#include <avcpp/av.h>
#include <avcpp/avtime.h>
#include <avcpp/format.h>
#include <avcpp/formatcontext.h>
#include <spdlog/spdlog.h>
#include <vector>

int main(int argc, char *argv[]) {

  if (argc < 4) {
    spdlog::error("Usage: {} <input-file> <output-file> <smear-frames>",
                  argv[0]);
    return 1;
  }

  const char *input_file = argv[1];
  const char *output_file = argv[2];
  int smear_frames = atoi(argv[3]);

  av::init();

  av::FormatContext ictx;
  av::FormatContext octx;
  ictx.openInput(input_file);
  ictx.findStreamInfo();

  std::vector<off_t> stream_map(ictx.streamsCount());

  off_t oix = 0;
  for (size_t i = 0; i < stream_map.size(); i++) {
    auto istream = ictx.stream(i);

    if (istream.codecParameters().codecType() != AVMEDIA_TYPE_AUDIO ||
        istream.codecParameters().codecType() != AVMEDIA_TYPE_VIDEO ||
        istream.codecParameters().codecType() != AVMEDIA_TYPE_SUBTITLE) {
      stream_map[i] = -1;
    }

    auto ostream = octx.addStream();
    ostream.setCodecParameters(istream.codecParameters());
    ostream.codecParameters().codecTag(0);
    stream_map[i] = oix++;
  }

  octx.openOutput(output_file);
  octx.writeHeader();

  av::Packet packet_buffer;

  for (;;) {
    auto pkt = ictx.readPacket();

    if (pkt.isNull()) {
      break;
    }

    auto istream = ictx.stream(pkt.streamIndex());

    if (pkt.streamIndex() >= stream_map.size() ||
        stream_map[pkt.streamIndex()] < 0 || pkt.isKeyPacket()) {
      continue;
    }

    pkt.setStreamIndex(stream_map[pkt.streamIndex()]);

    if (auto ts = pkt.pts().timestamp(); ts % smear_frames == 0) {
      packet_buffer = pkt;
    } else {
      auto dts = pkt.dts();
      auto pts = pkt.pts();
      auto dur = pkt.duration();
      pkt = packet_buffer;
      pkt.setDts(dts);
      pkt.setPts(pts);
      pkt.setDuration(dur);
    }

    octx.writePacket(pkt);
  }

  octx.writeTrailer();
}