Feature: Added experimental support for flattening folders

src/Files.App/Actions/FileSystem/FlattenToRootAction.cs

@@ -0,0 +1,140 @@
+// Copyright (c) 2024 Files Community
+// Licensed under the MIT License. See the LICENSE.
+
+using Microsoft.Extensions.Logging;
+using System.IO;
+using Windows.Storage;
+using Microsoft.UI.Xaml.Controls;
+using Windows.Foundation.Metadata;
+using Files.Shared.Helpers;
+
+namespace Files.App.Actions
+{
+	internal sealed class FlattenToRootAction : ObservableObject, IAction
+	{
+		private readonly IContentPageContext context;
+		private readonly IGeneralSettingsService GeneralSettingsService = Ioc.Default.GetRequiredService<IGeneralSettingsService>();
+
+		public string Label
+			=> "FlattenToRoot".GetLocalizedResource();
+
+		public string Description
+			=> "FlattenToRootDescription".GetLocalizedResource();
+
+		public RichGlyph Glyph
+			=> new(themedIconStyle: "App.ThemedIcons.Folder");
+
+		public bool IsExecutable =>
+			GeneralSettingsService.ShowFlattenOptions &&
+			context.ShellPage is not null &&
+			context.HasSelection &&
+			context.SelectedItems.Count is 1 &&
+			context.SelectedItem is not null &&
+			context.SelectedItem.PrimaryItemAttribute is StorageItemTypes.Folder;
+
+		public FlattenToRootAction()
+		{
+			context = Ioc.Default.GetRequiredService<IContentPageContext>();
+
+			context.PropertyChanged += Context_PropertyChanged;
+			GeneralSettingsService.PropertyChanged += GeneralSettingsService_PropertyChanged;
+		}
+
+		public async Task ExecuteAsync(object? parameter = null)
+		{
+			if (context.SelectedItem is null)
+				return;
+
+			var optionsDialog = new ContentDialog()
+			{
+				Title = "FlattenFolderDialogTitle".GetLocalizedResource(),
+				Content = "FlattenFolderDialogContent".GetLocalizedResource(),
+				PrimaryButtonText = "Flatten".GetLocalizedResource(),
+				SecondaryButtonText = "Cancel".GetLocalizedResource(),
+				DefaultButton = ContentDialogButton.Primary
+			};
+
+			if (ApiInformation.IsApiContractPresent("Windows.Foundation.UniversalApiContract", 8))
+				optionsDialog.XamlRoot = MainWindow.Instance.Content.XamlRoot;
+
+			var result = await optionsDialog.TryShowAsync();
+			if (result != ContentDialogResult.Primary)
+				return;
+
+			FlattenFolder(context.SelectedItem.ItemPath);
+		}
+
+		private void FlattenFolder(string path)
+		{
+			var containedFolders = Directory.GetDirectories(path);
+			var containedFiles = Directory.GetFiles(path);
+
+			foreach (var containedFolder in containedFolders)
+			{
+				FlattenFolder(containedFolder);
+
+				var folderName = Path.GetFileName(containedFolder);
+				var destinationPath = Path.Combine(context?.SelectedItem?.ItemPath ?? string.Empty, folderName);
+
+				if (Directory.Exists(destinationPath))
+					continue;
+
+				try
+				{
+					Directory.Move(containedFolder, destinationPath);
+				}
+				catch (Exception ex)
+				{
+					App.Logger.LogWarning(ex.Message, $"Folder '{folderName}' already exists in the destination folder.");
+				}
+			}
+
+			foreach (var containedFile in containedFiles)
+			{
+				var fileName = Path.GetFileName(containedFile);
+				var destinationPath = Path.Combine(context?.SelectedItem?.ItemPath ?? string.Empty, fileName);
+
+				if (File.Exists(destinationPath))
+					continue;
+
+				try
+				{
+					File.Move(containedFile, destinationPath);
+				}
+				catch (Exception ex)
+				{
+					App.Logger.LogWarning(ex.Message, $"Failed to move file '{fileName}'.");
+				}
+			}
+
+			if (Directory.GetFiles(path).Length == 0 && Directory.GetDirectories(path).Length == 0)
+			{
+				try
+				{
+					Directory.Delete(path);
+				}
+				catch (Exception ex)
+				{
+					App.Logger.LogWarning(ex.Message, $"Failed to delete folder '{path}'.");
+				}
+			}
+		}
+
+		private void Context_PropertyChanged(object? sender, PropertyChangedEventArgs e)
+		{
+			switch (e.PropertyName)
+			{
+				case nameof(IContentPageContext.HasSelection):
+				case nameof(IContentPageContext.SelectedItem):
+					OnPropertyChanged(nameof(IsExecutable));
+					break;
+			}
+		}
+
+		private void GeneralSettingsService_PropertyChanged(object? sender, PropertyChangedEventArgs e)
+		{
+			if (e.PropertyName is nameof(IGeneralSettingsService.ShowFlattenOptions))
+				OnPropertyChanged(nameof(IsExecutable));
+		}
+	}
+}

