/**

 * Java RTP Library (jlibrtp)

 * Copyright (C) 2006 Arne Kepp

 * 

 * This library 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 library 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 library; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA

 */

package jlibrtp;

import java.net.InetSocketAddress;

/**

 * A participant represents a peer in an RTPSession. Based on the information stored on 

 * these objects, packets are processed and statistics generated for RTCP.

 */

public class Participant {

	/** Whether the participant is unexpected, e.g. arrived through unicast with SDES */

	protected boolean unexpected = false;

	/** Where to send RTP packets (unicast)*/

	protected InetSocketAddress rtpAddress = null; 

	/** Where to send RTCP packets (unicast) */

	protected InetSocketAddress rtcpAddress = null;

	/** Where the first RTP packet was received from */

	protected InetSocketAddress rtpReceivedFromAddress = null;

	/** Where the first RTCP packet was received from */

	protected InetSocketAddress rtcpReceivedFromAddress = null;

	/** SSRC of participant */

	protected long ssrc = -1;

	/** SDES CNAME */

	protected String cname = null;

	/** SDES The participant's real name */

	protected String name = null;

	/** SDES The participant's email */

	protected String email = null;

	/** SDES The participant's phone number */

	protected String phone = null;

	/** SDES The participant's location*/

	protected String loc = null;

	/** SDES The tool the participants is using */

	protected String tool = null;

	/** SDES A note */

	protected String note = null;

	/** SDES A priv string, loosely defined */

	protected String priv = null;

	// Receiver Report Items

	/** RR First sequence number */

	protected int firstSeqNumber = -1;

	/** RR Last sequence number */

	protected int lastSeqNumber = 0;

	/** RR Number of times sequence number has rolled over */

	protected long seqRollOverCount = 0;

	/** RR Number of packets received */

	protected long receivedPkts = 0;

	/** RR Number of octets received */

	protected long receivedOctets = 0;

	/** RR Number of packets received since last SR */

	protected int receivedSinceLastSR = 0;

	/** RR Sequence number associated with last SR */

	protected int lastSRRseqNumber = 0;

	/** RR Interarrival jitter */

	protected double interArrivalJitter = -1.0;

	/** RR Last received RTP Timestamp */

	protected long lastRtpTimestamp = 0;

	/** RR Middle 32 bits of the NTP timestamp in the last SR */

	protected long timeStampLSR = 0;

	/** RR The time when we actually got the last SR */

	protected long timeReceivedLSR = 0;

	/** Gradient where UNIX timestamp = ntpGradient*RTPTimestamp * ntpOffset */

	protected double ntpGradient = -1;

	/** Offset where UNIX timestamp = ntpGradient*RTPTimestamp * ntpOffset */

	protected long ntpOffset = -1;

	/** Last NTP received in SR packet, MSB */

	protected long lastNtpTs1 = 0; //32 bits

	/** Last NTP received in SR packet, LSB */

	protected long lastNtpTs2 = 0; //32 bits

	/** RTP Timestamp in last SR packet */

	protected long lastSRRtpTs = 0; //32 bits

	/** UNIX time when a BYE was received from this participant, for pruning */

	protected long timestampBYE = -1;	// The user said BYE at this time

	/** Store the packets received from this participant */

	protected PktBuffer pktBuffer = null;

	/** UNIX time of last RTP packet, to check whether this participant has sent anything recently */

	protected long lastRtpPkt = -1; //Time of last RTP packet

	/** UNIX time of last RTCP packet, to check whether this participant has sent anything recently */

	protected long lastRtcpPkt = -1; //Time of last RTCP packet

	/** UNIX time this participant was added by application, to check whether we ever heard back */

	protected long addedByApp = -1; //Time the participant was added by application

	/** UNIX time of last time we sent an RR to this user */

	protected long lastRtcpRRPkt = -1; //Timestamp of last time we sent this person an RR packet

	/** Unix time of second to last time we sent and RR to this user */

	protected long secondLastRtcpRRPkt = -1; //Timestamp of 2nd to last time we sent this person an RR Packet

	/**

	 * Create a basic participant. If this is a <b>unicast</b> session you must provide network address (ipv4 or ipv6) and ports for RTP and RTCP, 

	 * as well as a cname for this contact. These things should be negotiated through SIP or a similar protocol.

