/**

 * 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;

/**

 * RTCP packets for Payload-Specific Feedback Messages 

 * 

 * @author Arne Kepp

 */

public class RtcpPktPSFB extends RtcpPkt {

	/** If this packet was for a different SSRC */

	protected boolean notRelevant = false;

	/** Parent RTP Session */

	private RTPSession rtpSession;

	/** SSRC we are sending feeback to */

	protected long ssrcMediaSource = -1;

	/** SLI macroblock (MB) address of the first lost macroblock number */

	protected int[] sliFirst;

	/** SLI number of lost macroblocks */

	protected int[] sliNumber;

	/** SLI six least significant bits of the codec-specific identifier */

	protected int[] sliPictureId;

	// Picture loss indication

	/** RPSI number of padded bits at end of bitString */

	protected int rpsiPadding = -1;

	/** RPSI payloadType RTP payload type */

	protected int rpsiPayloadType = -1;

	/** RPSI information as natively defined by the video codec */

	protected byte[] rpsiBitString;

	/** Application Layer Feedback Message */

	protected byte[] alfBitString;

	/**

	 * Generic constructor, then call make<something>

	 * 

	 * @param ssrcPacketSender

	 * @param ssrcMediaSource

	 */

	protected RtcpPktPSFB(long ssrcPacketSender, long ssrcMediaSource) {

		super.ssrc = ssrcPacketSender;

		this.ssrcMediaSource = ssrcMediaSource;

		super.packetType = 206; //PSFB

	}

	/**

	 * Make this packet a Picture loss indication

	 */

	protected void makePictureLossIndication() {

		super.itemCount = 1; //FMT

	}

	/**

	 * Make this packet a Slice Loss Indication

	 * 

	 * @param sliFirst macroblock (MB) address of the first lost macroblock

	 * @param sliNumber number of lost macroblocks

	 * @param sliPictureId six least significant bits of the codec-specific identifier

	 */

	protected void makeSliceLossIndication(int[] sliFirst, int[] sliNumber, int[] sliPictureId) {

		super.itemCount = 2; //FMT

		this.sliFirst = sliFirst;

		this.sliNumber = sliNumber;

		this.sliPictureId = sliPictureId;

	}

	/**

	 * Make this packet a Reference Picture Selection Indication

	 * 

	 * @param bitPadding number of padded bits at end of bitString

	 * @param payloadType RTP payload type for codec

	 * @param bitString RPSI information as natively defined by the video codec

	 */

	protected void makeRefPictureSelIndic(int bitPadding, int payloadType, byte[] bitString) {

		super.itemCount = 3; //FMT

		this.rpsiPadding = bitPadding;

		this.rpsiPayloadType = payloadType;

		this.rpsiBitString = bitString;

	}

	/** 

	 * Make this packet an Application specific feedback message

	 * 

	 * @param bitString the original application message

	 */

	protected void makeAppLayerFeedback(byte[] bitString) {

		super.itemCount = 15; //FMT

		this.alfBitString = bitString; 

	}

	/**

	 * Constructor that parses a raw packet to retrieve information

	 * 

	 * @param aRawPkt the raw packet to be parsed

	 * @param start the start of the packet, in bytes

	 * @param rtpSession the session on which the callback interface resides

	 */

	protected RtcpPktPSFB(byte[] aRawPkt, int start, RTPSession rtpSession) {		

		if(RTPSession.rtpDebugLevel > 8) {

			System.out.println("  -> RtcpPktPSFB(byte[], int start)");

		}

		this.rtpSession = rtpSession;

		rawPkt = aRawPkt;

		if(! super.parseHeaders(start) || packetType != 206 || super.length < 2 ) {

			if(RTPSession.rtpDebugLevel > 2) {

				System.out.println(" <-> RtcpPktRTPFB.parseHeaders() etc. problem");

			}

			super.problem = -206;

		} else {

			//FMT = super.itemCount;

			ssrcMediaSource = StaticProcs.bytesToUIntLong(aRawPkt,8+start);

			if(ssrcMediaSource == rtpSession.ssrc) {

				super.ssrc = StaticProcs.bytesToUIntLong(aRawPkt,4+start);

				switch(super.itemCount) {

				case 1: // Picture Loss Indication 

					decPictureLossIndic();

					break; 

				case 2: // Slice Loss Indication

					decSliceLossIndic(aRawPkt, start + 12); 

					break;

				case 3: // Reference Picture Selection Indication 

					decRefPictureSelIndic(aRawPkt, start + 12); 

					break;

				case 15: // Application Layer Feedback Messages

					decAppLayerFB(aRawPkt, start + 12); 

					break;

				default: 

