#include <avcpp/av.h>
#include <avcpp/codeccontext.h>
#include <avcpp/formatcontext.h>
#include <avcpp/stream.h>
#include <spdlog/spdlog.h>

int main(int argc, char *argv[]) {
  if (argc < 3) {
    spdlog::error("Please invoke with {} <ifile> <ofile>", argv[0]);
  }

  av::init();

  try {

    av::FormatContext ictx;
    ictx.openInput(argv[1]);
    ictx.findStreamInfo();

    off_t v_istream_ix = -1;
    for (off_t i = 0; i < ictx.streamsCount(); i++) {
      auto stream = ictx.stream(i);
      if (stream.isVideo() && stream.isValid()) {
        v_istream_ix = i;
      }
    }
    if (v_istream_ix == -1) {
      spdlog::error("No video stream found in {}", argv[1]);
      return 1;
    }
    av::VideoDecoderContext decoder(ictx.stream(v_istream_ix));
    decoder.open();

    av::FormatContext octx;
    av::OutputFormat ofmt;
    ofmt.setFormat("", argv[2]);
    octx.setFormat(ofmt);
    auto ocodec = av::findEncodingCodec("libxvid");
    av::VideoEncoderContext encoder(ocodec);
    encoder.setPixelFormat(decoder.pixelFormat());
    encoder.setWidth(decoder.width());
    encoder.setHeight(decoder.height());
    encoder.setGopSize(1000);
    encoder.setMaxBFrames(0);
    encoder.setGlobalQuality(1);
    encoder.raw()->qmin = 1;
    encoder.raw()->qmax = 1;
    encoder.setFlags(AV_CODEC_FLAG_QPEL | AV_CODEC_FLAG_4MV);
    encoder.setTimeBase({1, 1000});

    encoder.open();

    auto ostream = octx.addStream(encoder);
    ostream.setFrameRate(ictx.stream(v_istream_ix).frameRate());

    octx.openOutput(argv[2]);
    octx.writeHeader();

    for (;;) {
      auto pkt = ictx.readPacket();
      if (pkt.isNull()) {
        break;
      }

      if (pkt.streamIndex() != v_istream_ix) {
        continue;
      }

      auto frame = decoder.decode(pkt);

      if (frame) {
        frame.setTimeBase(encoder.timeBase());
        frame.setStreamIndex(0);
        frame.setPictureType();

        auto opkt = encoder.encode(frame);
        if (opkt) {
          opkt.setStreamIndex(0);
          octx.writePacket(opkt);
        }
      }
    }

    octx.writeTrailer();
    octx.flush();
  } catch (const av::Exception &e) {
    spdlog::error("{}", e.what());
  }
}