/*
 *  Copyright 2020 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 VIDEO_ADAPTATION_QUALITY_SCALER_RESOURCE_H_
#define VIDEO_ADAPTATION_QUALITY_SCALER_RESOURCE_H_

#include <memory>
#include <queue>
#include <string>

#include "api/video/video_adaptation_reason.h"
#include "api/video_codecs/video_encoder.h"
#include "call/adaptation/resource.h"
#include "call/adaptation/resource_adaptation_processor_interface.h"
#include "modules/video_coding/utility/quality_scaler.h"
#include "rtc_base/critical_section.h"
#include "rtc_base/ref_counted_object.h"
#include "rtc_base/task_queue.h"

namespace webrtc {

// Handles interaction with the QualityScaler.
class QualityScalerResource : public rtc::RefCountedObject<Resource>,
                              public QualityScalerQpUsageHandlerInterface {
 public:
  QualityScalerResource();
  ~QualityScalerResource() override;

  // TODO(https://crbug.com/webrtc/11542): When we have an adaptation queue,
  // pass it in here.
  void Initialize(rtc::TaskQueue* encoder_queue);
  void SetAdaptationProcessor(
      ResourceAdaptationProcessorInterface* adaptation_processor);

  bool is_started() const;

  void StartCheckForOveruse(VideoEncoder::QpThresholds qp_thresholds);
  void StopCheckForOveruse();

  void SetQpThresholds(VideoEncoder::QpThresholds qp_thresholds);
  bool QpFastFilterLow();
  void OnEncodeCompleted(const EncodedImage& encoded_image,
                         int64_t time_sent_in_us);
  void OnFrameDropped(EncodedImageCallback::DropReason reason);

  // QualityScalerQpUsageHandlerInterface implementation.
  void OnReportQpUsageHigh(
      rtc::scoped_refptr<QualityScalerQpUsageHandlerCallbackInterface> callback)
      override;
  void OnReportQpUsageLow(
      rtc::scoped_refptr<QualityScalerQpUsageHandlerCallbackInterface> callback)
      override;

  std::string name() const override { return "QualityScalerResource"; }

  // Resource implementation.
  void OnAdaptationApplied(
      const VideoStreamInputState& input_state,
      const VideoSourceRestrictions& restrictions_before,
      const VideoSourceRestrictions& restrictions_after,
      rtc::scoped_refptr<Resource> reason_resource) override;

 private:
  size_t QueuePendingCallback(
      rtc::scoped_refptr<QualityScalerQpUsageHandlerCallbackInterface>
          callback);
  void HandlePendingCallback(size_t callback_id, bool clear_qp_samples);
  void AbortPendingCallbacks();

  rtc::TaskQueue* encoder_queue_;
  // TODO(https://crbug.com/webrtc/11542): When we have an adaptation queue,
  // guard the processor by it instead.
  ResourceAdaptationProcessorInterface* adaptation_processor_
      RTC_GUARDED_BY(encoder_queue_);
  std::unique_ptr<QualityScaler> quality_scaler_ RTC_GUARDED_BY(encoder_queue_);
  // Every OnReportQpUsageHigh/Low() operation has a callback that MUST be
  // invoked on the |encoder_queue_|.
  // TODO(https://crbug.com/webrtc/11542): When we have an adaptation queue,
  // handling a measurement entails a task queue "ping" round-trip between the
  // encoder queue and the adaptation queue. Multiple callbacks in-flight would
  // then be possible.
  size_t num_handled_callbacks_ RTC_GUARDED_BY(encoder_queue_);
  std::queue<rtc::scoped_refptr<QualityScalerQpUsageHandlerCallbackInterface>>
      pending_callbacks_ RTC_GUARDED_BY(encoder_queue_);
  // TODO(https://crbug.com/webrtc/11542): When we have an adaptation queue,
  // guard processing_in_progress_/clear_cp_samples_ by it instead.
  bool processing_in_progress_ RTC_GUARDED_BY(encoder_queue_);
  bool clear_qp_samples_ RTC_GUARDED_BY(encoder_queue_);
};

}  // namespace webrtc

#endif  // VIDEO_ADAPTATION_QUALITY_SCALER_RESOURCE_H_