/*
    *  XNap Commons
    *
    *  Copyright (C) 2005  Felix Berger
    *
    *  This library is free software; you can redistribute it and/or
    *  modify it under the terms of the GNU Lesser General Public
    *  License as published by the Free Software Foundation; either
    *  version 2.1 of the License, or (at your option) any later version.
   *
   *  This library is distributed in the hope that it will be useful,
   *  but WITHOUT ANY WARRANTY; without even the implied warranty of
   *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   *  Lesser General Public License for more details.
   *
   *  You should have received a copy of the GNU Lesser General Public
   *  License along with this library; if not, write to the Free Software
   *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
   */
  package org.xnap.commons.gui.completion;
  
  import java.awt.ComponentOrientation;
  import java.awt.Dimension;
  import java.awt.event.ComponentAdapter;
  import java.awt.event.ComponentEvent;
  import java.awt.event.ComponentListener;
  import java.awt.event.FocusAdapter;
  import java.awt.event.FocusEvent;
  import java.awt.event.FocusListener;
  import java.awt.event.KeyAdapter;
  import java.awt.event.KeyEvent;
  import java.awt.event.KeyListener;
  import java.awt.event.MouseAdapter;
  import java.awt.event.MouseEvent;
  import java.beans.PropertyChangeEvent;
  import java.beans.PropertyChangeListener;
  import javax.swing.JList;
  import javax.swing.JPopupMenu;
  import javax.swing.JScrollPane;
  import javax.swing.JTextField;
  import javax.swing.ListSelectionModel;
  import javax.swing.text.JTextComponent;
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  
  /***
   * This class presents completed objects in a popup menu below a {@link
   * JTextComponent}.
   * 
   * @author Felix Berger
   */
  public class CompletionPopup extends JPopupMenu
  {
  		
  	/***
  	 * The completion mode handling when and how to complete.
  	 */
  	private Completion completion;
  	/***
  	 * The list presenting the completed items.
  	 */
  	private JList list = new JList();
  
  	private KeyListener keyListener = new KeyHandler();
  
  	private FocusListener focusListener = new FocusHandler();
  
  	private ComponentListener componentListener = new SizeHandler();
  	
  	private PropertyChangeListener propertyListener = new PropertyChangeHandler();
  		
  	private static Log logger = LogFactory.getLog(CompletionPopup.class);
  	
  	
  	/***
  	 * Constructs a new completion popup.
  	 */
  	public CompletionPopup()
  	{
  		list.setVisibleRowCount(4);
  		list.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
  		JScrollPane jsp = new JScrollPane(list);
  		add(jsp);
  
  		list.setFocusable(false);
  		jsp.setFocusable(false);
  		setFocusable(false);
  
  		list.addMouseListener(new MouseHandler());
  	}
  
      
  	public void enablePopup(Completion comp)
  	{
  		completion = comp;
  
  		applyComponentOrientation(completion.getTextComponent().getComponentOrientation());
  		
  		completion.getTextComponent().addKeyListener(keyListener);
 		completion.getTextComponent().addFocusListener(focusListener);
 		completion.getTextComponent().addPropertyChangeListener
 		("componentOrientation", propertyListener);
 
 		// set the model
 		list.setModel(completion.getModel());
 		
 		if (completion.isWholeTextCompletion()) {
 			setPreferredSize(new Dimension(completion.getTextComponent().getWidth(),
 										   getPreferredSize().height));
 			completion.getTextComponent().addComponentListener(componentListener);
 		}
 	}
 	
 	public void disablePopup()
 	{
 		/* this breaks completion popup navigateion for the history text field,
 		   but I guess completion + history is a bit too much anyway.  */
 		completion.getTextComponent().removeKeyListener(keyListener);
 		completion.getTextComponent().removeFocusListener(focusListener);
 		completion.getTextComponent().removePropertyChangeListener
 			("componentOrientation", propertyListener);
 		if (completion.isWholeTextCompletion()) {
 			completion.getTextComponent().removeComponentListener(componentListener);
 		}
 	}
 
 	private void selectNextCompletion()
 	{
 		if (completion.getModel().getSize() > 0) {
 			int cur = (list.getSelectedIndex() + 1) % completion.getModel().getSize();
 			list.setSelectedIndex(cur);
 			list.ensureIndexIsVisible(cur);
 		}
 	}
 
 	private void selectPreviousCompletion()
 	{
 		if (completion.getModel().getSize() > 0) {
 			int cur = (list.getSelectedIndex() == -1) ? 0 
 				: list.getSelectedIndex();
 			cur = (cur == 0) ? completion.getModel().getSize() - 1 : cur - 1;
 			list.setSelectedIndex(cur);
 			list.ensureIndexIsVisible(cur);
 		}
 	}
 
 	/***
 	 * Accessor for testing.
 	 */
 	JList getList()
 	{
 		return list;
 	}
 
 	/***
 	 * Listens for size changes of the text component and updates the popup's
 	 * width appropriately.
 	 *
 	 * This makes only sense for {@link JTextField}s.
 	 */
 	public class SizeHandler extends ComponentAdapter
 	{
 		public void componentResized(ComponentEvent e)
 		{
 			setPreferredSize
 				(new Dimension(completion.getTextComponent().getWidth(), 
 							   getPreferredSize().height));
 		}
 	}
 
 	/***
 	 * Listens for key events in the text component responsible for navigation
 	 * and confirmation.
 	 */
 	private class KeyHandler extends KeyAdapter
 	{
 		public void keyPressed(KeyEvent e)
 		{
 			int code = e.getKeyCode();
 			int modifiers = e.getModifiers();
 
 			// catch all up an down events
 			if (CompletionPopup.this.isVisible()) {
 				if (code == KeyEvent.VK_DOWN) {
 					selectNextCompletion();
 					e.consume();
 				}
 				else if (code == KeyEvent.VK_UP) {
 					selectPreviousCompletion();
 					e.consume();
 				}
 				else if (code == KeyEvent.VK_ENTER) {
 					if (list.getSelectedValue() != null) {
 						/* object violation, maybe we should throw an event or
                            do nothing at all.  */
 						completion.setText(list.getSelectedValue().toString());
 						e.consume();
 					}
 					CompletionPopup.this.setVisible(false);
 				} 
 				else if (code == KeyEvent.VK_ESCAPE) {
 					CompletionPopup.this.setVisible(false);
 					e.consume();
 				}
 			}
 		}
 	}
 
 	/***
 	 * Listens for the loss of focus and hides the popup if necessary.
 	 */
 	private class FocusHandler extends FocusAdapter
 	{
 		public void focusLost(FocusEvent e)
 		{
 			if (!e.isTemporary()) {
 				setVisible(false);
 			}
 		}
 	}
 
 	/***
 	 * Listens for click events in the completion list to update the text
 	 * component's text appropriately.
 	 */
 	private class MouseHandler extends MouseAdapter
 	{
 		public void mouseClicked(MouseEvent e)
 		{
 			completion.setText(list.getSelectedValue().toString());
 			CompletionPopup.this.setVisible(false);
 		}
 	}
 	
 	private class PropertyChangeHandler implements PropertyChangeListener
 	{
 
 		public void propertyChange(PropertyChangeEvent evt) 
 		{
 			ComponentOrientation o = (ComponentOrientation)evt.getNewValue();
 			applyComponentOrientation(o);
 		}
 		
 	}
 }