/*
 * LineFinder
 * Copyright (C) 2001  Scott Maxwell
 * 
 * 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.
 *
 * You can reach me at maxwell@ScottMaxwell.org.
 */


import java.applet.*;
import java.awt.*;
import java.awt.event.*;
import java.io.*;
import java.util.*;
import java.util.zip.*;
import java.net.*;




class LineAwareTextArea extends TextArea
{
//ed1    private final static int NUM_LINES = 39339;
    private final static int NUM_LINES = 48921;
    private final static int CHUNK = 1000;
    private int [] posns = new int [NUM_LINES / CHUNK + 1];
    private LineFinder applet;


    public LineAwareTextArea(LineFinder a)
    {
	applet = a;
    }


    public void setText(String txt)
    {
	posns[0] = 0;
	for (int i = 1; i < posns.length; ++i)
	    posns[i] = findPos(txt, i * CHUNK, posns[i - 1]);

	super.setText(txt);
    }


    public void scrollToLine(int line)
    {
	// This will allow using line number 0 to go to the top of the
	// file -- but that's OK by me.
	if ((line < 0) || (line > NUM_LINES))
	{
	    applet.setStatus("Line number " + line + " is out of range.");
	    return;
	}

	long before = System.currentTimeMillis();

	applet.beginBusy("Seeking line " + line + " ...");
	scrollToPos(1 + findPos(getText(), line, posns[line / CHUNK]));

	long after = System.currentTimeMillis();

	applet.endBusy("Found line " + line + " in " +
	    ((after - before) / 1000) + " seconds");
    }


    private void scrollToPos(int pos)
    {
	// I don't know why, but this sometimes doesn't work if you do
	// it only once (jdk 1.1.7 on Linux).
	setCaretPosition(pos);
	setCaretPosition(pos);
    }


    private int findPos(String txt, int line, int startFrom)
    {
	String find = "\n" + line + " ";
	return txt.indexOf(find, startFrom);
    }
}




class Filler extends Thread
{
    private static final long UPDATE_FREQ = 1000; // In msec.
    private static boolean allRead = false;
    private long prevUpdate = System.currentTimeMillis();
    private LineFinder applet;
    private TextArea display;
    String filename = "/mnt/cdrom/lckc_code";
    // String codeUrl = "http://www.ScottMaxwell.org/lckc_code.gz";
    String codeUrl = "http://home.pacbell.net/s-max/smorg/lckc/lckc_code.gz";


    public Filler(LineFinder a, TextArea ta, String file, String url)
    {
	applet = a;
	display = ta;

	if (file != null)
	    filename = file;
	if (url != null)
	    codeUrl = url;
    }


    public void run()
    {
	if (allRead)
	{
	    System.out.println("Filler.run() called after all code read.");
	    return;
	}

	String base = "Reading LCKC source code";
	applet.beginBusy(base + " ...");
//ed1	final int sz = 1312112;
	final int sz = 1631569;
	try
	{
	    InputStreamReader in;
	    if (filename.equals(""))
	    {
		URL url = new URL(codeUrl);
		in =
		    new InputStreamReader(
			new GZIPInputStream(
			    new BufferedInputStream(url.openStream())));
	    }
	    else
		in = new InputStreamReader(new FileInputStream(filename));

	    int totalRead = 0;
	    int nRead;
	    char [] buf = new char [4096]; // Larger != (much) faster.
	    String contents;
	    StringBuffer sbuf = new StringBuffer(sz);
	    while ((nRead = in.read(buf, 0, buf.length)) != -1)
	    {
		yield();

		totalRead += nRead;
		sbuf.append(buf, 0, nRead);

		long now = System.currentTimeMillis();
		if ((now - prevUpdate) >= UPDATE_FREQ)
		{
		    prevUpdate = now;
		    applet.setStatus(base + ": " + totalRead + " / " + sz + ": "
			+ (100 * totalRead / sz) + "% read");
		}
	    }
	    allRead = true;
	    contents = new String(sbuf);

	    display.setText(contents);
	}
	catch (FileNotFoundException e)
	{
	    System.out.println(e);
	}
	catch (IOException e)
	{
	    System.out.println(e);
	}
	applet.endBusy("All done reading; enjoy");
    }
}




