source: branches/Async/HeuristicLab.ExtLibs/HeuristicLab.AvalonEdit/5.0.1/AvalonEdit-5.0.1/CodeCompletion/CompletionWindowBase.cs @ 13401

// Copyright (c) 2014 AlphaSierraPapa for the SharpDevelop Team
// 
// Permission is hereby granted, free of charge, to any person obtaining a copy of this
// software and associated documentation files (the "Software"), to deal in the Software
// without restriction, including without limitation the rights to use, copy, modify, merge,
// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
// to whom the Software is furnished to do so, subject to the following conditions:
// 
// The above copyright notice and this permission notice shall be included in all copies or
// substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.

using System;
using System.Diagnostics;
using System.Linq;
using System.Windows;
using System.Windows.Controls.Primitives;
using System.Windows.Input;
using System.Windows.Threading;

using ICSharpCode.AvalonEdit.Document;
using ICSharpCode.AvalonEdit.Editing;
using ICSharpCode.AvalonEdit.Rendering;
using ICSharpCode.AvalonEdit.Utils;
using ICSharpCode.NRefactory.Editor;

namespace ICSharpCode.AvalonEdit.CodeCompletion
{
  /// <summary>
  /// Base class for completion windows. Handles positioning the window at the caret.
  /// </summary>
  public class CompletionWindowBase : Window
  {
    static CompletionWindowBase()
    {
      WindowStyleProperty.OverrideMetadata(typeof(CompletionWindowBase), new FrameworkPropertyMetadata(WindowStyle.None));
      ShowActivatedProperty.OverrideMetadata(typeof(CompletionWindowBase), new FrameworkPropertyMetadata(Boxes.False));
      ShowInTaskbarProperty.OverrideMetadata(typeof(CompletionWindowBase), new FrameworkPropertyMetadata(Boxes.False));
    }
    
    /// <summary>
    /// Gets the parent TextArea.
    /// </summary>
    public TextArea TextArea { get; private set; }
    
    Window parentWindow;
    TextDocument document;
    
    /// <summary>
    /// Gets/Sets the start of the text range in which the completion window stays open.
    /// This text portion is used to determine the text used to select an entry in the completion list by typing.
    /// </summary>
    public int StartOffset { get; set; }
    
    /// <summary>
    /// Gets/Sets the end of the text range in which the completion window stays open.
    /// This text portion is used to determine the text used to select an entry in the completion list by typing.
    /// </summary>
    public int EndOffset { get; set; }
    
    /// <summary>
    /// Gets whether the window was opened above the current line.
    /// </summary>
    protected bool IsUp { get; private set; }
    
    /// <summary>
    /// Creates a new CompletionWindowBase.
    /// </summary>
    public CompletionWindowBase(TextArea textArea)
    {
      if (textArea == null)
        throw new ArgumentNullException("textArea");
      this.TextArea = textArea;
      parentWindow = Window.GetWindow(textArea);
      this.Owner = parentWindow;
      this.AddHandler(MouseUpEvent, new MouseButtonEventHandler(OnMouseUp), true);
      
      StartOffset = EndOffset = this.TextArea.Caret.Offset;
      
      AttachEvents();
    }
    
    #region Event Handlers
    void AttachEvents()
    {
      document = this.TextArea.Document;
      if (document != null) {
        document.Changing += textArea_Document_Changing;
      }
      // LostKeyboardFocus seems to be more reliable than PreviewLostKeyboardFocus - see SD-1729
      this.TextArea.LostKeyboardFocus += TextAreaLostFocus;
      this.TextArea.TextView.ScrollOffsetChanged += TextViewScrollOffsetChanged;
      this.TextArea.DocumentChanged += TextAreaDocumentChanged;
      if (parentWindow != null) {
        parentWindow.LocationChanged += parentWindow_LocationChanged;
      }
      
      // close previous completion windows of same type
      foreach (InputHandler x in this.TextArea.StackedInputHandlers.OfType<InputHandler>()) {
        if (x.window.GetType() == this.GetType())
          this.TextArea.PopStackedInputHandler(x);
      }
      
      myInputHandler = new InputHandler(this);
      this.TextArea.PushStackedInputHandler(myInputHandler);
    }
    
    /// <summary>
    /// Detaches events from the text area.
    /// </summary>
    protected virtual void DetachEvents()
    {
      if (document != null) {
        document.Changing -= textArea_Document_Changing;
      }
      this.TextArea.LostKeyboardFocus -= TextAreaLostFocus;
      this.TextArea.TextView.ScrollOffsetChanged -= TextViewScrollOffsetChanged;
      this.TextArea.DocumentChanged -= TextAreaDocumentChanged;
      if (parentWindow != null) {
        parentWindow.LocationChanged -= parentWindow_LocationChanged;
      }
      this.TextArea.PopStackedInputHandler(myInputHandler);
    }
    
