Add selection orompt Search (#1289)

* Add selection prompt search as you type

* Fix small bug

* Simplify

* Simplify

* Remove spacebar as a selection prompt submit key

* Trigger CI

* Update src/Spectre.Console/Prompts/SelectionPrompt.cs

Co-authored-by: Martin Costello <martin@martincostello.com>

* Simplifty Mask method

* Handle multi-selection prompt better

* Update API naming

* Address feedback

* Add some tests

* Remove whitespace

* Improve search and highlighting

* Add test case for previous issue

* Add extra test case

* Make prompt searchable

---------

Co-authored-by: Martin Costello <martin@martincostello.com>
Co-authored-by: Patrik Svensson <patrik@patriksvensson.se>

examples/Console/Prompt/Program.cs

@@ -110,6 +110,7 @@ public static string AskFruit()
             {
                 fruit = AnsiConsole.Prompt(
                     new SelectionPrompt<string>()
+                        .EnableSearch()
                         .Title("Ok, but if you could only choose [green]one[/]?")
                         .MoreChoicesText("[grey](Move up and down to reveal more fruits)[/]")
                         .AddChoices(favorites));

src/Spectre.Console/Extensions/StringExtensions.cs

@@ -187,6 +187,13 @@ internal static bool ContainsExact(this string text, string value)
 #endif
     }
 
+#if NETSTANDARD2_0
+    internal static bool Contains(this string target, string value, System.StringComparison comparisonType)
+    {
+        return target.IndexOf(value, comparisonType) != -1;
+    }
+#endif
+
     /// <summary>
     /// "Masks" every character in a string.
     /// </summary>
@@ -195,18 +202,105 @@ internal static bool ContainsExact(this string text, string value)
     /// <returns>Masked string.</returns>
     public static string Mask(this string value, char? mask)
     {
-        var output = string.Empty;
-
         if (mask is null)
         {
-            return output;
+            return string.Empty;
+        }
+
+        return new string(mask.Value, value.Length);
+    }
+
+    /// <summary>
+    /// Highlights the first text match in provided value.
+    /// </summary>
+    /// <param name="value">Input value.</param>
+    /// <param name="searchText">Text to search for.</param>
+    /// <param name="highlightStyle">The style to apply to the matched text.</param>
+    /// <returns>Markup of input with the first matched text highlighted.</returns>
+    internal static string Highlight(this string value, string searchText, Style? highlightStyle)
+    {
+        if (value is null)
+        {
+            throw new ArgumentNullException(nameof(value));
+        }
+
+        if (searchText is null)
+        {
+            throw new ArgumentNullException(nameof(searchText));
+        }
+
+        if (highlightStyle is null)
+        {
+            throw new ArgumentNullException(nameof(highlightStyle));
+        }
+
+        if (searchText.Length == 0)
+        {
+            return value;
         }
 
-        foreach (var c in value)
+        var foundSearchPattern = false;
+        var builder = new StringBuilder();
+        using var tokenizer = new MarkupTokenizer(value);
+        while (tokenizer.MoveNext())
         {
-            output += mask;
+            var token = tokenizer.Current!;
+
+            switch (token.Kind)
+            {
+                case MarkupTokenKind.Text:
+                    {
+                        var tokenValue = token.Value;
+                        if (tokenValue.Length == 0)
+                        {
+                            break;
+                        }
+
+                        if (foundSearchPattern)
+                        {
+                            builder.Append(tokenValue);
+                            break;
+                        }
+
+                        var index = tokenValue.IndexOf(searchText, StringComparison.OrdinalIgnoreCase);
+                        if (index == -1)
+                        {
+                            builder.Append(tokenValue);
+                            break;
+                        }
+
+                        foundSearchPattern = true;
+                        var before = tokenValue.Substring(0, index);
+                        var match = tokenValue.Substring(index, searchText.Length);
+                        var after = tokenValue.Substring(index + searchText.Length);
+
+                        builder
+                            .Append(before)
+                            .AppendWithStyle(highlightStyle, match)
+                            .Append(after);
+
+                        break;
+                    }
+
+                case MarkupTokenKind.Open:
+                    {
+                        builder.Append("[" + token.Value + "]");
+                        break;
+                    }
+
+                case MarkupTokenKind.Close:
+                    {
+                        builder.Append("[/]");
+                        break;
+                    }
+
+                default:
+                    {
+                        throw new InvalidOperationException("Unknown markup token kind.");
+                    }
+            }
         }
 
