// Copyright 2017 Google LLC. All rights reserved.
//
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file or at
// https://developers.google.com/open-source/licenses/bsd

#include <packager/packager.h>

#include <algorithm>

#include <absl/strings/match.h>
#include <absl/strings/str_format.h>
#include <glog/logging.h>
#include <packager/app/job_manager.h>
#include <packager/app/muxer_factory.h>
#include <packager/app/packager_util.h>
#include <packager/app/single_thread_job_manager.h>
#include <packager/file/file.h>
#include <packager/hls/base/hls_notifier.h>
#include <packager/hls/base/simple_hls_notifier.h>
#include <packager/media/base/cc_stream_filter.h>
#include <packager/media/base/language_utils.h>
#include <packager/media/base/muxer.h>
#include <packager/media/base/muxer_util.h>
#include <packager/media/chunking/chunking_handler.h>
#include <packager/media/chunking/cue_alignment_handler.h>
#include <packager/media/chunking/text_chunker.h>
#include <packager/media/crypto/encryption_handler.h>
#include <packager/media/demuxer/demuxer.h>
#include <packager/media/event/muxer_listener_factory.h>
#include <packager/media/event/vod_media_info_dump_muxer_listener.h>
#include <packager/media/formats/ttml/ttml_to_mp4_handler.h>
#include <packager/media/formats/webvtt/text_padder.h>
#include <packager/media/formats/webvtt/webvtt_to_mp4_handler.h>
#include <packager/media/replicator/replicator.h>
#include <packager/media/trick_play/trick_play_handler.h>
#include <packager/mpd/base/media_info.pb.h>
#include <packager/mpd/base/simple_mpd_notifier.h>
#include <packager/status/status_macros.h>
#include <packager/version/version.h>
#include <chrono>
#include <optional>

namespace shaka {

// TODO(kqyang): Clean up namespaces.
using media::Demuxer;
using media::JobManager;
using media::KeySource;
using media::MuxerOptions;
using media::SingleThreadJobManager;
using media::SyncPointQueue;

namespace media {
namespace {

const char kMediaInfoSuffix[] = ".media_info";

const int64_t kDefaultTextZeroBiasMs = 10 * 60 * 1000;  // 10 minutes

MuxerListenerFactory::StreamData ToMuxerListenerData(
    const StreamDescriptor& stream) {
  MuxerListenerFactory::StreamData data;
  data.media_info_output = stream.output;

  data.hls_group_id = stream.hls_group_id;
  data.hls_name = stream.hls_name;
  data.hls_playlist_name = stream.hls_playlist_name;
  data.hls_iframe_playlist_name = stream.hls_iframe_playlist_name;
  data.hls_characteristics = stream.hls_characteristics;
  data.hls_only = stream.hls_only;

  data.dash_accessiblities = stream.dash_accessiblities;
  data.dash_roles = stream.dash_roles;
  data.dash_only = stream.dash_only;
  return data;
};

// TODO(rkuroiwa): Write TTML and WebVTT parser (demuxing) for a better check
// and for supporting live/segmenting (muxing).  With a demuxer and a muxer,
// CreateAllJobs() shouldn't treat text as a special case.
bool DetermineTextFileCodec(const std::string& file, std::string* out) {
  CHECK(out);

  std::string content;
  if (!File::ReadFileToString(file.c_str(), &content)) {
    LOG(ERROR) << "Failed to open file " << file
               << " to determine file format.";
    return false;
  }

  const uint8_t* content_data =
      reinterpret_cast<const uint8_t*>(content.data());
  MediaContainerName container_name =
      DetermineContainer(content_data, content.size());

  if (container_name == CONTAINER_WEBVTT) {
    *out = "wvtt";
    return true;
  }

  if (container_name == CONTAINER_TTML) {
    *out = "ttml";
    return true;
  }

  return false;
}

MediaContainerName GetOutputFormat(const StreamDescriptor& descriptor) {
  if (!descriptor.output_format.empty()) {
    MediaContainerName format =
        DetermineContainerFromFormatName(descriptor.output_format);
    if (format == CONTAINER_UNKNOWN) {
      LOG(ERROR) << "Unable to determine output format from '"
                 << descriptor.output_format << "'.";
    }
    return format;
  }

  std::optional<MediaContainerName> format_from_output;
  std::optional<MediaContainerName> format_from_segment;
  if (!descriptor.output.empty()) {
    format_from_output = DetermineContainerFromFileName(descriptor.output);
    if (format_from_output.value() == CONTAINER_UNKNOWN) {
      LOG(ERROR) << "Unable to determine output format from '"
                 << descriptor.output << "'.";
    }
  }
  if (!descriptor.segment_template.empty()) {
    format_from_segment =
        DetermineContainerFromFileName(descriptor.segment_template);
    if (format_from_segment.value() == CONTAINER_UNKNOWN) {
      LOG(ERROR) << "Unable to determine output format from '"
                 << descriptor.segment_template << "'.";
    }
  }

  if (format_from_output && format_from_segment) {
    if (format_from_output.value() != format_from_segment.value()) {
      LOG(ERROR) << "Output format determined from '" << descriptor.output
                 << "' differs from output format determined from '"
                 << descriptor.segment_template << "'.";
      return CONTAINER_UNKNOWN;
    }
  }

  if (format_from_output)
    return format_from_output.value();
  if (format_from_segment)
    return format_from_segment.value();
  return CONTAINER_UNKNOWN;
}

