CmdPal: replace custom fuzzy matching in Window Walker (#44807)

## Summary of the Pull Request

This PR replaces the custom search controller and fuzzy matching with
standard classes from the Extension SDK Toolkit.

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## PR Checklist

- [ ] Closes: #xxx
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issues) -->
- [ ] **Communication:** I've discussed this with core contributors
already. If the work hasn't been agreed, this work might be rejected
- [ ] **Tests:** Added/updated and all pass
- [ ] **Localization:** All end-user-facing strings can be localized
- [ ] **Dev docs:** Added/updated
- [ ] **New binaries:** Added on the required places
- [ ] [JSON for
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for new binaries
- [ ] [WXS for
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for new binaries and localization folder
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- [ ] **Documentation updated:** If checked, please file a pull request
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repo](https://github.com/MicrosoftDocs/windows-uwp/tree/docs/hub/powertoys)
and link it here: #xxx

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or any additional comments/features here -->
## Detailed Description of the Pull Request / Additional comments

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wherever possible, but list manual validation steps taken as well -->
## Validation Steps Performed

src/modules/cmdpal/ext/Microsoft.CmdPal.Ext.WindowWalker/Components/FuzzyMatching.cs

@@ -1,134 +0,0 @@
-// 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.
-
-// Code forked from Betsegaw Tadele's https://github.com/betsegaw/windowwalker/
-using System;
-using System.Collections.Generic;
-using System.Globalization;
-using System.Linq;
-
-namespace Microsoft.CmdPal.Ext.WindowWalker.Components;
-
-/// <summary>
-/// Class housing fuzzy matching methods
-/// </summary>
-internal static class FuzzyMatching
-{
-    /// <summary>
-    /// Finds the best match (the one with the most
-    /// number of letters adjacent to each other) and
-    /// returns the index location of each of the letters
-    /// of the matches
-    /// </summary>
-    /// <param name="text">The text to search inside of</param>
-    /// <param name="searchText">the text to search for</param>
-    /// <returns>returns the index location of each of the letters of the matches</returns>
-    internal static List<int> FindBestFuzzyMatch(string text, string searchText)
-    {
-        ArgumentNullException.ThrowIfNull(searchText);
-
-        ArgumentNullException.ThrowIfNull(text);
-
-        // Using CurrentCulture since this is user facing
-        searchText = searchText.ToLower(CultureInfo.CurrentCulture);
-        text = text.ToLower(CultureInfo.CurrentCulture);
-
-        // Create a grid to march matches like
-        // e.g.
-        //   a b c a d e c f g
-        // a x     x
-        // c     x       x
-        var matches = new bool[text.Length, searchText.Length];
-        for (var firstIndex = 0; firstIndex < text.Length; firstIndex++)
-        {
-            for (var secondIndex = 0; secondIndex < searchText.Length; secondIndex++)
-            {
-                matches[firstIndex, secondIndex] =
-                    searchText[secondIndex] == text[firstIndex] ?
-                    true :
-                    false;
-            }
-        }
-
-        // use this table to get all the possible matches
-        List<List<int>> allMatches = GetAllMatchIndexes(matches);
-
-        // return the score that is the max
-        var maxScore = allMatches.Count > 0 ? CalculateScoreForMatches(allMatches[0]) : 0;
-        List<int> bestMatch = allMatches.Count > 0 ? allMatches[0] : new List<int>();
-
-        foreach (var match in allMatches)
-        {
-            var score = CalculateScoreForMatches(match);
-            if (score > maxScore)
-            {
-                bestMatch = match;
-                maxScore = score;
-            }
-        }
-
-        return bestMatch;
-    }
-
-    /// <summary>
-    /// Gets all the possible matches to the search string with in the text
-    /// </summary>
-    /// <param name="matches"> a table showing the matches as generated by
-    /// a two dimensional array with the first dimension the text and the second
-    /// one the search string and each cell marked as an intersection between the two</param>
-    /// <returns>a list of the possible combinations that match the search text</returns>
-    internal static List<List<int>> GetAllMatchIndexes(bool[,] matches)
-    {
-        ArgumentNullException.ThrowIfNull(matches);
-
-        List<List<int>> results = new List<List<int>>();
-
-        for (var secondIndex = 0; secondIndex < matches.GetLength(1); secondIndex++)
-        {
-            for (var firstIndex = 0; firstIndex < matches.GetLength(0); firstIndex++)
-            {
-                if (secondIndex == 0 && matches[firstIndex, secondIndex])
-                {
-                    results.Add(new List<int> { firstIndex });
-                }
-                else if (matches[firstIndex, secondIndex])
-                {
-                    var tempList = results.Where(x => x.Count == secondIndex && x[x.Count - 1] < firstIndex).Select(x => x.ToList()).ToList();
-
-                    foreach (var pathSofar in tempList)
-                    {
-                        pathSofar.Add(firstIndex);
-                    }
-
-                    results.AddRange(tempList);
-                }
-            }
-
-            results = results.Where(x => x.Count == secondIndex + 1).ToList();
-        }
-
-        return results.Where(x => x.Count == matches.GetLength(1)).ToList();
-    }
-
-    /// <summary>
-    /// Calculates the score for a string
-    /// </summary>
-    /// <param name="matches">the index of the matches</param>
-    /// <returns>an integer representing the score</returns>
-    internal static int CalculateScoreForMatches(List<int> matches)
-    {
-        ArgumentNullException.ThrowIfNull(matches);
-
-        var score = 0;
-
-        for (var currentIndex = 1; currentIndex < matches.Count; currentIndex++)
-        {
-            var previousIndex = currentIndex - 1;
-
-            score -= matches[currentIndex] - matches[previousIndex];
-        }
-
-        return score == 0 ? -10000 : score;
-    }
-}