    #region InputHandler
    InputHandler myInputHandler;
    
    /// <summary>
    /// A dummy input handler (that justs invokes the default input handler).
    /// This is used to ensure the completion window closes when any other input handler
    /// becomes active.
    /// </summary>
    sealed class InputHandler : TextAreaStackedInputHandler
    {
      internal readonly CompletionWindowBase window;
      
      public InputHandler(CompletionWindowBase window)
        : base(window.TextArea)
      {
        Debug.Assert(window != null);
        this.window = window;
      }
      
      public override void Detach()
      {
        base.Detach();
        window.Close();
      }
      
      const Key KeyDeadCharProcessed = (Key)0xac; // Key.DeadCharProcessed; // new in .NET 4
      
      public override void OnPreviewKeyDown(KeyEventArgs e)
      {
        // prevents crash when typing deadchar while CC window is open
        if (e.Key == KeyDeadCharProcessed)
          return;
        e.Handled = RaiseEventPair(window, PreviewKeyDownEvent, KeyDownEvent,
                                   new KeyEventArgs(e.KeyboardDevice, e.InputSource, e.Timestamp, e.Key));
      }
      
      public override void OnPreviewKeyUp(KeyEventArgs e)
      {
        if (e.Key == KeyDeadCharProcessed)
          return;
        e.Handled = RaiseEventPair(window, PreviewKeyUpEvent, KeyUpEvent,
                                   new KeyEventArgs(e.KeyboardDevice, e.InputSource, e.Timestamp, e.Key));
      }
    }
    #endregion
    
    void TextViewScrollOffsetChanged(object sender, EventArgs e)
    {
      // Workaround for crash #1580 (reproduction steps unknown):
      // NullReferenceException in System.Windows.Window.CreateSourceWindow()
      if (!sourceIsInitialized)
        return;
      
      IScrollInfo scrollInfo = this.TextArea.TextView;
      Rect visibleRect = new Rect(scrollInfo.HorizontalOffset, scrollInfo.VerticalOffset, scrollInfo.ViewportWidth, scrollInfo.ViewportHeight);
      // close completion window when the user scrolls so far that the anchor position is leaving the visible area
      if (visibleRect.Contains(visualLocation) || visibleRect.Contains(visualLocationTop))
        UpdatePosition();
      else
        Close();
    }
    
    void TextAreaDocumentChanged(object sender, EventArgs e)
    {
      Close();
    }
    
    void TextAreaLostFocus(object sender, RoutedEventArgs e)
    {
      Dispatcher.BeginInvoke(new Action(CloseIfFocusLost), DispatcherPriority.Background);
    }
    
    void parentWindow_LocationChanged(object sender, EventArgs e)
    {
      UpdatePosition();
    }
    
    /// <inheritdoc/>
    protected override void OnDeactivated(EventArgs e)
    {
      base.OnDeactivated(e);
      Dispatcher.BeginInvoke(new Action(CloseIfFocusLost), DispatcherPriority.Background);
    }
    #endregion
    
    /// <summary>
    /// Raises a tunnel/bubble event pair for a WPF control.
    /// </summary>
    /// <param name="target">The WPF control for which the event should be raised.</param>
    /// <param name="previewEvent">The tunneling event.</param>
    /// <param name="event">The bubbling event.</param>
    /// <param name="args">The event args to use.</param>
    /// <returns>The <see cref="RoutedEventArgs.Handled"/> value of the event args.</returns>
    [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Design", "CA1030:UseEventsWhereAppropriate")]
    protected static bool RaiseEventPair(UIElement target, RoutedEvent previewEvent, RoutedEvent @event, RoutedEventArgs args)
    {
      if (target == null)
        throw new ArgumentNullException("target");
      if (previewEvent == null)
        throw new ArgumentNullException("previewEvent");
      if (@event == null)
        throw new ArgumentNullException("event");
      if (args == null)
        throw new ArgumentNullException("args");
      args.RoutedEvent = previewEvent;
      target.RaiseEvent(args);
      args.RoutedEvent = @event;
      target.RaiseEvent(args);
      return args.Handled;
    }
    
    // Special handler: handledEventsToo
    void OnMouseUp(object sender, MouseButtonEventArgs e)
    {
      ActivateParentWindow();
    }
    
    /// <summary>
    /// Activates the parent window.
    /// </summary>
    protected virtual void ActivateParentWindow()
    {
      if (parentWindow != null)
        parentWindow.Activate();
    }
    
    void CloseIfFocusLost()
    {
      if (CloseOnFocusLost) {
        Debug.WriteLine("CloseIfFocusLost: this.IsActive=" + this.IsActive + " IsTextAreaFocused=" + IsTextAreaFocused);
        if (!this.IsActive && !IsTextAreaFocused) {
          Close();
        }
      }
    }
    