// And now, the Applet itself.
public class LineFinder extends Applet
{
    private final static int defaultW = 512;
    private final static int defaultH = 512;

    private static long busyCount = 0;
    private boolean initialized = false;
    private TextField lineTxt = new TextField("", 5);
    private LineAwareTextArea display = new LineAwareTextArea(this);
    private Label statusLbl = new Label("OK");

    String filename = null, url = null;


    // Ctor.
    public LineFinder()
    {
	// Running as an applet, so don't try to read from a file.
	filename = "";
    }
    

    public LineFinder(String file, String u)
    {
	filename = file;
	url = u;
    }


    // One-time applet initialization.
    public void init()
    {
	// I've heard that some browsers may (incorrectly) invoke this
	// method more than once.  So guard against that.
	if (initialized)
	    return;
	initialized = true;

	// Set up the user interface.  This uses the default
	// FlowLayout, creating a full-width Panel for each row of
	// items.

	// First row.
	setLayout(new BorderLayout());

	Panel p = new Panel();
	p.add(new Label("Type line number and press Enter:"));
	p.add(lineTxt);
	add(p, BorderLayout.NORTH);

	// Second row.
	add(display, BorderLayout.CENTER);
	display.setFont(new Font("Courier", Font.PLAIN, 12));
	display.setEditable(false);

	add(statusLbl, BorderLayout.SOUTH);

	lineTxt.addActionListener(new MyActionListener(display));
	repaint();
    }


    public void stop()
    {
    }


    public void start()
    {
    }


    boolean started = false;
    public void paint(Graphics g)
    {
	if (!started)
	{
	    started = true;
	    new Filler(this, display, filename, url).run();
	}

	super.paint(g);
    }


    public void beginBusy(String msg)
    {
	setStatus(msg);

	if (++busyCount == 1)
	{
	    Cursor c = new Cursor(Cursor.WAIT_CURSOR);
	    setCursor(c);
	    display.setCursor(c);
	}
    }


    public void endBusy(String msg)
    {
	if ((busyCount > 0) && (--busyCount == 0))
	{
	    Cursor c = new Cursor(Cursor.DEFAULT_CURSOR);
	    setCursor(c);
	    display.setCursor(c);
	}

	setStatus(msg);
    }


    public void setStatus(String status)
    {
	statusLbl.setText(status);
    }


    // In case we're not running in in a Web browser.
    public static void main(String args [])
    {
	int w = defaultW;
	int h = defaultH;
	String filename = null;
	String url = null;

	Properties props = System.getProperties();
	filename = (String) props.get("file");
	url = (String) props.get("url");

	String sw = (String) props.get("width");
	String sh = (String) props.get("height");

	if (sw != null)
	    w = (new Integer(sw)).intValue();
	if (sh != null)
	    h = (new Integer(sh)).intValue();

	LineFinderFrame frame =
	    new LineFinderFrame(w, h, filename, url);
    }



    // Should be able to use an anonymous inner class defined at the
    // addActionListener() call, but that runs afoul of a bug (?) in
    // the Netscape JDK.
    private static class MyActionListener implements ActionListener
    {
	public MyActionListener(LineAwareTextArea d)
	{
	    disp = d;
	}

	// Contrary to the JDK documentation, the action events appear
	// to be generated only when the user hits Enter.
	public void actionPerformed(ActionEvent e)
	{
	    final TextField source = (TextField) e.getSource();
	    final String txt = source.getText();
	    try
	    {
		disp.scrollToLine(new Integer(txt).intValue());
	    }
	    catch (NumberFormatException e2) // E.g., "".
	    {
		System.out.println(e);
	    }
	}

	private final LineAwareTextArea disp;
    };
}




// Only used when the LineFinder applet is not running in a Web browser.
class LineFinderFrame extends Frame
{
    public LineFinderFrame(int w, int h, String filename, String url)
    {
	super("LCKC LineFinder");

	setSize(w, h);		// Approximately; will change later.
	LineFinder lf = new LineFinder(filename, url);
	//add(lf, BorderLayout.CENTER);
	add(lf);
	lf.init();
	lf.start();
	enableEvents(Event.WINDOW_DESTROY);
	show();
    }


    // Cleaner than a WindowListener with lots of empty methods.
    protected void processWindowEvent(WindowEvent e)
    {
	if (e.getID() == Event.WINDOW_DESTROY)
	    System.exit(0);

	super.processWindowEvent(e);
    }
}