MediaContainerName GetTextOutputCodec(const StreamDescriptor& descriptor) {
  const auto output_container = GetOutputFormat(descriptor);
  if (output_container != CONTAINER_MOV)
    return output_container;

  const auto input_container = DetermineContainerFromFileName(descriptor.input);
  if (absl::AsciiStrToLower(descriptor.output_format) == "vtt+mp4" ||
      absl::AsciiStrToLower(descriptor.output_format) == "webvtt+mp4") {
    return CONTAINER_WEBVTT;
  } else if (absl::AsciiStrToLower(descriptor.output_format) != "ttml+mp4" &&
             input_container == CONTAINER_WEBVTT) {
    // With WebVTT input, default to WebVTT output.
    return CONTAINER_WEBVTT;
  } else {
    // Otherwise default to TTML since it has more features.
    return CONTAINER_TTML;
  }
}

bool IsTextStream(const StreamDescriptor& stream) {
  if (stream.stream_selector == "text")
    return true;
  if (absl::AsciiStrToLower(stream.output_format) == "vtt+mp4" ||
      absl::AsciiStrToLower(stream.output_format) == "webvtt+mp4" ||
      absl::AsciiStrToLower(stream.output_format) == "ttml+mp4") {
    return true;
  }

  auto output_format = GetOutputFormat(stream);
  return output_format == CONTAINER_WEBVTT || output_format == CONTAINER_TTML;
}

Status ValidateStreamDescriptor(bool dump_stream_info,
                                const StreamDescriptor& stream) {
  if (stream.input.empty()) {
    return Status(error::INVALID_ARGUMENT, "Stream input not specified.");
  }

  // The only time a stream can have no outputs, is when dump stream info is
  // set.
  if (dump_stream_info && stream.output.empty() &&
      stream.segment_template.empty()) {
    return Status::OK;
  }

  if (stream.output.empty() && stream.segment_template.empty()) {
    return Status(error::INVALID_ARGUMENT,
                  "Streams must specify 'output' or 'segment template'.");
  }

  // Whenever there is output, a stream must be selected.
  if (stream.stream_selector.empty()) {
    return Status(error::INVALID_ARGUMENT,
                  "Stream stream_selector not specified.");
  }

  // If a segment template is provided, it must be valid.
  if (stream.segment_template.length()) {
    RETURN_IF_ERROR(ValidateSegmentTemplate(stream.segment_template));
  }

  // There are some specifics that must be checked based on which format
  // we are writing to.
  const MediaContainerName output_format = GetOutputFormat(stream);

  if (output_format == CONTAINER_UNKNOWN) {
    return Status(error::INVALID_ARGUMENT, "Unsupported output format.");
  }
  if (output_format == MediaContainerName::CONTAINER_MPEG2TS) {
    if (stream.segment_template.empty()) {
      return Status(
          error::INVALID_ARGUMENT,
          "Please specify 'segment_template'. Single file TS output is "
          "not supported.");
    }

    // Right now the init segment is saved in |output| for multi-segment
    // content. However, for TS all segments must be self-initializing so
    // there cannot be an init segment.
    if (stream.output.length()) {
      return Status(error::INVALID_ARGUMENT,
                    "All TS segments must be self-initializing. Stream "
                    "descriptors 'output' or 'init_segment' are not allowed.");
    }
  } else if (output_format == CONTAINER_WEBVTT ||
             output_format == CONTAINER_TTML ||
             output_format == CONTAINER_AAC || output_format == CONTAINER_MP3 ||
             output_format == CONTAINER_AC3 ||
             output_format == CONTAINER_EAC3) {
    // There is no need for an init segment when outputting because there is no
    // initialization data.
    if (stream.segment_template.length() && stream.output.length()) {
      return Status(
          error::INVALID_ARGUMENT,
          "Segmented subtitles or PackedAudio output cannot have an init "
          "segment.  Do not specify stream descriptors 'output' or "
          "'init_segment' when using 'segment_template'.");
    }
  } else {
    // For any other format, if there is a segment template, there must be an
    // init segment provided.
    if (stream.segment_template.length() && stream.output.empty()) {
      return Status(error::INVALID_ARGUMENT,
                    "Please specify 'init_segment'. All non-TS multi-segment "
                    "content must provide an init segment.");
    }
  }