					System.out.println("!!!! RtcpPktPSFB(byte[], int start) unexpected FMT " + super.itemCount);

				}

			} else {

				this.notRelevant = true;

			}

		}

		if(RTPSession.rtpDebugLevel > 8) {

			System.out.println("  <- RtcpPktPSFB()");

		}

	}

	/**

	 * Decode Picture Loss indication

	 *

	 */

	private void decPictureLossIndic() {

		if(this.rtpSession.rtcpAVPFIntf != null) {

			this.rtpSession.rtcpAVPFIntf.PSFBPktPictureLossReceived(

					super.ssrc);

		}

	}

	/**

	 * Decode Slice Loss Indication

	 * 

	 * @param aRawPkt

	 * @param start

	 */

	private void decSliceLossIndic(byte[] aRawPkt, int start) {	

		// 13 bit off-boundary numbers? That's rather cruel

		//    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1

		//   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

		//   |            First        |        Number           | PictureID |

		//   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

		int count = super.length - 2;

		sliFirst = new int[count];

		sliNumber = new int[count];

		sliPictureId = new int[count];

		// Loop over the FCI lines

		for(int i=0; i < count; i++) {

			sliFirst[i] = StaticProcs.bytesToUIntInt(aRawPkt, start) >> 3;

			sliNumber[i] = (int) (StaticProcs.bytesToUIntInt(aRawPkt, start) & 0x0007FFC0) >> 6;

			sliPictureId[i] = (StaticProcs.bytesToUIntInt(aRawPkt, start + 2) & 0x003F);

			start += 4;

		}

		if(this.rtpSession.rtcpAVPFIntf != null) {

			this.rtpSession.rtcpAVPFIntf.PSFBPktSliceLossIndic(

					super.ssrc,

					sliFirst, sliNumber, sliPictureId);

		}

	}

	/**

	 * Decode Reference Picture Selection Indication

	 * 

	 * @param aRawPkt

	 * @param start

	 */

	private void decRefPictureSelIndic(byte[] aRawPkt, int start) {	

		//  0                   1                   2                   3

		//  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1

		// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

		// |      PB       |0| Payload Type|    Native RPSI bit string     |

		// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

		// |   defined per codec          ...                | Padding (0) |

		// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

		rpsiPadding = aRawPkt[start];

		if(rpsiPadding  > 32) {

			System.out.println("!!!! RtcpPktPSFB.decRefPictureSelcIndic paddingBits: " 

					+ rpsiPadding);

		}

		rpsiPayloadType = (int) rawPkt[start];

		if(rpsiPayloadType < 0) {

			System.out.println("!!!! RtcpPktPSFB.decRefPictureSelcIndic 8th bit not zero: " 

					+ rpsiPayloadType);

		}

		rpsiBitString = new byte[(super.length - 2)*4 - 2];

		System.arraycopy(aRawPkt, start + 2, rpsiBitString, 0, rpsiBitString.length);

		if(this.rtpSession.rtcpAVPFIntf != null) {

			this.rtpSession.rtcpAVPFIntf.PSFBPktRefPictureSelIndic(

					super.ssrc,

					rpsiPayloadType, rpsiBitString, rpsiPadding);

		}

	}

	/**

	 * Decode Application specific feedback message

	 * 

	 * @param aRawPkt

	 * @param start

	 */

	private void decAppLayerFB(byte[] aRawPkt, int start) {	

		//Application Message (FCI): variable length

		int stringLength = (super.length - 2)*4;

		alfBitString = new byte[stringLength];

		System.arraycopy(aRawPkt, start, alfBitString, 0, stringLength);

		if(this.rtpSession.rtcpAVPFIntf != null) {

			this.rtpSession.rtcpAVPFIntf.PSFBPktAppLayerFBReceived(

					super.ssrc, alfBitString);

		}

	}

	/**

	 * Encode a Slice Loss Indication

	 */

	private void encSliceLossIndic() {

		byte[] firstBytes;

		byte[] numbBytes;

		byte[] picBytes;

		int offset = 8;

