/*
    * Licensed to the Apache Software Foundation (ASF) under one or more
    * contributor license agreements.  See the NOTICE file distributed with
    * this work for additional information regarding copyright ownership.
    * The ASF licenses this file to You under the Apache 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.apache.org/licenses/LICENSE-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.apache.log4j.chainsaw.messages;
  
  import java.awt.BorderLayout;
  import java.awt.Component;
  import java.awt.event.ActionEvent;
  import java.beans.PropertyChangeEvent;
  import java.beans.PropertyChangeListener;
  import java.beans.PropertyChangeSupport;
  
  import javax.swing.AbstractAction;
  import javax.swing.Action;
  import javax.swing.DefaultListCellRenderer;
  import javax.swing.ImageIcon;
  import javax.swing.JButton;
  import javax.swing.JComponent;
  import javax.swing.JList;
  import javax.swing.JPanel;
  import javax.swing.JPopupMenu;
  import javax.swing.JScrollPane;
  import javax.swing.JToolBar;
  import javax.swing.ListCellRenderer;
  import javax.swing.ListModel;
  import javax.swing.event.ListDataEvent;
  import javax.swing.event.ListDataListener;
  
  import org.apache.log4j.Layout;
  import org.apache.log4j.Level;
  import org.apache.log4j.Logger;
  import org.apache.log4j.TTCCLayout;
  import org.apache.log4j.chainsaw.ChainsawConstants;
  import org.apache.log4j.chainsaw.LoggingEventWrapper;
  import org.apache.log4j.chainsaw.PopupListener;
  import org.apache.log4j.chainsaw.SmallButton;
  import org.apache.log4j.chainsaw.icons.ChainsawIcons;
  import org.apache.log4j.varia.ListModelAppender;
  
  
  /**
   * The MessageCenter is central place for all elements within Chainsaw to
   * notify the user of important information.
   *
   * This class uses log4j itself quite significantly.  All user message
   * are sent to this classes log4j Logger (org.apache.log4j.chainsaw.message.MessageCenter).
   *
   * To register a message with the user, you can use the addMessage(String) style methods on
   * this class, or just as easily, get a handle to this class' logger, and log
   * it as you would normally do.
   *
   * All events to this logger are trapped within a Custom appender (additivity
   * will be switched OFF), which stores the events in a ListModel.
   *
   * You can invoke the setVisible() method to display all the messages
   *
   * @author Paul Smith <psmith@apache.org>
   *
   */
  public class MessageCenter {
    private static final MessageCenter instance = new MessageCenter();
    private final Logger logger = Logger.getLogger(MessageCenter.class);
    private Layout layout = new TTCCLayout();
    private final JList messageList = new JList();
    private final ListModelAppender appender = new ListModelAppender();
    private ListCellRenderer listCellRenderer =
      new LayoutListCellRenderer(layout);
    private PropertyChangeSupport propertySupport =
      new PropertyChangeSupport(this);
    private JScrollPane pane = new JScrollPane(messageList);
    private final JToolBar toolbar = new JToolBar();
    private JPopupMenu popupMenu = new JPopupMenu();
    private PopupListener popupListener = new PopupListener(popupMenu);
    private Action clearAction;
    private final JPanel componentPanel = new JPanel(new BorderLayout());
  
    private MessageCenter() {
      setupActions();
      setupComponentPanel();
      setupLogger();
      setupListeners();
      setupPopMenu();
      setupToolbar();
    }
  
   /**
    *
    */
   private void setupPopMenu() {
     popupMenu.add(clearAction);
   }
 
   /**
    *
    */
   private void setupToolbar() {
     JButton clearButton = new SmallButton(clearAction);
     clearButton.setText(null);
     toolbar.add(clearButton);
 
     toolbar.setFloatable(false);
   }
 
   private void setupActions() {
     clearAction =
       new AbstractAction("Clear") {
           public void actionPerformed(ActionEvent e) {
             appender.clearModel();
           }
         };
     clearAction.putValue(
       Action.SMALL_ICON, new ImageIcon(ChainsawIcons.DELETE));
   }
 
   private void setupListeners() {
     propertySupport.addPropertyChangeListener(
       "layout",
       new PropertyChangeListener() {
         public void propertyChange(PropertyChangeEvent evt) {
           Layout newLayout = (Layout) evt.getNewValue();
           messageList.setCellRenderer(new LayoutListCellRenderer(newLayout));
         }
       });
     messageList.addMouseListener(popupListener);
 
     appender.getModel().addListDataListener(
       new ListDataListener() {
         public void contentsChanged(ListDataEvent e) {
           updateActions();
         }
 
         public void intervalAdded(ListDataEvent e) {
           updateActions();
         }
 
         public void intervalRemoved(ListDataEvent e) {
           updateActions();
         }
       });
   }
 
   /**
    *
    */
   private void updateActions() {
     clearAction.putValue(
       "enabled",
       (appender.getModel().getSize() > 0) ? Boolean.TRUE : Boolean.FALSE);
   }
 
   private void setupLogger() {
     logger.addAppender(appender);
     logger.setAdditivity(true);
     logger.setLevel(Boolean.getBoolean("log4j.debug")?Level.DEBUG:Level.INFO);
   }
 
   private void setupComponentPanel() {
     messageList.setModel(appender.getModel());
     messageList.setCellRenderer(listCellRenderer);
 
     componentPanel.add(this.toolbar, BorderLayout.NORTH);
     componentPanel.add(this.pane, BorderLayout.CENTER);
   }
   
   public final JComponent getGUIComponent() {
     return componentPanel;
   }
 
   public ListModel getModel() {
     return messageList.getModel();
   }
 
   public static MessageCenter getInstance() {
     return instance;
   }
 
   public void addMessage(String message) {
     logger.info(message);
   }
 
 
   /**
    * @return Returns the layout used by the MessageCenter.
    */
   public final Layout getLayout() {
     return layout;
   }
 
   /**
    * @param layout Sets the layout to be used by the MessageCenter .
    */
   public final void setLayout(Layout layout) {
     Layout oldValue = this.layout;
     this.layout = layout;
     propertySupport.firePropertyChange("layout", oldValue, this.layout);
   }
 
   /**
    * Returns the logger that can be used to log
    * messages to display within the Message Center.
    * @return logger
    */
   public final Logger getLogger() {
     return this.logger;
   }
 
   /**
    * This class simply renders an event by delegating the effort to a
    * Log4j layout instance.
    * 
    * @author Paul Smith <psmith@apache.org>
    */
   private static class LayoutListCellRenderer extends DefaultListCellRenderer {
     private Layout layout;
 
     /**
      * @param layout
      */
     public LayoutListCellRenderer(Layout layout) {
       super();
       this.layout = layout;
     }
 
     /* (non-Javadoc)
      * @see javax.swing.ListCellRenderer#getListCellRendererComponent(javax.swing.JList, java.lang.Object, int, boolean, boolean)
      */
     public Component getListCellRendererComponent(
       JList list, Object value, int index, boolean isSelected,
       boolean cellHasFocus) {
       value = layout.format(((LoggingEventWrapper) value).getLoggingEvent());
 
       Component c =
         super.getListCellRendererComponent(
           list, value, index, isSelected, cellHasFocus);
       c.setBackground(
         ((index % 2) == 0) ? ChainsawConstants.COLOR_EVEN_ROW_BACKGROUND
                            : ChainsawConstants.COLOR_ODD_ROW_BACKGROUND);
 
       return c;
     }
   }
 }