/*
 *  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.
 */

#ifndef TEST_PC_E2E_ANALYZER_VIDEO_QUALITY_ANALYZING_VIDEO_ENCODER_H_
#define TEST_PC_E2E_ANALYZER_VIDEO_QUALITY_ANALYZING_VIDEO_ENCODER_H_

#include <list>
#include <memory>
#include <utility>
#include <vector>

#include "absl/strings/string_view.h"
#include "api/environment/environment.h"
#include "api/test/pclf/media_configuration.h"
#include "api/test/video_quality_analyzer_interface.h"
#include "api/video/video_frame.h"
#include "api/video_codecs/sdp_video_format.h"
#include "api/video_codecs/video_codec.h"
#include "api/video_codecs/video_encoder.h"
#include "api/video_codecs/video_encoder_factory.h"
#include "rtc_base/synchronization/mutex.h"
#include "test/pc/e2e/analyzer/video/encoded_image_data_injector.h"

namespace webrtc {
namespace webrtc_pc_e2e {

// QualityAnalyzingVideoEncoder is used to wrap origin video encoder and inject
// VideoQualityAnalyzerInterface before and after encoder.
//
// QualityAnalyzingVideoEncoder propagates all calls to the origin encoder.
// It registers its own EncodedImageCallback in the origin encoder and will
// store user specified callback inside itself.
//
// When Encode(...) will be invoked, quality encoder first calls video quality
// analyzer with original frame, then encodes frame with original encoder.
//
// When origin encoder encodes the image it will call quality encoder's special
// callback, where video analyzer will be called again and then frame id will be
// injected into EncodedImage with passed EncodedImageDataInjector. Then new
// EncodedImage will be passed to origin callback, provided by user.
//
// Quality encoder registers its own callback in origin encoder, at the same
// time the user registers their callback in quality encoder.
class QualityAnalyzingVideoEncoder : public VideoEncoder,
                                     public EncodedImageCallback {
 public:
  using EmulatedSFUConfigMap =
      std::map<std::string, absl::optional<EmulatedSFUConfig>>;

  QualityAnalyzingVideoEncoder(absl::string_view peer_name,
                               std::unique_ptr<VideoEncoder> delegate,
                               double bitrate_multiplier,
                               EmulatedSFUConfigMap stream_to_sfu_config,
                               EncodedImageDataInjector* injector,
                               VideoQualityAnalyzerInterface* analyzer);
  ~QualityAnalyzingVideoEncoder() override;

  // Methods of VideoEncoder interface.
  void SetFecControllerOverride(
      FecControllerOverride* fec_controller_override) override;
  int32_t InitEncode(const VideoCodec* codec_settings,
                     const Settings& settings) override;
  int32_t RegisterEncodeCompleteCallback(
      EncodedImageCallback* callback) override;
  int32_t Release() override;
  int32_t Encode(const VideoFrame& frame,
                 const std::vector<VideoFrameType>* frame_types) override;
  void SetRates(const VideoEncoder::RateControlParameters& parameters) override;
  EncoderInfo GetEncoderInfo() const override;

  // Methods of EncodedImageCallback interface.
  EncodedImageCallback::Result OnEncodedImage(
      const EncodedImage& encoded_image,
      const CodecSpecificInfo* codec_specific_info) override;
  void OnDroppedFrame(DropReason reason) override;

 private:
  enum SimulcastMode {
    // In this mode encoder assumes not more than 1 encoded image per video
    // frame
    kNormal,

    // Next modes are to test video conference behavior. For conference sender
    // will send multiple spatial layers/simulcast streams for single video
    // track and there is some Selective Forwarding Unit (SFU), that forwards
    // only best one, that will pass through downlink to the receiver.
    //
    // Here this behavior will be partly emulated. Sender will send all spatial
    // layers/simulcast streams and then some of them will be filtered out on
    // the receiver side. During test setup user can specify which spatial
    // layer/simulcast stream is required, what will simulated which spatial
    // layer/simulcast stream will be chosen by SFU in the real world. Then
    // sender will mark encoded images for all spatial layers above required or
    // all simulcast streams except required as to be discarded and on receiver
    // side they will be discarded in quality analyzing decoder and won't be
    // passed into delegate decoder.
    //
    // If the sender for some reasons won't send specified spatial layer, then
    // receiver still will fall back on lower spatial layers. But for simulcast
    // streams if required one won't be sent, receiver will assume all frames
    // in that period as dropped and will experience video freeze.
    //
    // Test based on this simulation will be used to evaluate video quality
    // of concrete spatial layers/simulcast streams and also check distribution
    // of bandwidth between spatial layers/simulcast streams by BWE.

