/*
 Program:       MoveBall Class
 Purpose:       Ball‚đ“®‚©‚·
 @author        segi.tetsu@ss.bch.ntt.jp
 @version       1.00; 20 Mar 1996
*/

import java.util.Random;
import java.applet.Applet;
import java.applet.AudioClip;
import java.awt.*;

public class MoveBall extends Applet implements Runnable {
    static final int r = 30;
    int x = r + 1;
    int y = 125;

    int movex = 3;
    int movey = 3;

    int color = 0;

    AudioClip au;
    Thread thread;

    Image off_im;
    Graphics off_g;

    public void init() {
        String audiofile = null;
        String s;
        s = getParameter("audiofile");
        if (s != null) audiofile = s;
        au = getAudioClip(getDocumentBase(), audiofile);

        resize(600, 250);
        setBackground(Color.blue);

        if (off_g == null)
        {
           off_im = this.createImage(600, 250);
           off_g = off_im.getGraphics();
        }        
    }

    public void start() {
        if (thread == null) {
            thread = new Thread(this);
            thread.start();
        }
    }

    public void stop() {
        if (thread != null) {
            thread.stop();
            thread = null;
        }
    }

    public void update(Graphics g) {
       off_g.setColor(getBackground());
       off_g.fillRect(0, 0, size().width, size().height);

        switch(color) {
        case 0:
        off_g.setColor(Color.yellow);
        break;
        case 1:
            off_g.setColor(Color.magenta);
            break;
        case 2:
                off_g.setColor(Color.orange);
                break;
            case 3:
                off_g.setColor(Color.pink);
                break;
            case 4:
                off_g.setColor(Color.red);
                break;
            case 5:
                off_g.setColor(Color.white);
                break;
            default:
                break;
            }
       off_g.fillOval(x, y, r, r);
       g.drawImage(off_im, 0, 0, this);
    }

    public void run() {
        Random aRandom = new Random();
        int sign;

        while(true) {
            try {
                Thread.sleep(0);
            } catch (InterruptedException e) {
                break;
            }

            if (x <= 0 && movex < 0) {
                movex = aRandom.nextInt() % 5;
                if (movex < 0) movex = -movex;
                if (movex == 0) movex = 1;

                if (movey > 0) {
                    sign = 1;
                } else {
                    sign = -1;
                }
                movey = aRandom.nextInt() % 5 + 1;
                if (sign * movey < 0) movey = -movey;

                repaint();
                au.play();
                color++;
            }

            if (x >= 600 - r && movex > 0) {
                movex = -movex;
                au.play();
            }

            if ((y <= 0 && movey < 0) || (y >= 250 - r && movey > 0)) {
                movey = -movey;
                au.play();
            }

            x += movex;
            y += movey;

            if (color > 5) color = 0;
            repaint();
        }
    }
}