!7

p-pretty {
  new CirclesAndLines cal;
  Circle a = cal.circle_autoVis("PLAYER", "Chess Player", 0.25, 0.75);
  Circle b = cal.circle_autoVis("PLAYER", "Chess Player", 0.75, 0.75);
  cal.arrow(a, "VS", b);
  cal.circle_autoVis("MAGNUS CARLSEN", 0.25, 0.25);
  cal.circle_autoVis("HIKARU NAKAMURA", 0.75, 0.25);
  cal.show(600, 600);
}

sclass Thinker {
  double delay = 2; // 2 seconds
  CirclesAndLines cal;
  Canvas canvas;
  volatile bool thinking;
  O think; // func -> bool
  
  void run {
    repeat {
    sleepSeconds(delay);
    if (thinking) pcall {
      print("Thinking");
      bool t;
      time { t = think(); }
      if (!t) {
        thinking(false);
        print("Done");
      } else {
        print("Updating");
        canvas.update();
      }
    }
  }
  
  void thinking(bool b) {
    thinking = b; status();
    setText(btnThink, b ? "<html><center>Stop<br>thinking</center></html>" : "Think!");
  }
  
  void thinkOrStop {
    thinking(!thinking);
  }
  
  bool think() {
    cal.lock.lock();
    try {
      ret !isFalse(pcallF(thinkFunction));
    } finally {
      cal.lock.unlock();
    }
  }
}