    // In this mode encoder assumes that for each frame simulcast encoded
    // images will be produced. So all simulcast streams except required will
    // be marked as to be discarded in decoder and won't reach video quality
    // analyzer.
    kSimulcast,
    // In this mode encoder assumes that for each frame encoded images for
    // different spatial layers will be produced. So all spatial layers above
    // required will be marked to be discarded in decoder and won't reach
    // video quality analyzer.
    kSVC,
    // In this mode encoder assumes that for each frame encoded images for
    // different spatial layers will be produced. Compared to kSVC mode
    // spatial layers that are above required will be marked to be discarded
    // only for key frames and for regular frames all except required spatial
    // layer will be marked as to be discarded in decoder and won't reach video
    // quality analyzer.
    kKSVC
  };

  bool ShouldDiscard(uint16_t frame_id, const EncodedImage& encoded_image)
      RTC_EXCLUSIVE_LOCKS_REQUIRED(mutex_);

  const std::string peer_name_;
  std::unique_ptr<VideoEncoder> delegate_;
  const double bitrate_multiplier_;
  // Contains mapping from stream label to optional spatial index.
  // If we have stream label "Foo" and mapping contains
  // 1. `absl::nullopt` means all streams are required
  // 2. Concrete value means that particular simulcast/SVC stream have to be
  //    analyzed.
  EmulatedSFUConfigMap stream_to_sfu_config_;
  EncodedImageDataInjector* const injector_;
  VideoQualityAnalyzerInterface* const analyzer_;

  // VideoEncoder interface assumes async delivery of encoded images.
  // This lock is used to protect shared state, that have to be propagated
  // from received VideoFrame to resulted EncodedImage.
  Mutex mutex_;

  VideoCodec codec_settings_ RTC_GUARDED_BY(mutex_);
  SimulcastMode mode_ RTC_GUARDED_BY(mutex_);
  EncodedImageCallback* delegate_callback_ RTC_GUARDED_BY(mutex_);
  std::list<std::pair<uint32_t, uint16_t>> timestamp_to_frame_id_list_
      RTC_GUARDED_BY(mutex_);
  VideoBitrateAllocation bitrate_allocation_ RTC_GUARDED_BY(mutex_);
};

// Produces QualityAnalyzingVideoEncoder, which hold decoders, produced by
// specified factory as delegates. Forwards all other calls to specified
// factory.
class QualityAnalyzingVideoEncoderFactory : public VideoEncoderFactory {
 public:
  QualityAnalyzingVideoEncoderFactory(
      absl::string_view peer_name,
      std::unique_ptr<VideoEncoderFactory> delegate,
      double bitrate_multiplier,
      QualityAnalyzingVideoEncoder::EmulatedSFUConfigMap stream_to_sfu_config,
      EncodedImageDataInjector* injector,
      VideoQualityAnalyzerInterface* analyzer);
  ~QualityAnalyzingVideoEncoderFactory() override;

  // Methods of VideoEncoderFactory interface.
  std::vector<SdpVideoFormat> GetSupportedFormats() const override;
  VideoEncoderFactory::CodecSupport QueryCodecSupport(
      const SdpVideoFormat& format,
      absl::optional<std::string> scalability_mode) const override;
  std::unique_ptr<VideoEncoder> Create(const Environment& env,
                                       const SdpVideoFormat& format) override;

 private:
  const std::string peer_name_;
  std::unique_ptr<VideoEncoderFactory> delegate_;
  const double bitrate_multiplier_;
  QualityAnalyzingVideoEncoder::EmulatedSFUConfigMap stream_to_sfu_config_;
  EncodedImageDataInjector* const injector_;
  VideoQualityAnalyzerInterface* const analyzer_;
};

}  // namespace webrtc_pc_e2e
}  // namespace webrtc

#endif  // TEST_PC_E2E_ANALYZER_VIDEO_QUALITY_ANALYZING_VIDEO_ENCODER_H_