// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "media/formats/mp4/mp4_stream_parser.h"

#include <stddef.h>
#include <limits>
#include <utility>
#include <vector>

#include "base/callback_helpers.h"
#include "base/logging.h"
#include "base/time/time.h"
#include "build/build_config.h"
#include "media/base/audio_decoder_config.h"
#include "media/base/stream_parser_buffer.h"
#include "media/base/text_track_config.h"
#include "media/base/timestamp_constants.h"
#include "media/base/video_decoder_config.h"
#include "media/base/video_util.h"
#include "media/formats/mp4/box_definitions.h"
#include "media/formats/mp4/box_reader.h"
#include "media/formats/mp4/es_descriptor.h"
#include "media/formats/mp4/rcheck.h"
#include "media/formats/mpeg/adts_constants.h"

namespace media {
namespace mp4 {

MP4StreamParser::MP4StreamParser(const std::set<int>& audio_object_types,
                                 bool has_sbr)
    : state_(kWaitingForInit),
      moof_head_(0),
      mdat_tail_(0),
      highest_end_offset_(0),
      has_audio_(false),
      has_video_(false),
      audio_track_id_(0),
      video_track_id_(0),
      audio_object_types_(audio_object_types),
      has_sbr_(has_sbr),
      is_audio_track_encrypted_(false),
      is_video_track_encrypted_(false),
      num_top_level_box_skipped_(0) {
}

MP4StreamParser::~MP4StreamParser() {}

void MP4StreamParser::Init(
    const InitCB& init_cb,
    const NewConfigCB& config_cb,
    const NewBuffersCB& new_buffers_cb,
    bool /* ignore_text_tracks */,
    const EncryptedMediaInitDataCB& encrypted_media_init_data_cb,
    const NewMediaSegmentCB& new_segment_cb,
    const EndMediaSegmentCB& end_of_segment_cb,
    const scoped_refptr<MediaLog>& media_log) {
  DCHECK_EQ(state_, kWaitingForInit);
  DCHECK(init_cb_.is_null());
  DCHECK(!init_cb.is_null());
  DCHECK(!config_cb.is_null());
  DCHECK(!new_buffers_cb.is_null());
  DCHECK(!encrypted_media_init_data_cb.is_null());
  DCHECK(!end_of_segment_cb.is_null());

  ChangeState(kParsingBoxes);
  init_cb_ = init_cb;
  config_cb_ = config_cb;
  new_buffers_cb_ = new_buffers_cb;
  encrypted_media_init_data_cb_ = encrypted_media_init_data_cb;
  new_segment_cb_ = new_segment_cb;
  end_of_segment_cb_ = end_of_segment_cb;
  media_log_ = media_log;
}

void MP4StreamParser::Reset() {
  queue_.Reset();
  runs_.reset();
  moof_head_ = 0;
  mdat_tail_ = 0;
}

void MP4StreamParser::Flush() {
  DCHECK_NE(state_, kWaitingForInit);
  Reset();
  ChangeState(kParsingBoxes);
}

bool MP4StreamParser::Parse(const uint8_t* buf, int size) {
  DCHECK_NE(state_, kWaitingForInit);

  if (state_ == kError)
    return false;

  queue_.Push(buf, size);

  BufferQueue audio_buffers;
  BufferQueue video_buffers;

  bool result = false;
  bool err = false;

  do {
    switch (state_) {
      case kWaitingForInit:
      case kError:
        NOTREACHED();
        return false;

      case kParsingBoxes:
        result = ParseBox(&err);
        break;

      case kWaitingForSampleData:
        result = HaveEnoughDataToEnqueueSamples();
        if (result)
          ChangeState(kEmittingSamples);
        break;

      case kEmittingSamples:
        result = EnqueueSample(&audio_buffers, &video_buffers, &err);
        if (result) {
          int64_t max_clear = runs_->GetMaxClearOffset() + moof_head_;
          err = !ReadAndDiscardMDATsUntil(max_clear);
        }
        break;
    }
  } while (result && !err);

  if (!err)
    err = !SendAndFlushSamples(&audio_buffers, &video_buffers);