src/Files.App/Data/Commands/Manager/CommandCodes.cs

@@ -97,6 +97,9 @@ public enum CommandCodes
 		DecompressArchiveHereSmart,
 		DecompressArchiveToChildFolder,
 
+		// Folders
+		FlattenToRoot,
+
 		// Image Manipulation
 		RotateLeft,
 		RotateRight,

src/Files.App/Data/Commands/Manager/CommandManager.cs

@@ -1,10 +1,10 @@
 // Copyright (c) 2024 Files Community
 // Licensed under the MIT License. See the LICENSE.
 
-using System.Collections.Frozen;
-using System.Collections.Immutable;
 using Files.App.Actions;
 using Microsoft.Extensions.Logging;
+using System.Collections.Frozen;
+using System.Collections.Immutable;
 
 namespace Files.App.Data.Commands
 {
@@ -102,6 +102,7 @@ public IRichCommand this[HotKey hotKey]
 		public IRichCommand DecompressArchiveHere => commands[CommandCodes.DecompressArchiveHere];
 		public IRichCommand DecompressArchiveHereSmart => commands[CommandCodes.DecompressArchiveHereSmart];
 		public IRichCommand DecompressArchiveToChildFolder => commands[CommandCodes.DecompressArchiveToChildFolder];
+		public IRichCommand FlattenToRoot => commands[CommandCodes.FlattenToRoot];
 		public IRichCommand RotateLeft => commands[CommandCodes.RotateLeft];
 		public IRichCommand RotateRight => commands[CommandCodes.RotateRight];
 		public IRichCommand OpenItem => commands[CommandCodes.OpenItem];
@@ -291,6 +292,7 @@ public IEnumerator<IRichCommand> GetEnumerator() =>
 			[CommandCodes.DecompressArchiveHere] = new DecompressArchiveHere(),
 			[CommandCodes.DecompressArchiveHereSmart] = new DecompressArchiveHereSmart(),
 			[CommandCodes.DecompressArchiveToChildFolder] = new DecompressArchiveToChildFolderAction(),
+			[CommandCodes.FlattenToRoot] = new FlattenToRootAction(),
 			[CommandCodes.RotateLeft] = new RotateLeftAction(),
 			[CommandCodes.RotateRight] = new RotateRightAction(),
 			[CommandCodes.OpenItem] = new OpenItemAction(),

src/Files.App/Data/Commands/Manager/ICommandManager.cs

@@ -89,6 +89,8 @@ public interface ICommandManager : IEnumerable<IRichCommand>
 		IRichCommand DecompressArchiveHereSmart { get; }
 		IRichCommand DecompressArchiveToChildFolder { get; }
 
