1 files changed, 242 insertions, 0 deletions
diff --git a/Software/Visual_Studio/Scripting/Tango.Scripting.Editors/Editing/TextAreaInputHandler.cs b/Software/Visual_Studio/Scripting/Tango.Scripting.Editors/Editing/TextAreaInputHandler.cs
new file mode 100644
index 000000000..3256875be
--- /dev/null
+++ b/Software/Visual_Studio/Scripting/Tango.Scripting.Editors/Editing/TextAreaInputHandler.cs
@@ -0,0 +1,242 @@
+// Copyright (c) AlphaSierraPapa for the SharpDevelop Team (for details please see \doc\copyright.txt)
+// This code is distributed under the GNU LGPL (for details please see \doc\license.txt)
+
+using Tango.Scripting.Editors.Utils;
+using System;
+using System.Collections.Generic;
+using System.Collections.ObjectModel;
+using System.Windows.Input;
+
+namespace Tango.Scripting.Editors.Editing
+{
+	/// <summary>
+	/// A set of input bindings and event handlers for the text area.
+	/// </summary>
+	/// <remarks>
+	/// <para>
+	/// There is one active input handler per text area (<see cref="Editing.TextArea.ActiveInputHandler"/>), plus
+	/// a number of active stacked input handlers.
+	/// </para>
+	/// <para>
+	/// The text area also stores a reference to a default input handler, but that is not necessarily active.
+	/// </para>
+	/// <para>
+	/// Stacked input handlers work in addition to the set of currently active handlers (without detaching them).
+	/// They are detached in the reverse order of being attached.
+	/// </para>
+	/// </remarks>
+	public interface ITextAreaInputHandler
+	{
+		/// <summary>
+		/// Gets the text area that the input handler belongs to.
+		/// </summary>
+		TextArea TextArea {
+			get;
+		}
+		
+		/// <summary>
+		/// Attaches an input handler to the text area.
+		/// </summary>
+		void Attach();
+		
+		/// <summary>
+		/// Detaches the input handler from the text area.
+		/// </summary>
+		void Detach();
+	}
+	
+	/// <summary>
+	/// Stacked input handler.
+	/// Uses OnEvent-methods instead of registering event handlers to ensure that the events are handled in the correct order.
+	/// </summary>
+	public abstract class TextAreaStackedInputHandler : ITextAreaInputHandler
+	{
+		readonly TextArea textArea;
+		
+		/// <inheritdoc/>
+		public TextArea TextArea {
+			get { return textArea; }
+		}
+		
+		/// <summary>
+		/// Creates a new TextAreaInputHandler.
+		/// </summary>
+		protected TextAreaStackedInputHandler(TextArea textArea)
+		{
+			if (textArea == null)
+				throw new ArgumentNullException("textArea");
+			this.textArea = textArea;
+		}
+		
+		/// <inheritdoc/>
+		public virtual void Attach()
+		{
+		}
+		
+		/// <inheritdoc/>
+		public virtual void Detach()
+		{
+		}
+		
+		/// <summary>
+		/// Called for the PreviewKeyDown event.
+		/// </summary>
+		public virtual void OnPreviewKeyDown(KeyEventArgs e)
+		{
+		}
+		
+		/// <summary>
+		/// Called for the PreviewKeyUp event.
+		/// </summary>
+		public virtual void OnPreviewKeyUp(KeyEventArgs e)
+		{
+		}
+	}
+	
+	/// <summary>
+	/// Default-implementation of <see cref="ITextAreaInputHandler"/>.
+	/// </summary>
+	/// <remarks><inheritdoc cref="ITextAreaInputHandler"/></remarks>
+	public class TextAreaInputHandler : ITextAreaInputHandler
+	{
+		readonly ObserveAddRemoveCollection<CommandBinding> commandBindings;
+		readonly ObserveAddRemoveCollection<InputBinding> inputBindings;
+		readonly ObserveAddRemoveCollection<ITextAreaInputHandler> nestedInputHandlers;
+		readonly TextArea textArea;
+		bool isAttached;
+		
+		/// <summary>
+		/// Creates a new TextAreaInputHandler.