  if (stream.output.find('$') != std::string::npos) {
    if (output_format == CONTAINER_WEBVTT) {
      return Status(
          error::UNIMPLEMENTED,
          "WebVTT output with one file per Representation per Period "
          "is not supported yet. Please use fMP4 instead. If that needs to be "
          "supported, please file a feature request on GitHub.");
    }
    // "$" is only allowed if the output file name is a template, which is
    // used to support one file per Representation per Period when there are
    // Ad Cues.
    RETURN_IF_ERROR(ValidateSegmentTemplate(stream.output));
  }

  return Status::OK;
}

Status ValidateParams(const PackagingParams& packaging_params,
                      const std::vector<StreamDescriptor>& stream_descriptors) {
  if (!packaging_params.chunking_params.segment_sap_aligned &&
      packaging_params.chunking_params.subsegment_sap_aligned) {
    return Status(error::INVALID_ARGUMENT,
                  "Setting segment_sap_aligned to false but "
                  "subsegment_sap_aligned to true is not allowed.");
  }

  if (stream_descriptors.empty()) {
    return Status(error::INVALID_ARGUMENT,
                  "Stream descriptors cannot be empty.");
  }

  // On demand profile generates single file segment while live profile
  // generates multiple segments specified using segment template.
  const bool on_demand_dash_profile =
      stream_descriptors.begin()->segment_template.empty();
  std::set<std::string> outputs;
  std::set<std::string> segment_templates;
  for (const auto& descriptor : stream_descriptors) {
    if (on_demand_dash_profile != descriptor.segment_template.empty()) {
      return Status(error::INVALID_ARGUMENT,
                    "Inconsistent stream descriptor specification: "
                    "segment_template should be specified for none or all "
                    "stream descriptors.");
    }

    RETURN_IF_ERROR(ValidateStreamDescriptor(
        packaging_params.test_params.dump_stream_info, descriptor));

    if (absl::StartsWith(descriptor.input, "udp://")) {
      const HlsParams& hls_params = packaging_params.hls_params;
      if (!hls_params.master_playlist_output.empty() &&
          hls_params.playlist_type == HlsPlaylistType::kVod) {
        LOG(WARNING)
            << "Seeing UDP input with HLS Playlist Type set to VOD. The "
               "playlists will only be generated when UDP socket is closed. "
               "If you want to do live packaging, --hls_playlist_type needs to "
               "be set to LIVE.";
      }
      // Skip the check for DASH as DASH defaults to 'dynamic' MPD when segment
      // template is provided.
    }

    if (!descriptor.output.empty()) {
      if (outputs.find(descriptor.output) != outputs.end()) {
        return Status(
            error::INVALID_ARGUMENT,
            "Seeing duplicated outputs '" + descriptor.output +
                "' in stream descriptors. Every output must be unique.");
      }
      outputs.insert(descriptor.output);
    }
    if (!descriptor.segment_template.empty()) {
      if (segment_templates.find(descriptor.segment_template) !=
          segment_templates.end()) {
        return Status(error::INVALID_ARGUMENT,
                      "Seeing duplicated segment templates '" +
                          descriptor.segment_template +
                          "' in stream descriptors. Every segment template "
                          "must be unique.");
      }
      segment_templates.insert(descriptor.segment_template);
    }
  }

  if (packaging_params.output_media_info && !on_demand_dash_profile) {
    // TODO(rkuroiwa, kqyang): Support partial media info dump for live.
    return Status(error::UNIMPLEMENTED,
                  "--output_media_info is only supported for on-demand profile "
                  "(not using segment_template).");
  }

  if (on_demand_dash_profile &&
      !packaging_params.mpd_params.mpd_output.empty() &&
      !packaging_params.mp4_output_params.generate_sidx_in_media_segments &&
      !packaging_params.mpd_params.use_segment_list) {
    return Status(error::UNIMPLEMENTED,
                  "--generate_sidx_in_media_segments is required for DASH "
                  "on-demand profile (not using segment_template or segment list).");
  }

  if (packaging_params.chunking_params.low_latency_dash_mode &&
      packaging_params.chunking_params.subsegment_duration_in_seconds) {
    // Low latency streaming requires data to be shipped as chunks,
    // the smallest unit of video. Right now, each chunk contains
    // one frame. Therefore, in low latency mode,
    // a user specified --fragment_duration is irrelevant.
    // TODO(caitlinocallaghan): Add a feature for users to specify the number
    // of desired frames per chunk.
    return Status(error::INVALID_ARGUMENT,
                  "--fragment_duration cannot be set "
                  "if --low_latency_dash_mode is enabled.");
  }

