Give feedback to the user when they clear engines/clear server content

SS14.Launcher/Utility/ButtonExtensions.cs

@@ -0,0 +1,21 @@
+using System.Threading.Tasks;
+using Avalonia.Controls;
+
+namespace SS14.Launcher.Utility;
+
+public static class ButtonExtensions
+{
+    /// <summary>
+    /// Sets the content of a button to a specified message ("Done!" by default) for a specified duration (2s by
+    /// default), and disabled the button for this duration.
+    /// </summary>
+    public static async Task DisplayDoneMessage(this Button button, string message = "Done!", int duration = 2000)
+    {
+        var previousContent = button.Content;
+        button.Content = message;
+        button.IsEnabled = false;
+        await Task.Delay(duration);
+        button.Content = previousContent;
+        button.IsEnabled = true;
+    }
+}

SS14.Launcher/Views/MainWindowTabs/OptionsTabView.xaml

@@ -13,10 +13,10 @@
   <ScrollViewer HorizontalScrollBarVisibility="Disabled">
     <DockPanel>
       <Button Content="*flip" DockPanel.Dock="Bottom" HorizontalAlignment="Right" Name="Flip" />
-      <Button Content="Clear installed engines" DockPanel.Dock="Bottom" HorizontalAlignment="Left"
-              Command="{Binding ClearEngines}"/>
-      <Button Content="Clear installed server content" DockPanel.Dock="Bottom" HorizontalAlignment="Left"
-              Command="{Binding ClearServerContent}"/>
+      <Button Name="ClearEnginesButton" Content="Clear installed engines" DockPanel.Dock="Bottom"
+              HorizontalAlignment="Left" Click="ClearEnginesPressed" />
+      <Button Name="ClearServerContentButton" Content="Clear installed server content" DockPanel.Dock="Bottom"
+              HorizontalAlignment="Left" Click="ClearServerContentPressed" />
       <Button Content="Open log directory" DockPanel.Dock="Bottom" HorizontalAlignment="Left"
               Command="{Binding OpenLogDirectory}"/>
 

SS14.Launcher/Views/MainWindowTabs/OptionsTabView.xaml.cs

@@ -1,8 +1,10 @@
 using System;
 using Avalonia.Controls;
-using Avalonia.Markup.Xaml;
+using Avalonia.Interactivity;
 using Avalonia.Threading;
 using ReactiveUI;
+using SS14.Launcher.Utility;
+using SS14.Launcher.ViewModels.MainWindowTabs;
 
 namespace SS14.Launcher.Views.MainWindowTabs;
 
@@ -24,4 +26,16 @@ public OptionsTabView()
             DispatcherTimer.RunOnce(() => { window.Classes.Remove("DoAFlip"); }, TimeSpan.FromSeconds(1));
         });
     }
+
+    public async void ClearEnginesPressed(object? _1, RoutedEventArgs _2)
+    {
+        (DataContext as OptionsTabViewModel)!.ClearEngines();
+        await ClearEnginesButton.DisplayDoneMessage();
+    }
+
+    public async void ClearServerContentPressed(object? _1, RoutedEventArgs _2)
+    {
+        (DataContext as OptionsTabViewModel)!.ClearServerContent();
+        await ClearServerContentButton.DisplayDoneMessage();
+    }
 }