/*
  GRANITE DATA SERVICES
  Copyright (C) 2011 GRANITE DATA SERVICES S.A.S.

  This file is part of Granite Data Services.

  Granite Data Services is free software; you can redistribute it and/or modify
  it under the terms of the GNU Library General Public License as published by
  the Free Software Foundation; either version 2 of the License, or (at your
  option) any later version.

  Granite Data Services is distributed in the hope that it will be useful, but
  WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public License
  for more details.

  You should have received a copy of the GNU Library General Public License
  along with this library; if not, see <http://www.gnu.org/licenses/>.
*/

package org.granite.gravity.jetty;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.granite.gravity.AbstractGravityServlet;
import org.granite.gravity.AsyncHttpContext;
import org.granite.gravity.Gravity;
import org.granite.gravity.GravityManager;
import org.granite.logging.Logger;
import org.mortbay.jetty.RetryRequest;
import org.mortbay.util.ajax.Continuation;
import org.mortbay.util.ajax.ContinuationSupport;

import flex.messaging.messages.AsyncMessage;
import flex.messaging.messages.Message;

/**
 * @author William DRAI
 */
public class GravityJettyServlet extends AbstractGravityServlet {

    private static final long serialVersionUID = 1L;

    private static final Logger log = Logger.getLogger(GravityJettyServlet.class);


    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        
        log.debug("doPost: from %s:%d", request.getRemoteAddr(), request.getRemotePort());

                Gravity gravity = GravityManager.getGravity(getServletContext());
                ContinuationChannelFactory channelFactory = new ContinuationChannelFactory(gravity);
                
                try {
                        // Setup context (thread local GraniteContext, etc.)
                        initializeRequest(gravity, request, response);
                        
                        AsyncMessage connect = getConnectMessage(request);
                        
                        // Resumed request (pending messages or timeout).
                        if (connect != null) {
                                String channelId = (String)connect.getClientId();
                                ContinuationChannel channel = gravity.getChannel(channelFactory, channelId);

                                // Reset channel continuation instance and deliver pending messages.
                                synchronized (channel) {
                                        channel.close();
                                        channel.runReceived(new AsyncHttpContext(request, response, connect));
                                }
                                
                                return;
                        }
                        
                        // New Request.
                        Message[] amf3Requests = deserialize(gravity, request);

            log.debug(">> [AMF3 REQUESTS] %s", (Object)amf3Requests);

            Message[] amf3Responses = null;
            
            boolean accessed = false;
            for (int i = 0; i < amf3Requests.length; i++) {
                Message amf3Request = amf3Requests[i];
                
                // Ask gravity to create a specific response (will be null with a connect request from tunnel).
                Message amf3Response = gravity.handleMessage(channelFactory, amf3Request);
                String channelId = (String)amf3Request.getClientId();
                
                // Mark current channel (if any) as accessed.
                if (!accessed)
                        accessed = gravity.access(channelId);
                
                // (Re)Connect message from tunnel.
                if (amf3Response == null) {
                    if (amf3Requests.length > 1)
                        throw new IllegalArgumentException("Only one request is allowed on tunnel.");

                        ContinuationChannel channel = gravity.getChannel(channelFactory, channelId);
                        if (channel == null)
                                throw new NullPointerException("No channel on tunnel connect");
                        
                    // Try to send pending messages if any (using current container thread).
                        if (!channel.runReceived(new AsyncHttpContext(request, response, amf3Request))) {
                        
                                // No pending messages, wait for new ones or timeout.
                            setConnectMessage(request, amf3Request);
                                synchronized (channel) {
                                        Continuation continuation = ContinuationSupport.getContinuation(request, channel);
                                        channel.setContinuation(continuation);
                                        
                                        // This call throws a RetryRequest exception, so we'll never reach return below...
                                        continuation.suspend(getLongPollingTimeout());
                                }
                        }
                        
                        return;
                }

                if (amf3Responses == null)
                        amf3Responses = new Message[amf3Requests.length];
                amf3Responses[i] = amf3Response;
            }

            log.debug("<< [AMF3 RESPONSES] %s", (Object)amf3Responses);

            serialize(gravity, response, amf3Responses);
                }
        catch (RetryRequest e) {
            throw e;
        }
        catch (IOException e) {
            log.error(e, "Gravity message error");
            throw e;
        }
        catch (Exception e) {
            log.error(e, "Gravity message error");
            throw new ServletException(e);
        }
                finally {
                        // Cleanup context (thread local GraniteContext, etc.)
                        cleanupRequest(request);
                }
    }
}