  if (packaging_params.mpd_params.low_latency_dash_mode &&
      packaging_params.mpd_params.utc_timings.empty()) {
    // Low latency DASH MPD requires a UTC Timing value
    return Status(error::INVALID_ARGUMENT,
                  "--utc_timings must be be set "
                  "if --low_latency_dash_mode is enabled.");
  }

  return Status::OK;
}

bool StreamDescriptorCompareFn(const StreamDescriptor& a,
                               const StreamDescriptor& b) {
  // This function is used by std::sort() to sort the stream descriptors.
  // Note that std::sort() need a comparator that return true iff the first
  // argument is strictly lower than the second one. That is: must return false
  // when they are equal. The requirement is enforced in gcc/g++ but not in
  // clang.
  if (a.input == b.input) {
    if (a.stream_selector == b.stream_selector) {
      // The MPD notifier requires that the main track comes first, so make
      // sure that happens.
      return a.trick_play_factor < b.trick_play_factor;
    }
    return a.stream_selector < b.stream_selector;
  }

  return a.input < b.input;
}

// A fake clock that always return time 0 (epoch). Should only be used for
// testing.
class FakeClock : public Clock {
 public:
  time_point now() noexcept override {
    return std::chrono::system_clock::time_point(std::chrono::seconds(0));
  }
};

bool StreamInfoToTextMediaInfo(const StreamDescriptor& stream_descriptor,
                               MediaInfo* text_media_info) {
  std::string codec;
  if (!DetermineTextFileCodec(stream_descriptor.input, &codec)) {
    LOG(ERROR) << "Failed to determine the text file format for "
               << stream_descriptor.input;
    return false;
  }

  MediaInfo::TextInfo* text_info = text_media_info->mutable_text_info();
  text_info->set_codec(codec);

  const std::string& language = stream_descriptor.language;
  if (!language.empty()) {
    text_info->set_language(language);
  }

  text_media_info->set_media_file_name(stream_descriptor.output);
  text_media_info->set_container_type(MediaInfo::CONTAINER_TEXT);

  if (stream_descriptor.bandwidth != 0) {
    text_media_info->set_bandwidth(stream_descriptor.bandwidth);
  } else {
    // Text files are usually small and since the input is one file; there's no
    // way for the player to do ranged requests. So set this value to something
    // reasonable.
    const int kDefaultTextBandwidth = 256;
    text_media_info->set_bandwidth(kDefaultTextBandwidth);
  }

  if (!stream_descriptor.dash_roles.empty()) {
    for (const auto& dash_role : stream_descriptor.dash_roles) {
      text_media_info->add_dash_roles(dash_role);
    }
  }

  return true;
}

/// Create a new demuxer handler for the given stream. If a demuxer cannot be
/// created, an error will be returned. If a demuxer can be created, this
/// |new_demuxer| will be set and Status::OK will be returned.
Status CreateDemuxer(const StreamDescriptor& stream,
                     const PackagingParams& packaging_params,
                     std::shared_ptr<Demuxer>* new_demuxer) {
  std::shared_ptr<Demuxer> demuxer = std::make_shared<Demuxer>(stream.input);
  demuxer->set_dump_stream_info(packaging_params.test_params.dump_stream_info);

  if (packaging_params.decryption_params.key_provider != KeyProvider::kNone) {
    std::unique_ptr<KeySource> decryption_key_source(
        CreateDecryptionKeySource(packaging_params.decryption_params));
    if (!decryption_key_source) {
      return Status(
          error::INVALID_ARGUMENT,
          "Must define decryption key source when defining key provider");
    }
    demuxer->SetKeySource(std::move(decryption_key_source));
  }

  *new_demuxer = std::move(demuxer);
  return Status::OK;
}

std::shared_ptr<MediaHandler> CreateEncryptionHandler(
    const PackagingParams& packaging_params,
    const StreamDescriptor& stream,
    KeySource* key_source) {
  if (stream.skip_encryption) {
    return nullptr;
  }

  if (!key_source) {
    return nullptr;
  }

  // Make a copy so that we can modify it for this specific stream.
  EncryptionParams encryption_params = packaging_params.encryption_params;

