/*
 *  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_PIXEL_LIMIT_RESOURCE_H_
#define VIDEO_ADAPTATION_PIXEL_LIMIT_RESOURCE_H_

#include <optional>
#include <string>

#include "api/adaptation/resource.h"
#include "api/field_trials_view.h"
#include "api/scoped_refptr.h"
#include "api/task_queue/task_queue_base.h"
#include "api/units/time_delta.h"
#include "api/video/video_adaptation_reason.h"
#include "call/adaptation/video_stream_input_state_provider.h"
#include "rtc_base/task_utils/repeating_task.h"
#include "rtc_base/thread_annotations.h"

namespace webrtc {

// An adaptation resource designed to be used in the TestBed. Used to simulate
// being CPU limited.
//
// Periodically reports "overuse" or "underuse" (every 5 seconds) until the
// stream is within the bounds specified in terms of a maximum resolution and
// one resolution step lower than that (this avoids toggling when this is the
// only resource in play). When multiple resources come in to play some amount
// of toggling is still possible in edge cases but that is OK for testing
// purposes.
class PixelLimitResource : public Resource {
 public:
  static scoped_refptr<PixelLimitResource> CreateIfFieldTrialEnabled(
      const FieldTrialsView& field_trials,
      TaskQueueBase* task_queue,
      VideoStreamInputStateProvider* input_state_provider);

  PixelLimitResource(TaskQueueBase* task_queue,
                     VideoStreamInputStateProvider* input_state_provider,
                     int target_pixels,
                     TimeDelta interval,
                     VideoAdaptationReason reason,
                     std::optional<TimeDelta> duration);
  ~PixelLimitResource() override;

  // Resource implementation.
  std::string Name() const override { return "PixelLimitResource"; }
  void SetResourceListener(ResourceListener* listener) override;

  VideoAdaptationReason adaptation_reason() const { return reason_; }

 private:
  TaskQueueBase* const task_queue_;
  VideoStreamInputStateProvider* const input_state_provider_;
  const int target_pixels_;
  const TimeDelta interval_;
  const VideoAdaptationReason reason_;
  const std::optional<TimeDelta> toggle_interval_;
  // If `toggle_interval_` was specified, we cyclically toggle "on" or "off".
  bool is_enabled_ RTC_GUARDED_BY(task_queue_);
  TimeDelta time_since_last_toggle_ RTC_GUARDED_BY(task_queue_);
  ResourceListener* listener_ RTC_GUARDED_BY(task_queue_);
  RepeatingTaskHandle repeating_task_ RTC_GUARDED_BY(task_queue_);
};

}  // namespace webrtc

#endif  // VIDEO_ADAPTATION_PIXEL_LIMIT_RESOURCE_H_