Resurrect the suggestion page

src/modules/cmdpal/Core/Microsoft.CmdPal.Core.ViewModels/ListViewModel.cs

@@ -66,6 +66,8 @@ public partial class ListViewModel : PageViewModel, IDisposable
 
     public bool IsMainPage { get; init; }
 
+    public bool IsTokenSearch { get; private set; }
+
     private bool _isDynamic;
 
     private Task? _initializeItemsTask;
@@ -604,6 +606,11 @@ public partial class ListViewModel : PageViewModel, IDisposable
         Filters?.InitializeProperties();
         UpdateProperty(nameof(Filters));
 
+        if (model is IExtendedAttributesProvider haveProperties)
+        {
+            LoadExtendedAttributes(haveProperties.GetProperties().AsReadOnly());
+        }
+
         FetchItems();
         model.ItemsChanged += Model_ItemsChanged;
     }
@@ -626,6 +633,17 @@ public partial class ListViewModel : PageViewModel, IDisposable
         return null;
     }
 
+    private void LoadExtendedAttributes(IReadOnlyDictionary<string, object> properties)
+    {
+        // Check if this is a token page
+        if (properties.TryGetValue("TokenSearch", out var isTokenSearchObj) &&
+            isTokenSearchObj is bool isTokenSearch)
+        {
+            IsTokenSearch = isTokenSearch;
+            UpdateProperty(nameof(IsTokenSearch));
+        }
+    }
+
     public void LoadMoreIfNeeded()
     {
         var model = _model.Unsafe;

src/modules/cmdpal/Microsoft.CmdPal.UI/Controls/SearchBar.xaml.cs

@@ -54,6 +54,8 @@ public sealed partial class SearchBar : UserControl,
     // 0.6+ suggestions
     private string? _textToSuggest;
 
+    private bool _tokenSearchEnabled;
+
     public PageViewModel? CurrentPageViewModel
     {
         get => (PageViewModel?)GetValue(CurrentPageViewModelProperty);
@@ -86,6 +88,11 @@ public sealed partial class SearchBar : UserControl,
             @this.FilterBox.Select(@this.FilterBox.Text.Length, 0);
 
             page.PropertyChanged += @this.Page_PropertyChanged;
+
+            if (page is ListViewModel listViewModel)
+            {
+                @this._tokenSearchEnabled = listViewModel.IsTokenSearch;
+            }
         }
 
         @this?.PropertyChanged?.Invoke(@this, new(nameof(PageType)));
@@ -201,6 +208,43 @@ public sealed partial class SearchBar : UserControl,
             {
                 // Mark backspace as held to handle continuous deletion
                 _isBackspaceHeld = true;
+
+                // Try to handle token deletion
+                if (_tokenSearchEnabled &&
+                    FilterBox.SelectionLength == 0)
+                {
+                    // Tokens are delimeted by zero-width space characters
+                    // (ZWSP, U+200B).
+                    //
+                    // What we're gonna do here is check if the character we're
+                    // about to backspace is the _second_ ZWSP in a pair
+                    var lastCaretPosition = FilterBox.SelectionStart;
+                    var text = FilterBox.Text;
+
+                    // Is the character before the caret a zwsp?
+                    if (lastCaretPosition > 0 &&
+                        text[lastCaretPosition - 1] == '\u200B')
+                    {
+                        // make sure that this is a pair. So, we'd need to see an odd number of zwsp's before this one.
+                        var zwspCount = 0;
+                        var previousZwspIndex = -1;
+                        for (var i = 0; i < lastCaretPosition - 1; i++)
+                        {
+                            if (text[i] == '\u200B')
+                            {
+                                zwspCount++;
+                                previousZwspIndex = i;
+                            }
+                        }
+
+                        if (zwspCount % 2 == 1 && previousZwspIndex != -1)
+                        {
+                            // We have a pair! Select the whole token for deletion
+                            FilterBox.Select(previousZwspIndex, lastCaretPosition - previousZwspIndex);
+                            e.Handled = true;
+                        }
+                    }
+                }
             }
         }
         else if (e.Key == VirtualKey.Up)

src/modules/cmdpal/doc/initial-sdk-spec/initial-sdk-spec.md

@@ -75,6 +75,8 @@ functionality.
   - [Advanced scenarios](#advanced-scenarios)
     - [Status messages](#status-messages)
     - [Rendering of ICommandItems in Lists and Menus](#rendering-of-icommanditems-in-lists-and-menus)
+  - [Addenda I: API additions (ICommandProvider2)](#addenda-i-api-additions-icommandprovider2)
+  - [Addenda II: Rich Search](#addenda-ii-rich-search)
   - [Class diagram](#class-diagram)
   - [Future considerations](#future-considerations)
     - [Arbitrary parameters and arguments](#arbitrary-parameters-and-arguments)
@@ -2066,7 +2068,44 @@ parts **C** and **D**.
   not necessarily a full rich search box, we'll provide a parameter page
   experience. 
 