  // Use Sample AES in MPEG2TS.
  // TODO(kqyang): Consider adding a new flag to enable Sample AES as we
  // will support CENC in TS in the future.
  if (GetOutputFormat(stream) == CONTAINER_MPEG2TS ||
      GetOutputFormat(stream) == CONTAINER_AAC ||
      GetOutputFormat(stream) == CONTAINER_AC3 ||
      GetOutputFormat(stream) == CONTAINER_EAC3) {
    VLOG(1) << "Use Apple Sample AES encryption for MPEG2TS or Packed Audio.";
    encryption_params.protection_scheme = kAppleSampleAesProtectionScheme;
  }

  if (!stream.drm_label.empty()) {
    const std::string& drm_label = stream.drm_label;
    encryption_params.stream_label_func =
        [drm_label](const EncryptionParams::EncryptedStreamAttributes&) {
          return drm_label;
        };
  } else if (!encryption_params.stream_label_func) {
    const int kDefaultMaxSdPixels = 768 * 576;
    const int kDefaultMaxHdPixels = 1920 * 1080;
    const int kDefaultMaxUhd1Pixels = 4096 * 2160;
    encryption_params.stream_label_func = std::bind(
        &Packager::DefaultStreamLabelFunction, kDefaultMaxSdPixels,
        kDefaultMaxHdPixels, kDefaultMaxUhd1Pixels, std::placeholders::_1);
  }

  return std::make_shared<EncryptionHandler>(encryption_params, key_source);
}

std::unique_ptr<MediaHandler> CreateTextChunker(
    const ChunkingParams& chunking_params) {
  const float segment_length_in_seconds =
      chunking_params.segment_duration_in_seconds;
  return std::unique_ptr<MediaHandler>(
      new TextChunker(segment_length_in_seconds));
}

Status CreateTtmlJobs(
    const std::vector<std::reference_wrapper<const StreamDescriptor>>& streams,
    const PackagingParams& packaging_params,
    SyncPointQueue* sync_points,
    MuxerFactory* muxer_factory,
    MpdNotifier* mpd_notifier,
    JobManager* job_manager) {
  DCHECK(job_manager);
  for (const StreamDescriptor& stream : streams) {
    // Check input to ensure that output is possible.
    if (!packaging_params.hls_params.master_playlist_output.empty() &&
        !stream.dash_only) {
      return Status(error::INVALID_ARGUMENT,
                    "HLS does not support TTML in xml format.");
    }

    if (!stream.segment_template.empty()) {
      return Status(error::INVALID_ARGUMENT,
                    "Segmented TTML is not supported.");
    }

    if (GetOutputFormat(stream) != CONTAINER_TTML) {
      return Status(error::INVALID_ARGUMENT,
                    "Converting TTML to other formats is not supported");
    }

    if (!stream.output.empty()) {
      if (!File::Copy(stream.input.c_str(), stream.output.c_str())) {
        std::string error;
        absl::StrAppendFormat(
            &error, "Failed to copy the input file (%s) to output file (%s).",
            stream.input.c_str(), stream.output.c_str());
        return Status(error::FILE_FAILURE, error);
      }

      MediaInfo text_media_info;
      if (!StreamInfoToTextMediaInfo(stream, &text_media_info)) {
        return Status(error::INVALID_ARGUMENT,
                      "Could not create media info for stream.");
      }

      // If we are outputting to MPD, just add the input to the outputted
      // manifest.
      if (mpd_notifier) {
        uint32_t unused;
        if (mpd_notifier->NotifyNewContainer(text_media_info, &unused)) {
          mpd_notifier->Flush();
        } else {
          return Status(error::PARSER_FAILURE,
                        "Failed to process text file " + stream.input);
        }
      }

      if (packaging_params.output_media_info) {
        VodMediaInfoDumpMuxerListener::WriteMediaInfoToFile(
            text_media_info, stream.output + kMediaInfoSuffix);
      }
    }
  }

  return Status::OK;
}

Status CreateAudioVideoJobs(
    const std::vector<std::reference_wrapper<const StreamDescriptor>>& streams,
    const PackagingParams& packaging_params,
    KeySource* encryption_key_source,
    SyncPointQueue* sync_points,
    MuxerListenerFactory* muxer_listener_factory,
    MuxerFactory* muxer_factory,
    JobManager* job_manager) {
  DCHECK(muxer_listener_factory);
  DCHECK(muxer_factory);
  DCHECK(job_manager);
  // Store all the demuxers in a map so that we can look up a stream's demuxer.
  // This is step one in making this part of the pipeline less dependant on
  // order.
  std::map<std::string, std::shared_ptr<Demuxer>> sources;
  std::map<std::string, std::shared_ptr<MediaHandler>> cue_aligners;

  for (const StreamDescriptor& stream : streams) {
    bool seen_input_before = sources.find(stream.input) != sources.end();
    if (seen_input_before) {
      continue;
    }

    RETURN_IF_ERROR(
        CreateDemuxer(stream, packaging_params, &sources[stream.input]));
    cue_aligners[stream.input] =
        sync_points ? std::make_shared<CueAlignmentHandler>(sync_points)
                    : nullptr;
  }

  for (auto& source : sources) {
    job_manager->Add("RemuxJob", source.second);
  }

