source: branches/Async/HeuristicLab.ExtLibs/HeuristicLab.AvalonEdit/5.0.1/AvalonEdit-5.0.1/Snippets/InsertionContext.cs @ 13401

// Copyright (c) 2014 AlphaSierraPapa for the SharpDevelop Team
// 
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// 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
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using System;
using System.Collections.Generic;
using System.Windows;
using ICSharpCode.NRefactory.Editor;
using ICSharpCode.AvalonEdit.Document;
using ICSharpCode.AvalonEdit.Editing;

namespace ICSharpCode.AvalonEdit.Snippets
{
  /// <summary>
  /// Represents the context of a snippet insertion.
  /// </summary>
  public class InsertionContext : IWeakEventListener
  {
    enum Status
    {
      Insertion,
      RaisingInsertionCompleted,
      Interactive,
      RaisingDeactivated,
      Deactivated
    }
    
    Status currentStatus = Status.Insertion;
    
    /// <summary>
    /// Creates a new InsertionContext instance.
    /// </summary>
    public InsertionContext(TextArea textArea, int insertionPosition)
    {
      if (textArea == null)
        throw new ArgumentNullException("textArea");
      this.TextArea = textArea;
      this.Document = textArea.Document;
      this.SelectedText = textArea.Selection.GetText();
      this.InsertionPosition = insertionPosition;
      this.startPosition = insertionPosition;
      
      DocumentLine startLine = this.Document.GetLineByOffset(insertionPosition);
      ISegment indentation = TextUtilities.GetWhitespaceAfter(this.Document, startLine.Offset);
      this.Indentation = Document.GetText(indentation.Offset, Math.Min(indentation.EndOffset, insertionPosition) - indentation.Offset);
      this.Tab = textArea.Options.IndentationString;
      
      this.LineTerminator = TextUtilities.GetNewLineFromDocument(this.Document, startLine.LineNumber);
    }
    
    /// <summary>
    /// Gets the text area.
    /// </summary>
    public TextArea TextArea { get; private set; }
    
    /// <summary>
    /// Gets the text document.
    /// </summary>
    public ICSharpCode.AvalonEdit.Document.TextDocument Document { get; private set; }
    
    /// <summary>
    /// Gets the text that was selected before the insertion of the snippet.
    /// </summary>
    public string SelectedText { get; private set; }
    
    /// <summary>
    /// Gets the indentation at the insertion position.
    /// </summary>
    public string Indentation { get; private set; }
    
    /// <summary>
    /// Gets the indentation string for a single indentation level.
    /// </summary>
    public string Tab { get; private set; }
    
    /// <summary>
    /// Gets the line terminator at the insertion position.
    /// </summary>
    public string LineTerminator { get; private set; }
    
    /// <summary>
    /// Gets/Sets the insertion position.
    /// </summary>
    public int InsertionPosition { get; set; }
    
    readonly int startPosition;
    ICSharpCode.AvalonEdit.Document.AnchorSegment wholeSnippetAnchor;
    bool deactivateIfSnippetEmpty;
    
    /// <summary>
    /// Gets the start position of the snippet insertion.
    /// </summary>
    public int StartPosition {
      get {
        if (wholeSnippetAnchor != null)
          return wholeSnippetAnchor.Offset;
        else
          return startPosition;
      }
    }
    
    /// <summary>
    /// Inserts text at the insertion position and advances the insertion position.
    /// This method will add the current indentation to every line in <paramref name="text"/> and will
    /// replace newlines with the expected newline for the document.
    /// </summary>
    public void InsertText(string text)
    {
      if (text == null)
        throw new ArgumentNullException("text");
      if (currentStatus != Status.Insertion)
        throw new InvalidOperationException();
      
      text = text.Replace("\t", this.Tab);
      
      using (this.Document.RunUpdate()) {
        int textOffset = 0;
        SimpleSegment segment;
        while ((segment = NewLineFinder.NextNewLine(text, textOffset)) != SimpleSegment.Invalid) {
          string insertString = text.Substring(textOffset, segment.Offset - textOffset)
            + this.LineTerminator + this.Indentation;
          this.Document.Insert(InsertionPosition, insertString);
          this.InsertionPosition += insertString.Length;
          textOffset = segment.EndOffset;
        }
        string remainingInsertString = text.Substring(textOffset);
        this.Document.Insert(InsertionPosition, remainingInsertString);
        this.InsertionPosition += remainingInsertString.Length;
      }
    }
    
    Dictionary<SnippetElement, IActiveElement> elementMap = new Dictionary<SnippetElement, IActiveElement>();
    List<IActiveElement> registeredElements = new List<IActiveElement>();
    
    /// <summary>
    /// Registers an active element. Elements should be registered during insertion and will be called back
    /// when insertion has completed.
    /// </summary>
    /// <param name="owner">The snippet element that created the active element.</param>
    /// <param name="element">The active element.</param>
    public void RegisterActiveElement(SnippetElement owner, IActiveElement element)
    {
      if (owner == null)
        throw new ArgumentNullException("owner");
      if (element == null)
        throw new ArgumentNullException("element");
      if (currentStatus != Status.Insertion)
        throw new InvalidOperationException();
      elementMap.Add(owner, element);
      registeredElements.Add(element);
    }
    
