fix: recover missed messages on mobile app resume

Valour/Client.Maui/Platforms/Android/MainActivity.cs

@@ -43,6 +43,12 @@ protected override void OnResume()
         AppLifecycle.NotifyResumed();
     }
 
+    protected override void OnPause()
+    {
+        base.OnPause();
+        AppLifecycle.NotifyBackground();
+    }
+
     protected override void OnActivityResult(int requestCode, Result resultCode, Intent? data)
     {
         if (requestCode == AudioPermissionChromeClient.FileChooserRequestCode)

Valour/Client.Maui/Platforms/MacCatalyst/AppDelegate.cs

@@ -1,9 +1,22 @@
-using Foundation;
+using Foundation;
+using UIKit;
 
 namespace Valour.Client.Maui;
 
 [Register("AppDelegate")]
 public class AppDelegate : MauiUIApplicationDelegate
 {
     protected override MauiApp CreateMauiApp() => MauiProgram.CreateMauiApp();
+
+    public override void DidEnterBackground(UIApplication application)
+    {
+        base.DidEnterBackground(application);
+        AppLifecycle.NotifyBackground();
+    }
+
+    public override void OnActivated(UIApplication application)
+    {
+        base.OnActivated(application);
+        AppLifecycle.NotifyResumed();
+    }
 }

Valour/Client.Maui/Platforms/iOS/AppDelegate.cs

@@ -1,9 +1,22 @@
-using Foundation;
+using Foundation;
+using UIKit;
 
 namespace Valour.Client.Maui;
 
 [Register("AppDelegate")]
 public class AppDelegate : MauiUIApplicationDelegate
 {
     protected override MauiApp CreateMauiApp() => MauiProgram.CreateMauiApp();
+
+    public override void DidEnterBackground(UIApplication application)
+    {
+        base.DidEnterBackground(application);
+        AppLifecycle.NotifyBackground();
+    }
+
+    public override void OnActivated(UIApplication application)
+    {
+        base.OnActivated(application);
+        AppLifecycle.NotifyResumed();
+    }
 }

Valour/Client/AppLifecycle.cs

@@ -1,25 +1,27 @@
-namespace Valour.Client;
-
-/// <summary>
-/// Static event bridge for native app lifecycle events (e.g. Android OnResume)
-/// that need to reach Blazor components.
-/// </summary>
-public static class AppLifecycle
-{
-    public static event Action? Resumed;
-
-    /// <summary>
-    /// Fired when a voice call begins. Platform projects can subscribe to start
-    /// keep-alive mechanisms (e.g. Android foreground service).
-    /// </summary>
-    public static event Action? CallStarted;
-
-    /// <summary>
-    /// Fired when a voice call ends.
-    /// </summary>
-    public static event Action? CallEnded;
-
-    public static void NotifyResumed() => Resumed?.Invoke();
-    public static void NotifyCallStarted() => CallStarted?.Invoke();
-    public static void NotifyCallEnded() => CallEnded?.Invoke();
-}
+namespace Valour.Client;
+
+/// <summary>
+/// Static event bridge for native app lifecycle events (e.g. Android OnResume)
+/// that need to reach Blazor components.
+/// </summary>
+public static class AppLifecycle
+{
+    public static event Action? Resumed;
+    public static event Action? Backgrounded;
+
+    /// <summary>
+    /// Fired when a voice call begins. Platform projects can subscribe to start
+    /// keep-alive mechanisms (e.g. Android foreground service).
+    /// </summary>
+    public static event Action? CallStarted;
+
+    /// <summary>
+    /// Fired when a voice call ends.
+    /// </summary>
+    public static event Action? CallEnded;
+
+    public static void NotifyResumed() => Resumed?.Invoke();
+    public static void NotifyBackground() => Backgrounded?.Invoke();
+    public static void NotifyCallStarted() => CallStarted?.Invoke();
+    public static void NotifyCallEnded() => CallEnded?.Invoke();
+}

Valour/Client/Components/Windows/ChannelWindows/ChatWindowComponent.razor

@@ -1,4 +1,4 @@
-@inherits WindowContentComponent<Channel>
+@inherits WindowContentComponent<Channel>
 @implements IAsyncDisposable
 @inject IJSRuntime JsRuntime
 @inject ValourClient Client
@@ -1258,6 +1258,27 @@
     {
         await InvokeAsync(async () =>
         {
+            // Wait for the relevant node to finish reconnecting before we attempt recovery.
+            // On mobile resume, CheckConnections() is fired by BrowserUtils.OnRefocus but
+            // the SignalR reconnection is async. If we recover too early, we'll fetch stale
+            // data and miss messages that arrived during the reconnection gap.
+            var node = Channel?.PlanetId is not null
+                ? Channel.Planet?.Node
+                : Client.PrimaryNode;
+
+            if (node?.IsReconnecting == true)
+            {
+                // Give the reconnect up to 5 seconds before proceeding anyway.
+                for (var i = 0; i < 50 && node.IsReconnecting; i++)
+                    await Task.Delay(100);
+
+                if (node.IsReconnecting)
+                {
+                    Client.Logger.Log<ChatWindowComponent>(
+                        "Node still reconnecting after focus; attempting message recovery anyway.", "yellow");
+                }
+            }
+
             if (Channel?.PlanetId is not null && Channel.ChannelType == ChannelTypeEnum.PlanetChat)
             {
                 try