  // Replicators are shared among all streams with the same input and stream
  // selector.
  std::shared_ptr<MediaHandler> replicator;

  std::string previous_input;
  std::string previous_selector;

  for (const StreamDescriptor& stream : streams) {
    // Get the demuxer for this stream.
    auto& demuxer = sources[stream.input];
    auto& cue_aligner = cue_aligners[stream.input];

    const bool new_input_file = stream.input != previous_input;
    const bool new_stream =
        new_input_file || previous_selector != stream.stream_selector;
    const bool is_text = IsTextStream(stream);
    previous_input = stream.input;
    previous_selector = stream.stream_selector;

    // If the stream has no output, then there is no reason setting-up the rest
    // of the pipeline.
    if (stream.output.empty() && stream.segment_template.empty()) {
      continue;
    }

    // Just because it is a different stream descriptor does not mean it is a
    // new stream. Multiple stream descriptors may have the same stream but
    // only differ by trick play factor.
    if (new_stream) {
      if (!stream.language.empty()) {
        demuxer->SetLanguageOverride(stream.stream_selector, stream.language);
      }

      std::vector<std::shared_ptr<MediaHandler>> handlers;
      if (is_text) {
        handlers.emplace_back(
            std::make_shared<TextPadder>(kDefaultTextZeroBiasMs));
      }
      if (sync_points) {
        handlers.emplace_back(cue_aligner);
      }
      if (!is_text) {
        handlers.emplace_back(std::make_shared<ChunkingHandler>(
            packaging_params.chunking_params));
        handlers.emplace_back(CreateEncryptionHandler(packaging_params, stream,
                                                      encryption_key_source));
      }

      replicator = std::make_shared<Replicator>();
      handlers.emplace_back(replicator);

      RETURN_IF_ERROR(MediaHandler::Chain(handlers));
      RETURN_IF_ERROR(demuxer->SetHandler(stream.stream_selector, handlers[0]));
    }

    // Create the muxer (output) for this track.
    const auto output_format = GetOutputFormat(stream);
    std::shared_ptr<Muxer> muxer =
        muxer_factory->CreateMuxer(output_format, stream);
    if (!muxer) {
      return Status(error::INVALID_ARGUMENT, "Failed to create muxer for " +
                                                 stream.input + ":" +
                                                 stream.stream_selector);
    }

    std::unique_ptr<MuxerListener> muxer_listener =
        muxer_listener_factory->CreateListener(ToMuxerListenerData(stream));
    muxer->SetMuxerListener(std::move(muxer_listener));

    std::vector<std::shared_ptr<MediaHandler>> handlers;
    handlers.emplace_back(replicator);

    // Trick play is optional.
    if (stream.trick_play_factor) {
      handlers.emplace_back(
          std::make_shared<TrickPlayHandler>(stream.trick_play_factor));
    }

    if (stream.cc_index >= 0) {
      handlers.emplace_back(
          std::make_shared<CcStreamFilter>(stream.language, stream.cc_index));
    }

    if (is_text &&
        (!stream.segment_template.empty() || output_format == CONTAINER_MOV)) {
      handlers.emplace_back(
          CreateTextChunker(packaging_params.chunking_params));
    }

    if (is_text && output_format == CONTAINER_MOV) {
      const auto output_codec = GetTextOutputCodec(stream);
      if (output_codec == CONTAINER_WEBVTT) {
        handlers.emplace_back(std::make_shared<WebVttToMp4Handler>());
      } else if (output_codec == CONTAINER_TTML) {
        handlers.emplace_back(std::make_shared<ttml::TtmlToMp4Handler>());
      }
    }

    handlers.emplace_back(muxer);
    RETURN_IF_ERROR(MediaHandler::Chain(handlers));
  }

  return Status::OK;
}

Status CreateAllJobs(const std::vector<StreamDescriptor>& stream_descriptors,
                     const PackagingParams& packaging_params,
                     MpdNotifier* mpd_notifier,
                     KeySource* encryption_key_source,
                     SyncPointQueue* sync_points,
                     MuxerListenerFactory* muxer_listener_factory,
                     MuxerFactory* muxer_factory,
                     JobManager* job_manager) {
  DCHECK(muxer_factory);
  DCHECK(muxer_listener_factory);
  DCHECK(job_manager);

  // Group all streams based on which pipeline they will use.
  std::vector<std::reference_wrapper<const StreamDescriptor>> ttml_streams;
  std::vector<std::reference_wrapper<const StreamDescriptor>>
      audio_video_streams;

  bool has_transport_audio_video_streams = false;
  bool has_non_transport_audio_video_streams = false;

  for (const StreamDescriptor& stream : stream_descriptors) {
    const auto input_container = DetermineContainerFromFileName(stream.input);
    const auto output_format = GetOutputFormat(stream);
    if (input_container == CONTAINER_TTML) {
      ttml_streams.push_back(stream);
    } else {
      audio_video_streams.push_back(stream);
      switch (output_format) {
        case CONTAINER_MPEG2TS:
        case CONTAINER_AAC:
        case CONTAINER_MP3:
        case CONTAINER_AC3:
        case CONTAINER_EAC3:
          has_transport_audio_video_streams = true;
          break;
        case CONTAINER_TTML:
        case CONTAINER_WEBVTT:
          break;
        default:
          has_non_transport_audio_video_streams = true;
          break;
      }
    }
  }

