/*
Wotonomy: OpenStep design patterns for pure Java applications.
Copyright (C) 2000 Blacksmith, Inc.

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, see http://www.gnu.org
*/

package net.wotonomy.ui.swing.components;

import java.awt.Component;
import java.awt.Dimension;

import javax.swing.JList;
import javax.swing.JViewport;
import javax.swing.ListCellRenderer;
import javax.swing.UIManager;
import javax.swing.border.Border;
import javax.swing.border.EmptyBorder;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;

/**
 * A list cell renderer that wraps its text to subsequent lines depending on the
 * length of text string and the width of the parent list.
 *
 * This renderer depends on listening to the parent list's viewport and fixing
 * the list's width to match the viewport's size.
 *
 * @author michael@mpowers.net
 * @author $Author: cgruber $
 * @date $Date: 2006-02-18 18:19:05 -0500 (Sat, 18 Feb 2006) $
 * @revision $Revision: 904 $
 */
public class LineWrappingRenderer extends MultiLineLabel implements ListCellRenderer, ChangeListener {
	protected static Border noFocusBorder;

	protected JList list;
	protected JViewport viewport;
	protected int preferredWidth;

	/**
	 * Required constructor. The renderer keeps a reference to the list in which it
	 * is used and its viewport. This list is the only list that may use this
	 * renderer. The renderer will use the current size of the list to determine
	 * where lines will initially break.
	 * 
	 * @param containerList The list that will be using this renderer.
	 */
	public LineWrappingRenderer(JList containerList) {
		super();
		setLineWrap(true);
		noFocusBorder = new EmptyBorder(1, 1, 1, 1);

		list = containerList;
		preferredWidth = 400;
		if (list.getParent() instanceof JViewport) {
			viewport = (JViewport) list.getParent();
			viewport.addChangeListener(this);
			int newWidth = viewport.getExtentSize().width;
			if (newWidth > 0)
				preferredWidth = newWidth;
		} else {
			// should function adequately in absence of a viewport
			// System.err.println( "LineWrappingRenderer.init: list.getParent = " +
			// list.getParent() );
		}
	}

	/**
	 * Returns the preferred size of the label, with width constrained to the
	 * current width.
	 * 
	 * @return the size
	 */
	public Dimension getPreferredSize() {
		int width = getWidth();
		if (width != preferredWidth) {
			// if component has not yet been placed within the list
			if (width < list.getWidth() / 2)
				width = list.getWidth();
			preferredWidth = width;
		}
		return new Dimension(preferredWidth, super.getPreferredSize().height);
	}

	/**
	 * Returns this component with the width set to the width of the specified
	 * JList.
	 * 
	 * @return this component.
	 */
	public Component getListCellRendererComponent(JList list, Object value, int index, boolean isSelected,
			boolean cellHasFocus) { // System.out.println( "LineWrappingRenderer.getListCellRendererComponent:" );

		if (list != this.list) {
			System.err.println("LineWrappingRenderer.getListCellRendererComponent: "
					+ "warning: the list using the renderer is not the list specified in the constructor.");
		}

		if (isSelected) {
			setBackground(this.list.getSelectionBackground());
			setForeground(this.list.getSelectionForeground());
		} else {
			setBackground(this.list.getBackground());
			setForeground(this.list.getForeground());
		}

		setText((value == null) ? "" : value.toString());

		setEnabled(this.list.isEnabled());
		setFont(this.list.getFont());
		setBorder((cellHasFocus) ? UIManager.getBorder("List.focusCellHighlightBorder") : noFocusBorder);

		return this;
	}

	/**
	 * Overridden to respond to viewport changes.
	 */
	public void stateChanged(ChangeEvent e) {
		int newWidth = viewport.getExtentSize().width;
		if (newWidth > 0)
			preferredWidth = newWidth;

		// set fixed width on list
		list.setFixedCellWidth(preferredWidth);
		setSize(preferredWidth, super.getSize().height);
	}

}