CmdPal: Add settings to control which fallbacks are enabled (#40505)

This adds settings to each provider to allow us to control if individual
fallback items are enabled or not, regardless of the provider being
enabled.

This is relevant to _all the threads where disabling fallback commands
came up_

This just adds another section to each provider's settings page, with a
list of the fallback commands.

This also has nothing to do with the "top-level apps search", which is
not really a fallback command - it's its own thing.

Ref #38288. Doesn't close that, because this only controls
enable/disable, not ranking.

From here, we should be able to add a dedicated page in the SUI that
shows all the fallbacks across all providers. That's where we'll enable
the ordering.

src/modules/cmdpal/Microsoft.CmdPal.UI.ViewModels/CommandProviderWrapper.cs

@@ -177,13 +177,13 @@ public sealed class CommandProviderWrapper
     private void InitializeCommands(ICommandItem[] commands, IFallbackCommandItem[] fallbacks, IServiceProvider serviceProvider, WeakReference<IPageContext> pageContext)
     {
         var settings = serviceProvider.GetService<SettingsModel>()!;
+        var providerSettings = GetProviderSettings(settings);
 
         Func<ICommandItem?, bool, TopLevelViewModel> makeAndAdd = (ICommandItem? i, bool fallback) =>
         {
             CommandItemViewModel commandItemViewModel = new(new(i), pageContext);
-            TopLevelViewModel topLevelViewModel = new(commandItemViewModel, fallback, ExtensionHost, ProviderId, settings, serviceProvider);
-
-            topLevelViewModel.ItemViewModel.SlowInitializeProperties();
+            TopLevelViewModel topLevelViewModel = new(commandItemViewModel, fallback, ExtensionHost, ProviderId, settings, providerSettings, serviceProvider);
+            topLevelViewModel.InitializeProperties();
 
             return topLevelViewModel;
         };

src/modules/cmdpal/Microsoft.CmdPal.UI.ViewModels/Commands/FallbackLogItem.cs

@@ -13,7 +13,7 @@ internal sealed partial class FallbackLogItem : FallbackCommandItem
     private readonly LogMessagesPage _logMessagesPage;
 
     public FallbackLogItem()
-        : base(new LogMessagesPage(), Resources.builtin_log_subtitle)
+        : base(new LogMessagesPage() { Id = "com.microsoft.cmdpal.log" }, Resources.builtin_log_subtitle)
     {
         _logMessagesPage = (LogMessagesPage)Command!;
         Title = string.Empty;

src/modules/cmdpal/Microsoft.CmdPal.UI.ViewModels/Commands/FallbackReloadItem.cs

@@ -12,7 +12,9 @@ internal sealed partial class FallbackReloadItem : FallbackCommandItem
     private readonly ReloadExtensionsCommand _reloadCommand;
 
     public FallbackReloadItem()
-        : base(new ReloadExtensionsCommand(), Properties.Resources.builtin_reload_display_title)
+        : base(
+            new ReloadExtensionsCommand() { Id = "com.microsoft.cmdpal.reload" },
+            Properties.Resources.builtin_reload_display_title)
     {
         _reloadCommand = (ReloadExtensionsCommand)Command!;
         Title = string.Empty;

src/modules/cmdpal/Microsoft.CmdPal.UI.ViewModels/Commands/QuitAction.cs

@@ -13,6 +13,7 @@ public partial class QuitCommand : InvokableCommand, IFallbackHandler
 {
     public QuitCommand()
     {
+        Id = "com.microsoft.cmdpal.quit";
         Icon = new IconInfo("\uE711");
     }
 

src/modules/cmdpal/Microsoft.CmdPal.UI.ViewModels/ProviderSettings.cs

@@ -10,6 +10,8 @@ public class ProviderSettings
 {
     public bool IsEnabled { get; set; } = true;
 
+    public Dictionary<string, bool> FallbackCommands { get; set; } = [];
+
     [JsonIgnore]
     public string ProviderDisplayName { get; set; } = string.Empty;
 
