Rename the [Ee]xts dir to ext (#38852)

**WARNING:** This PR will probably blow up all in-flight PRs

at some point in the early days of CmdPal, two of us created seperate
`Exts` and `exts` dirs. Depending on what the casing was on the branch
that you checked one of those out from, it'd get stuck like that on your
PC forever.

Windows didn't care, so we never noticed.

But GitHub does care, and now browsing the source on GitHub is basically
impossible.

Closes #38081

src/modules/cmdpal/ext/Microsoft.CmdPal.Ext.TimeDate/Helpers/TimeDateCalculator.cs

@@ -0,0 +1,108 @@
+// 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 System.Linq;
+using System.Text.RegularExpressions;
+using Microsoft.CommandPalette.Extensions.Toolkit;
+
+namespace Microsoft.CmdPal.Ext.TimeDate.Helpers;
+
+public sealed partial class TimeDateCalculator
+{
+    /// <summary>
+    /// Var that holds the delimiter between format and date
+    /// </summary>
+    private const string InputDelimiter = "::";
+
+    /// <summary>
+    /// A list of conjunctions that we ignore on search
+    /// </summary>
+    private static readonly string[] _conjunctionList = Resources.Microsoft_plugin_timedate_Search_ConjunctionList.Split("; ");
+
+    /// <summary>
+    /// Searches for results
+    /// </summary>
+    /// <param name="query">Search query object</param>
+    /// <returns>List of Wox <see cref="Result"/>s.</returns>
+    public static List<ListItem> ExecuteSearch(SettingsManager settings, string query)
+    {
+        var isEmptySearchInput = string.IsNullOrEmpty(query);
+        List<AvailableResult> availableFormats = new List<AvailableResult>();
+        List<ListItem> results = new List<ListItem>();
+
+        // currently, all of the search in V2 is keyword search.
+        var isKeywordSearch = true;
+
+        // Switch search type
+        if (isEmptySearchInput || (!isKeywordSearch && settings.OnlyDateTimeNowGlobal))
+        {
+            // Return all results for system time/date on empty keyword search
+            // or only time, date and now results for system time on global queries if the corresponding setting is enabled
+            availableFormats.AddRange(AvailableResultsList.GetList(isKeywordSearch, settings));
+        }
+        else if (Regex.IsMatch(query, @".+" + Regex.Escape(InputDelimiter) + @".+"))
+        {
+            // Search for specified format with specified time/date value
+            var userInput = query.Split(InputDelimiter);
+            if (TimeAndDateHelper.ParseStringAsDateTime(userInput[1], out DateTime timestamp))
+            {
+                availableFormats.AddRange(AvailableResultsList.GetList(isKeywordSearch, settings, null, null, timestamp));
+                query = userInput[0];
+            }
+        }
+        else if (TimeAndDateHelper.ParseStringAsDateTime(query, out DateTime timestamp))
+        {
+            // Return all formats for specified time/date value
+            availableFormats.AddRange(AvailableResultsList.GetList(isKeywordSearch, settings, null, null, timestamp));
+            query = string.Empty;
+        }
+        else
+        {
+            // Search for specified format with system time/date (All other cases)
+            availableFormats.AddRange(AvailableResultsList.GetList(isKeywordSearch, settings));
+        }
+
+        // Check searchTerm after getting results to select type of result list
+        if (string.IsNullOrEmpty(query))
+        {
+            // Generate list with all results
+            foreach (var f in availableFormats)
+            {
+                results.Add(f.ToListItem());
+            }
+        }
+        else
+        {
+            // Generate filtered list of results
+            foreach (var f in availableFormats)
+            {
+                var score = f.Score(query, f.Label, f.AlternativeSearchTag);
+
+                if (score > 0)
+                {
+                    results.Add(f.ToListItem());
+                }
+            }
+        }
+
+        // If search term is only a number that can't be parsed return an error message
+        if (!isEmptySearchInput && results.Count == 0 && Regex.IsMatch(query, @"\w+\d+.*$") && !query.Any(char.IsWhiteSpace) && (TimeAndDateHelper.IsSpecialInputParsing(query) || !Regex.IsMatch(query, @"\d+[\.:/]\d+")))
+        {
+            // Without plugin key word show only if message is not hidden by setting
+            if (!settings.HideNumberMessageOnGlobalQuery)
+            {
+                results.Add(ResultHelper.CreateNumberErrorResult());
+            }
+        }
+
+        if (results.Count == 0)
+        {
+            results.Add(ResultHelper.CreateInvalidInputErrorResult());
+        }
+
+        return results;
+    }
+}