/*

 * HEIF AVC codec.

 * Copyright (c) 2023 Brad Hards <bradh@frogmouth.net>

 *

 * 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_boxes.h"

#include <cstdint>

#include <iomanip>

#include <iostream>

#include <vector>

#include "file.h"

#include "context.h"

#include "avc_dec.h"

#include "hevc_boxes.h"

#include <utility>

#include <set>

Error Box_avcC::parse(BitstreamRange& range, const heif_security_limits* limits)

{

  m_configuration.configuration_version = range.read8();

  m_configuration.AVCProfileIndication = range.read8();

  m_configuration.profile_compatibility = range.read8();

  m_configuration.AVCLevelIndication = range.read8();

  uint8_t lengthSizeMinusOneWithReserved = range.read8();

  m_configuration.lengthSize =

      (lengthSizeMinusOneWithReserved & 0b00000011) + 1;

  uint8_t numOfSequenceParameterSets = (range.read8() & 0b00011111);

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

    uint16_t sequenceParameterSetLength = range.read16();

    std::vector<uint8_t> sps(sequenceParameterSetLength);

    range.read(sps.data(), sps.size());

    m_sps.push_back(sps);

  }

  uint8_t numOfPictureParameterSets = range.read8();

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

    uint16_t pictureParameterSetLength = range.read16();

    std::vector<uint8_t> pps(pictureParameterSetLength);

    range.read(pps.data(), pps.size());

    m_pps.push_back(pps);

  }

  // See ISO/IEC 14496-15 2017 Section 5.3.3.1.2

  if (range.get_remaining_bytes() > 0) {

    if ((m_configuration.AVCProfileIndication != 66) &&

        (m_configuration.AVCProfileIndication != 77) &&

        (m_configuration.AVCProfileIndication != 88)) {

      m_configuration.chroma_format = (heif_chroma) (range.read8() & 0b00000011);

      m_configuration.bit_depth_luma = 8 + (range.read8() & 0b00000111);

      m_configuration.bit_depth_chroma = 8 + (range.read8() & 0b00000111);

      uint8_t numOfSequenceParameterSetExt = range.read8();

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

        uint16_t sequenceParameterSetExtLength = range.read16();

        std::vector<uint8_t> sps_ext(sequenceParameterSetExtLength);

        range.read(sps_ext.data(), sps_ext.size());

        m_sps_ext.push_back(sps_ext);

      }

    }

  }

  return range.get_error();

}

Error Box_avcC::write(StreamWriter& writer) const

{

  size_t box_start = reserve_box_header_space(writer);

  writer.write8(m_configuration.configuration_version);

  writer.write8(m_configuration.AVCProfileIndication);

  writer.write8(m_configuration.profile_compatibility);

  writer.write8(m_configuration.AVCLevelIndication);

  uint8_t lengthSizeMinusOneWithReserved = 0b11111100 | ((m_configuration.lengthSize - 1) & 0b11);

  writer.write8(lengthSizeMinusOneWithReserved);

  if (m_sps.size() > 0b00011111) {

    return {

      heif_error_Encoding_error,

      heif_suberror_Unspecified,

      "Cannot write more than 31 PPS into avcC box."

    };

  }

  uint8_t numSpsWithReserved = 0b11100000 | (m_sps.size() & 0b00011111);

  writer.write8(numSpsWithReserved);

  for (const auto& sps : m_sps) {

    if (sps.size() > 0xFFFF) {

      return {

        heif_error_Encoding_error,

        heif_suberror_Unspecified,

        "Cannot write SPS larger than 65535 bytes into avcC box."

      };

    }

    writer.write16((uint16_t) sps.size());

    writer.write(sps);

  }

  if (m_pps.size() > 0xFF) {

    return {

      heif_error_Encoding_error,

      heif_suberror_Unspecified,

      "Cannot write more than 255 PPS into avcC box."

    };

  }

  writer.write8(m_pps.size() & 0xFF);

  for (const auto& pps : m_pps) {

    if (pps.size() > 0xFFFF) {

      return {

        heif_error_Encoding_error,

        heif_suberror_Unspecified,

        "Cannot write PPS larger than 65535 bytes into avcC box."

      };

    }

    writer.write16((uint16_t) pps.size());

    writer.write(pps);

  }

  if ((m_configuration.AVCProfileIndication != 66) &&

      (m_configuration.AVCProfileIndication != 77) &&

      (m_configuration.AVCProfileIndication != 88)) {

    writer.write8(m_configuration.chroma_format);

    writer.write8(m_configuration.bit_depth_luma - 8);

    writer.write8(m_configuration.bit_depth_chroma - 8);

    if (m_sps_ext.size() > 0xFF) {

      return {

        heif_error_Encoding_error,

        heif_suberror_Unspecified,

        "Cannot write more than 255 SPS-Ext into avcC box."