@@ -42,4 +44,14 @@ public class ProviderSettings
             throw new InvalidDataException("Did you add a built-in command and forget to set the Id? Make sure you do that!");
         }
     }
+
+    public bool IsFallbackEnabled(TopLevelViewModel command)
+    {
+        return FallbackCommands.TryGetValue(command.Id, out var enabled) ? enabled : true;
+    }
+
+    public void SetFallbackEnabled(TopLevelViewModel command, bool enabled)
+    {
+        FallbackCommands[command.Id] = enabled;
+    }
 }

src/modules/cmdpal/Microsoft.CmdPal.UI.ViewModels/ProviderSettingsViewModel.cs

@@ -25,7 +25,11 @@ public partial class ProviderSettingsViewModel(
 
     public string ExtensionName => _provider.Extension?.ExtensionDisplayName ?? "Built-in";
 
-    public string ExtensionSubtext => IsEnabled ? $"{ExtensionName}, {TopLevelCommands.Count} commands" : Resources.builtin_disabled_extension;
+    public string ExtensionSubtext => IsEnabled ?
+        HasFallbackCommands ?
+            $"{ExtensionName}, {TopLevelCommands.Count} commands, {FallbackCommands.Count} fallback commands" :
+            $"{ExtensionName}, {TopLevelCommands.Count} commands" :
+        Resources.builtin_disabled_extension;
 
     [MemberNotNullWhen(true, nameof(Extension))]
     public bool IsFromExtension => _provider.Extension != null;
@@ -139,6 +143,31 @@ public partial class ProviderSettingsViewModel(
         return [.. providersCommands];
     }
 
+    [field: AllowNull]
+    public List<TopLevelViewModel> FallbackCommands
+    {
+        get
+        {
+            if (field == null)
+            {
+                field = BuildFallbackViewModels();
+            }
+
+            return field;
+        }
+    }
+
+    public bool HasFallbackCommands => _provider.FallbackItems?.Length > 0;
+
+    private List<TopLevelViewModel> BuildFallbackViewModels()
+    {
+        var thisProvider = _provider;
+        var providersCommands = thisProvider.FallbackItems;
+
+        // Remember! This comes in on the UI thread!
+        return [.. providersCommands];
+    }
+
     private void Save() => SettingsModel.SaveSettings(_settings);
 
     private void InitializeSettingsPage()

src/modules/cmdpal/Microsoft.CmdPal.UI.ViewModels/TopLevelCommandManager.cs

@@ -98,19 +98,28 @@ public partial class TopLevelCommandManager : ObservableObject,
 
         await commandProvider.LoadTopLevelCommands(_serviceProvider, weakSelf);
 
-        var settings = _serviceProvider.GetService<SettingsModel>()!;
+        var commands = await Task.Factory.StartNew(
+            () =>
+            {
+                List<TopLevelViewModel> commands = [];
+                foreach (var item in commandProvider.TopLevelItems)
+                {
+                    TopLevelCommands.Add(item);
+                }
 
-        List<TopLevelViewModel> commands = [];
+                foreach (var item in commandProvider.FallbackItems)
+                {
+                    if (item.IsEnabled)
+                    {
+                        TopLevelCommands.Add(item);
+                    }
+                }
 
-        foreach (var item in commandProvider.TopLevelItems)
-        {
-            commands.Add(item);
-        }
-
-        foreach (var item in commandProvider.FallbackItems)
-        {
-            commands.Add(item);
-        }
+                return commands;
+            },
+            CancellationToken.None,
+            TaskCreationOptions.None,
+            _taskScheduler);
 
         commandProvider.CommandsChanged -= CommandProvider_CommandsChanged;
         commandProvider.CommandsChanged += CommandProvider_CommandsChanged;
@@ -176,7 +185,10 @@ public partial class TopLevelCommandManager : ObservableObject,
 
         foreach (var i in sender.FallbackItems)
         {
-            newItems.Add(i);
+            if (i.IsEnabled)
+            {
+                newItems.Add(i);
+            }
         }
 