src/modules/cmdpal/ext/Microsoft.CmdPal.Ext.WindowWalker/Components/ResultHelper.cs

@@ -3,7 +3,7 @@
 // See the LICENSE file in the project root for more information.
 using System;
 using System.Collections.Generic;
-using System.Linq;
+using System.Threading.Tasks;
 using Microsoft.CmdPal.Ext.WindowWalker.Commands;
 using Microsoft.CmdPal.Ext.WindowWalker.Helpers;
 using Microsoft.CmdPal.Ext.WindowWalker.Properties;
@@ -19,33 +19,58 @@ internal static class ResultHelper
     /// <summary>
     /// Returns a list of all results for the query.
     /// </summary>
-    /// <param name="searchControllerResults">List with all search controller matches</param>
+    /// <param name="scoredWindows">List with all search controller matches</param>
     /// <returns>List of results</returns>
-    internal static List<WindowWalkerListItem> GetResultList(List<SearchResult> searchControllerResults, bool isKeywordSearch)
+    internal static WindowWalkerListItem[] GetResultList(ICollection<Scored<Window>>? scoredWindows)
     {
-        if (searchControllerResults is null || searchControllerResults.Count == 0)
+        if (scoredWindows is null || scoredWindows.Count == 0)
         {
             return [];
         }
 
-        var resultsList = new List<WindowWalkerListItem>(searchControllerResults.Count);
+        var list = scoredWindows as IList<Scored<Window>> ?? new List<Scored<Window>>(scoredWindows);
-        var addExplorerInfo = searchControllerResults.Any(x =>
-            string.Equals(x.Result.Process.Name, "explorer.exe", StringComparison.OrdinalIgnoreCase) &&
-            x.Result.Process.IsShellProcess);
 
