[Peek]Add setting to close after losing focus (#26364)

* [Peek] WindowActivationState checks are added for focus and close after losing focus.

* Add setting to activate the behavior

---------

Co-authored-by: Jaime Bernardo <jaime@janeasystems.com>

src/modules/peek/Peek.UI/App.xaml.cs

@@ -46,6 +46,7 @@ namespace Peek.UI
             {
                 // Core Services
                 services.AddTransient<NeighboringItemsQuery>();
+                services.AddSingleton<IUserSettings, UserSettings>();
 
                 // Views and ViewModels
                 services.AddTransient<TitleBar>();

src/modules/peek/Peek.UI/MainWindow.xaml.cs

@@ -6,6 +6,7 @@ using System;
 using interop;
 using Microsoft.PowerToys.Telemetry;
 using Microsoft.UI.Windowing;
+using Microsoft.UI.Xaml;
 using Microsoft.UI.Xaml.Input;
 using Peek.Common.Constants;
 using Peek.FilePreviewer.Models;
@@ -28,6 +29,7 @@ namespace Peek.UI
         public MainWindow()
         {
             InitializeComponent();
+            this.Activated += PeekWindow_Activated;
 
             ViewModel = App.GetService<MainWindowViewModel>();
 
@@ -38,6 +40,23 @@ namespace Peek.UI
             AppWindow.Closing += AppWindow_Closing;
         }
 
+        private void PeekWindow_Activated(object sender, Microsoft.UI.Xaml.WindowActivatedEventArgs args)
+        {
+            if (args.WindowActivationState == Microsoft.UI.Xaml.WindowActivationState.CodeActivated)
+            {
+                this.BringToForeground();
+            }
+
+            if (args.WindowActivationState == Microsoft.UI.Xaml.WindowActivationState.Deactivated)
+            {
+                var userSettings = App.GetService<IUserSettings>();
+                if (userSettings.CloseAfterLosingFocus)
+                {
+                    Uninitialize();
+                }
+            }
+        }
+
         /// <summary>
         /// Handle Peek hotkey, by toggling the window visibility and querying files when necessary.
         /// </summary>

src/modules/peek/Peek.UI/Services/IUserSettings.cs

@@ -0,0 +1,13 @@
+// Copyright (c) Microsoft Corporation
+// The Microsoft Corporation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System;
+
+namespace Peek.UI
+{
+    public interface IUserSettings
+    {
+        public bool CloseAfterLosingFocus { get; }
+    }
+}

src/modules/peek/Peek.UI/Services/UserSettings.cs

@@ -0,0 +1,85 @@
+// Copyright (c) Microsoft Corporation
+// The Microsoft Corporation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System;
+using System.IO;
+using System.IO.Abstractions;
+using System.Threading;
+using ManagedCommon;
+using Microsoft.PowerToys.Settings.UI.Library;
+using Microsoft.PowerToys.Settings.UI.Library.Utilities;
+
+namespace Peek.UI
+{
+    public class UserSettings : IUserSettings
+    {
+        private const string PeekModuleName = "Peek";
+        private const int MaxNumberOfRetry = 5;
+
+        private readonly ISettingsUtils _settingsUtils;
+        private readonly IFileSystemWatcher _watcher;
+        private readonly object _loadingSettingsLock = new object();
+
+        public bool CloseAfterLosingFocus { get; private set; }
+
+        public UserSettings()
+        {
+            _settingsUtils = new SettingsUtils();
+            CloseAfterLosingFocus = false;
+
+            LoadSettingsFromJson();
+
+            _watcher = Helper.GetFileWatcher(PeekModuleName, "settings.json", () => LoadSettingsFromJson());
+        }
+
+        private void LoadSettingsFromJson()
+        {
+            lock (_loadingSettingsLock)
+            {
+                var retry = true;
+                var retryCount = 0;
+
+                while (retry)
+                {
+                    try
+                    {
+                        retryCount++;
+
+                        if (!_settingsUtils.SettingsExists(PeekModuleName))
+                        {
+                            Logger.LogInfo("Hosts settings.json was missing, creating a new one");
+                            var defaultSettings = new PeekSettings();
+                            defaultSettings.Save(_settingsUtils);
+                        }
+
+                        var settings = _settingsUtils.GetSettingsOrDefault<PeekSettings>(PeekModuleName);
+                        if (settings != null)
+                        {
+                            CloseAfterLosingFocus = settings.Properties.CloseAfterLosingFocus.Value;
+                        }
+
+                        retry = false;
+                    }
+                    catch (IOException e)
+                    {
+                        if (retryCount > MaxNumberOfRetry)
+                        {
+                            retry = false;
+                            Logger.LogError($"Failed to Deserialize PowerToys settings, Retrying {e.Message}", e);
+                        }
+                        else
+                        {
+                            Thread.Sleep(500);
+                        }
+                    }
+                    catch (Exception ex)
+                    {
+                        retry = false;
+                        Logger.LogError("Failed to read changed settings", ex);
+                    }
+                }
+            }
+        }
+    }
+}