      };

    }

    writer.write8(m_sps_ext.size() & 0xFF);

    for (const auto& spsext : m_sps_ext) {

      if (spsext.size() > 0xFFFF) {

        return {

          heif_error_Encoding_error,

          heif_suberror_Unspecified,

          "Cannot write SPS-Ext larger than 65535 bytes into avcC box."

        };

      }

      writer.write16((uint16_t) spsext.size());

      writer.write(spsext);

    }

  }

  prepend_header(writer, box_start);

  return Error::Ok;

}

std::string Box_avcC::dump(Indent& indent) const

{

  std::ostringstream sstr;

  sstr << Box::dump(indent);

  sstr << indent << "configuration_version: " << ((int) m_configuration.configuration_version) << "\n"

      << indent << "AVCProfileIndication: " << ((int) m_configuration.AVCProfileIndication) << " (" << profileIndicationAsText() << ")\n"

      << indent << "profile_compatibility: " << ((int) m_configuration.profile_compatibility) << "\n"

      << indent << "AVCLevelIndication: " << ((int) m_configuration.AVCLevelIndication) << "\n"

      << indent << "Chroma format: ";

  switch (m_configuration.chroma_format) {

    case heif_chroma_monochrome:

      sstr << "4:0:0\n";

      break;

    case heif_chroma_420:

      sstr << "4:2:0\n";

      break;

    case heif_chroma_422:

      sstr << "4:2:2\n";

      break;

    case heif_chroma_444:

      sstr << "4:4:4\n";

      break;

    default:

      sstr << "unsupported\n";

      break;

  }

  sstr << indent << "Bit depth luma: " << ((int) m_configuration.bit_depth_luma) << "\n"

      << indent << "Bit depth chroma: " << ((int) m_configuration.bit_depth_chroma) << "\n";

  for (const auto& sps : m_sps) {

    sstr << indent << "SPS: ";

    for (uint8_t b : sps) {

      sstr << std::setfill('0') << std::setw(2) << std::hex << ((int) b) << " ";

    }

    sstr << "\n";

    sstr << std::dec;

  }

  for (const auto& spsext : m_sps_ext) {

    sstr << indent << "SPS-EXT: ";

    for (uint8_t b : spsext) {

      sstr << std::setfill('0') << std::setw(2) << std::hex << ((int) b) << " ";

    }

    sstr << "\n";

    sstr << std::dec;

  }

  for (const auto& pps : m_pps) {

    sstr << indent << "PPS: ";

    for (uint8_t b : pps) {

      sstr << std::setfill('0') << std::setw(2) << std::hex << ((int) b) << " ";

    }

    sstr << "\n";

    sstr << std::dec;

  }

  return sstr.str();

}

std::string Box_avcC::profileIndicationAsText() const

{

  // See ISO/IEC 14496-10:2022 Annex A

  switch (m_configuration.AVCProfileIndication) {

    case 44:

      return "CALVC 4:4:4";

    case 66:

      return "Constrained Baseline";

    case 77:

      return "Main";

    case 88:

      return "Extended";

    case 100:

      return "High variant";

    case 110:

      return "High 10";

    case 122:

      return "High 4:2:2";

    case 244:

      return "High 4:4:4";

    default:

      return "Unknown";

  }

}

void Box_avcC::get_header_nals(std::vector<uint8_t>& data) const

{

  for (const auto& sps : m_sps) {

    data.push_back((sps.size() >> 24) & 0xFF);

    data.push_back((sps.size() >> 16) & 0xFF);

    data.push_back((sps.size() >> 8) & 0xFF);

    data.push_back((sps.size() >> 0) & 0xFF);

    data.insert(data.end(), sps.begin(), sps.end());

  }

  for (const auto& spsext : m_sps_ext) {

    data.push_back((spsext.size() >> 24) & 0xFF);

    data.push_back((spsext.size() >> 16) & 0xFF);

    data.push_back((spsext.size() >> 8) & 0xFF);

    data.push_back((spsext.size() >> 0) & 0xFF);

    data.insert(data.end(), spsext.begin(), spsext.end());

  }

  for (const auto& pps : m_pps) {

    data.push_back((pps.size() >> 24) & 0xFF);

    data.push_back((pps.size() >> 16) & 0xFF);

    data.push_back((pps.size() >> 8) & 0xFF);

    data.push_back((pps.size() >> 0) & 0xFF);

    data.insert(data.end(), pps.begin(), pps.end());

  }

}

void Box_avcC::append_sps_nal(const uint8_t* data, size_t size)

{

  std::vector<uint8_t> vec(data, data + size);

  m_sps.emplace_back(std::move(vec));

}

void Box_avcC::append_sps_ext_nal(const uint8_t* data, size_t size)

{

  std::vector<uint8_t> vec(data, data + size);

  m_sps_ext.emplace_back(std::move(vec));

}

void Box_avcC::append_pps_nal(const uint8_t* data, size_t size)

{

  std::vector<uint8_t> vec(data, data + size);

  m_pps.emplace_back(std::move(vec));

}

void skip_scaling_list(BitReader& reader, int sizeOfScalingList)

{

  int lastScale = 8;

  int nextScale = 8;

  // TODO: it seems that this can be simplified by exiting the loop

  //       as soon as nextScale==0.