	 * 

	 * jlibrtp will listen for RTCP packets to obtain a matching SSRC for this participant, based on cname.

	 * @param networkAddress string representation of network address (ipv4 or ipv6). Use "127.0.0.1" for multicast session.

	 * @param rtpPort port on which peer expects RTP packets. Use 0 if this is a sender-only, or this is a multicast session.

	 * @param rtcpPort port on which peer expects RTCP packets. Use 0 if this is a sender-only, or this is a multicast session.

	 */

	public Participant(String networkAddress, int rtpPort, int rtcpPort) {

		if(RTPSession.rtpDebugLevel > 6) {

			System.out.println("Creating new participant: " + networkAddress);

		}

		// RTP

		if(rtpPort > 0) {

			try {

				rtpAddress = new InetSocketAddress(networkAddress, rtpPort);

			} catch (Exception e) {

				System.out.println("Couldn't resolve " + networkAddress);

			}

			//isReceiver = true;

		}

		// RTCP 

		if(rtcpPort > 0) {

			try {

				rtcpAddress = new InetSocketAddress(networkAddress, rtcpPort);

			} catch (Exception e) {

				System.out.println("Couldn't resolve " + networkAddress);

			}

		}

		//By default this is a sender

		//isSender = true;

	}

	// We got a packet, but we don't know this person yet.

	protected Participant(InetSocketAddress rtpAdr, InetSocketAddress rtcpAdr, long SSRC) {

		rtpReceivedFromAddress = rtpAdr;

		rtcpReceivedFromAddress = rtcpAdr;

		ssrc = SSRC;

		unexpected = true;

	}

	// Dummy constructor to ease testing

	protected Participant() {

		System.out.println("Don't use the Participan(void) Constructor!");

	}

	/**

	 * RTP Address registered with this participant.

	 * 

	 * @return address of participant

	 */

	InetSocketAddress getRtpSocketAddress() {

		return rtpAddress;

	}

	/**

	 * RTCP Address registered with this participant.

	 * 

	 * @return address of participant

	 */

	InetSocketAddress getRtcpSocketAddress() {

		return rtcpAddress;

	}

	/**

	 * InetSocketAddress this participant has used to

	 * send us RTP packets.

	 * 

	 * @return address of participant

	 */

	InetSocketAddress getRtpReceivedFromAddress() {

		return rtpAddress;

	}

	/**

	 * InetSocketAddress this participant has used to

	 * send us RTCP packets.

	 * 

	 * @return address of participant

	 */

	InetSocketAddress getRtcpReceivedFromAddress() {

		return rtcpAddress;

	}

	/**

	 * CNAME registered for this participant.

	 * 

	 * @return the cname

	 */

	public String getCNAME() {

		return cname;

	}

	/**

	 * NAME registered for this participant.

	 * 

	 * @return the name

	 */

	public String getNAME() {

		return name;

	}

	/**

	 * EMAIL registered for this participant.

	 * 

	 * @return the email address

	 */

	public String getEmail() {

		return email;

	}

	/**

	 * PHONE registered for this participant.

	 * 

	 * @return the phone number

	 */

	public String getPhone() {

		return phone;

	}

	/**

	 * LOCATION registered for this participant.

	 * 

	 * @return the location

	 */

	public String getLocation() {

		return loc;

	}

	/**

	 * NOTE registered for this participant.

	 * 

	 * @return the note

	 */

	public String getNote() {

		return note;

	}

	/**

	 * PRIVATE something registered for this participant.

	 * 

	 * @return the private-string

	 */

	public String getPriv() {

		return priv;

	}

	/**

	 * TOOL something registered for this participant.

