/*

 * HEIF codec.

 * Copyright (c) 2025 Dirk Farin <dirk.farin@gmail.com>

 *

 * This file is part of libheif.

 *

 * libheif 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 3 of

 * the License, or (at your option) any later version.

 *

 * libheif 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 libheif.  If not, see <http://www.gnu.org/licenses/>.

 */

#include "avc_enc.h"

#include "avc_boxes.h"

#include "error.h"

#include "context.h"

#include "api_structs.h"

#include <string>

#include "plugins/nalu_utils.h"

// TODO: can we use the new sequences interface for this to avoid duplicate code.

Result<Encoder::CodedImageData> Encoder_AVC::encode(const std::shared_ptr<HeifPixelImage>& image,

                                                    heif_encoder* encoder,

                                                    const heif_encoding_options& options,

                                                    heif_image_input_class input_class)

{

  CodedImageData codedImage;

  auto avcC = std::make_shared<Box_avcC>();

  heif_image c_api_image;

  c_api_image.image = image;

  heif_error err = encoder->plugin->encode_image(encoder->encoder, &c_api_image, input_class);

  if (err.code) {

    return Error(err.code,

                 err.subcode,

                 err.message);

  }

  int encoded_width = 0;

  int encoded_height = 0;

  for (;;) {

    uint8_t* data;

    int size;

    encoder->plugin->get_compressed_data(encoder->encoder, &data, &size, nullptr);

    if (data == nullptr) {

      break;

    }

    uint8_t nal_type = data[0] & 0x1f;

    if (nal_type == AVC_NAL_UNIT_SPS_NUT) {

      parse_sps_for_avcC_configuration(data, size, &avcC->get_configuration(), &encoded_width, &encoded_height);

      codedImage.encoded_image_width = encoded_width;

      codedImage.encoded_image_height = encoded_height;

    }

    switch (nal_type) {

      case AVC_NAL_UNIT_SPS_NUT:

        avcC->append_sps_nal(data, size);

        break;

      case AVC_NAL_UNIT_SPS_EXT_NUT:

        avcC->append_sps_ext_nal(data, size);

        break;

      case AVC_NAL_UNIT_PPS_NUT:

        avcC->append_pps_nal(data, size);

        break;

      default:

        codedImage.append_with_4bytes_size(data, size);

    }

  }

  if (!encoded_width || !encoded_height) {

    return Error(heif_error_Encoder_plugin_error,

                 heif_suberror_Invalid_image_size);

  }

  codedImage.properties.push_back(avcC);

  // Make sure that the encoder plugin works correctly and the encoded image has the correct size.

  if (encoder->plugin->plugin_api_version >= 3 &&

      encoder->plugin->query_encoded_size != nullptr) {

    uint32_t check_encoded_width = image->get_width(), check_encoded_height = image->get_height();

    encoder->plugin->query_encoded_size(encoder->encoder,

                                        image->get_width(), image->get_height(),

                                        &check_encoded_width,

                                        &check_encoded_height);

    assert((int)check_encoded_width == encoded_width);

    assert((int)check_encoded_height == encoded_height);

  }

  codedImage.codingConstraints.intra_pred_used = true;

  codedImage.codingConstraints.all_ref_pics_intra = true; // TODO: change when we use predicted frames

  return codedImage;

}

Error Encoder_AVC::encode_sequence_frame(const std::shared_ptr<HeifPixelImage>& image,

                                         heif_encoder* encoder,

                                         const heif_sequence_encoding_options& options,

                                         heif_image_input_class input_class,

                                         uint32_t framerate_num, uint32_t framerate_denom,

                                         uintptr_t frame_number)

{

  heif_image c_api_image;

  c_api_image.image = image;

  if (!m_encoder_active) {

    heif_error err = encoder->plugin->start_sequence_encoding(encoder->encoder, &c_api_image,

                                                              input_class,

                                                              framerate_num, framerate_denom,

                                                              &options);

    if (err.code) {

      return {

        err.code,

        err.subcode,

        err.message

      };

    }

    m_avcC = std::make_shared<Box_avcC>();

    m_encoder_active = true;

  }

  Error dataErr = get_data(encoder);

  if (dataErr) {

    return dataErr;

  }

  heif_error err = encoder->plugin->encode_sequence_frame(encoder->encoder, &c_api_image, frame_number);

  if (err.code) {

    return {

      err.code,

      err.subcode,

      err.message

    };