  if (err) {
    DLOG(ERROR) << "Error while parsing MP4";
    moov_.reset();
    Reset();
    ChangeState(kError);
    return false;
  }

  return true;
}

bool MP4StreamParser::ParseBox(bool* err) {
  const uint8_t* buf;
  int size;
  queue_.Peek(&buf, &size);
  if (!size) return false;

  scoped_ptr<BoxReader> reader(
      BoxReader::ReadTopLevelBox(buf, size, media_log_, err));
  if (reader.get() == NULL) return false;

  if (reader->type() == FOURCC_MOOV) {
    *err = !ParseMoov(reader.get());
  } else if (reader->type() == FOURCC_MOOF) {
    moof_head_ = queue_.head();
    *err = !ParseMoof(reader.get());

    // Set up first mdat offset for ReadMDATsUntil().
    mdat_tail_ = queue_.head() + reader->size();

    // Return early to avoid evicting 'moof' data from queue. Auxiliary info may
    // be located anywhere in the file, including inside the 'moof' itself.
    // (Since 'default-base-is-moof' is mandated, no data references can come
    // before the head of the 'moof', so keeping this box around is sufficient.)
    return !(*err);
  } else {
    // TODO(wolenetz,chcunningham): Enforce more strict adherence to MSE byte
    // stream spec for ftyp and styp. See http://crbug.com/504514.
    DVLOG(2) << "Skipping unrecognized top-level box: "
             << FourCCToString(reader->type());
  }

  queue_.Pop(reader->size());
  return !(*err);
}

bool MP4StreamParser::ParseMoov(BoxReader* reader) {
  moov_.reset(new Movie);
  RCHECK(moov_->Parse(reader));
  runs_.reset();

  has_audio_ = false;
  has_video_ = false;

  AudioDecoderConfig audio_config;
  VideoDecoderConfig video_config;

  for (std::vector<Track>::const_iterator track = moov_->tracks.begin();
       track != moov_->tracks.end(); ++track) {
    // TODO(strobe): Only the first audio and video track present in a file are
    // used. (Track selection is better accomplished via Source IDs, though, so
    // adding support for track selection within a stream is low-priority.)
    const SampleDescription& samp_descr =
        track->media.information.sample_table.description;

    // TODO(strobe): When codec reconfigurations are supported, detect and send
    // a codec reconfiguration for fragments using a sample description index
    // different from the previous one
    size_t desc_idx = 0;
    for (size_t t = 0; t < moov_->extends.tracks.size(); t++) {
      const TrackExtends& trex = moov_->extends.tracks[t];
      if (trex.track_id == track->header.track_id) {
        desc_idx = trex.default_sample_description_index;
        break;
      }
    }
    RCHECK(desc_idx > 0);
    desc_idx -= 1;  // BMFF descriptor index is one-based

    if (track->media.handler.type == kAudio && !audio_config.IsValidConfig()) {
      RCHECK(!samp_descr.audio_entries.empty());

      // It is not uncommon to find otherwise-valid files with incorrect sample
      // description indices, so we fail gracefully in that case.
      if (desc_idx >= samp_descr.audio_entries.size())
        desc_idx = 0;
      const AudioSampleEntry& entry = samp_descr.audio_entries[desc_idx];
      const AAC& aac = entry.esds.aac;

      // For encrypted audio streams entry.format is FOURCC_ENCA and actual
      // format is in entry.sinf.format.format.
      FourCC audio_format = (entry.format == FOURCC_ENCA)
                                ? entry.sinf.format.format
                                : entry.format;

#if BUILDFLAG(ENABLE_AC3_EAC3_AUDIO_DEMUXING)
      if (audio_format != FOURCC_MP4A && audio_format != FOURCC_AC3 &&
          audio_format != FOURCC_EAC3) {
#else
      if (audio_format != FOURCC_MP4A) {
#endif
        MEDIA_LOG(ERROR, media_log_) << "Unsupported audio format 0x"
                                     << std::hex << entry.format
                                     << " in stsd box.";
        return false;
      }

      uint8_t audio_type = entry.esds.object_type;
#if BUILDFLAG(ENABLE_AC3_EAC3_AUDIO_DEMUXING)
      if (audio_type == kForbidden) {
        if (audio_format == FOURCC_AC3)
          audio_type = kAC3;
        if (audio_format == FOURCC_EAC3)
          audio_type = kEAC3;
      }
#endif
      DVLOG(1) << "audio_type 0x" << std::hex << static_cast<int>(audio_type);
      if (audio_object_types_.find(audio_type) == audio_object_types_.end()) {
        MEDIA_LOG(ERROR, media_log_)
            << "audio object type 0x" << std::hex
            << static_cast<int>(audio_type)
            << " does not match what is specified in the mimetype.";
        return false;
      }

