/* $RCSfile$
 * $Author: egonw $
 * $Date: 2007-01-04 18:26:00 +0100 (Thu, 04 Jan 2007) $
 * $Revision: 7634 $
 *
 * Copyright (C) 2002-2007  The Jmol Development Team
 *
 * Contact: jchempaint-devel@lists.sourceforge.net
 *
 * This program 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.
 * All we ask is that proper credit is given for our work, which includes
 * - but is not limited to - adding the above copyright notice to the beginning
 * of your source code files, and to any copyright notice that you may distribute
 * with programs based on this work.
 * 
 * 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 Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 */
package org.openscience.cdk.applications.jchempaint.dialogs;

import java.awt.BorderLayout;
import java.awt.Container;
import java.awt.Cursor;
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;

import javax.swing.JButton;
import javax.swing.JDialog;
import javax.swing.JEditorPane;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;
import javax.swing.event.HyperlinkEvent;
import javax.swing.event.HyperlinkListener;
import javax.swing.text.Document;

/**
 * Dialog to show information on the internet. The Java HTML browser is very
 * basic and only simple webpages can be shown. Use text only webpages whenever
 * possible, and certainly no frames.
 *
 * <p>Taken from the Jmol Project.
 * @cdk.module jchempaint
 */
public class WebDialog extends JDialog implements HyperlinkListener {

	private static final long serialVersionUID = -6928369087569980743L;
	
	JEditorPane html;
    
    public WebDialog(JFrame fr, URL url) {
        
        super(fr, "JChemPaint Webbrowser", true);
        
        try {
            if (url != null) {
                html = new JEditorPane(url);
            } else {
                html = new JEditorPane("text/plain",
                "Unable to find url '" + url + "'.");
            }
            html.setEditable(false);
            html.addHyperlinkListener(this);
        } catch (MalformedURLException e) {
            System.out.println("Malformed URL: " + e);
        } catch (IOException e) {
            System.out.println("IOException: " + e);
        }
        JScrollPane scroller = new JScrollPane() {

			private static final long serialVersionUID = -1946954399372989440L;

			public Dimension getPreferredSize() {
                return new Dimension(800, 500);
            }
            
            public float getAlignmentX() {
                return LEFT_ALIGNMENT;
            }
        };
        scroller.getViewport().add(html);
        
        JPanel htmlWrapper = new JPanel(new BorderLayout());
        htmlWrapper.setAlignmentX(LEFT_ALIGNMENT);
        htmlWrapper.add(scroller, BorderLayout.CENTER);
        
        JPanel buttonPanel = new JPanel();
        buttonPanel.setLayout(new FlowLayout(FlowLayout.RIGHT));
        JButton ok =
        new JButton("OK");
        ok.addActionListener(new ActionListener() {
            
            public void actionPerformed(ActionEvent e) {
                OKPressed();
            }
        });
        buttonPanel.add(ok);
        getRootPane().setDefaultButton(ok);
        
        JPanel container = new JPanel();
        container.setLayout(new BorderLayout());
        
        JTextField urlDisplay = new JTextField(url.toString());
        urlDisplay.setEditable(false);
        
        container.add(urlDisplay, BorderLayout.NORTH);
        container.add(htmlWrapper, BorderLayout.CENTER);
        container.add(buttonPanel, BorderLayout.SOUTH);
        
        getContentPane().add(container);
        pack();
        centerDialog();
    }

    public void hyperlinkUpdate(HyperlinkEvent e) {
        if (e.getEventType() == HyperlinkEvent.EventType.ACTIVATED) {
            linkActivated(e.getURL());
        }
    }
    
    /**
    * Follows the reference in an
    * link.  The given url is the requested reference.
    * By default this calls <a href="#setPage">setPage</a>,
    * and if an exception is thrown the original previous
    * document is restored and a beep sounded.  If an
    * attempt was made to follow a link, but it represented
    * a malformed url, this method will be called with a
    * null argument.
    *
    * @param u the URL to follow
    */
    protected void linkActivated(URL u) {
        Cursor c = html.getCursor();
        Cursor waitCursor = Cursor.getPredefinedCursor(Cursor.WAIT_CURSOR);
        html.setCursor(waitCursor);
        SwingUtilities.invokeLater(new PageLoader(u, c));
    }
    
    /**
    * temporary class that loads synchronously (although later than
    * the request so that a cursor change can be done).
    */
    class PageLoader implements Runnable {
        
        PageLoader(URL u, Cursor c) {
            url = u;
            cursor = c;
        }
        
        public void run() {
            
            if (url == null) {
                
                // restore the original cursor
                html.setCursor(cursor);
                
                // remove this hack when automatic validation is
                // activated.
                Container parent = html.getParent();
                parent.repaint();
            } else {
                Document doc = html.getDocument();
                try {
                    html.setPage(url);
                } catch (IOException ioe) {
                    html.setDocument(doc);
                    getToolkit().beep();
                } finally {
                    
                    // schedule the cursor to revert after the paint
                    // has happended.
                    url = null;
                    SwingUtilities.invokeLater(this);
                }
            }
        }
        
        URL url;
        Cursor cursor;
    }
    
    
    protected void centerDialog() {
        
        Dimension screenSize = this.getToolkit().getScreenSize();
        Dimension size = this.getSize();
        screenSize.height = screenSize.height / 2;
        screenSize.width = screenSize.width / 2;
        size.height = size.height / 2;
        size.width = size.width / 2;
        int y = screenSize.height - size.height;
        int x = screenSize.width - size.width;
        this.setLocation(x, y);
    }
    
    public void OKPressed() {
        this.setVisible(false);
    }
    
}