  // Audio/Video streams need to be in sorted order so that demuxers and trick
  // play handlers get setup correctly.
  std::sort(audio_video_streams.begin(), audio_video_streams.end(),
            media::StreamDescriptorCompareFn);

  if (packaging_params.transport_stream_timestamp_offset_ms > 0) {
    if (has_transport_audio_video_streams &&
        has_non_transport_audio_video_streams) {
      LOG(WARNING) << "There may be problems mixing transport streams and "
                      "non-transport streams. For example, the subtitles may "
                      "be out of sync with non-transport streams.";
    } else if (has_non_transport_audio_video_streams) {
      // Don't insert the X-TIMESTAMP-MAP in WebVTT if there is no transport
      // stream.
      muxer_factory->SetTsStreamOffset(0);
    }
  }

  RETURN_IF_ERROR(CreateTtmlJobs(ttml_streams, packaging_params, sync_points,
                                 muxer_factory, mpd_notifier, job_manager));
  RETURN_IF_ERROR(CreateAudioVideoJobs(
      audio_video_streams, packaging_params, encryption_key_source, sync_points,
      muxer_listener_factory, muxer_factory, job_manager));

  // Initialize processing graph.
  return job_manager->InitializeJobs();
}

}  // namespace
}  // namespace media

struct Packager::PackagerInternal {
  media::FakeClock fake_clock;
  std::unique_ptr<KeySource> encryption_key_source;
  std::unique_ptr<MpdNotifier> mpd_notifier;
  std::unique_ptr<hls::HlsNotifier> hls_notifier;
  BufferCallbackParams buffer_callback_params;
  std::unique_ptr<media::JobManager> job_manager;
};

Packager::Packager() {}

Packager::~Packager() {}

Status Packager::Initialize(
    const PackagingParams& packaging_params,
    const std::vector<StreamDescriptor>& stream_descriptors) {
  if (internal_)
    return Status(error::INVALID_ARGUMENT, "Already initialized.");

  RETURN_IF_ERROR(media::ValidateParams(packaging_params, stream_descriptors));

  if (!packaging_params.test_params.injected_library_version.empty()) {
    SetPackagerVersionForTesting(
        packaging_params.test_params.injected_library_version);
  }

  std::unique_ptr<PackagerInternal> internal(new PackagerInternal);

  // Create encryption key source if needed.
  if (packaging_params.encryption_params.key_provider != KeyProvider::kNone) {
    internal->encryption_key_source = CreateEncryptionKeySource(
        static_cast<media::FourCC>(
            packaging_params.encryption_params.protection_scheme),
        packaging_params.encryption_params);
    if (!internal->encryption_key_source)
      return Status(error::INVALID_ARGUMENT, "Failed to create key source.");
  }

  // Update MPD output and HLS output if needed.
  MpdParams mpd_params = packaging_params.mpd_params;
  HlsParams hls_params = packaging_params.hls_params;

  // |target_segment_duration| is needed for bandwidth estimation and also for
  // DASH approximate segment timeline.
  const double target_segment_duration =
      packaging_params.chunking_params.segment_duration_in_seconds;
  mpd_params.target_segment_duration = target_segment_duration;
  hls_params.target_segment_duration = target_segment_duration;

  // Store callback params to make it available during packaging.
  internal->buffer_callback_params = packaging_params.buffer_callback_params;
  if (internal->buffer_callback_params.write_func) {
    mpd_params.mpd_output = File::MakeCallbackFileName(
        internal->buffer_callback_params, mpd_params.mpd_output);
    hls_params.master_playlist_output = File::MakeCallbackFileName(
        internal->buffer_callback_params, hls_params.master_playlist_output);
  }

