Add compare file button

Author: Lamparter

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

@@ -4059,4 +4059,8 @@
     <value>Hashes don't match</value>
     <comment>Appears when two compared hashes don't match</comment>
   </data>
+  <data name="CompareFile" xml:space="preserve">
+    <value>Compare a file</value>
+    <comment>Button that appears in file hash properties that allows the user to compare two files</comment>
+  </data>
 </root>

src/Files.App/Views/Properties/HashesPage.xaml

@@ -240,6 +240,15 @@
 					VerticalAlignment="Center"
 					Visibility="Collapsed" />
 			</Grid>
+
+			<!--  Compare File Button  -->
+			<Button
+				x:Name="CompareFileButton"
+				Grid.Row="0"
+				Grid.Column="1"
+				Margin="12"
+				Click="CompareFileButton_Click"
+				Content="{helpers:ResourceString Name=CompareFile}" />
 		</Grid>
 	</Grid>
 </vm:BasePropertiesPage>

src/Files.App/Views/Properties/HashesPage.xaml.cs

@@ -1,16 +1,16 @@
-// Copyright (c) Files Community
+// Copyright (c) Files Community
 // Licensed under the MIT License.
 
 using Files.App.Data.Parameters;
 using Files.App.Utils;
 using Files.App.ViewModels.Properties;
 using Microsoft.UI.Xaml;
-using Microsoft.UI.Xaml.Media;
 using Microsoft.UI.Xaml.Controls;
 using Microsoft.UI.Xaml.Controls.Primitives;
 using Microsoft.UI.Xaml.Navigation;
+using System.IO;
+using System.Security.Cryptography;
 using System.Threading.Tasks;
-using Windows.UI;
 
 namespace Files.App.Views.Properties
 {
@@ -79,6 +79,46 @@ private void CompareHashes()
 			HashMatchIcon.Visibility = Visibility.Visible;
 		}
 
+		private async void CompareFileButton_Click(object sender, RoutedEventArgs e)
+		{
+			var picker = new Windows.Storage.Pickers.FileOpenPicker();
+			picker.SuggestedStartLocation = Windows.Storage.Pickers.PickerLocationId.Desktop;
+			picker.FileTypeFilter.Add("*");
+			WinRT.Interop.InitializeWithWindow.Initialize(picker, MainWindow.Instance.WindowHandle);
+
+			var file = await picker.PickSingleFileAsync();
+			if (file != null)
+			{
+				var selectedFileHash = await CalculateSHA384HashAsync(file.Path);
+				var currentFileHash = HashesViewModel.Hashes.FirstOrDefault(h => h.Algorithm == "SHA384")?.HashValue;
+
+				if (selectedFileHash == currentFileHash)
+				{
+					HashMatchIcon.Glyph = "\uE73E"; // Check mark
+					ToolTipService.SetToolTip(HashMatchIcon, Strings.HashesMatch.GetLocalizedResource());
+				}
+				else
+				{
+					HashMatchIcon.Glyph = "\uE711"; // Cross mark
+					ToolTipService.SetToolTip(HashMatchIcon, Strings.HashesMatch.GetLocalizedResource());
+				}
+
+				HashMatchIcon.Visibility = Visibility.Visible;
+			}
+		}
+
+		private async Task<string> CalculateSHA384HashAsync(string filePath)
+		{
+			using (var stream = File.OpenRead(filePath))
+			{
+				using (var sha384 = SHA384.Create())
+				{
+					var hash = await Task.Run(() => sha384.ComputeHash(stream));
+					return BitConverter.ToString(hash).Replace("-", "").ToLowerInvariant();
+				}
+			}
+		}
+
 		private void MenuFlyout_Closing(FlyoutBase sender, FlyoutBaseClosingEventArgs e)
 		{
 			e.Cancel = _cancel;