/*
 *  Copyright (C) 2013-2021 Jean-Luc Barrière
 *  Copyright (C) 2005-2014 Team Kodi (https://kodi.tv)
 *
 *  SPDX-License-Identifier: GPL-2.0-or-later
 *  See LICENSE.md for more information.
 */

#include "ES_AAC.h"
#include "bitstream.h"

using namespace TSDemux;

static int aac_sample_rates[16] =
{
  96000, 88200, 64000, 48000, 44100, 32000,
  24000, 22050, 16000, 12000, 11025, 8000, 7350,
  0, 0, 0
};


ES_AAC::ES_AAC(uint16_t pes_pid)
 : ElementaryStream(pes_pid)
{
  m_Configured                  = false;
  m_FrameLengthType             = 0;
  m_PTS                         = 0;
  m_DTS                         = 0;
  m_FrameSize                   = 0;
  m_SampleRate                  = 0;
  m_Channels                    = 0;
  m_BitRate                     = 0;
  m_AudioMuxVersion_A           = 0;
  es_alloc_init                 = 1920*2;
  Reset();
}

ES_AAC::~ES_AAC()
{
}

void ES_AAC::Parse(STREAM_PKT* pkt)
{
  int p = es_parsed;
  int l;
  while ((l = es_len - p) > 8)
  {
    if (FindHeaders(es_buf + p, l) < 0)
      break;
    p++;
  }
  es_parsed = p;

  if (es_found_frame && l >= m_FrameSize)
  {
    bool streamChange = SetAudioInformation(m_Channels, m_SampleRate, m_BitRate, 0, 0);
    pkt->pid            = pid;
    pkt->data           = &es_buf[p];
    pkt->size           = m_FrameSize;
    pkt->duration       = 1024 * 90000 / (!m_SampleRate ? aac_sample_rates[4] : m_SampleRate);
    pkt->dts            = m_DTS;
    pkt->pts            = m_PTS;
    pkt->streamChange   = streamChange;

    es_consumed = p + m_FrameSize;
    es_parsed = es_consumed;
    es_found_frame = false;
  }
}

int ES_AAC::FindHeaders(uint8_t *buf, int buf_size)
{
  if (es_found_frame)
    return -1;

  uint8_t *buf_ptr = buf;

  if (stream_type == STREAM_TYPE_AUDIO_AAC)
  {
    if (buf_ptr[0] == 0xFF && (buf_ptr[1] & 0xF0) == 0xF0)
      stream_type = STREAM_TYPE_AUDIO_AAC_ADTS;
    else if (buf_ptr[0] == 0x56 && (buf_ptr[1] & 0xE0) == 0xE0)
      stream_type = STREAM_TYPE_AUDIO_AAC_LATM;
  }

  // STREAM_TYPE_AUDIO_AAC_LATM
  if (stream_type == STREAM_TYPE_AUDIO_AAC_LATM)
  {
    if ((buf_ptr[0] == 0x56 && (buf_ptr[1] & 0xE0) == 0xE0))
    {
      // TODO
      if (buf_size < 16)
        return -1;

      CBitstream bs(buf_ptr, 16 * 8);
      bs.skipBits(11);
      m_FrameSize = bs.readBits(13) + 3;
      if (!ParseLATMAudioMuxElement(&bs))
        return 0;

      es_found_frame = true;
      m_DTS = c_pts;
      m_PTS = c_pts;
      c_pts += 90000 * 1024 / (!m_SampleRate ? aac_sample_rates[4] : m_SampleRate);
      return -1;
    }
  }
  // STREAM_TYPE_AUDIO_AAC_ADTS
  else if (stream_type == STREAM_TYPE_AUDIO_AAC_ADTS)
  {
    if(buf_ptr[0] == 0xFF && (buf_ptr[1] & 0xF0) == 0xF0)
    {
      // need at least 7 bytes for header
      if (buf_size < 7)
        return -1;

