import java.util.LinkedList;
import java.util.List;
import java.util.concurrent.CountDownLatch;

public class GameOfLife {
	
	public GameOfLife(Environment env) {
		this.env = env;
	}
	
	Environment env;

	List<GOLThread> threads = new LinkedList<GOLThread>();
	
	public void start() {
		setThreadCount(1);
	}
	
	synchronized void setThreadCount(int numberOfThreads) {
		for (GOLThread golThread : threads) {
			golThread.exiting();
		}
		for (GOLThread golThread : threads) {
			try {
				golThread.join();
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
		}
		for (int i = 0; i < numberOfThreads; ++i) {
			GOLThread golThread = new GOLThread(this);
			threads.add(golThread);
			golThread.start();
		}
	}
	
	CountDownLatch countDown;
	
	synchronized void step() {
		int i = 0;
		countDown = new CountDownLatch(threads.size());
		for (Point cell : env.living) {
			threads.get(i % threads.size()).addPoint(cell);
			++i;
		}
		for (GOLThread golThread : threads) {
			golThread.pointsProcessed();
		}
		try {
			countDown.await();
		} catch (InterruptedException e) {
			e.printStackTrace();
		}
		env = env.next();
	}
	
	public void threadFinished() {
		countDown.countDown();
	}
	
}