/*
    * Copyright 1999-2006 Faculty of Mathematics, Physics
    * and Informatics, Comenius University, Bratislava. This file is protected by
    * the Mozilla Public License version 1.1 (the License); you may not use this
    * file except in compliance with the License. You may obtain a copy of the
    * License at http://euromath2.sourceforge.net/license.html Unless required by
    * applicable law or agreed to in writing, software distributed under the
    * License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS
    * OF ANY KIND, either express or implied. See the License for the specific
   * language governing permissions and limitations under the License.
   */
  package sk.uniba.euromath.editor.textEditor.policies;
  
  import java.util.ArrayList;
  import java.util.List;
  
  import org.eclipse.draw2d.ColorConstants;
  import org.eclipse.draw2d.FigureUtilities;
  import org.eclipse.draw2d.Graphics;
  import org.eclipse.draw2d.IFigure;
  import org.eclipse.draw2d.RectangleFigure;
  import org.eclipse.draw2d.geometry.Rectangle;
  import org.eclipse.gef.Request;
  import org.eclipse.gef.editpolicies.SelectionEditPolicy;
  
  import sk.uniba.euromath.editor.textEditor.ITextPieceKeeper;
  import sk.uniba.euromath.editor.textEditor.Interval;
  import sk.uniba.euromath.editor.textEditor.requests.RequestConstants;
  import sk.uniba.euromath.editor.textEditor.requests.selectionRequest.TextSelectRequest;
  
  /***
   * Creates and cares about figures that represent selection. It cares about
   * figures of two kinds
   * <ul>
   * <li> border of the selection - this figure is painted when the selections
   * ends
   * <li> filled selection - this figure is created when the selection starts and
   * is justified when draging in method updateDraggingFeedback
   * </ul>
   * 
   * Should be installed in EditPolicy.SELECTION_FEEDBACK_ROLE
   * 
   * @author Martin Kollar
   */
  abstract public class AbstractTextSelectionEditPolicy extends
          SelectionEditPolicy {
  
      /***
       * 
       */
      protected final List<IFigure> selectionFigures = new ArrayList<IFigure>();
  
      /***
       * Constructor.
       */
      public AbstractTextSelectionEditPolicy() {
          super();
      }
  
      /***
       * Creates Figure that is used when the selection is finished is used to
       * show what is selected after selection is finished
       * 
       * @param start
       * @param end
       * 
       * @return <code>RectangleFigure</code> that is painted
       */
      private IFigure createSelectionFigure(int start, int end) {
          RectangleFigure result = new RectangleFigure();
  
          if (!getHostFigure().isShowing()) {
              getHost().getViewer().reveal(getHost());
          }
  
          Rectangle r = getHostKeeper().getTextLocator()
                  .getTextBounds(start, end);
  
          if (r == null)
              r = new Rectangle(0, 0, 0, 0);
          result.setBounds(r);
          result.setLineStyle(Graphics.LINE_SOLID);
          result.setForegroundColor(ColorConstants.white);
  
          FigureUtilities.makeGhostShape(result);
          return result;
      }
  
      /***
       * @see org.eclipse.gef.editpolicies.SelectionEditPolicy#hideSelection()
       */
      @Override
      protected void hideSelection() {
          for (IFigure figure : this.selectionFigures) {
              removeFeedback(figure);
          }
      }
  
      /***
      * 
      * @see org.eclipse.gef.editpolicies.SelectionEditPolicy#showSelection()
      */
     @Override
     protected void showSelection() {
         for (IFigure figure : this.selectionFigures) {
             addFeedback(figure);
         }
     }
 
     /***
      * 
      */
     private void updateSelectionFigures() {
         this.selectionFigures.clear();
         for (Interval interval : getHostKeeper().getSelectionStatus()
                 .getSelectionIntervals()) {
             this.selectionFigures.add(createSelectionFigure(interval.getStart(),
                     interval.getEnd()));
         }
     }
 
     @Override
     public void showSourceFeedback(Request request) {
         if (!request.getType().equals(RequestConstants.TEXT_SELECT))
             throw new IllegalArgumentException();
         hideSelection();
         // set new selection state according to request
         updateHostSelectionState((TextSelectRequest) request);
         updateSelectionFigures();
         showSelection();
     }
 
     /***
      * @param request
      */
     protected void updateHostSelectionState(TextSelectRequest request) {
         if (request.getSelectType().equals(TextSelectRequest.NEW_SELECTION)) {
             // set new selection
             // TODO SELEKCIE posunut o offset ...
             getHostKeeper().getSelectionStatus().setSelectionIntervals(
                     request.getSelection());
         } else {
             // xor selections
             getHostKeeper().getSelectionStatus().xorSelectionIntervals(
                     request.getSelection());
         }
 
     }
 
     /***
      * Helper method.
      * 
      * @return
      */
     protected ITextPieceKeeper getHostKeeper() {
         return (ITextPieceKeeper) getHost();
     }
 
     /***
      * @see org.eclipse.gef.EditPolicy#understandsRequest(org.eclipse.gef.Request)
      * 
      * @return <code>true</code> if request is TextSelectionRequest else
      *         return <code>false</code>
      */
     @Override
     public boolean understandsRequest(Request req) {
         if (RequestConstants.TEXT_SELECT.equals(req.getType())) {
             return true;
         }
         return false;
     }
 
 }