/**
 * 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.DatagramPacket;
import java.net.InetSocketAddress;
import java.util.Enumeration;
import java.util.Iterator;

/**
 * This thread sends scheduled RTCP packets
 * 
 * It also performs maintenance of various queues and the participant database.
 * 
 * @author Arne Kepp
 * 
 */
public class RTCPSenderThread extends Thread {
	/** Parent RTP Session */
	private RTPSession rtpSession = null;
	/** Parent RTCP Session */
	private RTCPSession rtcpSession = null;

	/** Whether we have sent byes for the last conflict */
	private boolean byesSent = false;

	/**
	 * Constructor for new thread
	 * 
	 * @param rtcpSession
	 *            parent RTCP session
	 * @param rtpSession
	 *            parent RTP session
	 */
	protected RTCPSenderThread(RTCPSession rtcpSession, RTPSession rtpSession) {
		this.rtpSession = rtpSession;
		this.rtcpSession = rtcpSession;
		if (RTPSession.rtpDebugLevel > 1) {
			System.out.println("<-> RTCPSenderThread created");
		}
	}

	/**
	 * Send BYE messages to all the relevant participants
	 * 
	 */
	protected void sendByes() {
		// Create the packet
		CompRtcpPkt compPkt = new CompRtcpPkt();

		// Need a SR for validation
		RtcpPktSR srPkt = new RtcpPktSR(this.rtpSession.ssrc,
				this.rtpSession.sentPktCount, this.rtpSession.sentOctetCount,
				null);
		compPkt.addPacket(srPkt);

		byte[] reasonBytes;

		// Add the actualy BYE Pkt
		long[] ssrcArray = { this.rtpSession.ssrc };
		if (rtpSession.conflict) {
			reasonBytes = "SSRC collision".getBytes();
		} else {
			reasonBytes = "jlibrtp says bye bye!".getBytes();
		}
		RtcpPktBYE byePkt = new RtcpPktBYE(ssrcArray, reasonBytes);

		compPkt.addPacket(byePkt);

		// Send it off
		if (rtpSession.mcSession) {
			mcSendCompRtcpPkt(compPkt);
		} else {
			Iterator<Participant> iter = rtpSession.partDb
					.getUnicastReceivers();

			while (iter.hasNext()) {
				Participant part = (Participant) iter.next();
				if (part.rtcpAddress != null)
					sendCompRtcpPkt(compPkt, part.rtcpAddress);
			}
			// System.out.println("SENT BYE PACKETS!!!!!");
		}
	}

	/**
	 * Multicast version of sending a Compound RTCP packet
	 * 
	 * @param pkt
	 *            the packet to best
	 * @return 0 is successful, -1 otherwise
	 */
	protected int mcSendCompRtcpPkt(CompRtcpPkt pkt) {
		byte[] pktBytes = pkt.encode();
		DatagramPacket packet;

		// Create datagram
		try {
			packet = new DatagramPacket(pktBytes, pktBytes.length,
					rtpSession.mcGroup, rtcpSession.rtcpMCSock.getPort());
		} catch (Exception e) {
			System.out
					.println("RCTPSenderThread.MCSendCompRtcpPkt() packet creation failed.");
			e.printStackTrace();
			return -1;
		}

		// Send packet
		if (RTPSession.rtcpDebugLevel > 5) {
			System.out
					.println("<-> RTCPSenderThread.SendCompRtcpPkt() multicast");
		}
		try {
			rtcpSession.rtcpMCSock.send(packet);
			// Debug
			if (this.rtpSession.debugAppIntf != null) {
				this.rtpSession.debugAppIntf.packetSent(3,
						(InetSocketAddress) packet.getSocketAddress(),
						new String("Sent multicast RTCP packet of size "
								+ packet.getLength()
								+ " to "
								+ packet.getSocketAddress().toString()
								+ " via "
								+ this.rtcpSession.rtcpMCSock
										.getLocalSocketAddress().toString()));
			}
		} catch (Exception e) {
			System.out
					.println("RCTPSenderThread.MCSendCompRtcpPkt() multicast failed.");
			e.printStackTrace();
			return -1;
		}
		return packet.getLength();
	}

	/**
	 * Unicast version of sending a Compound RTCP packet
	 * 
	 * @param pkt
	 *            the packet to best
	 * @param receiver
	 *            the socket address of the recipient
	 * @return 0 is successful, -1 otherwise
	 */
	protected int sendCompRtcpPkt(CompRtcpPkt pkt, InetSocketAddress receiver) {
		byte[] pktBytes = pkt.encode();
		DatagramPacket packet;

		// Create datagram
		try {
			// System.out.println("receiver: " + receiver);
			packet = new DatagramPacket(pktBytes, pktBytes.length, receiver);
		} catch (Exception e) {
			System.out
					.println("RCTPSenderThread.SendCompRtcpPkt() packet creation failed.");
			e.printStackTrace();
			return -1;
		}

