import java.lang.*;
import java.awt.*;
import java.awt.image.*;
import java.applet.*;
import netscape.javascript.*;

class CallbackThread extends Thread
{
    Widget parent;

    public CallbackThread(Widget w)
    {
	super();
	System.err.println("MAKE");
	parent=w;
    }

    public synchronized void run()
    {
	System.err.println("RUN");
	try {
	    System.err.println("WAIT");
	    wait();
	} catch (Exception e) {
	}
	System.err.println("GONE");
	parent.jsCall();
    }

    public synchronized void go()
    {
	System.err.println("GO");
	notify();
    }
}

public class Widget extends Applet
{

    static String id = "x2 ";

    static Color [] colors = new Color [] { Color.red, Color.blue, Color.green, Color.yellow, Color.cyan , Color.magenta };

    static String [] pars = new String [] { 
	"java.version",
	    "java.vendor",
	    "java.vendor.url",
	    "java.class.version",
	    "java.class.path",
	    "java.home",
	    "java.compiler",
	    "os.name",
	    "os.arch",
	    "os.version"
	    };

    Color c;
    Dimension sz;
    JSObject  reciever;
    CallbackThread cbThread=null;

    Image img;

    public void   init()
    {
	System.err.println("INIT");

	for(int i=0; i<pars.length; i++)
	    {
		String p = pars[i];

		try {
		    System.err.println("par "+p+"="+System.getProperty(p));
		} catch (Exception ex) {
		    System.err.println("par "+p+"="+"SECURE");
		}
	    }
	setColor(0);
	if (getParameter("js_on_init") != null)
	    checkJSReciever();

	System.err.println("MAKE");
	System.err.println("START");
    }

    private boolean checkJSReciever()
    {
	System.err.println("CHECKJSOBJECT");
	if (reciever==null)
	    {
		System.err.println("GETJSOBJECT");
		try {
		    reciever=JSObject.getWindow(this);
		} catch (Exception ex) {
		    // brain dead browser
		    System.err.println("JSOBJECTFAIL");
		    System.err.println(ex);
		    reciever=null;
		    return false;
		}
	    }
	return true;
    }

    public void jsGet()
    {
	checkJSReciever();
	cbThread = new CallbackThread(this);
	cbThread.start();
    }

    public void jsCall()
    {
	Object [] args = new Object [0];

	checkJSReciever();
	reciever.call("set_colour", args);
    }

    public void setColor(int cn)
    {
	c = colors[cn%colors.length];
	repaint();
    }

    public void loadImage(String i)
    {
	prepare(img=getImage(i, false));
    }

    public SubWidget getSub()
    {
	return new SubWidget("XYZZY");
    }

    protected Image getImage(String urls, boolean prepare)
    {
	Image im = null;

	System.err.println("GetImage "+urls);

	if (urls != null)
	    {
		System.err.println("GET");
		im = getImage(getCodeBase(), urls);

		if (prepare && im != null)
		    prepare(im);
	    }

	return im;
    }

    protected void prepare(Image im)
    {
	if (im != null && prepareImage(im, this))
	    imageUpdate(im, ImageObserver.ALLBITS, 
			0, 0, 
			im.getWidth(null), im.getHeight(null));
    }

    public boolean imageUpdate(Image img,
			       int infoFlags,
			       int x,
			       int y,
			       int width,
			       int height)
    {

	System.err.println("imageUpdate "+x+"/"+y+"/"+width+"/"+height);

	if ((infoFlags & ImageObserver.ALLBITS) != 0)
	    {
		System.err.println("all");
		if (cbThread != null)
		    cbThread.go();
	    }
	repaint(100L);
	return true;
    }

    public boolean mouseUp(Event e, int x, int y)
    {
	jsCall();
	return true;
    }

    public void paint(Graphics g)
    {
	System.err.println("PAINT");

	if (sz==null)
	    sz=getSize();
	g.setColor(Color.white);
	g.fillRect(0,0,sz.width,sz.height);

	Color sc = c;

	for (int i=30; i<80; i+=10)
	    {
		g.setColor(sc);
		g.fillRect(i,i,(100-i)*2,(100-i)*2);
		sc = sc.darker();
	    }
	String t = id+c+"";
	g.setColor(Color.black);
	for (int i=-1; i<2; i++)
	    for (int j=-1; j<2; j++)
		g.drawString(t, 0+i,20+j);
	g.setColor(Color.white);
	g.drawString(t, 0,20);

	if (img != null)
	    g.drawImage(img, 90, 90, 20, 20, null, this);
    }

}