/*
 *  Copyright (c) 2019 The WebRTC project authors. All Rights Reserved.
 *
 *  Use of this source code is governed by a BSD-style license
 *  that can be found in the LICENSE file in the root of the source
 *  tree. An additional intellectual property rights grant can be found
 *  in the file PATENTS.  All contributing project authors may
 *  be found in the AUTHORS file in the root of the source tree.
 */

#include "test/pc/e2e/analyzer/video/quality_analyzing_video_encoder.h"

#include <cmath>
#include <memory>
#include <utility>

#include "api/video/video_codec_type.h"
#include "api/video_codecs/video_encoder.h"
#include "modules/video_coding/include/video_error_codes.h"
#include "rtc_base/critical_section.h"
#include "rtc_base/logging.h"

namespace webrtc {
namespace webrtc_pc_e2e {
namespace {

constexpr size_t kMaxFrameInPipelineCount = 1000;
constexpr double kNoMultiplier = 1.0;
constexpr double kEps = 1e-6;

std::pair<uint32_t, uint32_t> GetMinMaxBitratesBps(const VideoCodec& codec,
                                                   size_t spatial_idx) {
  uint32_t min_bitrate = codec.minBitrate;
  uint32_t max_bitrate = codec.maxBitrate;
  if (spatial_idx < codec.numberOfSimulcastStreams &&
      codec.codecType != VideoCodecType::kVideoCodecVP9) {
    min_bitrate =
        std::max(min_bitrate, codec.simulcastStream[spatial_idx].minBitrate);
    max_bitrate =
        std::min(max_bitrate, codec.simulcastStream[spatial_idx].maxBitrate);
  }
  if (codec.codecType == VideoCodecType::kVideoCodecVP9 &&
      spatial_idx < codec.VP9().numberOfSpatialLayers) {
    min_bitrate =
        std::max(min_bitrate, codec.spatialLayers[spatial_idx].minBitrate);
    max_bitrate =
        std::min(max_bitrate, codec.spatialLayers[spatial_idx].maxBitrate);
  }
  RTC_DCHECK_GT(max_bitrate, min_bitrate);
  return {min_bitrate * 1000, max_bitrate * 1000};
}

}  // namespace

QualityAnalyzingVideoEncoder::QualityAnalyzingVideoEncoder(
    int id,
    std::unique_ptr<VideoEncoder> delegate,
    double bitrate_multiplier,
    std::map<std::string, absl::optional<int>> stream_required_spatial_index,
    EncodedImageDataInjector* injector,
    VideoQualityAnalyzerInterface* analyzer)
    : id_(id),
      delegate_(std::move(delegate)),
      bitrate_multiplier_(bitrate_multiplier),
      stream_required_spatial_index_(std::move(stream_required_spatial_index)),
      injector_(injector),
      analyzer_(analyzer),
      mode_(SimulcastMode::kNormal),
      delegate_callback_(nullptr) {}
QualityAnalyzingVideoEncoder::~QualityAnalyzingVideoEncoder() = default;

void QualityAnalyzingVideoEncoder::SetFecControllerOverride(
    FecControllerOverride* fec_controller_override) {
  // Ignored.
}

int32_t QualityAnalyzingVideoEncoder::InitEncode(
    const VideoCodec* codec_settings,
    const Settings& settings) {
  rtc::CritScope crit(&lock_);
  codec_settings_ = *codec_settings;
  mode_ = SimulcastMode::kNormal;
  if (codec_settings->codecType == kVideoCodecVP9) {
    if (codec_settings->VP9().numberOfSpatialLayers > 1) {
      switch (codec_settings->VP9().interLayerPred) {
        case InterLayerPredMode::kOn:
          mode_ = SimulcastMode::kSVC;
          break;
        case InterLayerPredMode::kOnKeyPic:
          mode_ = SimulcastMode::kKSVC;
          break;
        case InterLayerPredMode::kOff:
          mode_ = SimulcastMode::kSimulcast;
          break;
        default:
          RTC_NOTREACHED() << "Unknown codec_settings->VP9().interLayerPred";
          break;
      }
    }
  }
  if (codec_settings->numberOfSimulcastStreams > 1) {
    mode_ = SimulcastMode::kSimulcast;
  }
  return delegate_->InitEncode(codec_settings, settings);
}