+```csharp
+[uuid("a2590cc9-510c-4af7-b562-a6b56fe37f55")]
+interface IParameterRun requires INotifyPropChanged
+{
+};
 
+interface ILabelRun requires IParameterRun
+{
+    String Text{ get; };
+};
+
+interface IParameterValueRun requires IParameterRun
+{
+    String PlaceholderText{ get; };
+    Boolean NeedsValue{ get; }; // TODO! name is weird
+};
+
+interface IStringParameterRun requires IParameterValueRun
+{
+    String Text{ get; set; };
+
+    // TODO! do we need a way to validate string inputs?
+};
+
+interface ICommandParameterRun requires IParameterValueRun
+{
+    String DisplayText{ get; };
+    ICommand GetSelectValueCommand(UInt64 hostHwnd);
+    IIconInfo Icon{ get; }; // ? maybe
+
+};
+
+interface IParametersPage requires IPage
+{
+    IParameterRun[] Parameters{ get; };
+    IListItem Command{ get; };
+};
+```
 
 ## Class diagram
 

src/modules/cmdpal/ext/SamplePagesExtension/Pages/SampleSuggestionsPage.cs

@@ -0,0 +1,361 @@
+// 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.Collections.Generic;
+using Microsoft.CommandPalette.Extensions;
+using Microsoft.CommandPalette.Extensions.Toolkit;
+using Windows.Foundation;
+using Windows.Foundation.Collections;
+
+namespace SamplePagesExtension.Pages;
+
+#nullable enable
+
+#pragma warning disable SA1402 // File may only contain a single type
+internal sealed partial class SampleSuggestionsPage : DynamicListPage, IExtendedAttributesProvider
+{
+    private PeopleSearchPage _peopleSearchPage = new();
+    private CommandsListPage _commandsListPage = new();
+    private DynamicListPage? _suggestionPage;
+    private List<MyTokenType> _pickedTokens = new();
+    private int _lastPrefixPosition = -1;
+    private ListItem _queryItem;
+
+    // private int _lastCaretPosition = 0;
+    private string _searchText = string.Empty;
+
+    public override string SearchText
+    {
+        get => _searchText;
+        set
+        {
+            var oldSearch = _searchText;
+            if (value != oldSearch)
+            {
+                _searchText = value;
+                UpdateSearch(oldSearch, new SearchUpdateArgs(value, null));
+            }
+        }
+    }
+
+    internal SampleSuggestionsPage()
+    {
+        _peopleSearchPage.SuggestionPicked += OnSuggestionPicked;
+        _commandsListPage.SuggestionPicked += OnSuggestionPicked;
+        Name = "Open";
+        Title = "Sample prefixed search";
+        PlaceholderText = "Type a query, and use '@' to add a person";
+        Icon = new("\uE779");
+
+        _queryItem = new ListItem(new NoOpCommand())
+        {
+            Title = string.Empty,
+            Icon = new IconInfo("\uE8F2"), // ChatBubbles
+        };
+    }
+
+    public override IListItem[] GetItems()
+    {
+        return _suggestionPage?.GetItems() ??
+            (string.IsNullOrEmpty(this.SearchText) ?
+                [] :
+                [_queryItem]);
+    }
+
+    public void UpdateSearch(string oldSearchText, ISearchUpdateArgs args)
+    {
+        // if (args.GetProperties() is IDictionary<string, object> props)
+        // {
+        //     if (props.TryGetValue("CaretPosition", out var caretPosObj) && caretPosObj is int caretPos)
+        //     {
+        //         _lastCaretPosition = caretPos;
+        //     }
+        // }
+        var newSearchText = args.NewSearchText;
+        UpdateListItem(newSearchText);
+        if (string.IsNullOrEmpty(newSearchText) != string.IsNullOrEmpty(oldSearchText))
+        {
+            RaiseItemsChanged();
+        }
+
+        if (newSearchText.Length < oldSearchText.Length)
+        {
+            HandleDeletion(oldSearchText, newSearchText);
+            return;
+        }
+
+        this.SearchText = newSearchText;
+
+        // We're not doing caret tracking in this sample.
+        // Just assume caret is at end of text.
+        var lastCaretPosition = newSearchText.Length;
+
+        if (_suggestionPage == null)
+        {
+            var lastChar = newSearchText.Length > 0 && lastCaretPosition > 0 ?
+                newSearchText[lastCaretPosition - 1] :
+                '\0';
+
+            if (lastChar == '@')
+            {
+                // User typed '@', switch to people suggestion page
+                _lastPrefixPosition = lastCaretPosition - 1;
+                UpdateSuggestionPage(_peopleSearchPage);
+            }
+            else if (lastChar == '/')
+            {
+                // User typed '/', switch to commands suggestion page
+                _lastPrefixPosition = lastCaretPosition - 1;
+                UpdateSuggestionPage(_commandsListPage);