         // Slice out the old commands

src/modules/cmdpal/Microsoft.CmdPal.UI.ViewModels/TopLevelViewModel.cs

@@ -4,7 +4,9 @@
 
 using System.Collections.ObjectModel;
 using CommunityToolkit.Mvvm.ComponentModel;
+using CommunityToolkit.Mvvm.Messaging;
 using ManagedCommon;
+using Microsoft.CmdPal.UI.ViewModels.Messages;
 using Microsoft.CmdPal.UI.ViewModels.Settings;
 using Microsoft.CommandPalette.Extensions;
 using Microsoft.CommandPalette.Extensions.Toolkit;
@@ -17,6 +19,7 @@ namespace Microsoft.CmdPal.UI.ViewModels;
 public sealed partial class TopLevelViewModel : ObservableObject, IListItem
 {
     private readonly SettingsModel _settings;
+    private readonly ProviderSettings _providerSettings;
     private readonly IServiceProvider _serviceProvider;
     private readonly CommandItemViewModel _commandItemViewModel;
 
@@ -77,6 +80,9 @@ public sealed partial class TopLevelViewModel : ObservableObject, IListItem
     ////// INotifyPropChanged
     public event TypedEventHandler<object, IPropChangedEventArgs>? PropChanged;
 
+    // Fallback items
+    public string DisplayTitle { get; private set; } = string.Empty;
+
     public HotkeySettings? Hotkey
     {
         get => _hotkey;
@@ -133,16 +139,32 @@ public sealed partial class TopLevelViewModel : ObservableObject, IListItem
         }
     }
 
+    public bool IsEnabled
+    {
+        get => _providerSettings.IsFallbackEnabled(this);
+        set
+        {
+            if (value != IsEnabled)
+            {
+                _providerSettings.SetFallbackEnabled(this, value);
+                Save();
+                WeakReferenceMessenger.Default.Send<ReloadCommandsMessage>(new());
+            }
+        }
+    }
+
     public TopLevelViewModel(
         CommandItemViewModel item,
         bool isFallback,
         CommandPaletteHost extensionHost,
         string commandProviderId,
         SettingsModel settings,
+        ProviderSettings providerSettings,
         IServiceProvider serviceProvider)
     {
         _serviceProvider = serviceProvider;
         _settings = settings;
+        _providerSettings = providerSettings;
         _commandProviderId = commandProviderId;
         _commandItemViewModel = item;
 
@@ -156,6 +178,22 @@ public sealed partial class TopLevelViewModel : ObservableObject, IListItem
         // UpdateTags();
     }
 
+    internal void InitializeProperties()
+    {
+        ItemViewModel.SlowInitializeProperties();
+
+        if (IsFallback)
+        {
+            var model = _commandItemViewModel.Model.Unsafe;
+
+            // RPC to check type
+            if (model is IFallbackCommandItem fallback)
+            {
+                DisplayTitle = fallback.DisplayTitle;
+            }
+        }
+    }
+
     private void Item_PropertyChanged(object? sender, System.ComponentModel.PropertyChangedEventArgs e)
     {
         if (!string.IsNullOrEmpty(e.PropertyName))
@@ -240,7 +278,7 @@ public sealed partial class TopLevelViewModel : ObservableObject, IListItem
     {
         // Use WyHash64 to generate stable ID hashes.
         // manually seeding with 0, so that the hash is stable across launches
-        var result = WyHash64.ComputeHash64(_commandProviderId + Title + Subtitle, seed: 0);
+        var result = WyHash64.ComputeHash64(_commandProviderId + DisplayTitle + Title + Subtitle, seed: 0);
         _generatedId = $"{_commandProviderId}{result}";
     }
 
@@ -263,6 +301,11 @@ public sealed partial class TopLevelViewModel : ObservableObject, IListItem
             return false;
         }
 
+        if (!IsEnabled)
+        {
+            return false;
+        }
+
         try
         {
             return UnsafeUpdateFallbackSynchronous(newQuery);