+		/// </summary>
+		public TextAreaInputHandler(TextArea textArea)
+		{
+			if (textArea == null)
+				throw new ArgumentNullException("textArea");
+			this.textArea = textArea;
+			commandBindings = new ObserveAddRemoveCollection<CommandBinding>(CommandBinding_Added, CommandBinding_Removed);
+			inputBindings = new ObserveAddRemoveCollection<InputBinding>(InputBinding_Added, InputBinding_Removed);
+			nestedInputHandlers = new ObserveAddRemoveCollection<ITextAreaInputHandler>(NestedInputHandler_Added, NestedInputHandler_Removed);
+		}
+		
+		/// <inheritdoc/>
+		public TextArea TextArea {
+			get { return textArea; }
+		}
+		
+		/// <summary>
+		/// Gets whether the input handler is currently attached to the text area.
+		/// </summary>
+		public bool IsAttached {
+			get { return isAttached; }
+		}
+		
+		#region CommandBindings / InputBindings
+		/// <summary>
+		/// Gets the command bindings of this input handler.
+		/// </summary>
+		public ICollection<CommandBinding> CommandBindings {
+			get { return commandBindings; }
+		}
+		
+		void CommandBinding_Added(CommandBinding commandBinding)
+		{
+			if (isAttached)
+				textArea.CommandBindings.Add(commandBinding);
+		}
+		
+		void CommandBinding_Removed(CommandBinding commandBinding)
+		{
+			if (isAttached)
+				textArea.CommandBindings.Remove(commandBinding);
+		}
+		
+		/// <summary>
+		/// Gets the input bindings of this input handler.
+		/// </summary>
+		public ICollection<InputBinding> InputBindings {
+			get { return inputBindings; }
+		}
+		
+		void InputBinding_Added(InputBinding inputBinding)
+		{
+			if (isAttached)
+				textArea.InputBindings.Add(inputBinding);
+		}
+		
+		void InputBinding_Removed(InputBinding inputBinding)
+		{
+			if (isAttached)
+				textArea.InputBindings.Remove(inputBinding);
+		}
+		
+		/// <summary>
+		/// Adds a command and input binding.
+		/// </summary>
+		/// <param name="command">The command ID.</param>
+		/// <param name="modifiers">The modifiers of the keyboard shortcut.</param>
+		/// <param name="key">The key of the keyboard shortcut.</param>
+		/// <param name="handler">The event handler to run when the command is executed.</param>
+		public void AddBinding(ICommand command, ModifierKeys modifiers, Key key, ExecutedRoutedEventHandler handler)
+		{
+			this.CommandBindings.Add(new CommandBinding(command, handler));
+			this.InputBindings.Add(new KeyBinding(command, key, modifiers));
+		}
+		#endregion
+		
+		#region NestedInputHandlers
+		/// <summary>
+		/// Gets the collection of nested input handlers. NestedInputHandlers are activated and deactivated
+		/// together with this input handler.
+		/// </summary>
+		public ICollection<ITextAreaInputHandler> NestedInputHandlers {
+			get { return nestedInputHandlers; }
+		}
+		
+		void NestedInputHandler_Added(ITextAreaInputHandler handler)
+		{
+			if (handler == null)
+				throw new ArgumentNullException("handler");
+			if (handler.TextArea != textArea)
+				throw new ArgumentException("The nested handler must be working for the same text area!");
+			if (isAttached)
+				handler.Attach();
+		}
+		
+		void NestedInputHandler_Removed(ITextAreaInputHandler handler)
+		{
+			if (isAttached)
+				handler.Detach();
+		}
+		#endregion
+		
+		#region Attach/Detach
+		/// <inheritdoc/>
+		public virtual void Attach()
+		{
+			if (isAttached)
+				throw new InvalidOperationException("Input handler is already attached");
+			isAttached = true;
+			
+			textArea.CommandBindings.AddRange(commandBindings);
+			textArea.InputBindings.AddRange(inputBindings);
+			foreach (ITextAreaInputHandler handler in nestedInputHandlers)
+				handler.Attach();
+		}
+		
+		/// <inheritdoc/>
+		public virtual void Detach()
+		{
+			if (!isAttached)
+				throw new InvalidOperationException("Input handler is not attached");
+			isAttached = false;
+			
+			foreach (CommandBinding b in commandBindings)
+				textArea.CommandBindings.Remove(b);
+			foreach (InputBinding b in inputBindings)
+				textArea.InputBindings.Remove(b);
+			foreach (ITextAreaInputHandler handler in nestedInputHandlers)
+				handler.Detach();
+		}
+		#endregion
+	}
+}