/*******************************************************************************
 * Copyright (c) 2010 Boeing.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     Boeing - initial API and implementation
 *******************************************************************************/
package org.eclipse.osee.framework.ui.skynet;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import org.eclipse.jface.viewers.ISelection;
import org.eclipse.jface.viewers.ISelectionChangedListener;
import org.eclipse.jface.viewers.ISelectionProvider;
import org.eclipse.jface.viewers.SelectionChangedEvent;
import org.eclipse.jface.viewers.StructuredSelection;

public class SelectionProviderWrapper implements ISelectionProvider {

   private ISelectionProvider provider;
   private List<Object> selectionListeners;
   private ISelection sel = StructuredSelection.EMPTY;

   @Override
   public void addSelectionChangedListener(ISelectionChangedListener listener) {
      if (selectionListeners == null) {
         selectionListeners = new ArrayList<Object>(1);
      }
      selectionListeners.add(listener);
      if (provider != null) {
         provider.addSelectionChangedListener(listener);
      }
   }

   @Override
   public void removeSelectionChangedListener(ISelectionChangedListener listener) {
      if (selectionListeners != null) {
         selectionListeners.remove(listener);
         if (provider != null) {
            provider.removeSelectionChangedListener(listener);
         }
      }
   }

   @Override
   public ISelection getSelection() {
      return provider != null ? provider.getSelection() : sel;
   }

   @Override
   public void setSelection(ISelection selection) {
      if (provider != null) {
         provider.setSelection(selection);
      } else {
         sel = selection;
         if (selectionListeners != null) {
            SelectionChangedEvent event = new SelectionChangedEvent(this, selection);
            for (Iterator<?> it = selectionListeners.iterator(); it.hasNext();) {
               ((ISelectionChangedListener) it.next()).selectionChanged(event);
            }
         }

      }
   }

   public void setSelectionProvider(ISelectionProvider provider) {
      if (this.provider != provider) {
         ISelection _sel = null;
         if (selectionListeners != null) {
            int c = selectionListeners.size();
            ISelectionChangedListener listener;
            if (this.provider != null) {
               for (int i = 0; i < c; i++) {
                  listener = (ISelectionChangedListener) selectionListeners.get(i);
                  this.provider.removeSelectionChangedListener(listener);
               }
            }

            if (provider != null) {
               for (int i = 0; i < c; i++) {
                  listener = (ISelectionChangedListener) selectionListeners.get(i);
                  provider.addSelectionChangedListener(listener);
               }

               _sel = provider.getSelection();
            } else {
               _sel = sel;
            }
         }
         this.provider = provider;
         if (_sel != null) {
            //force a selection change event propagation
            setSelection(_sel);
         }
      }
   }

   public ISelectionProvider getSelectionProvider() {
      return provider;
   }
}