+		IRichCommand FlattenToRoot { get; }
+
 		IRichCommand RotateLeft { get; }
 		IRichCommand RotateRight { get; }
 

src/Files.App/Data/Contracts/IGeneralSettingsService.cs

@@ -225,6 +225,11 @@ public interface IGeneralSettingsService : IBaseSettingsService, INotifyProperty
 		/// </summary>
 		bool ShowCompressionOptions { get; set; }
 
+		/// <summary>
+		/// Gets or sets a value indicating whether or not to show the flatten options e.g. single, recursive.
+		/// </summary>
+		bool ShowFlattenOptions { get; set; }
+
 		/// <summary>
 		/// Gets or sets a value indicating whether or not to show the Send To menu.
 		/// </summary>

src/Files.App/Data/Factories/ContentPageContextFlyoutFactory.cs

@@ -547,6 +547,7 @@ public static List<ContextMenuFlyoutItemViewModel> GetBaseItemMenuItems(
 					],
 					ShowItem = UserSettingsService.GeneralSettingsService.ShowCompressionOptions && StorageArchiveService.CanDecompress(selectedItems)
 				},
+				new ContextMenuFlyoutItemViewModelBuilder(Commands.FlattenToRoot).Build(),
 				new ContextMenuFlyoutItemViewModel()
 				{
 					Text = "SendTo".GetLocalizedResource(),
@@ -587,7 +588,7 @@ public static List<ContextMenuFlyoutItemViewModel> GetBaseItemMenuItems(
 					ShowItem = isDriveRoot,
 					IsEnabled = false
 				},
-				new ContextMenuFlyoutItemViewModelBuilder(Commands.EditInNotepad).Build(),				
+				new ContextMenuFlyoutItemViewModelBuilder(Commands.EditInNotepad).Build(),
 				new ContextMenuFlyoutItemViewModel()
 				{
 					ItemType = ContextMenuFlyoutItemType.Separator,

src/Files.App/Services/Settings/GeneralSettingsService.cs

@@ -239,6 +239,12 @@ public bool ShowCompressionOptions
 			set => Set(value);
 		}
 
+		public bool ShowFlattenOptions
+		{
+			get => Get(false);
+			set => Set(value);
+		}
+
 		public bool ShowSendToMenu
 		{
 			get => Get(true);

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

@@ -1853,6 +1853,9 @@
   <data name="SettingsSetAsDefaultFileManagerDescription" xml:space="preserve">
     <value>This option modifies the system registry and can have unexpected side effects on your device. Continue at your own risk.</value>
   </data>
+  <data name="ShowFlattenOptionsDescription" xml:space="preserve">
+    <value>The flatten operations are permanent and not recommended. Continue at your own risk.</value>
+  </data>
   <data name="FolderWidgetCreateNewLibraryDialogTitleText" xml:space="preserve">
     <value>Create Library</value>
   </data>
@@ -2027,6 +2030,24 @@
   <data name="Compress" xml:space="preserve">
     <value>Compress</value>
   </data>
+  <data name="Flatten" xml:space="preserve">
+    <value>Flatten</value>
+  </data>
+  <data name="FlattenToRoot" xml:space="preserve">
+    <value>Flatten to root</value>
+  </data>
+  <data name="FlattenToRootDescription" xml:space="preserve">
+    <value>Move all contents from subfolders into the selected location</value>
+  </data>
+  <data name="FlattenFolderDialogTitle" xml:space="preserve">
+    <value>Flatten folder</value>
+  </data>
+  <data name="FlattenFolderDialogContent" xml:space="preserve">
+    <value>Flattening a folder will move all contents from its subfolders to the selected location. This operation is permanent and cannot be undone. By using this experimental feature, you acknowledge the risk and agree not to hold the Files team responsible for any data loss.</value>
+  </data>
+  <data name="ShowFlattenOptions" xml:space="preserve">
+    <value>Show flatten options</value>
+  </data>
   <data name="SelectFilesAndFoldersOnHover" xml:space="preserve">
     <value>Select files and folders when hovering over them</value>
   </data>

