/**
    * Copyright 2010 The Kuali Foundation Licensed under the
    * Educational Community License, Version 2.0 (the "License"); you may
    * not use this file except in compliance with the License. You may
    * obtain a copy of the License at
    *
    * http://www.osedu.org/licenses/ECL-2.0
    *
    * 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 org.kuali.student.common.ui.client.widgets.progress;
  
  import java.util.LinkedList;
  
  import org.kuali.student.common.ui.client.widgets.KSLightBox;
  
  import com.google.gwt.user.client.ui.HorizontalPanel;
  import com.google.gwt.user.client.ui.Image;
  import com.google.gwt.user.client.ui.Label;
  import com.google.gwt.user.client.ui.VerticalPanel;
  
  /**
   * This class handles a static list of BlockingTasks, when a blocking task is added to the list, the blocking
   * progress indicator is shown to the user and the user can perform no action until all blocking tasks are finished/removed.
   *
   * @author Bsmith
   *
   */
  public class KSBlockingProgressIndicator{
  
      private static LinkedList<BlockingTask> tasks = new LinkedList<BlockingTask>();
  
  	private static final VerticalPanel mainPanel = new VerticalPanel();
  	private static final VerticalPanel listPanel = new VerticalPanel();
  
  	private static KSLightBox popupIndicator;
  
  	private static boolean initialized = false;
      private static int width = 200;
      private static int height = 30;
  	/**
  	 * Initializes the blocking progress indicator.  This must be called before
  	 * blocking task are added.
  	 *
  	 */
  	public static void initialize(){
  
  
  		mainPanel.add(listPanel);
  
  		//popupIndicator = new KSLightBox(false);
  		popupIndicator = new KSLightBox(false);
  		//popupIndicator.setShowCloseLink(false);
  		
  		popupIndicator.setWidget(mainPanel);
  		popupIndicator.setSize(200, 30);
  		popupIndicator.setGlassStyleName("KS-Blocking-Glass");
  		popupIndicator.showButtons(false);
  		setupDefaultStyle();
  		initialized = true;
  	}
  
  	/**
  	 * Adds a blocking task to the queue.  When all tasks are removed, the indicator
  	 * is no longer shown.
  	 *
  	 * @param task the task description to be added
  	 */
  	public static void addTask(BlockingTask task) {
  		tasks.add(task);
  		updateIndicator();
  	}
  
  	/**
  	 * Removes the blocking task from the queue
  	 *
  	 * @param task the task to be removed from the blocking task queue
  	 */
  	public static void removeTask(BlockingTask task) {
  		tasks.remove(task);
  		if (tasks.isEmpty()) {
  			hideIndicator();
  		} else {
  			updateIndicator();
  		}
  	}
      public static void setSize(final int w, final int h) {
       width = w;
       height = h;
      }
  	private static void updateIndicator() {
  
  		listPanel.clear();
  		BlockingTask task = tasks.getLast();
 		HorizontalPanel taskPanel = new HorizontalPanel();
 	    Image Image = new Image("images/common/twiddler3.gif");
 
 		taskPanel.add(Image);
 		taskPanel.add(new Label(task.getDescription()));
 		listPanel.add(taskPanel);
 		
         showIndicator();		
 	}
 	private static void showIndicator(){
 		if(!initialized){
 			initialize();
 		}
 		popupIndicator.setSize(width, height);
 		popupIndicator.show();
 	}
 
 	private static void hideIndicator() {
 		popupIndicator.hide();
 	}
 
 	private static  void setupDefaultStyle(){
 		listPanel.addStyleName("KS-Blocking-Task-List");
 		mainPanel.addStyleName("KS-Blocking-Task-Main");
 		mainPanel.addStyleName("KS-Mouse-Normal");
 	}
 }