		// Send packet
		if (RTPSession.rtcpDebugLevel > 5) {
			Iterator<RtcpPkt> iter = pkt.rtcpPkts.iterator();
			String str = " ";
			while (iter.hasNext()) {
				RtcpPkt aPkt = iter.next();
				str += (aPkt.getClass().toString() + ":" + aPkt.itemCount + ", ");
			}
			System.out
					.println("<-> RTCPSenderThread.SendCompRtcpPkt() unicast to "
							+ receiver + str);
		}
		try {
			rtcpSession.rtcpSock.send(packet);
			// Debug
			if (this.rtpSession.debugAppIntf != null) {
				this.rtpSession.debugAppIntf.packetSent(2,
						(InetSocketAddress) packet.getSocketAddress(),
						new String("Sent unicast RTCP packet of size "
								+ packet.getLength()
								+ " to "
								+ packet.getSocketAddress().toString()
								+ " via "
								+ this.rtcpSession.rtcpSock
										.getLocalSocketAddress().toString()));
			}
		} catch (Exception e) {
			System.out
					.println("RTCPSenderThread.SendCompRtcpPkt() unicast failed.");
			e.printStackTrace();
			return -1;
		}
		return packet.getLength();
	}

	/**
	 * Check whether we can send an immediate feedback packet to this person
	 * 
	 * @param ssrc
	 *            SSRC of participant
	 */
	protected void reconsiderTiming(long ssrc) {
		Participant part = this.rtpSession.partDb.getParticipant(ssrc);

		if (part != null && this.rtcpSession.fbSendImmediately()) {
			CompRtcpPkt compPkt = preparePacket(part, false);
			/*********** Send the packet ***********/
			// Keep track of sent packet length for average;
			int datagramLength;
			if (rtpSession.mcSession) {
				datagramLength = this.mcSendCompRtcpPkt(compPkt);
			} else {
				// part.debugPrint();
				datagramLength = this
						.sendCompRtcpPkt(compPkt, part.rtcpAddress);
			}
			/*********** Administrative tasks ***********/
			// Update average packet size
			if (datagramLength > 0) {
				rtcpSession.updateAvgPacket(datagramLength);
			}
		} else if (part != null && this.rtcpSession.fbAllowEarly
				&& this.rtcpSession.fbSendEarly()) {

			// Make sure we dont do it too often
			this.rtcpSession.fbAllowEarly = false;

			CompRtcpPkt compPkt = preparePacket(part, true);
			/*********** Send the packet ***********/
			// Keep track of sent packet length for average;
			int datagramLength;
			if (rtpSession.mcSession) {
				datagramLength = this.mcSendCompRtcpPkt(compPkt);
			} else {
				// part.debugPrint();
				datagramLength = this
						.sendCompRtcpPkt(compPkt, part.rtcpAddress);
			}
			/*********** Administrative tasks ***********/
			// Update average packet size
			if (datagramLength > 0) {
				rtcpSession.updateAvgPacket(datagramLength);
			}
			rtcpSession.calculateDelay();
		}

		// Out of luck, fb message will have to go with next regular packet
		// Sleep for the remaining time.
		this.rtcpSession.nextDelay -= System.currentTimeMillis()
				- this.rtcpSession.prevTime;
		if (this.rtcpSession.nextDelay < 0)
			this.rtcpSession.nextDelay = 0;

	}

	/**
	 * Prepare a packet. The output depends on the participant and how the
	 * packet is scheduled.
	 * 
	 * @param part
	 *            the participant to report to
	 * @param regular
	 *            whether this is a regularly, or early scheduled RTCP packet
	 * @return compound RTCP packet
	 */
	protected CompRtcpPkt preparePacket(Participant part, boolean regular) {
		/*********** Figure out what we are going to send ***********/
		// Check whether this person has sent RTP packets since the last RR.
		boolean incRR = false;
		if (part.secondLastRtcpRRPkt > part.lastRtcpRRPkt) {
			incRR = true;
			part.secondLastRtcpRRPkt = part.lastRtcpRRPkt;
			part.lastRtcpRRPkt = System.currentTimeMillis();
		}

		// Are we sending packets? -> add SR
		boolean incSR = false;
		if (rtpSession.sentPktCount > 0 && regular) {
			incSR = true;
		}

		/*********** Actually create the packet ***********/
		// Create compound packet
		CompRtcpPkt compPkt = new CompRtcpPkt();

		// If we're sending packets we'll use a SR for header
		if (incSR) {
			RtcpPktSR srPkt = new RtcpPktSR(this.rtpSession.ssrc,
					this.rtpSession.sentPktCount,
					this.rtpSession.sentOctetCount, null);
			compPkt.addPacket(srPkt);

			if (part.ssrc > 0) {
				RtcpPkt[] ar = this.rtcpSession.getFromFbQueue(part.ssrc);
				if (ar != null) {
					for (int i = 0; i < ar.length; i++) {
						compPkt.addPacket(ar[i]);
					}
				}
			}