int32_t QualityAnalyzingVideoEncoder::RegisterEncodeCompleteCallback(
    EncodedImageCallback* callback) {
  // We need to get a lock here because delegate_callback can be hypothetically
  // accessed from different thread (encoder one) concurrently.
  rtc::CritScope crit(&lock_);
  delegate_callback_ = callback;
  return delegate_->RegisterEncodeCompleteCallback(this);
}

int32_t QualityAnalyzingVideoEncoder::Release() {
  // Release encoder first. During release process it can still encode some
  // frames, so we don't take a lock to prevent deadlock.
  int32_t result = delegate_->Release();

  rtc::CritScope crit(&lock_);
  delegate_callback_ = nullptr;
  return result;
}

int32_t QualityAnalyzingVideoEncoder::Encode(
    const VideoFrame& frame,
    const std::vector<VideoFrameType>* frame_types) {
  {
    rtc::CritScope crit(&lock_);
    // Store id to be able to retrieve it in analyzing callback.
    timestamp_to_frame_id_list_.push_back({frame.timestamp(), frame.id()});
    // If this list is growing, it means that we are not receiving new encoded
    // images from encoder. So it should be a bug in setup on in the encoder.
    RTC_DCHECK_LT(timestamp_to_frame_id_list_.size(), kMaxFrameInPipelineCount);
  }
  analyzer_->OnFramePreEncode(frame);
  int32_t result = delegate_->Encode(frame, frame_types);
  if (result != WEBRTC_VIDEO_CODEC_OK) {
    // If origin encoder failed, then cleanup data for this frame.
    {
      rtc::CritScope crit(&lock_);
      // The timestamp-frame_id pair can be not the last one, so we need to
      // find it first and then remove. We will search from the end, because
      // usually it will be the last or close to the last one.
      auto it = timestamp_to_frame_id_list_.end();
      while (it != timestamp_to_frame_id_list_.begin()) {
        --it;
        if (it->first == frame.timestamp()) {
          timestamp_to_frame_id_list_.erase(it);
          break;
        }
      }
    }
    analyzer_->OnEncoderError(frame, result);
  }
  return result;
}

void QualityAnalyzingVideoEncoder::SetRates(
    const VideoEncoder::RateControlParameters& parameters) {
  RTC_DCHECK_GT(bitrate_multiplier_, 0.0);
  if (fabs(bitrate_multiplier_ - kNoMultiplier) < kEps) {
    {
      rtc::CritScope crit(&lock_);
      bitrate_allocation_ = parameters.bitrate;
    }
    return delegate_->SetRates(parameters);
  }

  // Simulating encoder overshooting target bitrate, by configuring actual
  // encoder too high. Take care not to adjust past limits of config,
  // otherwise encoders may crash on DCHECK.
  VideoBitrateAllocation multiplied_allocation;
  for (size_t si = 0; si < kMaxSpatialLayers; ++si) {
    const uint32_t spatial_layer_bitrate_bps =
        parameters.bitrate.GetSpatialLayerSum(si);
    if (spatial_layer_bitrate_bps == 0) {
      continue;
    }

    uint32_t min_bitrate_bps;
    uint32_t max_bitrate_bps;
    std::tie(min_bitrate_bps, max_bitrate_bps) =
        GetMinMaxBitratesBps(codec_settings_, si);
    double bitrate_multiplier = bitrate_multiplier_;
    const uint32_t corrected_bitrate = rtc::checked_cast<uint32_t>(
        bitrate_multiplier * spatial_layer_bitrate_bps);
    if (corrected_bitrate < min_bitrate_bps) {
      bitrate_multiplier = min_bitrate_bps / spatial_layer_bitrate_bps;
    } else if (corrected_bitrate > max_bitrate_bps) {
      bitrate_multiplier = max_bitrate_bps / spatial_layer_bitrate_bps;
    }

    for (size_t ti = 0; ti < kMaxTemporalStreams; ++ti) {
      if (parameters.bitrate.HasBitrate(si, ti)) {
        multiplied_allocation.SetBitrate(
            si, ti,
            rtc::checked_cast<uint32_t>(bitrate_multiplier *
                                        parameters.bitrate.GetBitrate(si, ti)));
      }
    }
  }