-        // Process each SearchResult to convert it into a Result.
+        var addExplorerInfo = false;
-        // Using parallel processing if the operation is CPU-bound and the list is large.
+        for (var i = 0; i < list.Count; i++)
-        resultsList = searchControllerResults
+        {
-            .AsParallel()
+            var window = list[i].Item;
-            .Select(x => CreateResultFromSearchResult(x))
+            if (window?.Process is null)
-            .ToList();
+            {
+                continue;
+            }
+
+            if (string.Equals(window.Process.Name, "explorer.exe", StringComparison.OrdinalIgnoreCase) && window.Process.IsShellProcess)
+            {
+                addExplorerInfo = true;
+                break;
+            }
+        }
+
+        var projected = new WindowWalkerListItem[list.Count];
+        if (list.Count >= 32)
+        {
+            Parallel.For(0, list.Count, i =>
+            {
+                projected[i] = CreateResultFromSearchResult(list[i]);
+            });
+        }
+        else
+        {
+            for (var i = 0; i < list.Count; i++)
+            {
+                projected[i] = CreateResultFromSearchResult(list[i]);
+            }
+        }
 
         if (addExplorerInfo && !SettingsManager.Instance.HideExplorerSettingInfo)
         {
-            resultsList.Insert(0, GetExplorerInfoResult());
+            var withInfo = new WindowWalkerListItem[projected.Length + 1];
+            withInfo[0] = GetExplorerInfoResult();
+            Array.Copy(projected, 0, withInfo, 1, projected.Length);
+            return withInfo;
         }
 
-        return resultsList;
+        return projected;
     }
 
     /// <summary>
@@ -53,16 +78,15 @@ internal static class ResultHelper
     /// </summary>
     /// <param name="searchResult">The SearchResult object to convert.</param>
     /// <returns>A Result object populated with data from the SearchResult.</returns>
-    private static WindowWalkerListItem CreateResultFromSearchResult(SearchResult searchResult)
+    private static WindowWalkerListItem CreateResultFromSearchResult(Scored<Window> searchResult)
     {
-        var item = new WindowWalkerListItem(searchResult.Result)
+        var item = new WindowWalkerListItem(searchResult.Item)
         {
-            Title = searchResult.Result.Title,
+            Title = searchResult.Item.Title,
-            Subtitle = GetSubtitle(searchResult.Result),
+            Subtitle = GetSubtitle(searchResult.Item),
-            Tags = GetTags(searchResult.Result),
+            Tags = GetTags(searchResult.Item),
         };
         item.MoreCommands = ContextMenuHelper.GetContextMenuResults(item).ToArray();
-
         return item;
     }
 

src/modules/cmdpal/ext/Microsoft.CmdPal.Ext.WindowWalker/Components/SearchController.cs