  }

  return get_data(encoder);

}

Error Encoder_AVC::encode_sequence_flush(heif_encoder* encoder)

{

  encoder->plugin->end_sequence_encoding(encoder->encoder);

  m_encoder_active = false;

  m_end_of_sequence_reached = true;

  return get_data(encoder);

}

std::optional<Encoder::CodedImageData> Encoder_AVC::encode_sequence_get_data()

{

  if (m_output_image_complete) {

    m_output_image_complete = false;

    return std::move(m_current_output_data);

  }

  else {

    return std::nullopt;

  }

}

Error Encoder_AVC::get_data(heif_encoder* encoder)

{

  //CodedImageData codedImage;

  for (;;) {

    uint8_t* data;

    int size;

    uintptr_t frameNr=0;

    int more_frame_packets = 1;

    encoder->plugin->get_compressed_data2(encoder->encoder, &data, &size, &frameNr, nullptr, &more_frame_packets);

    if (data == nullptr) {

      break;

    }

    const uint8_t nal_type = (data[0] & 0x1f);

    const bool is_sync = (nal_type == 5);

    const bool is_image_data = (nal_type > 0 && nal_type <= AVC_NAL_UNIT_MAX_VCL);

    m_output_image_complete |= is_image_data;

    // std::cout << "received frameNr=" << frameNr << " nal_type:" << ((int)nal_type) << " size: " << size << "\n";

    if (nal_type == AVC_NAL_UNIT_SPS_NUT && m_avcC) {

      parse_sps_for_avcC_configuration(data, size,

                                       &m_avcC->get_configuration(),

                                       &m_encoded_image_width, &m_encoded_image_height);

    }

    if (is_image_data) {

      // more_frame_packets = 0;

    }

    switch (nal_type) {

      case AVC_NAL_UNIT_SPS_NUT:

        if (m_avcC && !m_avcC_has_SPS) m_avcC->append_sps_nal(data, size);

        m_avcC_has_SPS = true;

        break;

      case AVC_NAL_UNIT_SPS_EXT_NUT:

        if (m_avcC /*&& !m_avcC_has_SPS*/) m_avcC->append_sps_ext_nal(data, size);

        //m_avcC_has_SPS = true;

        break;

      case AVC_NAL_UNIT_PPS_NUT:

        if (m_avcC && !m_avcC_has_PPS) m_avcC->append_pps_nal(data, size);

        m_avcC_has_PPS = true;

        break;

      default:

        if (!m_current_output_data) {

          m_current_output_data = CodedImageData{};

        }

        m_current_output_data->append_with_4bytes_size(data, size);

        if (is_image_data) {

          m_current_output_data->is_sync_frame = is_sync;

          m_current_output_data->frame_nr = frameNr;

        }

    }

    if (!more_frame_packets) {

      break;

    }

  }

  if (!m_output_image_complete) {

    return {};

  }

  if (!m_encoded_image_width || !m_encoded_image_height) {

    return Error(heif_error_Encoder_plugin_error,

                 heif_suberror_Invalid_image_size);

  }

  // --- return avcC when all headers are included and it was not returned yet

  //     TODO: it's maybe better to return this at the end so that we are sure to have all headers

  //           and also complete codingConstraints.

  if (m_end_of_sequence_reached && m_avcC && !m_avcC_sent) {

    m_current_output_data->properties.push_back(m_avcC);

    m_avcC = nullptr;

    m_avcC_sent = true;

  }

  m_current_output_data->encoded_image_width = m_encoded_image_width;

  m_current_output_data->encoded_image_height = m_encoded_image_height;

  m_current_output_data->codingConstraints.intra_pred_used = true;

  m_current_output_data->codingConstraints.all_ref_pics_intra = true; // TODO: change when we use predicted frames

  return {};

}

std::shared_ptr<Box_VisualSampleEntry> Encoder_AVC::get_sample_description_box(const CodedImageData& data) const

{

  auto avc1 = std::make_shared<Box_avc1>();

  avc1->get_VisualSampleEntry().compressorname = "AVC";

  for (auto prop : data.properties) {

    if (prop->get_short_type() == fourcc("avcC")) {

      avc1->append_child_box(prop);

      return avc1;

    }

  }

  // box not yet available

  return nullptr;

}