/*
    *  XNap - A P2P framework and client.
    *
    *  See the file AUTHORS for copyright information.
    *
    *  This program is free software; you can redistribute it and/or modify
    *  it under the terms of the GNU General Public License as published by
    *  the Free Software Foundation.
    *
   *  This program 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 General Public License for more details.
   *
   *  You should have received a copy of the GNU General Public License
   *  along with this program; if not, write to the Free Software
   *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
   */
  
  package org.xnap.gui.component;
  
  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.lang.reflect.Method;
  
  import javax.swing.JList;
  import javax.swing.JPopupMenu;
  import javax.swing.JScrollPane;
  import javax.swing.ListSelectionModel;
  
  import org.apache.log4j.Logger;
  
  /***
   * This class presents completed objects in a popup menu below a {@link
   * JTextComponent}.
   */
  public class CompletionPopup extends JPopupMenu
  {
  	//--- Constant(s) ---
  	
  	//--- Data field(s) ---
  	
  	/***
  	 * The completion mode handling when and how to complete.
  	 */
  	private CompletionMode mode;
  	/***
  	 * The list presenting the completed items.
  	 */
  	private JList list;
  
  	private KeyListener keyListener = new KeyHandler();
  
  	private FocusListener focusListener = new FocusHandler();
  
  	private ComponentListener componentListener = new SizeHandler();
  		
      private static Logger logger = Logger.getLogger(CompletionPopup.class);
  	
  	//--- Constructor(s) ---
  
  	/***
  	 * Constructs a new completion popup for the given text component.
  	 *
  	 * @param mode the completion mode
  	 */
  	public CompletionPopup(CompletionMode mode)
  	{
  		this.mode = mode;
  	
  		list = new JList(mode.getModel());
  		list.setVisibleRowCount(4);
  		
  		list.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
  		JScrollPane jsp = new JScrollPane(list);
  		add(jsp);
  
  		try {
  			Method m = list.getClass().getMethod
  				("setFocusable", new Class[] { Boolean.TYPE });
  			m.invoke(list, new Object[] { new Boolean(false) });
  			m = jsp.getClass().getMethod
  				("setFocusable", new Class[] { Boolean.TYPE });
  			m.invoke(jsp, new Object[] { new Boolean(false) });
  			m = getClass().getMethod
  				("setFocusable", new Class[] { Boolean.TYPE });
  			m.invoke(this, new Object[] { new Boolean(false) });
  		}
  		catch (Exception e) {
 			logger.debug("setFocusable not available", e);
 		}
 
 		list.addMouseListener(new MouseHandler());
 	}
 
     //--- Method(s) ---
 	
 	public void enablePopup()
 	{
 		mode.getTextComponent().addKeyListener(keyListener);
 		mode.getTextComponent().addFocusListener(focusListener);
 
 		// the model could have changed
 		list.setModel(mode.getModel());
 		
 		if (mode.isWholeTextCompletion()) {
 			setPreferredSize(new Dimension(mode.getTextComponent().getWidth(),
 										   getPreferredSize().height));
 			mode.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.  */
 		mode.getTextComponent().removeKeyListener(keyListener);
 		mode.getTextComponent().removeFocusListener(focusListener);
 		if (mode.isWholeTextCompletion()) {
 			mode.getTextComponent().removeComponentListener(componentListener);
 		}
 	}
 
 	private void selectNextCompletion()
 	{
 		if (mode.getModel().getSize() > 0) {
 			int cur = (list.getSelectedIndex() + 1) % mode.getModel().getSize();
 			list.setSelectedIndex(cur);
 			list.ensureIndexIsVisible(cur);
 		}
 	}
 
 	private void selectPreviousCompletion()
 	{
 		if (mode.getModel().getSize() > 0) {
 			int cur = (list.getSelectedIndex() == -1) ? 0 
 				: list.getSelectedIndex();
 			cur = (cur == 0) ? mode.getModel().getSize() - 1 : cur - 1;
 			list.setSelectedIndex(cur);
 			list.ensureIndexIsVisible(cur);
 		}
 	}
 
 	//--- Inner class(es) ---
 
 	/***
 	 * 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(mode.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.  */
 						mode.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)
 		{
 			mode.setText(list.getSelectedValue().toString());
 			CompletionPopup.this.setVisible(false);
 		}
 	}
 }