@@ -1,150 +0,0 @@
-// 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.
-
-// Code forked from Betsegaw Tadele's https://github.com/betsegaw/windowwalker/
-using System;
-using System.Collections.Generic;
-using System.Globalization;
-using System.Linq;
-using Microsoft.CmdPal.Ext.WindowWalker.Helpers;
-
-namespace Microsoft.CmdPal.Ext.WindowWalker.Components;
-
-/// <summary>
-/// Responsible for searching and finding matches for the strings provided.
-/// Essentially the UI independent model of the application
-/// </summary>
-internal sealed class SearchController
-{
-    /// <summary>
-    /// the current search text
-    /// </summary>
-    private string searchText;
-
-    /// <summary>
-    /// Open window search results
-    /// </summary>
-    private List<SearchResult>? searchMatches;
-
-    /// <summary>
-    /// Singleton pattern
-    /// </summary>
-    private static SearchController? instance;
-
-    /// <summary>
-    /// Gets or sets the current search text
-    /// </summary>
-    internal string SearchText
-    {
-        get => searchText;
-
-        set =>
-            searchText = value.ToLower(CultureInfo.CurrentCulture).Trim();
-    }
-
-    /// <summary>
-    /// Gets the open window search results
-    /// </summary>
-    internal List<SearchResult> SearchMatches => new List<SearchResult>(searchMatches ?? []).OrderByDescending(x => x.Score).ToList();
-
-    /// <summary>
-    /// Gets singleton Pattern
-    /// </summary>
-    internal static SearchController Instance
-    {
-        get
-        {
-            instance ??= new SearchController();
-
-            return instance;
-        }
-    }
-
-    /// <summary>
-    /// Initializes a new instance of the <see cref="SearchController"/> class.
-    /// Initializes the search controller object
-    /// </summary>
-    private SearchController()
-    {
-        searchText = string.Empty;
-    }
-
-    /// <summary>
-    /// Event handler for when the search text has been updated
-    /// </summary>
-    internal void UpdateSearchText(string searchText)
-    {
-        SearchText = searchText;
-        SyncOpenWindowsWithModel();
-    }
-
-    /// <summary>
-    /// Syncs the open windows with the OpenWindows Model
-    /// </summary>
-    internal void SyncOpenWindowsWithModel()
-    {
-        System.Diagnostics.Debug.Print("Syncing WindowSearch result with OpenWindows Model");
-
-        var snapshotOfOpenWindows = OpenWindows.Instance.Windows;
-
-        searchMatches = string.IsNullOrWhiteSpace(SearchText) ? AllOpenWindows(snapshotOfOpenWindows) : FuzzySearchOpenWindows(snapshotOfOpenWindows);
-    }
-
-    /// <summary>
-    /// Search method that matches the title of windows with the user search text
-    /// </summary>
-    /// <param name="openWindows">what windows are open</param>
-    /// <returns>Returns search results</returns>
-    private List<SearchResult> FuzzySearchOpenWindows(List<Window> openWindows)
-    {
-        List<SearchResult> result = [];
-        var searchStrings = new SearchString(searchText, SearchResult.SearchType.Fuzzy);
-
-        foreach (var window in openWindows)
-        {
-            var titleMatch = FuzzyMatching.FindBestFuzzyMatch(window.Title, searchStrings.SearchText);
-            var processMatch = FuzzyMatching.FindBestFuzzyMatch(window.Process.Name ?? string.Empty, searchStrings.SearchText);
-
-            if ((titleMatch.Count != 0 || processMatch.Count != 0) && window.Title.Length != 0)
-            {
-                result.Add(new SearchResult(window, titleMatch, processMatch, searchStrings.SearchType));
-            }
-        }
-
-        System.Diagnostics.Debug.Print("Found " + result.Count + " windows that match the search text");
-
-        return result;
-    }
-
-    /// <summary>
-    /// Search method that matches all the windows with a title
-    /// </summary>
-    /// <param name="openWindows">what windows are open</param>
-    /// <returns>Returns search results</returns>
-    private List<SearchResult> AllOpenWindows(List<Window> openWindows)
-    {
-        List<SearchResult> result = [];
-
-        foreach (var window in openWindows)
-        {
-            if (window.Title.Length != 0)
-            {
-                result.Add(new SearchResult(window));
-            }
-        }
-
-        return SettingsManager.Instance.InMruOrder
-            ? result.ToList()
-            : result
-                .OrderBy(w => w.Result.Title)
-                .ToList();
-    }
-
-    /// <summary>
-    /// Event args for a window list update event
-    /// </summary>
-    internal sealed class SearchResultUpdateEventArgs : EventArgs
-    {
-    }
-}

src/modules/cmdpal/ext/Microsoft.CmdPal.Ext.WindowWalker/Components/SearchResult.cs