    /// <summary>
    /// Gets whether the completion window should automatically close when the text editor looses focus.
    /// </summary>
    protected virtual bool CloseOnFocusLost {
      get { return true; }
    }
    
    bool IsTextAreaFocused {
      get {
        if (parentWindow != null && !parentWindow.IsActive)
          return false;
        return this.TextArea.IsKeyboardFocused;
      }
    }
    
    bool sourceIsInitialized;
    
    /// <inheritdoc/>
    protected override void OnSourceInitialized(EventArgs e)
    {
      base.OnSourceInitialized(e);
      
      if (document != null && this.StartOffset != this.TextArea.Caret.Offset) {
        SetPosition(new TextViewPosition(document.GetLocation(this.StartOffset)));
      } else {
        SetPosition(this.TextArea.Caret.Position);
      }
      sourceIsInitialized = true;
    }
    
    /// <inheritdoc/>
    protected override void OnClosed(EventArgs e)
    {
      base.OnClosed(e);
      DetachEvents();
    }
    
    /// <inheritdoc/>
    protected override void OnKeyDown(KeyEventArgs e)
    {
      base.OnKeyDown(e);
      if (!e.Handled && e.Key == Key.Escape) {
        e.Handled = true;
        Close();
      }
    }
    
    Point visualLocation, visualLocationTop;
    
    /// <summary>
    /// Positions the completion window at the specified position.
    /// </summary>
    protected void SetPosition(TextViewPosition position)
    {
      TextView textView = this.TextArea.TextView;
      
      visualLocation = textView.GetVisualPosition(position, VisualYPosition.LineBottom);
      visualLocationTop = textView.GetVisualPosition(position, VisualYPosition.LineTop);
      UpdatePosition();
    }
    
    /// <summary>
    /// Updates the position of the CompletionWindow based on the parent TextView position and the screen working area.
    /// It ensures that the CompletionWindow is completely visible on the screen.
    /// </summary>
    protected void UpdatePosition()
    {
      TextView textView = this.TextArea.TextView;
      // PointToScreen returns device dependent units (physical pixels)
      Point location = textView.PointToScreen(visualLocation - textView.ScrollOffset);
      Point locationTop = textView.PointToScreen(visualLocationTop - textView.ScrollOffset);
      
      // Let's use device dependent units for everything
      Size completionWindowSize = new Size(this.ActualWidth, this.ActualHeight).TransformToDevice(textView);
      Rect bounds = new Rect(location, completionWindowSize);
      Rect workingScreen = System.Windows.Forms.Screen.GetWorkingArea(location.ToSystemDrawing()).ToWpf();
      if (!workingScreen.Contains(bounds)) {
        if (bounds.Left < workingScreen.Left) {
          bounds.X = workingScreen.Left;
        } else if (bounds.Right > workingScreen.Right) {
          bounds.X = workingScreen.Right - bounds.Width;
        }
        if (bounds.Bottom > workingScreen.Bottom) {
          bounds.Y = locationTop.Y - bounds.Height;
          IsUp = true;
        } else {
          IsUp = false;
        }
        if (bounds.Y < workingScreen.Top) {
          bounds.Y = workingScreen.Top;
        }
      }
      // Convert the window bounds to device independent units
      bounds = bounds.TransformFromDevice(textView);
      this.Left = bounds.X;
      this.Top = bounds.Y;
    }
    
    /// <inheritdoc/>
    protected override void OnRenderSizeChanged(SizeChangedInfo sizeInfo)
    {
      base.OnRenderSizeChanged(sizeInfo);
      if (sizeInfo.HeightChanged && IsUp) {
        this.Top += sizeInfo.PreviousSize.Height - sizeInfo.NewSize.Height;
      }
    }
    
    /// <summary>
    /// Gets/sets whether the completion window should expect text insertion at the start offset,
    /// which not go into the completion region, but before it.
    /// </summary>
    /// <remarks>This property allows only a single insertion, it is reset to false
    /// when that insertion has occurred.</remarks>
    public bool ExpectInsertionBeforeStart { get; set; }
    
    void textArea_Document_Changing(object sender, DocumentChangeEventArgs e)
    {
      if (e.Offset + e.RemovalLength == this.StartOffset && e.RemovalLength > 0) {
        Close(); // removal immediately in front of completion segment: close the window
        // this is necessary when pressing backspace after dot-completion
      }
      if (e.Offset == StartOffset && e.RemovalLength == 0 && ExpectInsertionBeforeStart) {
        StartOffset = e.GetNewOffset(StartOffset, AnchorMovementType.AfterInsertion);
        this.ExpectInsertionBeforeStart = false;
      } else {
        StartOffset = e.GetNewOffset(StartOffset, AnchorMovementType.BeforeInsertion);
      }
      EndOffset = e.GetNewOffset(EndOffset, AnchorMovementType.AfterInsertion);
    }
  }
}