		// Loop over the FCI lines

		for(int i=0; i < sliFirst.length; i++) {

			offset = 8 + 8*i;

			firstBytes = StaticProcs.uIntLongToByteWord(sliFirst[i] << 3);

			numbBytes = StaticProcs.uIntLongToByteWord(sliNumber[i] << 2);

			picBytes = StaticProcs.uIntIntToByteWord(sliPictureId[i]);

			super.rawPkt[offset] = firstBytes[2];

			super.rawPkt[offset+1] = (byte) (firstBytes[3] | numbBytes[2]);

			super.rawPkt[offset+2] = numbBytes[3];

			super.rawPkt[offset+3] = (byte) (numbBytes[3] | picBytes[1]);

		}

	}

	/**

	 * Encode a Reference Picture Selection Indication

	 *

	 */

	private void encRefPictureSelIndic() {	

		byte[] someBytes;

		someBytes = StaticProcs.uIntIntToByteWord(rpsiPadding);

		super.rawPkt[8] = someBytes[1];

		someBytes = StaticProcs.uIntIntToByteWord(rpsiPayloadType);

		super.rawPkt[9] = someBytes[1];

		System.arraycopy(rpsiBitString, 0, super.rawPkt, 10, rpsiBitString.length);

	}

	/**

	 * Encode Application Layer Feedback

	 *

	 */

	private void encAppLayerFB() {	

		//Application Message (FCI): variable length

		System.arraycopy(alfBitString, 0, super.rawPkt, 8, alfBitString.length);

	}

	/** 

	 * Get the FMT (Feedback Message Type)

	 * @return value stored in .itemcount, same field

	 */

	protected int getFMT() {

		return this.itemCount;

	}

	/**

	 * Encode the packet into a byte[], saved in .rawPkt

	 * 

	 * CompRtcpPkt will call this automatically

	 */

	protected void encode() {

		switch(super.itemCount) {

		case 1: // Picture Loss Indication 

			//Nothing to do really

			super.rawPkt = new byte[24];

			break; 

		case 2: // Slice Loss Indication

			super.rawPkt = new byte[24 + 4*this.sliFirst.length];

			encSliceLossIndic(); 

			break;

		case 3: // Reference Picture Selection Indication

			super.rawPkt = new byte[24 + 2 + this.rpsiBitString.length/4];

			encRefPictureSelIndic();

			break;

		case 15: // Application Layer Feedback Messages

			super.rawPkt = new byte[24 + this.alfBitString.length/4];

			encAppLayerFB();

			break;

		}

		byte[] someBytes = StaticProcs.uIntLongToByteWord(super.ssrc);

		System.arraycopy(someBytes, 0, super.rawPkt, 4, 4);

		someBytes = StaticProcs.uIntLongToByteWord(this.ssrcMediaSource);

		System.arraycopy(someBytes, 0, super.rawPkt, 8, 4);

		writeHeaders();

	}

	/**

	 * Debug purposes only

	 */

	public void debugPrint() {

		System.out.println("->RtcpPktPSFB.debugPrint() ");

		String str;

		switch(super.itemCount) {

		case 1: // Picture Loss Indication 

			System.out.println("  FMT: Picture Loss Indication");

			break; 

		case 2: // Slice Loss Indication

			if(sliFirst != null) {

				str = "sliFirst[].length: " + sliFirst.length;

			} else {

				str = "sliFirst[] is null";

			}

			System.out.println("  FMT: Slice Loss Indication, " + str);

			break;

		case 3: // Reference Picture Selection Indication

			if(rpsiBitString != null) {

				str = "rpsiBitString[].length: " + rpsiBitString.length;

			} else {

				str = "rpsiBitString[] is null";

			}

			System.out.println("  FMT: Reference Picture Selection Indication, " 

					+ str + " payloadType: " + this.rpsiPayloadType);

			break;

		case 15: // Application Layer Feedback Messages

			if(alfBitString != null) {

				str = "alfBitString[].length: " + alfBitString.length;

			} else {

				str = "alfBitString[] is null";

			}

			System.out.println("  FMT: Application Layer Feedback Messages, " + str);

			break;

		}

		System.out.println("<-RtcpPktPSFB.debugPrint() ");

	}

}