      AudioCodec codec = kUnknownAudioCodec;
      ChannelLayout channel_layout = CHANNEL_LAYOUT_NONE;
      int sample_per_second = 0;
      std::vector<uint8_t> extra_data;
      // Check if it is MPEG4 AAC defined in ISO 14496 Part 3 or
      // supported MPEG2 AAC varients.
      if (ESDescriptor::IsAAC(audio_type)) {
        codec = kCodecAAC;
        channel_layout = aac.GetChannelLayout(has_sbr_);
        sample_per_second = aac.GetOutputSamplesPerSecond(has_sbr_);
#if defined(OS_ANDROID)
        extra_data = aac.codec_specific_data();
#endif
#if BUILDFLAG(ENABLE_AC3_EAC3_AUDIO_DEMUXING)
      } else if (audio_type == kAC3) {
        codec = kCodecAC3;
        channel_layout = GuessChannelLayout(entry.channelcount);
        sample_per_second = entry.samplerate;
      } else if (audio_type == kEAC3) {
        codec = kCodecEAC3;
        channel_layout = GuessChannelLayout(entry.channelcount);
        sample_per_second = entry.samplerate;
#endif
      } else {
        MEDIA_LOG(ERROR, media_log_) << "Unsupported audio object type 0x"
                                     << std::hex << static_cast<int>(audio_type)
                                     << " in esds.";
        return false;
      }

      SampleFormat sample_format;
      if (entry.samplesize == 8) {
        sample_format = kSampleFormatU8;
      } else if (entry.samplesize == 16) {
        sample_format = kSampleFormatS16;
      } else if (entry.samplesize == 32) {
        sample_format = kSampleFormatS32;
      } else {
        LOG(ERROR) << "Unsupported sample size.";
        return false;
      }

      is_audio_track_encrypted_ = entry.sinf.info.track_encryption.is_encrypted;
      DVLOG(1) << "is_audio_track_encrypted_: " << is_audio_track_encrypted_;
      audio_config.Initialize(codec, sample_format, channel_layout,
                              sample_per_second, extra_data,
                              is_audio_track_encrypted_, base::TimeDelta(), 0);
      has_audio_ = true;
      audio_track_id_ = track->header.track_id;
    }
    if (track->media.handler.type == kVideo && !video_config.IsValidConfig()) {
      RCHECK(!samp_descr.video_entries.empty());
      if (desc_idx >= samp_descr.video_entries.size())
        desc_idx = 0;
      const VideoSampleEntry& entry = samp_descr.video_entries[desc_idx];

      if (!entry.IsFormatValid()) {
        MEDIA_LOG(ERROR, media_log_) << "Unsupported video format 0x"
                                     << std::hex << entry.format
                                     << " in stsd box.";
        return false;
      }

      // TODO(strobe): Recover correct crop box
      gfx::Size coded_size(entry.width, entry.height);
      gfx::Rect visible_rect(coded_size);

      // If PASP is available, use the coded size and PASP to calculate the
      // natural size. Otherwise, use the size in track header for natural size.
      gfx::Size natural_size(visible_rect.size());
      if (entry.pixel_aspect.h_spacing != 1 ||
          entry.pixel_aspect.v_spacing != 1) {
        natural_size =
            GetNaturalSize(visible_rect.size(), entry.pixel_aspect.h_spacing,
                           entry.pixel_aspect.v_spacing);
      } else if (track->header.width && track->header.height) {
        natural_size =
            gfx::Size(track->header.width, track->header.height);
      }

      is_video_track_encrypted_ = entry.sinf.info.track_encryption.is_encrypted;
      DVLOG(1) << "is_video_track_encrypted_: " << is_video_track_encrypted_;
      video_config.Initialize(
          entry.video_codec, entry.video_codec_profile, PIXEL_FORMAT_YV12,
          COLOR_SPACE_HD_REC709, coded_size, visible_rect, natural_size,
          // No decoder-specific buffer needed for AVC;
          // SPS/PPS are embedded in the video stream
          std::vector<uint8_t>(), is_video_track_encrypted_);
      has_video_ = true;
      video_track_id_ = track->header.track_id;
    }
  }

  if (!moov_->pssh.empty())
    OnEncryptedMediaInitData(moov_->pssh);

