/*
 * SimplyHTML, a word processor based on Java, HTML and CSS
 * Copyright (C) 2002 Ulrich Hilger
 *
 * 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; either version 2
 * of the License, or (at your option) any later version.
 *
 * 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 com.lightdev.app.shtm;

import javax.swing.event.ListSelectionListener;
import javax.swing.event.ListSelectionEvent;
import javax.swing.event.CaretListener;
import javax.swing.event.CaretEvent;
import java.awt.event.FocusListener;
import java.awt.event.FocusEvent;
import java.awt.event.KeyListener;
import java.awt.event.KeyEvent;
import javax.swing.*;
import java.awt.BorderLayout;
import java.util.Vector;
import java.util.EventObject;
import java.util.EventListener;
import java.util.Enumeration;

/**
 * A pick list typically being used in font dialogs, consisting
 * of a list title, a text field for the currently selected
 * value and the actual pick list containing all possible values.
 *
 * As three different lists are needed in our font panel for
 * family, style and size, its quite handy to have the code
 * making up such a component in a separate class only once.
 *
 * As well in a separate class it is easier to implement the
 * special 'behaviour', i.e. when list is clicked, the value
 * of the text field is set accordingly and when a value is
 * typed in the text field, the value in the list changes
 * accordingly.
 *
 * @author Ulrich Hilger
 * @author Light Development
 * @author <a href="http://www.lightdev.com">http://www.lightdev.com</a>
 * @author <a href="mailto:info@lightdev.com">info@lightdev.com</a>
 * @author published under the terms and conditions of the
 *      GNU General Public License,
 *      for details see file gpl.txt in the distribution
 *      package of this software
 *
 * 
 */
class TitledPickList extends JPanel
  implements ListSelectionListener, CaretListener, FocusListener, KeyListener
{
  /** the chosen list entry */
  private JTextField choice;

  boolean ignoreTextChanges = false;

  /** the list having all possible entries */
  private JList optionsList;

  /**
   * constructor
   *
   * @param options  the options to be selectable in this list
   * @param titleText  the title for the pick list
   */
  public TitledPickList(String[] options, String titleText) {
    super(new BorderLayout());

    choice = new JTextField();
    choice.addCaretListener(this);
    choice.addFocusListener(this);
    choice.addKeyListener(this);

    optionsList = new JList(options);
    optionsList.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
    optionsList.addListSelectionListener(this);

    JScrollPane scrollableList = new JScrollPane(optionsList);

    JPanel pickListPanel = new JPanel(new BorderLayout());
    pickListPanel.add(choice, BorderLayout.NORTH);
    pickListPanel.add(scrollableList, BorderLayout.CENTER);

    JLabel title = new JLabel();
    title.setText(titleText);

    add(title, BorderLayout.NORTH);
    add(pickListPanel, BorderLayout.CENTER);
  }

  /**
   * if the caret was updated, i.e. the user typed into
   * the text field, try to find a font family name starting
   * with what was typed so far, set the list to that family
   */
  public void caretUpdate(CaretEvent ce) {
    if(!ignoreTextChanges) {
      if(choice.hasFocus()) {
	ListModel model = optionsList.getModel();
	String key = choice.getText().toLowerCase();
	if(key != null) {
	  int i = 0;
	  int modelSize = model.getSize();
	  String listEntry = (String) model.getElementAt(i);
	  while(++i < modelSize && !listEntry.toLowerCase().startsWith(key)) {
	    listEntry = (String) model.getElementAt(i);
	  }
	  if(i < modelSize) {
	    optionsList.setSelectedValue(listEntry, true);
	  }
	}
      }
    }
  }

  /** for FocusListener implementation, but unused here */
  public void focusGained(FocusEvent e) {
  }

  /**
   * put the currently selected value in the list
   * into the text field when user leaves field
   */
  public void focusLost(FocusEvent e) {
    updateTextFromList();
  }

  /**
   * put the currently selected value in the list
   * into the text field when user pressed enter in field
   */
  public void keyPressed(KeyEvent e) {
    if(e.getKeyCode() == KeyEvent.VK_ENTER) {
      updateTextFromList();
    }
  }

  /** for KeyListener implementation, but unused here */
  public void keyReleased(KeyEvent e) {
  }

  /** for KeyListener implementation, but unused here */
  public void keyTyped(KeyEvent e) {
  }

  /** put selected value into text field */
  private void updateTextFromList() {
    Object value = optionsList.getSelectedValue();
    if(value != null) {
      choice.setText(value.toString());
    }
  }

  /**
   * get the value selected from the pick list
   *
   * @return the selected value or null if nothing is selected
   */
  public Object getSelection() {
    return optionsList.getSelectedValue();
  }

  /**
   * set the value selected in the pick list
   *
   * @param value  the value to be selected in the list
   */
  public void setSelection(Object value) {
    optionsList.setSelectedValue(value.toString(), true);
    updateTextFromList();
  }

  /**
   * set the selected index in the pick list
   *
   * @param index  the index of the value to be selected in the list
   */
  public void setSelection(int index) {
    optionsList.setSelectedIndex(index);
    updateTextFromList();
  }

  /**
   * get the index of the value selected in the pick list
   *
   * @return the index of the selected value or -1 if none is selected
   */
  public int getIndex() {
    return optionsList.getSelectedIndex();
  }

  /**
   * if another value was picked from the list, set the
   * textfield according to the choice and update the
   * sample
   */
  public void valueChanged(ListSelectionEvent e) {
    if(optionsList.hasFocus()) {
      updateTextFromList();
    }
    fireValueChanged();
  }

  /* ------------- event handling start ------------ */

  /** the listeners for TitledPickkListEvents */
  private Vector listeners = new Vector(0);

  /**
   * add an event listener.
   *
   * @param  listener  the event listener to add
   */
  public void addTitledPickListListener(TitledPickListListener listener) {
    listeners.addElement(listener);
  }

  /**
   * remove an event listener.
   *
   * @param  listener  the event listener to remove
   */
  public void removeTitledPickListListener(TitledPickListListener listener) {
    listeners.removeElement(listener);
  }

  /** fire a value changed event to all registered listeners */
  void fireValueChanged() {
    Enumeration listenerList = listeners.elements();
    while(listenerList.hasMoreElements()) {
      ((TitledPickListListener) listenerList.nextElement()).valueChanged(
                                          new TitledPickListEvent(this));
    }
  }

  /** the event object definition for ColorPanels */
  class TitledPickListEvent extends EventObject {
    public TitledPickListEvent(Object source) {
      super(source);
    }
  }

  /** the event listener definition for ColorPanels */
  interface TitledPickListListener extends EventListener {
    public void valueChanged(TitledPickListEvent e);
  }

  /* ------------- event handling end ------------ */

}