//ZoneMinder Packet Queue Implementation Class
//Copyright 2016 Steve Gilvarry
//
//This file is part of ZoneMinder.
//
//ZoneMinder is free software: you can redistribute it and/or modify
//it under the terms of the GNU General Public License as published by
//the Free Software Foundation, either version 3 of the License, or
//(at your option) any later version.
//
//ZoneMinder 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 General Public License for more details.
//
//You should have received a copy of the GNU General Public License
//along with ZoneMinder.  If not, see <http://www.gnu.org/licenses/>.


#include "zm_packetqueue.h"
#include "zm_ffmpeg.h"
#include <sys/time.h>

#define VIDEO_QUEUESIZE 200
#define AUDIO_QUEUESIZE 50

zm_packetqueue::zm_packetqueue() {
  video_packet_count = 0;
}

zm_packetqueue::~zm_packetqueue() {
  clearQueue();
}

bool zm_packetqueue::queuePacket( ZMPacket* zm_packet ) {
	pktQueue.push_back( zm_packet );
  if ( zm_packet->codec_type == AVMEDIA_TYPE_VIDEO )
    video_packet_count += 1;

	return true;
}

ZMPacket* zm_packetqueue::popPacket( ) {
	if ( pktQueue.empty() ) {
		return NULL;
	}

	ZMPacket *packet = pktQueue.front();
	pktQueue.pop_front();
  if ( packet->codec_type == AVMEDIA_TYPE_VIDEO )
    video_packet_count -= 1;

	return packet;
}

unsigned int zm_packetqueue::clearQueue( unsigned int frames_to_keep, int stream_id ) {
  
  Debug(3, "Clearing all but %d frames, queue has %d", frames_to_keep, pktQueue.size() );
  frames_to_keep += 1;

	if ( pktQueue.empty() ) {
    Debug(3, "Queue is empty");
    return 0;
  }

  std::list<ZMPacket *>::reverse_iterator it;
  ZMPacket *packet = NULL;

  for ( it = pktQueue.rbegin(); it != pktQueue.rend() && frames_to_keep; ++it ) {
    ZMPacket *zm_packet = *it;
    AVPacket *av_packet = &(zm_packet->packet);
       
    Debug(4, "Looking at packet with stream index (%d) with keyframe, frames_to_keep is (%d)", av_packet->stream_index, ( av_packet->flags & AV_PKT_FLAG_KEY ), frames_to_keep );
    
    // Want frames_to_keep video frames.  Otherwise, we may not have enough
    if ( av_packet->stream_index == stream_id ) {
      frames_to_keep --;
    }
  }
  // Might not be starting with a keyframe, but should always start with a keyframe

  if ( frames_to_keep ) {
    Debug(3, "Hit end of queue, still need (%d) video keyframes", frames_to_keep );
  } else {
    AVPacket *av_packet = &( (*it)->packet );
    while ( ( av_packet->stream_index != stream_id ) || ! ( av_packet->flags & AV_PKT_FLAG_KEY ) && ( it != pktQueue.rend() ) ) {
      ++it;
    }
  }
  unsigned int delete_count = 0;
  while ( it != pktQueue.rend() ) {
    Debug(4, "Deleting a packet from the front, count is (%d)", delete_count );

    packet = pktQueue.front();
    if ( packet->codec_type == AVMEDIA_TYPE_VIDEO )
      video_packet_count -= 1;
    pktQueue.pop_front();
    delete packet;

    delete_count += 1;
  }    
  Debug(3, "Deleted (%d) packets", delete_count );
  return delete_count; 
} // end unsigned int zm_packetqueue::clearQueue( unsigned int frames_to_keep, int stream_id )

void zm_packetqueue::clearQueue() {
  ZMPacket *packet = NULL;
	while(!pktQueue.empty()) {
    packet = pktQueue.front();
    pktQueue.pop_front();
    delete packet;
	}
  video_packet_count = 0;
}

unsigned int zm_packetqueue::size() {
  return pktQueue.size();
}

unsigned int zm_packetqueue::get_video_packet_count() {
  return video_packet_count;
}

void zm_packetqueue::clear_unwanted_packets( timeval *recording_started, int mVideoStreamId ) {
  // Need to find the keyframe <= recording_started.  Can get rid of audio packets.
	if ( pktQueue.empty() ) {
		return;
	}

  // Step 1 - find keyframe < recording_started.
  // Step 2 - pop packets until we get to the packet in step 2
  std::list<ZMPacket *>::reverse_iterator it;

  Debug(3, "Looking for keyframe after start recording stream id (%d)", mVideoStreamId );
  for ( it = pktQueue.rbegin(); it != pktQueue.rend(); ++ it ) {
    ZMPacket *zm_packet = *it;
    AVPacket *av_packet = &(zm_packet->packet);
    if ( 
        ( av_packet->flags & AV_PKT_FLAG_KEY ) 
        && 
        ( av_packet->stream_index == mVideoStreamId )
        && 
        timercmp( zm_packet->timestamp, recording_started, < )
       ) {
    Debug(3, "Found keyframe before start with stream index (%d) with keyframe (%d)", av_packet->stream_index, ( av_packet->flags & AV_PKT_FLAG_KEY ) );
      break;
    }
  }
  if ( it == pktQueue.rend() ) {
    Debug(1, "Didn't find a keyframe packet keeping all" );
    return;
  }

  ZMPacket *zm_packet = *it;
  AVPacket *av_packet = &(zm_packet->packet);
  Debug(3, "Found packet before start with stream index (%d) with keyframe (%d), distance(%d), size(%d)", 
      av_packet->stream_index, 
      ( av_packet->flags & AV_PKT_FLAG_KEY ), 
      distance( it, pktQueue.rend() ),
      pktQueue.size() );

  unsigned int deleted_frames = 0;
  ZMPacket *packet = NULL;
  while ( distance( it, pktQueue.rend() ) > 1 ) {
  //while ( pktQueue.rend() != it ) {
    packet = pktQueue.front();
    pktQueue.pop_front();
    delete packet;
    deleted_frames += 1;
  }

  zm_packet = pktQueue.front();
  av_packet = &(zm_packet->packet);
  if ( ( ! ( av_packet->flags & AV_PKT_FLAG_KEY ) ) || ( av_packet->stream_index != mVideoStreamId ) ) {
    Error( "Done looking for keyframe.  Deleted %d frames. Remaining frames in queue: %d stream of head packet is (%d), keyframe (%d), distance(%d), packets(%d)", deleted_frames, pktQueue.size(), av_packet->stream_index, ( av_packet->flags & AV_PKT_FLAG_KEY ), distance( it, pktQueue.rend() ), pktQueue.size() );
  } else {
    Debug(1, "Done looking for keyframe.  Deleted %d frames. Remaining frames in queue: %d stream of head packet is (%d), keyframe (%d), distance(%d), packets(%d)", deleted_frames, pktQueue.size(), av_packet->stream_index, ( av_packet->flags & AV_PKT_FLAG_KEY ), distance( it, pktQueue.rend() ), pktQueue.size() );
  }
}