    /// <summary>
    /// Returns the active element belonging to the specified snippet element, or null if no such active element is found.
    /// </summary>
    public IActiveElement GetActiveElement(SnippetElement owner)
    {
      if (owner == null)
        throw new ArgumentNullException("owner");
      IActiveElement element;
      if (elementMap.TryGetValue(owner, out element))
        return element;
      else
        return null;
    }
    
    /// <summary>
    /// Gets the list of active elements.
    /// </summary>
    public IEnumerable<IActiveElement> ActiveElements {
      get { return registeredElements; }
    }
    
    /// <summary>
    /// Calls the <see cref="IActiveElement.OnInsertionCompleted"/> method on all registered active elements
    /// and raises the <see cref="InsertionCompleted"/> event.
    /// </summary>
    /// <param name="e">The EventArgs to use</param>
    [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Design", "CA1030:UseEventsWhereAppropriate",
                                                     Justification="There is an event and this method is raising it.")]
    public void RaiseInsertionCompleted(EventArgs e)
    {
      if (currentStatus != Status.Insertion)
        throw new InvalidOperationException();
      if (e == null)
        e = EventArgs.Empty;
      
      currentStatus = Status.RaisingInsertionCompleted;
      int endPosition = this.InsertionPosition;
      this.wholeSnippetAnchor = new AnchorSegment(Document, startPosition, endPosition - startPosition);
      TextDocumentWeakEventManager.UpdateFinished.AddListener(Document, this);
      deactivateIfSnippetEmpty = (endPosition != startPosition);
      
      foreach (IActiveElement element in registeredElements) {
        element.OnInsertionCompleted();
      }
      if (InsertionCompleted != null)
        InsertionCompleted(this, e);
      currentStatus = Status.Interactive;
      if (registeredElements.Count == 0) {
        // deactivate immediately if there are no interactive elements
        Deactivate(new SnippetEventArgs(DeactivateReason.NoActiveElements));
      } else {
        myInputHandler = new SnippetInputHandler(this);
        // disable existing snippet input handlers - there can be only 1 active snippet
        foreach (TextAreaStackedInputHandler h in TextArea.StackedInputHandlers) {
          if (h is SnippetInputHandler)
            TextArea.PopStackedInputHandler(h);
        }
        TextArea.PushStackedInputHandler(myInputHandler);
      }
    }
    
    SnippetInputHandler myInputHandler;
    
    /// <summary>
    /// Occurs when the all snippet elements have been inserted.
    /// </summary>
    public event EventHandler InsertionCompleted;
    
    /// <summary>
    /// Calls the <see cref="IActiveElement.Deactivate"/> method on all registered active elements.
    /// </summary>
    /// <param name="e">The EventArgs to use</param>
    public void Deactivate(SnippetEventArgs e)
    {
      if (currentStatus == Status.Deactivated || currentStatus == Status.RaisingDeactivated)
        return;
      if (currentStatus != Status.Interactive)
        throw new InvalidOperationException("Cannot call Deactivate() until RaiseInsertionCompleted() has finished.");
      if (e == null)
        e = new SnippetEventArgs(DeactivateReason.Unknown);
      
      TextDocumentWeakEventManager.UpdateFinished.RemoveListener(Document, this);
      currentStatus = Status.RaisingDeactivated;
      TextArea.PopStackedInputHandler(myInputHandler);
      foreach (IActiveElement element in registeredElements) {
        element.Deactivate(e);
      }
      if (Deactivated != null)
        Deactivated(this, e);
      currentStatus = Status.Deactivated;
    }
    
    /// <summary>
    /// Occurs when the interactive mode is deactivated.
    /// </summary>
    public event EventHandler<SnippetEventArgs> Deactivated;
    
    bool IWeakEventListener.ReceiveWeakEvent(Type managerType, object sender, EventArgs e)
    {
      return ReceiveWeakEvent(managerType, sender, e);
    }
    
    /// <inheritdoc cref="IWeakEventListener.ReceiveWeakEvent"/>
    protected virtual bool ReceiveWeakEvent(Type managerType, object sender, EventArgs e)
    {
      if (managerType == typeof(TextDocumentWeakEventManager.UpdateFinished)) {
        // Deactivate if snippet is deleted. This is necessary for correctly leaving interactive
        // mode if Undo is pressed after a snippet insertion.
        if (wholeSnippetAnchor.Length == 0 && deactivateIfSnippetEmpty)
          Deactivate(new SnippetEventArgs(DeactivateReason.Deleted));
        return true;
      }
      return false;
    }
    
    /// <summary>
    /// Adds existing segments as snippet elements.
    /// </summary>
    public void Link(ISegment mainElement, ISegment[] boundElements)
    {
      var main = new SnippetReplaceableTextElement { Text = Document.GetText(mainElement) };
      RegisterActiveElement(main, new ReplaceableActiveElement(this, mainElement.Offset, mainElement.EndOffset));
      foreach (var boundElement in boundElements) {
        var bound = new SnippetBoundElement { TargetElement = main };
        var start = Document.CreateAnchor(boundElement.Offset);
        start.MovementType = AnchorMovementType.BeforeInsertion;
        start.SurviveDeletion = true;
        var end = Document.CreateAnchor(boundElement.EndOffset);
        end.MovementType = AnchorMovementType.BeforeInsertion;
        end.SurviveDeletion = true;
        
        RegisterActiveElement(bound, new BoundActiveElement(this, main, bound, new AnchorSegment(start, end)));
      }
    }
  }
}