@@ -1,147 +0,0 @@
-// 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.
-
-// Code forked from Betsegaw Tadele's https://github.com/betsegaw/windowwalker/
-using System.Collections.Generic;
-
-namespace Microsoft.CmdPal.Ext.WindowWalker.Components;
-
-/// <summary>
-/// Contains search result windows with each window including the reason why the result was included
-/// </summary>
-internal sealed class SearchResult
-{
-    /// <summary>
-    /// Gets the actual window reference for the search result
-    /// </summary>
-    internal Window Result
-    {
-        get;
-        private set;
-    }
-
-    /// <summary>
-    /// Gets the list of indexes of the matching characters for the search in the title window
-    /// </summary>
-    internal List<int> SearchMatchesInTitle
-    {
-        get;
-        private set;
-    }
-
-    /// <summary>
-    /// Gets the list of indexes of the matching characters for the search in the
-    /// name of the process
-    /// </summary>
-    internal List<int> SearchMatchesInProcessName
-    {
-        get;
-        private set;
-    }
-
-    /// <summary>
-    /// Gets the type of match (shortcut, fuzzy or nothing)
-    /// </summary>
-    internal SearchType SearchResultMatchType
-    {
-        get;
-        private set;
-    }
-
-    /// <summary>
-    /// Gets a score indicating how well this matches what we are looking for
-    /// </summary>
-    internal int Score
-    {
-        get;
-        private set;
-    }
-
-    /// <summary>
-    /// Gets the source of where the best score was found
-    /// </summary>
-    internal TextType BestScoreSource
-    {
-        get;
-        private set;
-    }
-
-    /// <summary>
-    /// Initializes a new instance of the <see cref="SearchResult"/> class.
-    /// Constructor
-    /// </summary>
-    internal SearchResult(Window window, List<int> matchesInTitle, List<int> matchesInProcessName, SearchType matchType)
-    {
-        Result = window;
-        SearchMatchesInTitle = matchesInTitle;
-        SearchMatchesInProcessName = matchesInProcessName;
-        SearchResultMatchType = matchType;
-        CalculateScore();
-    }
-
-    /// <summary>
-    /// Initializes a new instance of the <see cref="SearchResult"/> class.
-    /// </summary>
-    internal SearchResult(Window window)
-    {
-        Result = window;
-        SearchMatchesInTitle = new List<int>();
-        SearchMatchesInProcessName = new List<int>();
-        SearchResultMatchType = SearchType.Empty;
-        CalculateScore();
-    }
-
-    /// <summary>
-    /// Calculates the score for how closely this window matches the search string
-    /// </summary>
-    /// <remarks>
-    /// Higher Score is better
-    /// </remarks>
-    private void CalculateScore()
-    {
-        if (FuzzyMatching.CalculateScoreForMatches(SearchMatchesInProcessName) >
-            FuzzyMatching.CalculateScoreForMatches(SearchMatchesInTitle))
-        {
-            Score = FuzzyMatching.CalculateScoreForMatches(SearchMatchesInProcessName);
-            BestScoreSource = TextType.ProcessName;
-        }
-        else
-        {
-            Score = FuzzyMatching.CalculateScoreForMatches(SearchMatchesInTitle);
-            BestScoreSource = TextType.WindowTitle;
-        }
-    }
-
-    /// <summary>
-    /// The type of text that a string represents
-    /// </summary>
-    internal enum TextType
-    {
-        ProcessName,
-        WindowTitle,
-    }
-
-    /// <summary>
-    /// The type of search
-    /// </summary>
-    internal enum SearchType
-    {
-        /// <summary>
-        /// the search string is empty, which means all open windows are
-        /// going to be returned
-        /// </summary>
-        Empty,
-
-        /// <summary>
-        /// Regular fuzzy match search
-        /// </summary>
-        Fuzzy,
-
-        /// <summary>
-        /// The user has entered text that has been matched to a shortcut
-        /// and the shortcut is now being searched
-        /// </summary>
-        Shortcut,
-    }
-}

src/modules/cmdpal/ext/Microsoft.CmdPal.Ext.WindowWalker/Components/SearchString.cs

