Code Quality: Adding the possibility of plural translation using ICU format

src/Files.App/Extensions/MessageFormatExtensions.cs

@@ -0,0 +1,68 @@
+// Copyright (c) 2024 Files Community
+// Licensed under the MIT License. See the LICENSE.
+
+using Jeffijoe.MessageFormat;
+using Microsoft.Windows.ApplicationModel.Resources;
+using Windows.Globalization;
+using System.Globalization;
+using Microsoft.Extensions.Logging;
+
+namespace Files.App.Extensions
+{
+	public static class MessageFormatExtensions
+	{
+		// Resource map for accessing localized strings
+		private static readonly ResourceMap resourcesTree = new ResourceManager().MainResourceMap.TryGetSubtree("Resources");
+
+		// CultureInfo based on the application's primary language override
+		private static readonly CultureInfo locale = new(ApplicationLanguages.PrimaryLanguageOverride);
+
+		// Message formatter with caching enabled, using the current UI culture's two-letter ISO language name
+		private static readonly MessageFormatter formatter = new(useCache: true, locale: locale.TwoLetterISOLanguageName);
+
+		// Extension method to create a dictionary for format pairs with a string key
+		public static IReadOnlyDictionary<string, object?> ToFormatPairs(this string key, object value) => new Dictionary<string, object?> { [key] = value };
+
+		// Extension method to create a dictionary for format pairs with an integer key
+		public static IReadOnlyDictionary<string, object?> ToFormatPairs(this int key, object value) => new Dictionary<string, object?> { [key.ToString()] = value };
+
+		// Retrieves a localized resource string, formatting it with the provided pairs
+		public static string GetLocalizedFormatResource(this string resourceKey, IReadOnlyDictionary<string, object?> pairs)
+		{
+			var value = resourcesTree?.TryGetValue(resourceKey)?.ValueAsString;
+
+			if (value is null)
+				return string.Empty;
+
+			try
+			{
+				value = formatter.FormatMessage(value, pairs);
+			}
+			catch
+			{
+				value = string.Empty;
+				App.Logger.LogWarning($"Formatter could not get a valid result value for: '{resourceKey}'");
+			}
+
+			return value;
+		}
+
+		// Overloaded method to accept multiple dictionaries of pairs and merge them
+		public static string GetLocalizedFormatResource(this string resourceKey, params IReadOnlyDictionary<string, object?>[] pairs)
+		{
+			var mergedPairs = pairs.SelectMany(dict => dict).ToDictionary(pair => pair.Key, pair => pair.Value);
+			return GetLocalizedFormatResource(resourceKey, mergedPairs);
+		}
+
+		// Overloaded method to accept multiple values and convert them to a dictionary with their indices as keys
+		public static string GetLocalizedFormatResource(this string resourceKey, params object[] values)
+		{
+			var pairs = values.Select((value, index) => new KeyValuePair<string, object?>(index.ToString(), value))
+							  .ToDictionary(pair => pair.Key, pair => pair.Value);
+			return GetLocalizedFormatResource(resourceKey, pairs);
+		}
+
+		//TODO: Could replace `GetLocalizedResource()` in the future
+		public static string GetLocalizedFormatResource(this string resourceKey) => GetLocalizedFormatResource(resourceKey, new Dictionary<string, object?>());
+	}
+}

src/Files.App/Files.App.csproj

@@ -75,6 +75,7 @@
         <PackageReference Include="LibGit2Sharp" Version="0.30.0" />
         <PackageReference Include="LiteDB" Version="5.0.19" />
         <PackageReference Include="LiveChartsCore.SkiaSharpView.WinUI" Version="2.0.0-rc1.2" />
+        <PackageReference Include="MessageFormat" Version="7.1.0" />
         <PackageReference Include="Microsoft.AppCenter.Analytics" Version="5.0.3" />
         <PackageReference Include="Microsoft.AppCenter.Crashes" Version="5.0.3" />
         <PackageReference Include="Microsoft.Data.Sqlite.Core" Version="8.0.4" />

src/Files.App/Strings/en-US/Resources.resw

@@ -426,17 +426,13 @@
   <data name="InvalidFilename.Text" xml:space="preserve">
     <value>The item name specified is invalid</value>
   </data>
-  <data name="ItemSelected.Text" xml:space="preserve">
-    <value>item selected</value>
+  <data name="SelectedItems" xml:space="preserve">
+    <value>{0, plural, one {# item selected} other {# items selected}}</value>
+    <comment>ICU format for plurals, more information here: https://support.crowdin.com/icu-message-syntax/#plural</comment>
   </data>
-  <data name="ItemsSelected.Text" xml:space="preserve">
-    <value>items selected</value>
-  </data>
-  <data name="ItemCount.Text" xml:space="preserve">
-    <value>item</value>
-  </data>
-  <data name="ItemsCount.Text" xml:space="preserve">
-    <value>items</value>
+  <data name="Items" xml:space="preserve">
+    <value>{0, plural, one {item} other {items}}</value>
+    <comment>ICU format for plurals, more information here: https://support.crowdin.com/icu-message-syntax/#plural</comment>
   </data>
   <data name="Yes" xml:space="preserve">
     <value>Yes</value>

src/Files.App/Views/Layouts/BaseLayoutPage.cs

@@ -244,10 +244,10 @@ internal set
 						UpdateSelectionSize();
 
 						SelectedItemsPropertiesViewModel.SelectedItemsCount = selectedItems.Count;
+						SelectedItemsPropertiesViewModel.SelectedItemsCountString = "SelectedItems".GetLocalizedFormatResource(selectedItems!.Count);
 
 						if (selectedItems.Count == 1)
 						{
-							SelectedItemsPropertiesViewModel.SelectedItemsCountString = $"{selectedItems.Count} {"ItemSelected/Text".GetLocalizedResource()}";
 							DispatcherQueue.EnqueueOrInvokeAsync(async () =>
 							{
 								// Tapped event must be executed first
@@ -256,10 +256,7 @@ internal set
 							});
 						}
 						else
-						{
-							SelectedItemsPropertiesViewModel.SelectedItemsCountString = $"{selectedItems!.Count} {"ItemsSelected/Text".GetLocalizedResource()}";
 							ResetRenameDoubleClick();
-						}
 					}
 
 					NotifyPropertyChanged(nameof(SelectedItems));

src/Files.App/Views/Shells/BaseShellPage.cs

@@ -239,9 +239,7 @@ protected async void FilesystemViewModel_DirectoryInfoUpdated(object sender, Eve
 			if (ContentPage is null)
 				return;
 
-			var directoryItemCountLocalization = (FilesystemViewModel.FilesAndFolders.Count == 1)
-				? "ItemCount/Text".GetLocalizedResource()
-				: "ItemsCount/Text".GetLocalizedResource();
+			var directoryItemCountLocalization = "Items".GetLocalizedFormatResource(FilesystemViewModel.FilesAndFolders.Count);
 
 			BranchItem? headBranch = headBranch = InstanceViewModel.IsGitRepository
 					? await GitHelpers.GetRepositoryHead(InstanceViewModel.GitRepositoryPath)