  RateControlParameters adjusted_params = parameters;
  adjusted_params.bitrate = multiplied_allocation;
  {
    rtc::CritScope crit(&lock_);
    bitrate_allocation_ = adjusted_params.bitrate;
  }
  return delegate_->SetRates(adjusted_params);
}

VideoEncoder::EncoderInfo QualityAnalyzingVideoEncoder::GetEncoderInfo() const {
  return delegate_->GetEncoderInfo();
}

// It is assumed, that encoded callback will be always invoked with encoded
// images that correspond to the frames in the same sequence, that frames
// arrived. In other words, assume we have frames F1, F2 and F3 and they have
// corresponding encoded images I1, I2 and I3. In such case if we will call
// encode first with F1, then with F2 and then with F3, then encoder callback
// will be called first with all spatial layers for F1 (I1), then F2 (I2) and
// then F3 (I3).
//
// Basing on it we will use a list of timestamp-frame_id pairs like this:
//  1. If current encoded image timestamp is equals to timestamp in the front
//     pair - pick frame id from that pair
//  2. If current encoded image timestamp isn't equals to timestamp in the front
//     pair - remove the front pair and got to the step 1.
EncodedImageCallback::Result QualityAnalyzingVideoEncoder::OnEncodedImage(
    const EncodedImage& encoded_image,
    const CodecSpecificInfo* codec_specific_info,
    const RTPFragmentationHeader* fragmentation) {
  uint16_t frame_id;
  bool discard = false;
  uint32_t target_encode_bitrate = 0;
  {
    rtc::CritScope crit(&lock_);
    std::pair<uint32_t, uint16_t> timestamp_frame_id;
    while (!timestamp_to_frame_id_list_.empty()) {
      timestamp_frame_id = timestamp_to_frame_id_list_.front();
      if (timestamp_frame_id.first == encoded_image.Timestamp()) {
        break;
      }
      timestamp_to_frame_id_list_.pop_front();
    }

    // After the loop the first element should point to current |encoded_image|
    // frame id. We don't remove it from the list, because there may be
    // multiple spatial layers for this frame, so encoder can produce more
    // encoded images with this timestamp. The first element will be removed
    // when the next frame would be encoded and EncodedImageCallback would be
    // called with the next timestamp.

    if (timestamp_to_frame_id_list_.empty()) {
      // Ensure, that we have info about this frame. It can happen that for some
      // reasons encoder response, that he failed to decode, when we were
      // posting frame to it, but then call the callback for this frame.
      RTC_LOG(LS_ERROR) << "QualityAnalyzingVideoEncoder::OnEncodedImage: No "
                           "frame id for encoded_image.Timestamp()="
                        << encoded_image.Timestamp();
      return EncodedImageCallback::Result(
          EncodedImageCallback::Result::Error::OK);
    }
    frame_id = timestamp_frame_id.second;

    discard = ShouldDiscard(frame_id, encoded_image);
    if (!discard) {
      target_encode_bitrate = bitrate_allocation_.GetSpatialLayerSum(
          encoded_image.SpatialIndex().value_or(0));
    }
  }

  if (!discard) {
    // Analyzer should see only encoded images, that weren't discarded. But all
    // not discarded layers have to be passed.
    VideoQualityAnalyzerInterface::EncoderStats stats;
    stats.target_encode_bitrate = target_encode_bitrate;
    analyzer_->OnFrameEncoded(frame_id, encoded_image, stats);
  }