  RCHECK(config_cb_.Run(audio_config, video_config, TextTrackConfigMap()));

  StreamParser::InitParameters params(kInfiniteDuration());
  if (moov_->extends.header.fragment_duration > 0) {
    params.duration = TimeDeltaFromRational(
        moov_->extends.header.fragment_duration, moov_->header.timescale);
    params.liveness = DemuxerStream::LIVENESS_RECORDED;
  } else if (moov_->header.duration > 0 &&
             moov_->header.duration != std::numeric_limits<uint64_t>::max()) {
    params.duration =
        TimeDeltaFromRational(moov_->header.duration, moov_->header.timescale);
    params.liveness = DemuxerStream::LIVENESS_RECORDED;
  } else {
    // In ISO/IEC 14496-12:2005(E), 8.30.2: ".. If an MP4 file is created in
    // real-time, such as used in live streaming, it is not likely that the
    // fragment_duration is known in advance and this (mehd) box may be
    // omitted."
    // TODO(wolenetz): Investigate gating liveness detection on timeline_offset
    // when it's populated. See http://crbug.com/312699
    params.liveness = DemuxerStream::LIVENESS_LIVE;
  }

  DVLOG(1) << "liveness: " << params.liveness;

  if (!init_cb_.is_null())
    base::ResetAndReturn(&init_cb_).Run(params);

  return true;
}

bool MP4StreamParser::ParseMoof(BoxReader* reader) {
  RCHECK(moov_.get());  // Must already have initialization segment
  MovieFragment moof;
  RCHECK(moof.Parse(reader));
  if (!runs_)
    runs_.reset(new TrackRunIterator(moov_.get(), media_log_));
  RCHECK(runs_->Init(moof));
  RCHECK(ComputeHighestEndOffset(moof));

  if (!moof.pssh.empty())
    OnEncryptedMediaInitData(moof.pssh);

  new_segment_cb_.Run();
  ChangeState(kWaitingForSampleData);
  return true;
}

void MP4StreamParser::OnEncryptedMediaInitData(
    const std::vector<ProtectionSystemSpecificHeader>& headers) {
  // TODO(strobe): ensure that the value of init_data (all PSSH headers
  // concatenated in arbitrary order) matches the EME spec.
  // See https://www.w3.org/Bugs/Public/show_bug.cgi?id=17673.
  size_t total_size = 0;
  for (size_t i = 0; i < headers.size(); i++)
    total_size += headers[i].raw_box.size();

  std::vector<uint8_t> init_data(total_size);
  size_t pos = 0;
  for (size_t i = 0; i < headers.size(); i++) {
    memcpy(&init_data[pos], &headers[i].raw_box[0],
           headers[i].raw_box.size());
    pos += headers[i].raw_box.size();
  }
  encrypted_media_init_data_cb_.Run(EmeInitDataType::CENC, init_data);
}

bool MP4StreamParser::PrepareAACBuffer(
    const AAC& aac_config,
    std::vector<uint8_t>* frame_buf,
    std::vector<SubsampleEntry>* subsamples) const {
  // Append an ADTS header to every audio sample.
  RCHECK(aac_config.ConvertEsdsToADTS(frame_buf));