	 * 

	 * @return the tool

	 */

	public String getTool() {

		return tool;

	}

	/**

	 * SSRC for participant, determined through RTCP SDES

	 * 

	 * @return SSRC (32 bit unsigned integer as long)

	 */

	public long getSSRC() {

		return this.ssrc;

	}

	/** 

	 * Updates the participant with information for receiver reports.

	 * 

	 * @param packetLength to keep track of received octets

	 * @param pkt the most recently received packet

	 */

	protected void updateRRStats(int packetLength, RtpPkt pkt) {

		int curSeqNum = pkt.getSeqNumber();

		if(firstSeqNumber < 0) {

			firstSeqNumber = curSeqNum;

		}

		receivedOctets += packetLength;

		receivedSinceLastSR++;

		receivedPkts++;

		long curTime =  System.currentTimeMillis();

		if( this.lastSeqNumber < curSeqNum ) {

			//In-line packet, best thing you could hope for

			this.lastSeqNumber = curSeqNum;

		} else if(this.lastSeqNumber - this.lastSeqNumber < -100) {

			//Sequence counter rolled over

			this.lastSeqNumber = curSeqNum;

			seqRollOverCount++;

		} else {

			//This was probably a duplicate or a late arrival.

		}

		// Calculate jitter

		if(this.lastRtpPkt > 0) {

			long D = (pkt.getTimeStamp() - curTime) - (this.lastRtpTimestamp - this.lastRtpPkt);

			if(D < 0)

				D = (-1)*D;

			this.interArrivalJitter += ((double)D - this.interArrivalJitter) / 16.0;

		}

		lastRtpPkt = curTime;

		lastRtpTimestamp = pkt.getTimeStamp();

	}

	/**

	 * Calculates the extended highest sequence received by adding 

	 * the last sequence number to 65536 times the number of times 

	 * the sequence counter has rolled over.

	 * 

	 * @return extended highest sequence

	 */

	protected long getExtHighSeqRecv() {

		return (65536*seqRollOverCount + lastSeqNumber);

	}

	/**

	 * Get the fraction of lost packets, calculated as described

	 * in RFC 3550 as a fraction of 256.

	 * 

	 * @return the fraction of lost packets since last SR received

	 */

	protected int getFractionLost() {

		int expected = (lastSeqNumber - lastSRRseqNumber);

		if(expected < 0)

			expected = 65536 + expected;

		int fraction = 256 * (expected - receivedSinceLastSR);

		if(expected > 0) {

			fraction = (fraction / expected);

		} else {

			fraction = 0;

		}

		//Clear counters 

		receivedSinceLastSR = 0;

		lastSRRseqNumber = lastSeqNumber;

		return fraction;

	}

	/**

	 * The total number of packets lost during the session.

	 * 

	 * Returns zero if loss is negative, i.e. duplicates have been received.

	 * 

	 * @return number of lost packets, or zero.

	 */

	protected long getLostPktCount() {

		long lost = (this.getExtHighSeqRecv() - this.firstSeqNumber) - receivedPkts;

		if(lost < 0)

			lost = 0;

		return lost;

	}

	/** 

	 * 

	 * @return the interArrivalJitter, calculated continuously

	 */

	protected double getInterArrivalJitter() {

		return this.interArrivalJitter;

	}

	/**

	 * Set the timestamp for last sender report

	 * 

	 * @param ntp1 high order bits

	 * @param ntp2 low order bits

	 */

	protected void setTimeStampLSR(long ntp1, long ntp2) {

		// Use what we've got

		byte[] high = StaticProcs.uIntLongToByteWord(ntp1);

		byte[] low = StaticProcs.uIntLongToByteWord(ntp2);

		low[3] = low[1];

		low[2] = low[0];

		low[1] = high[3];

		low[0] = high[2];

		this.timeStampLSR = StaticProcs.bytesToUIntLong(low, 0);

	}

	/**

	 * Calculate the delay between the last received sender report

	 * and now.