//-*-java-*-

per class coordinator Worm {

  Point[][] locations = new Point[3][];
  Point[] nexts = new Point[3];
  condition[] blocked = new boolean[3];

  run {
    on entry { locations[id] = coords; }
  }

  newDirection {
    on exit {
      nexts[id] = next;
      for(int i=0;i<3;i++)
	if(i != id)
	  for(int j=0;j<WORM_LENGTH;j++) {
	    int dx = nexts[id].x - locations[i][j].x;
	    int dy = nexts[id].y - locations[i][j].y;
	    if(Math.sqrt(dx*dx + dy*dy) < WORM_THICKNESS) {
	      blocked[id] = true;
	      break;
	    }
	  }
    }
  }

  step requires(!blocked[id]) {
    on exit {
      for(int i=0;i<3;i++)
	if(blocked[i]) { // If another was blocked...
	  blocked[i] = false;
	  for(int j=0;j<3;j++)
	    if(j != i)
	      // see if it should stay blocked.
	      for(int k=0;k<WORM_LENGTH;k++) {
		int dx = nexts[i].x - locations[j][k].x;
		int dy = nexts[i].y - locations[j][k].y;
		if(Math.sqrt(dx*dx + dy*dy) < WORM_THICKNESS) {
		  blocked[i] = true;
		  break;
		}
	      }
	}
    }
  }

  selfex step;
  mutex { step, newDirection }
}