Show a popup when renaming an item to an existing name

Author: d2dyno1

src/Platforms/SecureFolderFS.UI/Strings/en-US/Resources.resx

@@ -1415,4 +1415,7 @@
   <data name="Decrypted" xml:space="preserve">
       <value>Decrypted</value>
   </data>
+  <data name="ItemAlreadyExists" xml:space="preserve">
+      <value>Item with the same name already exists</value>
+  </data>
 </root>

src/Sdk/SecureFolderFS.Sdk/ViewModels/Controls/Storage/Browser/BrowserItemViewModel.cs

@@ -233,17 +233,19 @@ protected virtual async Task RenameAsync(CancellationToken cancellationToken)
                 if (string.IsNullOrWhiteSpace(viewModel.NewName))
                     return;
 
-                var formattedName = CollisionHelpers.GetAvailableName(
-                    FormattingHelpers.SanitizeItemName(viewModel.NewName, "Renamed item"),
-                    ParentFolder.Items.Select(x => x.Inner.Name));
-
+                var formattedName = FormattingHelpers.SanitizeItemName(viewModel.NewName, "Renamed item");
                 if (!Path.HasExtension(formattedName))
                     formattedName = $"{formattedName}{Path.GetExtension(innerChild.Name)}";
 
                 var existingItem = await renamableFolder.TryGetFirstByNameAsync(formattedName, cancellationToken);
                 if (existingItem is not null)
                 {
-                    // TODO: Report that the item already exists
+                    await OverlayService.ShowAsync(new MessageOverlayViewModel()
+                    {
+                        Title = "InvalidItemName".ToLocalized(),
+                        Message = "ItemAlreadyExists".ToLocalized(formattedName),
+                        SecondaryText = "Close".ToLocalized()
+                    });
                     return;
                 }
 

src/Shared/SecureFolderFS.Shared/Extensions/CollectionExtensions.cs

@@ -3,6 +3,7 @@
 using System.Collections.Generic;
 using System.Diagnostics.CodeAnalysis;
 using System.Linq;
+using System.Threading.Tasks;
 using SecureFolderFS.Shared.ComponentModel;
 
 namespace SecureFolderFS.Shared.Extensions