.IsConnected)
+                        {
+                            //_idleConnection?.SendAsync(new NoIdleCommand());
+                            _idleConnection?.DisconnectAsync();
                             break;
+                        }
+                        
+                        var message = idleChangesTask.Result;
 
-                        var idleChanges = await _idleConnection.SendAsync(new IdleCommand("stored_playlist playlist player mixer output options update"));
-
-                        if (idleChanges.IsResponseValid)
-                            await HandleIdleResponseAsync(idleChanges.Response.Content);
+                        if (message.IsResponseValid)
+                            await HandleIdleResponseAsync(message.Response.Content);
                         else
-                            throw new Exception(idleChanges.Response?.Content);
+                            throw new Exception(message.Response?.Content);
                     }
                     catch (Exception e)
                     {

Sources/Stylophone.Common/ViewModels/Bases/PlaybackViewModelBase.cs

@@ -61,10 +61,9 @@ public PlaybackViewModelBase(INavigationService navigationService, INotification
 
             _internalVolume = _mpdService.CurrentStatus.Volume;
 
-            // Bind timer methods and start it
+            // Bind timer methods 
             _updateInformationTimer = new System.Timers.Timer(500);
             _updateInformationTimer.Elapsed += UpdateInformation;
-            _updateInformationTimer.Start();
 
             // Update info to current track
             _mpdService.ConnectionChanged += OnConnectionChanged;
@@ -82,6 +81,7 @@ private void OnConnectionChanged(object sender, EventArgs e)
             else
             {
                 IsTrackInfoAvailable = false;
+                _updateInformationTimer?.Stop();
             }
         }
 
@@ -90,6 +90,7 @@ private void Initialize()
             OnTrackChange(this, new SongChangedEventArgs { NewSongId = -1 });
             CurrentTimeValue = _mpdService.CurrentStatus.Elapsed.TotalSeconds;
 
+            _updateInformationTimer.Start();
             OnStateChange(this, null);
         }
 

Sources/Stylophone/App.xaml.cs

@@ -16,6 +16,7 @@
 using Microsoft.Toolkit.Uwp.Helpers;
 using Windows.Foundation;
 using Microsoft.Services.Store.Engagement;
+using Windows.ApplicationModel;
 #if DEBUG
 #else
 using System.Collections.Generic;
@@ -40,6 +41,8 @@ public App()
 
             InitializeComponent();
             UnhandledException += OnAppUnhandledException;
+            Suspending += OnAppSuspending;
+            Resuming += OnAppResuming;
 
             // Deferred execution until used. Check https://msdn.microsoft.com/library/dd642331(v=vs.110).aspx for further info on Lazy<T> class.
             _activationService = new Lazy<ActivationService>(CreateActivationService);
@@ -119,6 +122,18 @@ private void OnAppUnhandledException(object sender, Windows.UI.Xaml.UnhandledExc
             e.Handled = true;
         }
 
+        private async void OnAppResuming(object sender, object e)
+        {
+            await Ioc.Default.GetRequiredService<MPDConnectionService>().InitializeAsync(true);
+            Ioc.Default.GetRequiredService<AlbumArtService>().Initialize();
+        }
+
+        private void OnAppSuspending(object sender, SuspendingEventArgs e)
+        {
+            Ioc.Default.GetRequiredService<MPDConnectionService>().Disconnect();
+            Ioc.Default.GetRequiredService<AlbumArtService>().Stop();
+        }
+
         private ActivationService CreateActivationService()
         {
             return new ActivationService(this, typeof(QueueViewModel), new Lazy<UIElement>(CreateShell));