-        return output;
+        return builder.ToString();
     }
 }

src/Spectre.Console/Internal/Extensions/EnumerableExtensions.cs

@@ -31,12 +31,11 @@ public static IEnumerable<T> Repeat<T>(this IEnumerable<T> source, int count)
     }
 
     public static int IndexOf<T>(this IEnumerable<T> source, T item)
-        where T : class
     {
         var index = 0;
         foreach (var candidate in source)
         {
-            if (candidate == item)
+            if (Equals(candidate, item))
             {
                 return index;
             }

src/Spectre.Console/Prompts/List/IListPromptStrategy.cs

@@ -31,6 +31,9 @@ internal interface IListPromptStrategy<T>
     /// <param name="scrollable">Whether or not the list is scrollable.</param>
     /// <param name="cursorIndex">The cursor index.</param>
     /// <param name="items">The visible items.</param>
+    /// <param name="skipUnselectableItems">A value indicating whether or not the prompt should skip unselectable items.</param>
+    /// <param name="searchText">The search text.</param>
     /// <returns>A <see cref="IRenderable"/> representing the items.</returns>
-    public IRenderable Render(IAnsiConsole console, bool scrollable, int cursorIndex, IEnumerable<(int Index, ListPromptItem<T> Node)> items);
+    public IRenderable Render(IAnsiConsole console, bool scrollable, int cursorIndex,
+        IEnumerable<(int Index, ListPromptItem<T> Node)> items, bool skipUnselectableItems, string searchText);
 }

src/Spectre.Console/Prompts/List/ListPrompt.cs

@@ -14,9 +14,12 @@ public ListPrompt(IAnsiConsole console, IListPromptStrategy<T> strategy)
 
     public async Task<ListPromptState<T>> Show(
         ListPromptTree<T> tree,
-        CancellationToken cancellationToken,
-        int requestedPageSize = 15,
-        bool wrapAround = false)
+        SelectionMode selectionMode,
+        bool skipUnselectableItems,
+        bool searchEnabled,
+        int requestedPageSize,
+        bool wrapAround,
+        CancellationToken cancellationToken = default)
     {
         if (tree is null)
         {
@@ -38,7 +41,7 @@ public async Task<ListPromptState<T>> Show(
         }
 
         var nodes = tree.Traverse().ToList();
-        var state = new ListPromptState<T>(nodes, _strategy.CalculatePageSize(_console, nodes.Count, requestedPageSize), wrapAround);
+        var state = new ListPromptState<T>(nodes, _strategy.CalculatePageSize(_console, nodes.Count, requestedPageSize), wrapAround, selectionMode, skipUnselectableItems, searchEnabled);
         var hook = new ListPromptRenderHook<T>(_console, () => BuildRenderable(state));
 
         using (new RenderHookScope(_console, hook))
@@ -62,7 +65,7 @@ public async Task<ListPromptState<T>> Show(
                     break;
                 }
 
-                if (state.Update(key.Key) || result == ListPromptInputResult.Refresh)
+                if (state.Update(key) || result == ListPromptInputResult.Refresh)
                 {
                     hook.Refresh();
                 }
@@ -110,6 +113,8 @@ private IRenderable BuildRenderable(ListPromptState<T> state)
             _console,
             scrollable, cursorIndex,
             state.Items.Skip(skip).Take(take)
-                .Select((node, index) => (index, node)));
+                .Select((node, index) => (index, node)),
+            state.SkipUnselectableItems,
+            state.SearchText);
     }
 }

src/Spectre.Console/Prompts/List/ListPromptConstants.cs

@@ -8,4 +8,5 @@ internal sealed class ListPromptConstants
     public const string GroupSelectedCheckbox = "[[[grey]X[/]]]";
     public const string InstructionsMarkup = "[grey](Press <space> to select, <enter> to accept)[/]";
     public const string MoreChoicesMarkup = "[grey](Move up and down to reveal more choices)[/]";
+    public const string SearchPlaceholderMarkup = "[grey](Type to search)[/]";
 }

src/Spectre.Console/Prompts/List/ListPromptState.cs

@@ -7,37 +7,155 @@ internal sealed class ListPromptState<T>
     public int ItemCount => Items.Count;
     public int PageSize { get; }
     public bool WrapAround { get; }
+    public SelectionMode Mode { get; }
+    public bool SkipUnselectableItems { get; private set; }
+    public bool SearchEnabled { get; }
     public IReadOnlyList<ListPromptItem<T>> Items { get; }
+    private readonly IReadOnlyList<int>? _leafIndexes;
 
     public ListPromptItem<T> Current => Items[Index];
+    public string SearchText { get; private set; }
 