src/Files.App/ViewModels/Settings/AdvancedViewModel.cs

@@ -348,6 +348,20 @@ public bool ShowSystemTrayIcon
 			}
 		}
 
+		// TODO remove when feature is marked as stable
+		public bool ShowFlattenOptions
+		{
+			get => UserSettingsService.GeneralSettingsService.ShowFlattenOptions;
+			set
+			{
+				if (value == UserSettingsService.GeneralSettingsService.ShowFlattenOptions)
+					return;
+
+				UserSettingsService.GeneralSettingsService.ShowFlattenOptions = value;
+				OnPropertyChanged();
+			}
+		}
+
 		public async Task OpenFilesOnWindowsStartupAsync()
 		{
 			var stateMode = await ReadState();

src/Files.App/ViewModels/Settings/GeneralViewModel.cs

@@ -454,6 +454,20 @@ public bool ShowCompressionOptions
 			}
 		}
 
+		// TODO uncomment code when feature is marked as stable
+		//public bool ShowFlattenOptions
+		//{
+		//	get => UserSettingsService.GeneralSettingsService.ShowFlattenOptions;
+		//	set
+		//	{
+		//		if (value == UserSettingsService.GeneralSettingsService.ShowFlattenOptions)
+		//			return;
+
+		//		UserSettingsService.GeneralSettingsService.ShowFlattenOptions = value;
+		//		OnPropertyChanged();
+		//	}
+		//}
+
 		public bool ShowSendToMenu
 		{
 			get => UserSettingsService.GeneralSettingsService.ShowSendToMenu;

src/Files.App/Views/Settings/AdvancedPage.xaml

@@ -189,6 +189,20 @@
 					</i:Interaction.Behaviors>
 				</ToggleSwitch>
 			</local:SettingsBlockControl>
+
+			<!--  Flatten options  -->
+			<local:SettingsBlockControl
+				Title="{helpers:ResourceString Name=ShowFlattenOptions}"
+				HorizontalAlignment="Stretch"
+				Description="{helpers:ResourceString Name=ShowFlattenOptionsDescription}">
+				<local:SettingsBlockControl.Icon>
+					<FontIcon Glyph="&#xE8B7;" />
+				</local:SettingsBlockControl.Icon>
+				<ToggleSwitch
+					AutomationProperties.Name="{helpers:ResourceString Name=ShowFlattenOptions}"
+					IsOn="{x:Bind ViewModel.ShowFlattenOptions, Mode=TwoWay}"
+					Style="{StaticResource RightAlignedToggleSwitchStyle}" />
+			</local:SettingsBlockControl>
 		</StackPanel>
 	</Grid>
 </Page>

src/Files.App/Views/Settings/GeneralPage.xaml

@@ -325,6 +325,15 @@
 								Style="{StaticResource RightAlignedToggleSwitchStyle}" />
 						</local:SettingsBlockControl>
 
+						<!--  Flatten options  -->
+						<!--  TODO uncomment code when feature is marked as stable  -->
+						<!--<local:SettingsBlockControl Title="{helpers:ResourceString Name=ShowFlattenOptions}" HorizontalAlignment="Stretch">
+							<ToggleSwitch
+								AutomationProperties.Name="{helpers:ResourceString Name=ShowFlattenOptions}"
+								IsOn="{x:Bind ViewModel.ShowFlattenOptions, Mode=TwoWay}"
+								Style="{StaticResource RightAlignedToggleSwitchStyle}" />
+						</local:SettingsBlockControl>-->
+
 						<!--  Send To  -->
 						<local:SettingsBlockControl Title="{helpers:ResourceString Name=ShowSendToMenu}" HorizontalAlignment="Stretch">
 							<ToggleSwitch