      CBitstream bs(buf_ptr, 9 * 8);
      bs.skipBits(15);

      // check if CRC is present, means header is 9 byte long
      int noCrc = bs.readBits(1);
      if (!noCrc && (buf_size < 9))
        return -1;

      bs.skipBits(2); // profile
      int SampleRateIndex = bs.readBits(4);
      bs.skipBits(1); // private
      m_Channels = bs.readBits(3);
      bs.skipBits(4);

      m_FrameSize = bs.readBits(13);
      m_SampleRate    = aac_sample_rates[SampleRateIndex & 0x0F];

      es_found_frame = true;
      m_DTS = c_pts;
      m_PTS = c_pts;
      c_pts += 90000 * 1024 / (!m_SampleRate ? aac_sample_rates[4] : m_SampleRate);
      return -1;
    }
  }
  return 0;
}

bool ES_AAC::ParseLATMAudioMuxElement(CBitstream *bs)
{
  if (!bs->readBits1())
    ReadStreamMuxConfig(bs);

  if (!m_Configured)
    return false;

  return true;
}

void ES_AAC::ReadStreamMuxConfig(CBitstream *bs)
{
  int AudioMuxVersion = bs->readBits(1);
  m_AudioMuxVersion_A = 0;
  if (AudioMuxVersion)                       // audioMuxVersion
    m_AudioMuxVersion_A = bs->readBits(1);

  if(m_AudioMuxVersion_A)
    return;

  if (AudioMuxVersion)
    LATMGetValue(bs);                      // taraFullness

  bs->skipBits(1);                         // allStreamSameTimeFraming = 1
  bs->skipBits(6);                         // numSubFrames = 0
  bs->skipBits(4);                         // numPrograms = 0

  // for each program (which there is only on in DVB)
  bs->skipBits(3);                         // numLayer = 0

  // for each layer (which there is only on in DVB)
  if (!AudioMuxVersion)
    ReadAudioSpecificConfig(bs);
  else
    return;

  // these are not needed... perhaps
  m_FrameLengthType = bs->readBits(3);
  switch (m_FrameLengthType)
  {
    case 0:
      bs->readBits(8);
      break;
    case 1:
      bs->readBits(9);
      break;
    case 3:
    case 4:
    case 5:
      bs->readBits(6);                 // celp_table_index
      break;
    case 6:
    case 7:
      bs->readBits(1);                 // hvxc_table_index
      break;
  }

  if (bs->readBits(1))
  {                   // other data?
    int esc;
    do
    {
      esc = bs->readBits(1);
      bs->skipBits(8);
    } while (esc);
  }

  if (bs->readBits(1))                   // crc present?
    bs->skipBits(8);                     // config_crc
  m_Configured = true;
}

void ES_AAC::ReadAudioSpecificConfig(CBitstream *bs)
{
  int aot = bs->readBits(5);
  if (aot == 31)
    aot = 32 + bs->readBits(6);

  int SampleRateIndex = bs->readBits(4);

  if (SampleRateIndex == 0xf)
    m_SampleRate = bs->readBits(24);
  else
    m_SampleRate = aac_sample_rates[SampleRateIndex & 0xf];

  m_Channels = bs->readBits(4);

  if (aot == 5) { // AOT_SBR
    if (bs->readBits(4) == 0xf) { // extensionSamplingFrequencyIndex
      bs->skipBits(24);
    }
    aot = bs->readBits(5); // this is the main object type (i.e. non-extended)
    if (aot == 31)
      aot = 32 + bs->readBits(6);
  }

  if(aot != 2)
    return;

  bs->skipBits(1);      //framelen_flag
  if (bs->readBits1())  // depends_on_coder
    bs->skipBits(14);

  if (bs->readBits(1))  // ext_flag
    bs->skipBits(1);    // ext3_flag
}

void ES_AAC::Reset()
{
  ElementaryStream::Reset();
  m_Configured = false;
}