		}

		// If we got anything from this participant since we sent the 2nd to
		// last RtcpPkt
		if (incRR || !incSR) {
			Participant[] partArray = { part };

			if (part.receivedPkts < 1)
				partArray = null;

			RtcpPktRR rrPkt = new RtcpPktRR(partArray, rtpSession.ssrc);
			compPkt.addPacket(rrPkt);

			if (!incSR && part.ssrc > 0) {
				RtcpPkt[] ar = this.rtcpSession.getFromFbQueue(part.ssrc);
				if (ar != null) {
					for (int i = 0; i < ar.length; i++) {
						compPkt.addPacket(ar[i]);
					}
				}
			}
		}

		// APP packets
		if (regular && part.ssrc > 0) {
			RtcpPkt[] ar = this.rtcpSession.getFromAppQueue(part.ssrc);
			if (ar != null) {
				for (int i = 0; i < ar.length; i++) {
					compPkt.addPacket(ar[i]);
				}
			} else {
				// Nope
			}
		}

		// For now we'll stick the SDES on every time, and only for us
		// if(regular) {
		RtcpPktSDES sdesPkt = new RtcpPktSDES(true, this.rtpSession, null);
		compPkt.addPacket(sdesPkt);
		// }

		return compPkt;
	}

	/**
	 * Start the RTCP sender thread.
	 * 
	 * RFC 4585 is more complicated, but in general it will 1) Wait a
	 * precalculated amount of time 2) Determine the next RTCP recipient 3)
	 * Construct a compound packet with all the relevant information 4) Send the
	 * packet 5) Calculate next delay before going to sleep
	 */
	public void run() {
		if (RTPSession.rtcpDebugLevel > 1) {
			System.out.println("<-> RTCPSenderThread running");
		}

		// Give the application a chance to register some participants
		try {
			Thread.sleep(10);
		} catch (Exception e) {
			System.out.println("RTCPSenderThread didn't get any initial rest.");
		}

		// Set up an iterator for the member list
		Enumeration<Participant> enu = null;
		Iterator<Participant> iter = null;

		// TODO Change to rtcpReceivers
		if (rtpSession.mcSession) {
			enu = rtpSession.partDb.getParticipants();
		} else {
			iter = rtpSession.partDb.getUnicastReceivers();
		}
		while (!rtpSession.endSession) {
			if (RTPSession.rtcpDebugLevel > 5) {
				System.out.println("<-> RTCPSenderThread sleeping for "
						+ rtcpSession.nextDelay + " ms");
			}

			try {
				Thread.sleep(rtcpSession.nextDelay);
			} catch (Exception e) {
				System.out.println("RTCPSenderThread Exception message:"
						+ e.getMessage());
				// Is the party over?
				if (this.rtpSession.endSession) {
					continue;
				}

				if (rtcpSession.fbWaiting != -1) {
					reconsiderTiming(rtcpSession.fbWaiting);
					continue;
				}
			}

			/** Came here the regular way */
			this.rtcpSession.fbAllowEarly = true;

			if (RTPSession.rtcpDebugLevel > 5) {
				System.out.println("<-> RTCPSenderThread waking up");
			}

			// Regenerate nextDelay, before anything happens.
			rtcpSession.calculateDelay();

			// We'll wait here until a conflict (if any) has been resolved,
			// so that the bye packets for our current SSRC can be sent.
			if (rtpSession.conflict) {
				if (!this.byesSent) {
					sendByes();
					this.byesSent = true;
				}
				continue;
			}
			this.byesSent = false;

			// Grab the next person
			Participant part = null;

			// Multicast
			if (this.rtpSession.mcSession) {
				if (!enu.hasMoreElements())
					enu = rtpSession.partDb.getParticipants();

				if (enu.hasMoreElements()) {
					part = enu.nextElement();
				} else {
					continue;
				}

				// Unicast
			} else {
				if (!iter.hasNext()) {
					iter = rtpSession.partDb.getUnicastReceivers();
				}

				if (iter.hasNext()) {
					while (iter.hasNext()
							&& (part == null || part.rtcpAddress == null)) {
						part = iter.next();
					}
				}

				if (part == null || part.rtcpAddress == null)
					continue;
			}

			CompRtcpPkt compPkt = preparePacket(part, true);

			/*********** Send the packet ***********/
			// Keep track of sent packet length for average;
			int datagramLength;
			if (rtpSession.mcSession) {
				datagramLength = this.mcSendCompRtcpPkt(compPkt);
			} else {
				// part.debugPrint();
				datagramLength = this
						.sendCompRtcpPkt(compPkt, part.rtcpAddress);
			}

			/*********** Administrative tasks ***********/
			// Update average packet size
			if (datagramLength > 0) {
				rtcpSession.updateAvgPacket(datagramLength);
			}
		}

		// Be polite, say Bye to everone
		sendByes();
		try {
			Thread.sleep(200);
		} catch (Exception e) {
		}

		if (RTPSession.rtcpDebugLevel > 0) {
			System.out.println("<-> RTCPSenderThread terminating");
		}
	}
}