-    public ListPromptState(IReadOnlyList<ListPromptItem<T>> items, int pageSize, bool wrapAround)
+    public ListPromptState(IReadOnlyList<ListPromptItem<T>> items, int pageSize, bool wrapAround, SelectionMode mode, bool skipUnselectableItems, bool searchEnabled)
     {
-        Index = 0;
         Items = items;
         PageSize = pageSize;
         WrapAround = wrapAround;
+        Mode = mode;
+        SkipUnselectableItems = skipUnselectableItems;
+        SearchEnabled = searchEnabled;
+        SearchText = string.Empty;
+
+        if (SkipUnselectableItems && mode == SelectionMode.Leaf)
+        {
+            _leafIndexes =
+                Items
+                    .Select((item, index) => new { item, index })
+                    .Where(x => !x.item.IsGroup)
+                    .Select(x => x.index)
+                    .ToList()
+                    .AsReadOnly();
+
+            Index = _leafIndexes.FirstOrDefault();
+        }
+        else
+        {
+            Index = 0;
+        }
     }
 
-    public bool Update(ConsoleKey key)
+    public bool Update(ConsoleKeyInfo keyInfo)
     {
-        var index = key switch
+        var index = Index;
+        if (SkipUnselectableItems && Mode == SelectionMode.Leaf)
         {
-            ConsoleKey.UpArrow => Index - 1,
-            ConsoleKey.DownArrow => Index + 1,
-            ConsoleKey.Home => 0,
-            ConsoleKey.End => ItemCount - 1,
-            ConsoleKey.PageUp => Index - PageSize,
-            ConsoleKey.PageDown => Index + PageSize,
-            _ => Index,
-        };
+            Debug.Assert(_leafIndexes != null, nameof(_leafIndexes) + " != null");
+            var currentLeafIndex = _leafIndexes.IndexOf(index);
+            switch (keyInfo.Key)
+            {
+                case ConsoleKey.UpArrow:
+                    if (currentLeafIndex > 0)
+                    {
+                        index = _leafIndexes[currentLeafIndex - 1];
+                    }
+                    else if (WrapAround)
+                    {
+                        index = _leafIndexes.LastOrDefault();
+                    }
+
+                    break;
+
+                case ConsoleKey.DownArrow:
+                    if (currentLeafIndex < _leafIndexes.Count - 1)
+                    {
+                        index = _leafIndexes[currentLeafIndex + 1];
+                    }
+                    else if (WrapAround)
+                    {
+                        index = _leafIndexes.FirstOrDefault();
+                    }
+
+                    break;
+
+                case ConsoleKey.Home:
+                    index = _leafIndexes.FirstOrDefault();
+                    break;
+
+                case ConsoleKey.End:
+                    index = _leafIndexes.LastOrDefault();
+                    break;
+
+                case ConsoleKey.PageUp:
+                    index = Math.Max(currentLeafIndex - PageSize, 0);
+                    if (index < _leafIndexes.Count)
+                    {
+                        index = _leafIndexes[index];
+                    }
+
+                    break;
+
+                case ConsoleKey.PageDown:
+                    index = Math.Min(currentLeafIndex + PageSize, _leafIndexes.Count - 1);
+                    if (index < _leafIndexes.Count)
+                    {
+                        index = _leafIndexes[index];
+                    }
+
+                    break;
+            }
+        }
+        else
+        {
+            index = keyInfo.Key switch
+            {
+                ConsoleKey.UpArrow => Index - 1,
+                ConsoleKey.DownArrow => Index + 1,
+                ConsoleKey.Home => 0,
+                ConsoleKey.End => ItemCount - 1,
+                ConsoleKey.PageUp => Index - PageSize,
+                ConsoleKey.PageDown => Index + PageSize,
+                _ => Index,
+            };
+        }
+
+        var search = SearchText;
+
+        if (SearchEnabled)
+        {
+            // If is text input, append to search filter
+            if (!char.IsControl(keyInfo.KeyChar))
+            {
+                search = SearchText + keyInfo.KeyChar;
+                var item = Items.FirstOrDefault(x => x.Data.ToString()?.Contains(search, StringComparison.OrdinalIgnoreCase) == true && (!x.IsGroup || Mode != SelectionMode.Leaf));
+                if (item != null)
+                {
+                    index = Items.IndexOf(item);
+                }
+            }
+
+            if (keyInfo.Key == ConsoleKey.Backspace)
+            {
+                if (search.Length > 0)
+                {
+                    search = search.Substring(0, search.Length - 1);
+                }
+
+                var item = Items.FirstOrDefault(x => x.Data.ToString()?.Contains(search, StringComparison.OrdinalIgnoreCase) == true && (!x.IsGroup || Mode != SelectionMode.Leaf));
+                if (item != null)
+                {
+                    index = Items.IndexOf(item);
+                }
+            }
+        }
 
         index = WrapAround
             ? (ItemCount + (index % ItemCount)) % ItemCount
             : index.Clamp(0, ItemCount - 1);
-        if (index != Index)
+
+        if (index != Index || SearchText != search)
         {
             Index = index;
+            SearchText = search;
             return true;
         }