/*******************************************************************************
 * 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.ote.ui.message.watch;

import java.util.ArrayList;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.ScheduledFuture;
import java.util.concurrent.TimeUnit;
import org.eclipse.jface.viewers.ISelectionChangedListener;
import org.eclipse.jface.viewers.IStructuredSelection;
import org.eclipse.jface.viewers.SelectionChangedEvent;
import org.eclipse.osee.framework.jdk.core.util.benchmark.Benchmark;
import org.eclipse.osee.framework.ui.swt.Displays;
import org.eclipse.osee.ote.message.tool.MessageMode;
import org.eclipse.ote.ui.message.tree.AbstractTreeNode;
import org.eclipse.ote.ui.message.tree.MessageNode;
import org.eclipse.ote.ui.message.tree.WatchList;
import org.eclipse.ote.ui.message.tree.WatchedMessageNode;

/**
 * @author Andrew M. Finkbeiner
 */
public class ViewRefresher implements Runnable {
   private final ArrayList<AbstractTreeNode> deltas = new ArrayList<AbstractTreeNode>(256);
   private final Benchmark benchMark = new Benchmark("Message Watch Update Time");
   private final WatchView view;
   private volatile AbstractTreeNode selectedNode;
   private final int period;
   private ScheduledFuture<?> handle = null;
   private final WatchList list;

   public ViewRefresher(WatchList list, final WatchView view, int period) {
      this.period = period;
      this.view = view;
      this.list = list;
      view.getTreeViewer().addSelectionChangedListener(new ISelectionChangedListener() {

         @Override
         public void selectionChanged(SelectionChangedEvent event) {
            final IStructuredSelection selection = (IStructuredSelection) view.getTreeViewer().getSelection();
            selectedNode = (AbstractTreeNode) selection.getFirstElement();
         }
      });
   }

   private final ScheduledExecutorService scheduler = Executors.newScheduledThreadPool(1);
   private volatile boolean writerIsPresent;

   private final Runnable task = new Runnable() {

      @Override
      public void run() {
         if (viewIsAvailable()) {
            view.setWriterPresent(writerIsPresent);
            if (selectedNode != null) {
               view.setDetailText(selectedNode);
            }
            for (AbstractTreeNode node : deltas) {
               view.getTreeViewer().update(node, null);
            }
         }
      }

   };

   public void start() {
      handle = scheduler.scheduleWithFixedDelay(this, period, period, TimeUnit.MILLISECONDS);
   }

   public void stop() {
      if (handle != null) {
         handle.cancel(false);
         handle = null;
      }
   }

   public void dispose() {
      scheduler.shutdown();
   }

   @Override
   public void run() {
      try {
         benchMark.startSample();
         deltas.clear();
         writerIsPresent = false;
         for (MessageNode node : list.getMessages()) {
            final WatchedMessageNode watchedNode = (WatchedMessageNode) node;
            watchedNode.determineDeltas(deltas);
            MessageMode messageMode = watchedNode.getSubscription().getMessageMode();
            if( messageMode == MessageMode.WRITER) {
               writerIsPresent = true;
            }
         }
         Displays.pendInDisplayThread(task);
         benchMark.endSample();

      } catch (Throwable th) {
         th.printStackTrace();
      }
   }

   private boolean viewIsAvailable() {
      return view != null && !view.getTreeViewer().getTree().isDisposed();
   }

}