#if 0

  // original version

  for (int j = 0; j < sizeOfScalingList; j++) {

    if (nextScale != 0) {

      int delta_scale;

      reader.get_svlc(&delta_scale);

      nextScale = (lastScale + delta_scale + 256) % 256;

    }

    lastScale = (nextScale == 0) ? lastScale : nextScale;

  }

#else

  // fast version

  for (int j = 0; j < sizeOfScalingList; j++) {

    int delta_scale;

    reader.get_svlc(&delta_scale);

    nextScale = (lastScale + delta_scale + 256) % 256;

    if (nextScale == 0) {

      break;

    }

    lastScale = nextScale;

  }

#endif

}

Error parse_sps_for_avcC_configuration(const uint8_t* sps, size_t size,

                                       Box_avcC::configuration* config,

                                       int* width, int* height)

{

  // remove start-code emulation bytes from SPS header stream

  std::vector<uint8_t> sps_no_emul = remove_start_code_emulation(sps, size);

  sps = sps_no_emul.data();

  size = sps_no_emul.size();

  BitReader reader(sps, (int) size);

  // skip NAL header

  reader.skip_bits(8);

  config->configuration_version = 1;

  config->AVCProfileIndication = reader.get_bits8(8);

  config->profile_compatibility = reader.get_bits8(8);

  config->AVCLevelIndication = reader.get_bits8(8);

  config->lengthSize = 4;

  int value;

  reader.get_uvlc(&value); // SPS ID

  Error invalidUVLC{

    heif_error_Invalid_input,

    heif_suberror_Unspecified,

    "Invalid variable length code in AVC SPS header"

  };

  if (std::set<int>{100, 110, 122, 244, 44, 83, 86}.contains(config->AVCProfileIndication)) {

    if (!reader.get_uvlc(&value)) {

      return invalidUVLC;

    }

    config->chroma_format = (heif_chroma) value;

    if (config->chroma_format == heif_chroma_444) {

      reader.skip_bits(1);

    }

    if (!reader.get_uvlc(&value)) {

      return invalidUVLC;

    }

    config->bit_depth_luma = static_cast<uint8_t>(8 + value);

    if (!reader.get_uvlc(&value)) {

      return invalidUVLC;

    }

    config->bit_depth_chroma = static_cast<uint8_t>(8 + value);

    reader.skip_bits(1);

    int seq_scaling_matrix_present_flag = reader.get_bits(1);

    if (seq_scaling_matrix_present_flag) {

      for (int i = 0; i < ((config->chroma_format != heif_chroma_444) ? 8 : 12); i++) {

        int scaling_list_present_flag = reader.get_bits(1);

        if (scaling_list_present_flag) {

          if (i < 6) {

            skip_scaling_list(reader, 16);

          }

          else {

            skip_scaling_list(reader, 64);

          }

        }

      }

    }

  }

  else {

    config->chroma_format = heif_chroma_420;

    config->bit_depth_luma = 8;

    config->bit_depth_chroma = 8;

  }

  reader.get_uvlc(&value); // log2_max_frame_num_minus4

  int pic_order_cnt_type;

  reader.get_uvlc(&pic_order_cnt_type);

  if (pic_order_cnt_type == 0) {

    reader.get_uvlc(&value);

  }

  else if (pic_order_cnt_type == 1) {

    reader.get_bits(1);

    reader.get_svlc(&value);

    reader.get_svlc(&value);

    int num_ref_franes_in_pic_order_cnt_cycle;

    reader.get_uvlc(&num_ref_franes_in_pic_order_cnt_cycle);

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

      reader.get_uvlc(&value);

    }

  }

  reader.get_uvlc(&value); // num_ref_frames

  reader.skip_bits(1);

  int pic_width_in_mbs_minus1;

  int pic_height_in_mbs_minus1;

  reader.get_uvlc(&pic_width_in_mbs_minus1);

  reader.get_uvlc(&pic_height_in_mbs_minus1);

  *width = (pic_width_in_mbs_minus1 + 1) * 16;

  *height = (pic_height_in_mbs_minus1 + 1) * 16;

  uint32_t frame_mbs_only_flag = reader.get_bits(1);

  if (!frame_mbs_only_flag) {

    reader.skip_bits(1);

  }

  reader.skip_bits(1);

  uint32_t frame_cropping_flag = reader.get_bits(1);

  if (frame_cropping_flag) {

    int left, right, top, bottom;

    reader.get_uvlc(&left);

    reader.get_uvlc(&right);

    reader.get_uvlc(&top);

    reader.get_uvlc(&bottom);

    *width -= left + right;

    *height -= top + bottom;

  }

  return {};

}