@@ -1,45 +0,0 @@
-// 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.
-
-// Code forked from Betsegaw Tadele's https://github.com/betsegaw/windowwalker/
-namespace Microsoft.CmdPal.Ext.WindowWalker.Components;
-
-/// <summary>
-/// A class to represent a search string
-/// </summary>
-/// <remarks>Class was added in order to be able to attach various context data to
-/// a search string</remarks>
-internal sealed class SearchString
-{
-    /// <summary>
-    /// Gets where is the search string coming from (is it a shortcut
-    /// or direct string, etc...)
-    /// </summary>
-    internal SearchResult.SearchType SearchType
-    {
-        get;
-        private set;
-    }
-
-    /// <summary>
-    /// Gets the actual text we are searching for
-    /// </summary>
-    internal string SearchText
-    {
-        get;
-        private set;
-    }
-
-    /// <summary>
-    /// Initializes a new instance of the <see cref="SearchString"/> class.
-    /// Constructor
-    /// </summary>
-    /// <param name="searchText">text from search</param>
-    /// <param name="searchType">type of search</param>
-    internal SearchString(string searchText, SearchResult.SearchType searchType)
-    {
-        SearchText = searchText;
-        SearchType = searchType;
-    }
-}

src/modules/cmdpal/ext/Microsoft.CmdPal.Ext.WindowWalker/Pages/WindowWalkerListPage.cs

@@ -3,9 +3,8 @@
 // See the LICENSE file in the project root for more information.
 
 using System;
-using System.Collections.Generic;
-using System.Globalization;
 using Microsoft.CmdPal.Ext.WindowWalker.Components;
+using Microsoft.CmdPal.Ext.WindowWalker.Helpers;
 using Microsoft.CmdPal.Ext.WindowWalker.Properties;
 using Microsoft.CommandPalette.Extensions;
 using Microsoft.CommandPalette.Extensions.Toolkit;
@@ -33,10 +32,12 @@ internal sealed partial class WindowWalkerListPage : DynamicListPage, IDisposabl
         };
     }
 
-    public override void UpdateSearchText(string oldSearch, string newSearch) =>
+    public override void UpdateSearchText(string oldSearch, string newSearch)
+    {
         RaiseItemsChanged(0);
+    }
 
-    public List<WindowWalkerListItem> Query(string query)
+    private WindowWalkerListItem[] Query(string query)
     {
         ArgumentNullException.ThrowIfNull(query);
 
@@ -46,13 +47,37 @@ internal sealed partial class WindowWalkerListPage : DynamicListPage, IDisposabl
 
         WindowWalkerCommandsProvider.VirtualDesktopHelperInstance.UpdateDesktopList();
         OpenWindows.Instance.UpdateOpenWindowsList(_cancellationTokenSource.Token);
-        SearchController.Instance.UpdateSearchText(query);
-        var searchControllerResults = SearchController.Instance.SearchMatches;
 
-        return ResultHelper.GetResultList(searchControllerResults, !string.IsNullOrEmpty(query));
+        var windows = OpenWindows.Instance.Windows;
+
+        if (string.IsNullOrWhiteSpace(query))
+        {
+            if (!SettingsManager.Instance.InMruOrder)
+            {
+                windows.Sort(static (a, b) => string.Compare(a?.Title, b?.Title, StringComparison.OrdinalIgnoreCase));
             }
 
-    public override IListItem[] GetItems() => Query(SearchText).ToArray();
+            var results = new Scored<Window>[windows.Count];
+            for (var i = 0; i < windows.Count; i++)
+            {
+                results[i] = new Scored<Window> { Item = windows[i], Score = 100 };
+            }
+
+            return ResultHelper.GetResultList(results);
+        }
+
+        var scored = ListHelpers.FilterListWithScores(windows, query, ScoreFunction);
+        return ResultHelper.GetResultList([.. scored]);
+    }
+
+    private static int ScoreFunction(string q, Window window)
+    {
+        var titleScore = FuzzyStringMatcher.ScoreFuzzy(q, window.Title);
+        var processNameScore = FuzzyStringMatcher.ScoreFuzzy(q, window.Process?.Name ?? string.Empty);
+        return Math.Max(titleScore, processNameScore);
+    }
+
+    public override IListItem[] GetItems() => Query(SearchText);
 
     public void Dispose()
     {