Fix concurrent overlay issue [VPNWIN-2882]

Author: Thomas Felices

src/Client/Common/ProtonVPN.Client.Common.UI/Controls/Custom/BaseWindow.cs

@@ -0,0 +1,62 @@
+/*
+ * Copyright (c) 2025 Proton AG
+ *
+ * This file is part of ProtonVPN.
+ *
+ * ProtonVPN is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * ProtonVPN is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with ProtonVPN.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+using System;
+using Microsoft.UI.Xaml;
+using WinUIEx;
+
+namespace ProtonVPN.Client.Common.UI.Controls.Custom;
+
+public class BaseWindow : WindowEx
+{
+    public bool IsLoaded { get; private set; }
+
+    public BaseWindow()
+    {
+        Activated += OnActivated;
+    }
+
+    public event EventHandler? Loaded;
+
+    protected virtual void OnActivated(object sender, WindowActivatedEventArgs e)
+    {
+        if (!IsLoaded && Content is FrameworkElement rootElement)
+        {
+            rootElement.Loaded -= OnRootLoaded;
+            rootElement.Loaded += OnRootLoaded;
+        }
+    }
+
+    protected virtual void OnLoaded()
+    { }
+
+    private void OnRootLoaded(object sender, RoutedEventArgs e)
+    {
+        IsLoaded = true;
+
+        OnLoaded();
+
+        Loaded?.Invoke(this, EventArgs.Empty);
+
+        if (sender is FrameworkElement rootElement)
+        {
+            rootElement.Loaded -= OnRootLoaded;
+        }
+    }
+}

src/Client/Common/ProtonVPN.Client.Common.UI/ProtonVPN.Client.Common.UI.csproj

@@ -896,6 +896,7 @@
 		<PackageReference Include="Vanara.PInvoke.SHCore" />
 		<PackageReference Include="Vanara.PInvoke.Shell32" />
 		<PackageReference Include="Vanara.PInvoke.User32" />
+		<PackageReference Include="WinUIEx" />
     </ItemGroup>
     <ItemGroup>
         <Page Update="Controls\Map\MapControl.xaml">

src/Client/ProtonVPN.Client.Core/Services/Activation/Bases/ActivatorBase.cs

@@ -28,6 +28,8 @@ public abstract class ActivatorBase<THost> : IActivator<THost>
 
     public THost? Host { get; private set; }
 
+    protected string HostTypeName { get; private set; } = string.Empty;
+
     protected ActivatorBase(
         ILogger logger)
     {
@@ -42,6 +44,8 @@ public void Initialize(THost host)
 
         if (Host != null)
         {
+            HostTypeName = Host.GetType().Name;
+
             RegisterToHostEvents();
 
             OnInitialized();
@@ -56,6 +60,8 @@ public void Reset()
 
             UnregisterFromHostEvents();
 
+            HostTypeName = string.Empty;
+
             Host = null;
         }
     }

src/Client/ProtonVPN.Client.Core/Services/Activation/Bases/DialogActivatorBase.cs

@@ -20,21 +20,21 @@
 using Microsoft.UI.Xaml;
 using ProtonVPN.Client.Common.Dispatching;
 using ProtonVPN.Client.Common.Messages;
+using ProtonVPN.Client.Common.UI.Controls.Custom;
 using ProtonVPN.Client.Contracts.Messages;
 using ProtonVPN.Client.Core.Extensions;
 using ProtonVPN.Client.Core.Services.Selection;
 using ProtonVPN.Client.EventMessaging.Contracts;
 using ProtonVPN.Client.Localization.Contracts;
 using ProtonVPN.Client.Settings.Contracts;
 using ProtonVPN.Logging.Contracts;
-using WinUIEx;
 
 namespace ProtonVPN.Client.Core.Services.Activation.Bases;
 
 public abstract class DialogActivatorBase<TWindow> : WindowActivatorBase<TWindow>,
     IEventMessageReceiver<MainWindowVisibilityChangedMessage>,
     IEventMessageReceiver<ApplicationStoppedMessage>
-    where TWindow : WindowEx
+    where TWindow : BaseWindow
 {
     protected readonly IMainWindowActivator MainWindowActivator;
 

src/Client/ProtonVPN.Client.Core/Services/Activation/Bases/OverlayActivatorBase.cs

@@ -33,15 +33,17 @@
 using ProtonVPN.Client.Core.Extensions;
 using ProtonVPN.Client.Core.Services.Mapping;
 using ProtonVPN.Client.Core.Services.Selection;
-using WinUIEx;
+using System.Threading;
 
 namespace ProtonVPN.Client.Core.Services.Activation.Bases;
 
 public abstract class OverlayActivatorBase<TWindow> : WindowHostActivatorBase<TWindow>, IOverlayActivator
-    where TWindow : WindowEx
+    where TWindow : BaseWindow
 {
     protected readonly IOverlayViewMapper OverlayViewMapper;
 
+    private SemaphoreSlim _overlaySemaphore = new(0, 1);
+
     private ContentDialog? _currentOverlay;
 
     public bool HasActiveOverlay => _currentOverlay != null;
@@ -110,6 +112,14 @@ protected Task<ContentDialogResult> ShowOverlayAsync<TViewModel>(object? paramet
         return ShowOverlayAsync(overlayType, parameter);
     }
 
+    protected override void OnWindowLoaded()
+    {
+        base.OnWindowLoaded();        
+        
+        // Host ready, release the semaphore to allow showing overlays
+        _overlaySemaphore.Release();
+    }
+
     protected override void RegisterToHostEvents()
     {
         base.RegisterToHostEvents();
@@ -171,7 +181,12 @@ private async Task<ContentDialogResult> ShowOverlayAsync(Type overlayType, objec
     }
 
     private async Task<ContentDialogResult> ShowOverlayAsync(ContentDialog overlay, object? parameter = null)
-    {
+    {        
+        // Close current overlayViewModel if any, then register the new one. Cannot have two overlays at the same time
+        CloseCurrentOverlay();
+
+        await _overlaySemaphore.WaitAsync();
+
         try
         {
             RegisterOverlay(overlay);
@@ -189,22 +204,22 @@ private async Task<ContentDialogResult> ShowOverlayAsync(ContentDialog overlay,
         catch (Exception e)
         {
             Logger.Error<AppLog>($"Error when trying to show message '{overlay}'", e);
-            throw;
+
+            return ContentDialogResult.None;
         }
         finally
         {
             UnregisterCurrentOverlay();
+
+            _overlaySemaphore.Release();
         }
     }
 
     private void RegisterOverlay(ContentDialog overlay)
     {
-        // Close current overlayViewModel if any, then register the new one. Cannot have two overlays at the same time
-        CloseCurrentOverlay();
-
         if (Host == null)
         {
-            throw new InvalidOperationException("Window has not been initialized.");
+            throw new InvalidOperationException("Host window has not been initialized.");
         }
 
         overlay.XamlRoot = Host.GetXamlRoot();