import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.util.*;

public class SnowStorm extends JFrame {

   private Cloud cloud = new Cloud();

   public static void main(String[] args) {
      new SnowStorm();
   }

   public SnowStorm() {
      P p = new P();
      getContentPane().add(p);
      addWindowListener(new L1());
      addKeyListener(new L2());
      setSize(500, 500);
      show();
      p.requestFocus();
   }

   class L1 extends WindowAdapter {
      public void windowClosing(WindowEvent e) {
         System.exit(0);
      }
   }

   class L2 extends KeyAdapter {
      public void keyPressed(KeyEvent e) {
         if(e.getKeyChar() == '1')
            cloud.stopGenerator();
         if(e.getKeyChar() == '2')
            cloud.startGenerator();
      }
   }

   class P extends JPanel implements Runnable {

      Thread thread = new Thread(this);

      public P() {
         setBackground(Color.black);
         setForeground(Color.white);
         thread.start();
      }

      public void run() {
         while(true) {
            try { thread.sleep(100); } catch(Exception e) { }
            repaint();
         }
      }  

      public void paintComponent(Graphics g) {
         super.paintComponent(g);
         setTitle("Växelverka med 1 och 2 - antal snöflingor/trådar: " + new Integer(cloud.getContent().size()).toString());
         cloud.paintComponent(g);
      }
   }
}

class Cloud implements Runnable {
   private Vector content = new Vector();
   private boolean generate = true;
   private Random rnd = new Random();
   private Thread thread = new Thread(this);

   public Cloud() {
      thread.start();
   }

   public void stopGenerator() {
      generate = false;
   }
      
   public void startGenerator() {
      generate = true;
   }

   public Vector getContent() {
      return content;
   }

   public void paintComponent(Graphics g) {
      for(int i = 0; i < content.size(); i++) {
         ((Snow)content.elementAt(i)).paintComponent(g);   
      }
   }

   public void run() {
      while(true) {
         int sleepTime = rnd.nextInt(200) + 10;
         try { thread.sleep(sleepTime); } catch(Exception e) { }
         if(generate) content.add(new Snow(this));
      }
   }
}

class Snow extends Thread {
   private static Random rnd = new Random();
   private Cloud cloud;
   private int x = rnd.nextInt(492), y = 0;
   private int size = rnd.nextInt(5) + 1;
   private Color color = Color.white;

   public Snow(Cloud cloud) {
      this.cloud = cloud;
      start();
   }

   public Color getColor() {
      return color;
   }

   private int getNewX() {
      if(rnd.nextBoolean()) {
         x = x + rnd.nextInt(3);
         if(x > 492) x = 492;
      } else {
         x = x - rnd.nextInt(3);
         if(x < 0) x = 0;
      }
      return x;
   }

   public void paintComponent(Graphics g) {
      g.setColor(color);
      g.fillOval(x, y, size, size);   
   }

   public void run() {
      while(y != 473) {
         // Slumpmässig fart beroende på size - 3D
         int sleepTime = rnd.nextInt(700/(size*2)) + 1;
         try { sleep(sleepTime); } catch(Exception e) { }
         x = getNewX();
         y = y + 1;
         if(rnd.nextInt(100) < 10)
            color = Color.white;
         else
            color = Color.gray;
      }
      cloud.getContent().remove(this);
   }
}