  // As above, adjust subsample information to account for the headers. AAC is
  // not required to use subsample encryption, so we may need to add an entry.
  if (subsamples->empty()) {
    subsamples->push_back(SubsampleEntry(
        kADTSHeaderMinSize, frame_buf->size() - kADTSHeaderMinSize));
  } else {
    (*subsamples)[0].clear_bytes += kADTSHeaderMinSize;
  }
  return true;
}

bool MP4StreamParser::EnqueueSample(BufferQueue* audio_buffers,
                                    BufferQueue* video_buffers,
                                    bool* err) {
  DCHECK_EQ(state_, kEmittingSamples);

  if (!runs_->IsRunValid()) {
    // Flush any buffers we've gotten in this chunk so that buffers don't
    // cross NewSegment() calls
    *err = !SendAndFlushSamples(audio_buffers, video_buffers);
    if (*err)
      return false;

    // Remain in kEmittingSamples state, discarding data, until the end of
    // the current 'mdat' box has been appended to the queue.
    if (!queue_.Trim(mdat_tail_))
      return false;

    ChangeState(kParsingBoxes);
    end_of_segment_cb_.Run();
    return true;
  }

  if (!runs_->IsSampleValid()) {
    runs_->AdvanceRun();
    return true;
  }

  DCHECK(!(*err));

  const uint8_t* buf;
  int buf_size;
  queue_.Peek(&buf, &buf_size);
  if (!buf_size) return false;

  bool audio = has_audio_ && audio_track_id_ == runs_->track_id();
  bool video = has_video_ && video_track_id_ == runs_->track_id();

  // Skip this entire track if it's not one we're interested in
  if (!audio && !video) {
    runs_->AdvanceRun();
    return true;
  }

  // Attempt to cache the auxiliary information first. Aux info is usually
  // placed in a contiguous block before the sample data, rather than being
  // interleaved. If we didn't cache it, this would require that we retain the
  // start of the segment buffer while reading samples. Aux info is typically
  // quite small compared to sample data, so this pattern is useful on
  // memory-constrained devices where the source buffer consumes a substantial
  // portion of the total system memory.
  if (runs_->AuxInfoNeedsToBeCached()) {
    queue_.PeekAt(runs_->aux_info_offset() + moof_head_, &buf, &buf_size);
    if (buf_size < runs_->aux_info_size()) return false;
    *err = !runs_->CacheAuxInfo(buf, buf_size);
    return !*err;
  }

  queue_.PeekAt(runs_->sample_offset() + moof_head_, &buf, &buf_size);
  if (buf_size < runs_->sample_size()) return false;

  scoped_ptr<DecryptConfig> decrypt_config;
  std::vector<SubsampleEntry> subsamples;
  if (runs_->is_encrypted()) {
    decrypt_config = runs_->GetDecryptConfig();
    if (!decrypt_config) {
      *err = true;
      return false;
    }
    subsamples = decrypt_config->subsamples();
  }

  std::vector<uint8_t> frame_buf(buf, buf + runs_->sample_size());
  if (video) {
    DCHECK(runs_->video_description().frame_bitstream_converter);
    if (!runs_->video_description().frame_bitstream_converter->ConvertFrame(
        &frame_buf, runs_->is_keyframe(), &subsamples)) {
      MEDIA_LOG(ERROR, media_log_)
          << "Failed to prepare video sample for decode";
      *err = true;
      return false;
    }
  }

  if (audio) {
    if (ESDescriptor::IsAAC(runs_->audio_description().esds.object_type) &&
        !PrepareAACBuffer(runs_->audio_description().esds.aac,
                          &frame_buf, &subsamples)) {
      MEDIA_LOG(ERROR, media_log_) << "Failed to prepare AAC sample for decode";
      *err = true;
      return false;
    }
  }

  if (decrypt_config) {
    if (!subsamples.empty()) {
    // Create a new config with the updated subsamples.
    decrypt_config.reset(new DecryptConfig(
        decrypt_config->key_id(),
        decrypt_config->iv(),
        subsamples));
    }
    // else, use the existing config.
  } else if ((audio && is_audio_track_encrypted_) ||
             (video && is_video_track_encrypted_)) {
    // The media pipeline requires a DecryptConfig with an empty |iv|.
    // TODO(ddorwin): Refactor so we do not need a fake key ID ("1");
    decrypt_config.reset(
        new DecryptConfig("1", "", std::vector<SubsampleEntry>()));
  }

  StreamParserBuffer::Type buffer_type = audio ? DemuxerStream::AUDIO :
      DemuxerStream::VIDEO;

