// Agents.java

import java.applet.Applet;
import java.applet.AppletContext;
import java.awt.*;
import java.net.MalformedURLException;
import java.net.URL;

public class Agents extends Applet  implements Runnable
{
   public void assignRandomTargets (int mode)
   {  for (int i = 0; i < MAXANTZ; i++) {
        int j;
         while ((j = (int)(Math.random() * (double)MAXANTZ)) == i) ;
         antz[i].SetTarget (antz[j]);
         antz[i].SetMode   (mode);
      }
   }

   public void assignCircularTargets (int mode)
   {  for (int i = 1; i < MAXANTZ; i++) {
         antz[i].SetTarget(antz[i-1]);
         antz[i].SetMode  (mode);
      }
      antz[0].SetTarget (antz[MAXANTZ-1]);
      antz[0].SetMode   (mode);
   }

   public void init ()
   {  _w   = getWidth ();
      _h   = getHeight ();
      _img = createImage (_w, _h);
      _gfx = _img.getGraphics ();
      Ant.SetBounds (_w, _h);
      setBackground (new Color (0x404040));
      antz = new Ant [MAXANTZ];
      for (int i = 0; i < MAXANTZ; i++) {
         antz[i] = new Ant();
         antz[i].SetPosition (Math.random() * (double)_w,
                              Math.random() * (double)_h);
         antz[i].SetMode  (1);
         antz[i].SetColor (new Color (0xff6600));
      }
      assignRandomTargets (1);
   }

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

   public void run ()
   { int i1 = 1000;
      _gfx.setColor (new Color (0x404040));
      _gfx.fillRect (0, 0, _w, _h);
      repaint ();
      do {
         do {
            try {Thread.sleep (20L);}
            catch (InterruptedException interruptedexception)  {}
            _gfx.setColor (new Color (0x404040));
            _gfx.fillRect (0, 0, _w, _h);
            for (int j = 0; j < MAXANTZ; j++) {
               antz[j]._fx = 0D;
               antz[j]._fy = 0D;
            }
            for (int k = 0; k < MAXANTZ; k++) {
               for (int i = k + 1; i < MAXANTZ; i++) {
                 double d1 = antz[i]._x - antz[k]._x;
                 double d2 = antz[i]._y - antz[k]._y;
                  if (d1 <= 6D && d1 >= -6D && d2 <= 6D && d2 >= -6D) {
                    double d3 = d1 * d1;
                     d3 += d2 * d2;
                     if (d3 <= 36D) {
                        antz[i]._fx += d1 * ( 6D / d3);
                        antz[i]._fy += d2 * ( 6D / d3);
                        antz[k]._fx += d1 * (-6D / d3);
                        antz[k]._fy += d2 * (-6D / d3);
                     }
                  }
               }
            }
            for (int l = 0; l < MAXANTZ; l++)
               {antz[l].Think ();   antz[l].Move ();   antz[l].Display (_gfx);}
            repaint ();
         } while (--i1 != 0);
        double d = Math.random();
         if (d < 0.25D) {
            i1 = (int)(Math.random()*500D + 200D);  assignCircularTargets (1);}
         else if(d < 0.6D) {
            i1 = (int)(Math.random()*500D + 200D);  assignRandomTargets   (2);}
         else {
            i1 = (int)(Math.random()*500D + 100D);  assignRandomTargets   (1);}
      } while (true);
   }

   public void update (Graphics g)  {paint (g);}

   public void paint  (Graphics g)  {g.drawImage (_img, 0, 0, this);}

   int       _w, _h;
   Graphics  _gfx;
   Image     _img;
   Thread    _thr;
   int       MAXANTZ = 300;
   Ant       antz [];
}