/*

 * JBoss, Home of Professional Open Source

 * Copyright 2011, Red Hat, Inc. and individual contributors

 * by the @authors tag. See the copyright.txt in the distribution for a

 * full listing of individual contributors.

 *

 * This is free software; you can redistribute it and/or modify it

 * under the terms of the GNU Lesser General Public License as

 * published by the Free Software Foundation; either version 2.1 of

 * the License, or (at your option) any later version.

 *

 * This software 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

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with this software; if not, write to the Free

 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA

 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.

 */



package org.mobicents.ss7.hardware.dialogic;



import java.io.ByteArrayInputStream;

import java.io.DataInputStream;

import java.io.IOException;

import java.util.concurrent.ExecutorService;

import java.util.concurrent.Executors;



import org.apache.log4j.Logger;

import org.mobicents.protocols.ss7.mtp.Mtp3PausePrimitive;

import org.mobicents.protocols.ss7.mtp.Mtp3ResumePrimitive;

import org.mobicents.protocols.ss7.mtp.Mtp3StatusCause;

import org.mobicents.protocols.ss7.mtp.Mtp3StatusPrimitive;

import org.mobicents.protocols.ss7.mtp.Mtp3TransferPrimitive;

import org.mobicents.protocols.ss7.mtp.Mtp3UserPartBaseImpl;



/**

 * @author amit bhayani

 * @author sergey vetyutnev

 * 

 */

public class DialogicMtp3UserPart extends Mtp3UserPartBaseImpl {



	private static final Logger logger = Logger.getLogger(DialogicMtp3UserPart.class);



	private static final int MTP3_PAUSE = 3;

	private static final int MTP3_RESUME = 4;

	private static final int MTP3_STATUS = 5;



	private int sourceModuleId;

	private int destinationModuleId;



	private InterProcessCommunicator ipc = null;

	private MtpStreamHandler streamHandler;



	protected ExecutorService layer3exec;



	

	public DialogicMtp3UserPart() {

	}





	public int getSourceModuleId() {

		return sourceModuleId;

	}



	public void setSourceModuleId(int sourceModuleId) {

		this.sourceModuleId = sourceModuleId;

	}



	public int getDestinationModuleId() {

		return destinationModuleId;

	}



	public void setDestinationModuleId(int destinationModuleId) {

		this.destinationModuleId = destinationModuleId;

	}



	@Override

	public void start() throws Exception {

		

		ipc = new InterProcessCommunicator(sourceModuleId, destinationModuleId);

		

		layer3exec = Executors.newFixedThreadPool(1);

		this.streamHandler = new MtpStreamHandler();

		layer3exec.execute(this.streamHandler);

		

		super.start();

	}	



	@Override

	public void stop() throws Exception {



		super.stop();

		

		this.streamHandler.stop();

		layer3exec.shutdown();

	}	



	@Override

	public void sendMessage(Mtp3TransferPrimitive msg) throws IOException {

		

		if (this.isStarted) {

			byte[] buf = msg.encodeMtp3();

			this.ipc.write(buf);

		}

	}



	private class MtpStreamHandler implements Runnable {



		private boolean handlerIsStarted = true;

		

		public void run() {



			// Execute only till state is Running

			while (this.handlerIsStarted) {

				try {

					byte[] buf = ipc.read();

					

					if (!this.handlerIsStarted)

						return;

					

					if (buf == null) {



						// TODO: test if this event is regular we should remove the following warning

						logger.warn("No data received while reading data from the Dialogic card");

						

						// return from GCT_receive() with no message - may be the error case: 

						// make the delay to escape processor overloading

						Thread.sleep(10);

					} else {



						if (buf.length >= 6) {

							if (buf[0] == 0) {

								this.parseMtp3Msg(buf);

							} else {

								Mtp3TransferPrimitive msg = new Mtp3TransferPrimitive();

								msg.decodeMtp3(buf);

								sendTransferMessageToLocalUser(msg, msg.getSls());

							}

						} else {

							logger.error("Error while reading data from the Dialogic card: received the message with length less then 6 bytes");

						}

					}

				} catch (Exception e) {

					logger.error("Error while reading data from the Dialogic card", e);

				}

			}

		}

		

		public void stop() {

			this.handlerIsStarted = false;

		}



		/**

		 * 

		 * Parsing and delivering MTP-PAUSE, MTP-RESUME, MTP-STATUS primitives

		 * 

		 * The structure of <i>PAUSE</i> is SI=0 (byte), type=3 (byte), affected

		 * dpc = int(4 bytes)</li> <li>

		 * The structure of <i>RESUME</i> is SI=0 (byte), type=4 (byte),

		 * affected dpc = int(4 bytes)</li> <li>

		 * The structure of <i>STATUS</i> is SI=0 (byte), type=5 (byte),

		 * status=1 or 2 (byte) where 1 = Remote User Unavailable and 2 =

		 * Signaling Network Congestion, affected dpc = int(4 bytes), congestion

		 * status = 2 bytes in range of 0 to 3 where 0 means no congestion and 3

		 * means maximum congestion, Unavailabilty cause = 2 bytes (if status =

		 * Remote User Unavailable(1)). The unavailabilty cause may be one of

		 * the following: 0 = Unknown 1 = Unequipped User 2 = Inaccessible User

		 * 

		 * @param buf

		 */

		private void parseMtp3Msg(byte[] buf) {

			

			try {

				DataInputStream in = new DataInputStream(new ByteArrayInputStream(buf));

				in.readUnsignedByte(); // sio zero byte



				int type = in.readUnsignedByte(); //

				switch (type) {

				case MTP3_PAUSE:

					Mtp3PausePrimitive msgPause = new Mtp3PausePrimitive(in.readInt());

					sendPauseMessageToLocalUser(msgPause);

					break;



				case MTP3_RESUME:

					Mtp3ResumePrimitive msgResume = new Mtp3ResumePrimitive(in.readInt());

					sendResumeMessageToLocalUser(msgResume);

					break;



				case MTP3_STATUS:

					if (buf.length < 9) {

						logger.error("Error while parsing data from the Dialogic card: unsufficient data length for message MTP3_STATUS");

						return;

					}



					int status = in.readUnsignedByte();

					int affectedDpc = in.readInt();

					int congestionLevel = in.readShort();

					int unavailabiltyCause = in.readShort();

					Mtp3StatusCause cause;

					if (status == 1) { // 1 = Remote User Unavailable

						switch (unavailabiltyCause) {

						case 1:

							cause = Mtp3StatusCause.UserPartUnavailability_UnequippedRemoteUser;

							break;

						case 2:

							cause = Mtp3StatusCause.UserPartUnavailability_InaccessibleRemoteUser;

							break;

						default:

							cause = Mtp3StatusCause.UserPartUnavailability_Unknown;

							break;

						}

						congestionLevel = 0;

					} else { // 2 = Signaling Network Congestion

						cause = Mtp3StatusCause.SignallingNetworkCongested;

						congestionLevel = 0;

					}

					Mtp3StatusPrimitive msgStatus = new Mtp3StatusPrimitive(affectedDpc, cause, congestionLevel);

					sendStatusMessageToLocalUser(msgStatus);

					break;



				default:

					logger.error("Error while parsing system messages from the Dialogic card: unknown primitive type: " + type);

				}

				

			} catch (IOException e) {

				logger.error("IOException while parsing system messages from the Dialogic card: " + e.getMessage(), e);

			}

		}

	}

}