  // TODO(wolenetz/acolwell): Validate and use a common cross-parser TrackId
  // type and allow multiple tracks for same media type, if applicable. See
  // https://crbug.com/341581.
  scoped_refptr<StreamParserBuffer> stream_buf =
      StreamParserBuffer::CopyFrom(&frame_buf[0], frame_buf.size(),
                                   runs_->is_keyframe(),
                                   buffer_type, 0);

  if (decrypt_config)
    stream_buf->set_decrypt_config(std::move(decrypt_config));

  stream_buf->set_duration(runs_->duration());
  stream_buf->set_timestamp(runs_->cts());
  stream_buf->SetDecodeTimestamp(runs_->dts());

  DVLOG(3) << "Pushing frame: aud=" << audio
           << ", key=" << runs_->is_keyframe()
           << ", dur=" << runs_->duration().InMilliseconds()
           << ", dts=" << runs_->dts().InMilliseconds()
           << ", cts=" << runs_->cts().InMilliseconds()
           << ", size=" << runs_->sample_size();

  if (audio) {
    audio_buffers->push_back(stream_buf);
  } else {
    video_buffers->push_back(stream_buf);
  }

  runs_->AdvanceSample();
  return true;
}

bool MP4StreamParser::SendAndFlushSamples(BufferQueue* audio_buffers,
                                          BufferQueue* video_buffers) {
  if (audio_buffers->empty() && video_buffers->empty())
    return true;

  TextBufferQueueMap empty_text_map;
  bool success = new_buffers_cb_.Run(*audio_buffers,
                                     *video_buffers,
                                     empty_text_map);
  audio_buffers->clear();
  video_buffers->clear();
  return success;
}

bool MP4StreamParser::ReadAndDiscardMDATsUntil(int64_t max_clear_offset) {
  bool err = false;
  int64_t upper_bound = std::min(max_clear_offset, queue_.tail());
  while (mdat_tail_ < upper_bound) {
    const uint8_t* buf = NULL;
    int size = 0;
    queue_.PeekAt(mdat_tail_, &buf, &size);

    FourCC type;
    int box_sz;
    if (!BoxReader::StartTopLevelBox(buf, size, media_log_, &type, &box_sz,
                                     &err))
      break;

    if (type != FOURCC_MDAT) {
      MEDIA_LOG(DEBUG, media_log_)
          << "Unexpected box type while parsing MDATs: "
          << FourCCToString(type);
    }
    mdat_tail_ += box_sz;
  }
  queue_.Trim(std::min(mdat_tail_, upper_bound));
  return !err;
}

void MP4StreamParser::ChangeState(State new_state) {
  DVLOG(2) << "Changing state: " << new_state;
  state_ = new_state;
}

bool MP4StreamParser::HaveEnoughDataToEnqueueSamples() {
  DCHECK_EQ(state_, kWaitingForSampleData);
  // For muxed content, make sure we have data up to |highest_end_offset_|
  // so we can ensure proper enqueuing behavior. Otherwise assume we have enough
  // data and allow per sample offset checks to meter sample enqueuing.
  // TODO(acolwell): Fix trun box handling so we don't have to special case
  // muxed content.
  return !(has_audio_ && has_video_ &&
           queue_.tail() < highest_end_offset_ + moof_head_);
}

bool MP4StreamParser::ComputeHighestEndOffset(const MovieFragment& moof) {
  highest_end_offset_ = 0;

  TrackRunIterator runs(moov_.get(), media_log_);
  RCHECK(runs.Init(moof));

  while (runs.IsRunValid()) {
    int64_t aux_info_end_offset = runs.aux_info_offset() + runs.aux_info_size();
    if (aux_info_end_offset > highest_end_offset_)
      highest_end_offset_ = aux_info_end_offset;

    while (runs.IsSampleValid()) {
      int64_t sample_end_offset = runs.sample_offset() + runs.sample_size();
      if (sample_end_offset > highest_end_offset_)
        highest_end_offset_ = sample_end_offset;

      runs.AdvanceSample();
    }
    runs.AdvanceRun();
  }

  return true;
}

}  // namespace mp4
}  // namespace media