+            }
+        }
+        else if (_suggestionPage != null)
+        {
+            // figure out what part of the text applies to the current suggestion page
+            var startOfSubSearch = _lastPrefixPosition + 1;
+            var subString = _searchText.Substring(startOfSubSearch, lastCaretPosition - startOfSubSearch);
+            _suggestionPage.SearchText = subString;
+
+            // When the suggestion page updates its items, it should raise ItemsChanged event, which we will bubble through
+        }
+    }
+
+    private void OnSuggestionPicked(object sender, MyTokenType suggestion)
+    {
+        _pickedTokens.Add(suggestion);
+        UpdateSuggestionPage(null); // Clear suggestion page
+
+        var displayText = suggestion.DisplayName;
+        var tokenText = $"\u200B{displayText}\u200B "; // Add ZWSP before and after token, and a trailing space
+
+        // remove the prefix character and any partial text after it
+        if (_lastPrefixPosition >= 0 && _lastPrefixPosition < _searchText.Length)
+        {
+            _searchText = _searchText.Remove(_lastPrefixPosition);
+        }
+
+        // this.SearchText = this.SearchText.Insert(_lastCaretPosition, tokenText);
+        this.SearchText = _searchText + tokenText;
+        OnPropertyChanged(nameof(SearchText));
+    }
+
+    private void UpdateSuggestionPage(DynamicListPage? page)
+    {
+        if (_suggestionPage != null)
+        {
+            _suggestionPage.ItemsChanged -= OnSuggestedItemsChanged;
+        }
+
+        _suggestionPage = page;
+        if (_suggestionPage != null)
+        {
+            _suggestionPage.SearchText = string.Empty; // reset search text
+            _suggestionPage.ItemsChanged += OnSuggestedItemsChanged;
+        }
+
+        RaiseItemsChanged();
+    }
+
+    private void OnSuggestedItemsChanged(object sender, IItemsChangedEventArgs e)
+    {
+        RaiseItemsChanged();
+    }
+
+    private void HandleDeletion(string oldSearch, string newSearch)
+    {
+        var lastCaretPosition = newSearch.Length;
+
+        if (_suggestionPage != null)
+        {
+            if (lastCaretPosition <= _lastPrefixPosition)
+            {
+                // User deleted back over the prefix character, so close the suggestion page
+                UpdateSuggestionPage(null);
+                _lastPrefixPosition = -1;
+                return;
+            }
+
+            // figure out what part of the text applies to the current suggestion page
+            var startOfSubSearch = _lastPrefixPosition + 1;
+            if (lastCaretPosition <= _lastPrefixPosition)
+            {
+                // User deleted back over the prefix character, so close the suggestion page
+                UpdateSuggestionPage(null);
+                _lastPrefixPosition = -1;
+            }
+            else
+            {
+                var subString = newSearch.Substring(startOfSubSearch, lastCaretPosition - startOfSubSearch);
+                _suggestionPage.SearchText = subString;
+            }
+        }
+    }
+
+    private void UpdateListItem(string newSearchText)
+    {
+        // Iterate over the search text.
+        // Find all the strings that are surrounded by ZWSP characters.
+        // Use those strings to find all the matching picked tokens.
+        var index = 0;
+        var tokenSpans = new List<(int Start, int End, MyTokenType? Token)>();
+        while (index < newSearchText.Length)
+        {
+            var startIndex = newSearchText.IndexOf('\u200B', index);
+            if (startIndex < 0)
+            {
+                break;
+            }
+
+            var endIndex = newSearchText.IndexOf('\u200B', startIndex + 1);
+            if (endIndex < 0)
+            {
+                break;
+            }
+
+            var tokenText = newSearchText.Substring(startIndex + 1, endIndex - startIndex - 1);
+            var token = _pickedTokens.Find(t => t.DisplayName == tokenText);
+            tokenSpans.Add((startIndex, endIndex, token));
+
+            index = endIndex + 1;
+        }
+
+        // for each span, construct a string like $"[{start}, {end}): {token.DisplayName} {token.Id}\n"
+        var displayText = string.Empty;
+        foreach (var (start, end, token) in tokenSpans)
+        {
+            if (token != null)
+            {
+                displayText += $"[{start}, {end}): {token.DisplayName} {token.Id}\n";
+            }
+        }
+
+        _queryItem.Title = newSearchText;
+        _queryItem.Subtitle = string.IsNullOrEmpty(displayText) ? "no tokens" : displayText;