  // Image data injector injects frame id and discard flag into provided
  // EncodedImage and returns the image with a) modified original buffer (in
  // such case the current owner of the buffer will be responsible for deleting
  // it) or b) a new buffer (in such case injector will be responsible for
  // deleting it).
  const EncodedImage& image =
      injector_->InjectData(frame_id, discard, encoded_image, id_);
  {
    rtc::CritScope crit(&lock_);
    RTC_DCHECK(delegate_callback_);
    return delegate_callback_->OnEncodedImage(image, codec_specific_info,
                                              fragmentation);
  }
}

void QualityAnalyzingVideoEncoder::OnDroppedFrame(
    EncodedImageCallback::DropReason reason) {
  rtc::CritScope crit(&lock_);
  analyzer_->OnFrameDropped(reason);
  RTC_DCHECK(delegate_callback_);
  delegate_callback_->OnDroppedFrame(reason);
}

bool QualityAnalyzingVideoEncoder::ShouldDiscard(
    uint16_t frame_id,
    const EncodedImage& encoded_image) {
  std::string stream_label = analyzer_->GetStreamLabel(frame_id);
  absl::optional<int> required_spatial_index =
      stream_required_spatial_index_[stream_label];
  if (required_spatial_index) {
    if (*required_spatial_index == kAnalyzeAnySpatialStream) {
      return false;
    }
    absl::optional<int> cur_spatial_index = encoded_image.SpatialIndex();
    if (!cur_spatial_index) {
      cur_spatial_index = 0;
    }
    RTC_CHECK(mode_ != SimulcastMode::kNormal)
        << "Analyzing encoder is in kNormal "
           "mode, but spatial layer/simulcast "
           "stream met.";
    if (mode_ == SimulcastMode::kSimulcast) {
      // In simulcast mode only encoded images with required spatial index are
      // interested, so all others have to be discarded.
      return *cur_spatial_index != *required_spatial_index;
    } else if (mode_ == SimulcastMode::kSVC) {
      // In SVC mode encoded images with spatial indexes that are equal or
      // less than required one are interesting, so all above have to be
      // discarded.
      return *cur_spatial_index > *required_spatial_index;
    } else if (mode_ == SimulcastMode::kKSVC) {
      // In KSVC mode for key frame encoded images with spatial indexes that
      // are equal or less than required one are interesting, so all above
      // have to be discarded. For other frames only required spatial index
      // is interesting, so all others have to be discarded.
      if (encoded_image._frameType == VideoFrameType::kVideoFrameKey) {
        return *cur_spatial_index > *required_spatial_index;
      } else {
        return *cur_spatial_index != *required_spatial_index;
      }
    } else {
      RTC_NOTREACHED() << "Unsupported encoder mode";
    }
  }
  return false;
}

QualityAnalyzingVideoEncoderFactory::QualityAnalyzingVideoEncoderFactory(
    std::unique_ptr<VideoEncoderFactory> delegate,
    double bitrate_multiplier,
    std::map<std::string, absl::optional<int>> stream_required_spatial_index,
    IdGenerator<int>* id_generator,
    EncodedImageDataInjector* injector,
    VideoQualityAnalyzerInterface* analyzer)
    : delegate_(std::move(delegate)),
      bitrate_multiplier_(bitrate_multiplier),
      stream_required_spatial_index_(std::move(stream_required_spatial_index)),
      id_generator_(id_generator),
      injector_(injector),
      analyzer_(analyzer) {}
QualityAnalyzingVideoEncoderFactory::~QualityAnalyzingVideoEncoderFactory() =
    default;

std::vector<SdpVideoFormat>
QualityAnalyzingVideoEncoderFactory::GetSupportedFormats() const {
  return delegate_->GetSupportedFormats();
}

VideoEncoderFactory::CodecInfo
QualityAnalyzingVideoEncoderFactory::QueryVideoEncoder(
    const SdpVideoFormat& format) const {
  return delegate_->QueryVideoEncoder(format);
}

std::unique_ptr<VideoEncoder>
QualityAnalyzingVideoEncoderFactory::CreateVideoEncoder(
    const SdpVideoFormat& format) {
  return std::make_unique<QualityAnalyzingVideoEncoder>(
      id_generator_->GetNextId(), delegate_->CreateVideoEncoder(format),
      bitrate_multiplier_, stream_required_spatial_index_, injector_,
      analyzer_);
}

}  // namespace webrtc_pc_e2e
}  // namespace webrtc