/*
 * $Id$
 *
 * Copyright (c) 2006 by Joel Uckelman
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License (LGPL) as published by the Free Software Foundation.
 *
 * 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
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, copies are available
 * at http://www.opensource.org.
 */
package VASSAL.tools;

import java.awt.Component;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;

import javax.swing.JScrollPane;

import VASSAL.build.GameModule;
import VASSAL.configure.IntConfigurer;
import VASSAL.i18n.Resources;
import VASSAL.preferences.Prefs;

/**
 *  AdjustableSpeedScrollPane extends {@link ScrollPane} by making the
 *  scroll speed user-configurable. Use AdjustableScrollPane instead
 *  of ScrollPane wherever a scrollpane for large images is needed.
 *
 *  @author Joel Uckelman
 *  @see VASSAL.tools.ScrollPane
 *  @see javax.swing.JScrollPane
 */
public class AdjustableSpeedScrollPane extends ScrollPane {
  private static final long serialVersionUID = 1L;
  private static final String SCROLL_SPEED = "scrollSpeed"; //$NON-NLS-1$
  private static final int defaultSpeed = 50;

  /**
   * Creates an AdjustableSpeedScrollPane that displays the contents of the
   *  specified component, where both horizontal and vertical scrollbars
   * appear whenever the component's contents are larger than the view.
   *
   *  @param view the component to display in the scrollpane's viewport
   */
  public AdjustableSpeedScrollPane(Component view) {
    this(view, VERTICAL_SCROLLBAR_AS_NEEDED, HORIZONTAL_SCROLLBAR_AS_NEEDED);
  }

  /**
   * Creates an AdjustableSpeedScrollPane that displays the view component
   *  in a viewport with the specified scrollbar policies. The available
   * policy settings are listed at
   * {@link JScrollPane#setVerticalScrollBarPolicy} and
   * {@link JScrollPane#setHorizontalScrollBarPolicy}.
   *
   * @param view the component to display in the scrollpane's viewport
   * @param vsbPolicy an integer that specifies the vertical scrollbar policy
   * @param hsbPolicy an integer that specifies the horizontal scrollbar
   * policy
   */
  public AdjustableSpeedScrollPane(Component view,
                                   int vsbPolicy, int hsbPolicy) {

    super(view, vsbPolicy, hsbPolicy);

    // set configurer
    final IntConfigurer config = new IntConfigurer(
      SCROLL_SPEED,
      Resources.getString("AdjustableSpeedScrollPane.scroll_increment"),
      defaultSpeed
    );

    config.addPropertyChangeListener(new PropertyChangeListener() {
      public void propertyChange(PropertyChangeEvent e) {
        if (SCROLL_SPEED.equals(e.getPropertyName()))
          setSpeed(((Integer) e.getNewValue()).intValue());
      }
    });

    final GameModule g = GameModule.getGameModule();
    if (g == null) {
      setSpeed(defaultSpeed);
    }
    else {
      final Prefs prefs = g.getPrefs();
      prefs.addOption(Resources.getString("Prefs.general_tab"), config); //$NON-NLS-1$
      setSpeed(((Integer) prefs.getValue(SCROLL_SPEED)).intValue());
    }
  }

  private void setSpeed(int speed) {
    verticalScrollBar.setUnitIncrement(speed);
    horizontalScrollBar.setUnitIncrement(speed);
  }
}