package servlet;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.ArrayList;
import javax.servlet.ServletException;
import javax.servlet.ServletResponse;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.catalina.comet.CometEvent;
import org.apache.catalina.comet.CometProcessor;

/**
 *
 * @author mark
 */
@WebServlet(name = "Psych2", urlPatterns = {"/Psych2"})
public class Psych2
        extends HttpServlet implements CometProcessor {

    protected MessageSender messageSender = null;

    public void init() throws ServletException {
        messageSender = new MessageSender();
        Thread messageSenderThread = new Thread(messageSender);
        messageSenderThread.setDaemon(true);
        messageSenderThread.start();
    }

    public void destroy() {
        messageSender = null;
    }

    /**
     * Process the given Comet event.
     *
     * @param event The Comet event that will be processed
     * @throws IOException
     * @throws ServletException
     */
    public void event(CometEvent event)
            throws IOException, ServletException {
        HttpServletRequest request = event.getHttpServletRequest();
        HttpServletResponse response = event.getHttpServletResponse();

        if (event.getEventType() == CometEvent.EventType.BEGIN) {
            
            // Параметр отвечает за текущее действие в 
            // данном случае это только команда Send.
            String action = request.getParameter("action");

            if (action != null) {

                System.out.println("action! " + action);
                messageSender.setResponse(response);

                if ("Send".equals(action)) {
                    messageSender.send("zhazhah! " + request.getParameter("data"));
                }

            }

        } else if (event.getEventType() == CometEvent.EventType.ERROR) {
            event.close();

        } else if (event.getEventType() == CometEvent.EventType.END) {
            event.close();

        }
    }

    private class MessageSender implements Runnable {

        protected boolean running = true;
        protected final ArrayList<String> messages = new ArrayList<String>();
        private ServletResponse response;

        private synchronized void setResponse(ServletResponse response) {
            this.response = response;
            //notify();
        }

        public void send(String message) {
            synchronized (messages) {
                messages.add(message);
                // при добавлении сообщения возобновляем заснувший поток.
                messages.notify();
            }
        }

        public void run() {
            while (running) {

                // если messages не содержит сообщения
                // переводим текущий поток в режим ожидания и передаем
                // управление главному потоку.
                if (messages.isEmpty()) {
                    try {
                        synchronized (messages) {
                            messages.wait();
                        }
                    } catch (InterruptedException e) {
                        // Ignore
                    }
                }

                String[] pendingMessages = null;
                synchronized (messages) {
                    pendingMessages = messages.toArray(new String[0]);
                    messages.clear();
                }
                
                try {

                    if (response == null) {
                        try {
                            synchronized (this) {
                                wait();
                            }
                        } catch (InterruptedException e) {
                            // Ignore
                        }
                    }

                    PrintWriter writer = response.getWriter();
                    for (int j = 0; j < pendingMessages.length; j++) {
                        writer.println(pendingMessages[j]);
                    }
                    
                    writer.flush();
                    writer.close();
                    response = null;
                    
                } catch (IOException e) {
                    log("IOExeption sending message", e);
                }
            }
        }
    }
}