+    }
+
+    public override void UpdateSearchText(string oldSearch, string newSearch)
+    {
+        // from DynamicListPage, not used
+    }
+
+    public IDictionary<string, object> GetProperties()
+    {
+        return new ValueSet()
+        {
+            { "TokenSearch", true },
+        };
+    }
+}
+
+internal interface ISearchUpdateArgs
+{
+    string NewSearchText { get; }
+}
+
+internal sealed partial class SearchUpdateArgs : ISearchUpdateArgs, IExtendedAttributesProvider
+{
+    public string NewSearchText { get; }
+
+    private IDictionary<string, object> _properties;
+
+    public SearchUpdateArgs(string newSearchText, IDictionary<string, object>? properties)
+    {
+        NewSearchText = newSearchText;
+        _properties = properties ?? new Dictionary<string, object>();
+    }
+
+    public IDictionary<string, object> GetProperties() => _properties;
+}
+
+internal sealed partial class PeopleSearchPage : DynamicListPage
+{
+    internal event TypedEventHandler<object, MyTokenType>? SuggestionPicked;
+
+    public override void UpdateSearchText(string oldSearch, string newSearch)
+    {
+        // do nothing
+    }
+
+    public override IListItem[] GetItems()
+    {
+        var items = new List<IListItem>();
+        for (var i = 1; i <= 5; i++)
+        {
+            var name = $"Person {i}";
+            var suggestion = new MyTokenType
+            {
+                DisplayName = name,
+                Id = Guid.NewGuid().ToString(),
+                Value = name,
+            };
+            items.Add(new ListItem(new PickSuggestionCommand(suggestion, SuggestionPicked))
+            {
+                Title = name,
+                Subtitle = $"Email: person{i}@example.com",
+            });
+        }
+
+        return items.ToArray();
+    }
+}
+
+internal sealed partial class CommandsListPage : DynamicListPage
+{
+    internal event TypedEventHandler<object, MyTokenType>? SuggestionPicked;
+
+    public override void UpdateSearchText(string oldSearch, string newSearch)
+    {
+        // do nothing
+    }
+
+    public override IListItem[] GetItems()
+    {
+        var items = new List<IListItem>();
+        items.Add(new ListItem(new PickSuggestionCommand(new() { DisplayName = "Chat", Id = "chat" }, SuggestionPicked))
+        {
+            Title = "/chat",
+            Subtitle = $"send a message",
+        });
+        items.Add(new ListItem(new PickSuggestionCommand(new() { DisplayName = "Status", Id = "status" }, SuggestionPicked))
+        {
+            Title = "/status",
+            Subtitle = $"set your status",
+        });
+
+        return items.ToArray();
+    }
+}
+
+internal sealed partial class MyTokenType
+{
+    public required string DisplayName { get; set; }
+
+    public string Id { get; set; } = string.Empty;
+
+    public object? Value { get; set; }
+}
+
+internal sealed partial class PickSuggestionCommand : InvokableCommand
+{
+    internal MyTokenType Suggestion { get; private set; }
+
+    private TypedEventHandler<object, MyTokenType>? _pickedHandler;
+
+    public PickSuggestionCommand(MyTokenType suggestion, TypedEventHandler<object, MyTokenType>? pickedHandler)
+    {
+        Suggestion = suggestion;
+        _pickedHandler = pickedHandler;
+        Name = $"Select";
+    }
+
+    public override CommandResult Invoke()
+    {
+        _pickedHandler?.Invoke(this, Suggestion);
+        return CommandResult.KeepOpen();
+    }
+}
+
+#pragma warning restore SA1402 // File may only contain a single type
+#nullable disable

src/modules/cmdpal/ext/SamplePagesExtension/SamplesListPage.cs

@@ -1,4 +1,4 @@
-// Copyright (c) Microsoft Corporation
+// 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.
 
@@ -54,6 +54,11 @@ public partial class SamplesListPage : ListPage
             Title = "Slow loading list page",
             Subtitle = "A demo of a list page that takes a while to load",
         },
+        new ListItem(new SampleSuggestionsPage())
+        {
+            Title = "Sample Prefix Suggestions",
+            Subtitle = "A demo of using 'nested' pages to provide 'suggestions' as the user types",
+        },
 
         // Content pages
         new ListItem(new SampleContentPage())
@@ -122,6 +127,7 @@ public partial class SamplesListPage : ListPage
             Title = "Mixed parameter types (file first)",
             Subtitle = "A demo of a command that takes multiple types of parameters",
         },
+
         // List parameters aren't yet supported
         // new ListItem(new CreateNoteParametersPage())
         // {