  // Both DASH and HLS require language to follow RFC5646
  // (https://tools.ietf.org/html/rfc5646), which requires the language to be
  // in the shortest form.
  mpd_params.default_language =
      LanguageToShortestForm(mpd_params.default_language);
  mpd_params.default_text_language =
      LanguageToShortestForm(mpd_params.default_text_language);
  hls_params.default_language =
      LanguageToShortestForm(hls_params.default_language);
  hls_params.default_text_language =
      LanguageToShortestForm(hls_params.default_text_language);
  hls_params.is_independent_segments =
      packaging_params.chunking_params.segment_sap_aligned;

  if (!mpd_params.mpd_output.empty()) {
    const bool on_demand_dash_profile =
        stream_descriptors.begin()->segment_template.empty();
    const MpdOptions mpd_options =
        media::GetMpdOptions(on_demand_dash_profile, mpd_params);
    internal->mpd_notifier.reset(new SimpleMpdNotifier(mpd_options));
    if (!internal->mpd_notifier->Init()) {
      LOG(ERROR) << "MpdNotifier failed to initialize.";
      return Status(error::INVALID_ARGUMENT,
                    "Failed to initialize MpdNotifier.");
    }
  }

  if (!hls_params.master_playlist_output.empty()) {
    internal->hls_notifier.reset(new hls::SimpleHlsNotifier(hls_params));
  }

  std::unique_ptr<SyncPointQueue> sync_points;
  if (!packaging_params.ad_cue_generator_params.cue_points.empty()) {
    sync_points.reset(
        new SyncPointQueue(packaging_params.ad_cue_generator_params));
  }
  if (packaging_params.single_threaded) {
    internal->job_manager.reset(
        new SingleThreadJobManager(std::move(sync_points)));
  } else {
    internal->job_manager.reset(new JobManager(std::move(sync_points)));
  }

  std::vector<StreamDescriptor> streams_for_jobs;

  for (const StreamDescriptor& descriptor : stream_descriptors) {
    // We may need to overwrite some values, so make a copy first.
    StreamDescriptor copy = descriptor;

    if (internal->buffer_callback_params.read_func) {
      copy.input = File::MakeCallbackFileName(internal->buffer_callback_params,
                                              descriptor.input);
    }

    if (internal->buffer_callback_params.write_func) {
      copy.output = File::MakeCallbackFileName(internal->buffer_callback_params,
                                               descriptor.output);
      copy.segment_template = File::MakeCallbackFileName(
          internal->buffer_callback_params, descriptor.segment_template);
    }

    // Update language to ISO_639_2 code if set.
    if (!copy.language.empty()) {
      copy.language = LanguageToISO_639_2(descriptor.language);
      if (copy.language == "und") {
        return Status(
            error::INVALID_ARGUMENT,
            "Unknown/invalid language specified: " + descriptor.language);
      }
    }

    streams_for_jobs.push_back(copy);
  }

  media::MuxerFactory muxer_factory(packaging_params);
  if (packaging_params.test_params.inject_fake_clock) {
    muxer_factory.OverrideClock(&internal->fake_clock);
  }

  media::MuxerListenerFactory muxer_listener_factory(
      packaging_params.output_media_info,
      packaging_params.mpd_params.use_segment_list,
      internal->mpd_notifier.get(), internal->hls_notifier.get());

  RETURN_IF_ERROR(media::CreateAllJobs(
      streams_for_jobs, packaging_params, internal->mpd_notifier.get(),
      internal->encryption_key_source.get(),
      internal->job_manager->sync_points(), &muxer_listener_factory,
      &muxer_factory, internal->job_manager.get()));

  internal_ = std::move(internal);
  return Status::OK;
}

Status Packager::Run() {
  if (!internal_)
    return Status(error::INVALID_ARGUMENT, "Not yet initialized.");

  RETURN_IF_ERROR(internal_->job_manager->RunJobs());

  if (internal_->hls_notifier) {
    if (!internal_->hls_notifier->Flush())
      return Status(error::INVALID_ARGUMENT, "Failed to flush Hls.");
  }
  if (internal_->mpd_notifier) {
    if (!internal_->mpd_notifier->Flush())
      return Status(error::INVALID_ARGUMENT, "Failed to flush Mpd.");
  }
  return Status::OK;
}

void Packager::Cancel() {
  if (!internal_) {
    LOG(INFO) << "Not yet initialized. Return directly.";
    return;
  }
  internal_->job_manager->CancelJobs();
}

std::string Packager::GetLibraryVersion() {
  return GetPackagerVersion();
}

std::string Packager::DefaultStreamLabelFunction(
    int max_sd_pixels,
    int max_hd_pixels,
    int max_uhd1_pixels,
    const EncryptionParams::EncryptedStreamAttributes& stream_attributes) {
  if (stream_attributes.stream_type ==
      EncryptionParams::EncryptedStreamAttributes::kAudio)
    return "AUDIO";
  if (stream_attributes.stream_type ==
      EncryptionParams::EncryptedStreamAttributes::kVideo) {
    const int pixels = stream_attributes.oneof.video.width *
                       stream_attributes.oneof.video.height;
    if (pixels <= max_sd_pixels)
      return "SD";
    if (pixels <= max_hd_pixels)
      return "HD";
    if (pixels <= max_uhd1_pixels)
      return "UHD1";
    return "UHD2";
  }
  return "";
}

}  // namespace shaka