/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef mozilla_gfx_layers_composite_Diagnostics_h
#define mozilla_gfx_layers_composite_Diagnostics_h

#include "FPSCounter.h"
#include "mozilla/Maybe.h"
#include "mozilla/StaticPrefs_layers.h"
#include "mozilla/TimeStamp.h"
#include <deque>
#include <string>
#include <utility>

namespace mozilla {
namespace layers {

class PaintTiming;

class TimedMetric {
  typedef std::pair<float, TimeStamp> Entry;

 public:
  void Add(float aValue) {
    if (mHistory.size() > kMaxHistory) {
      mHistory.pop_front();
    }
    mHistory.push_back(Entry(aValue, TimeStamp::Now()));
  }

  float Average() const;
  bool Empty() const { return mHistory.empty(); }

 private:
  static const size_t kMaxHistory = 60;

  std::deque<Entry> mHistory;
};

// These statistics are collected by layers backends, preferably by the GPU
struct GPUStats {
  GPUStats() : mInvalidPixels(0), mScreenPixels(0), mPixelsFilled(0) {}

  uint32_t mInvalidPixels;
  uint32_t mScreenPixels;
  uint32_t mPixelsFilled;
  Maybe<float> mDrawTime;
};

// Collects various diagnostics about layers performance.
class Diagnostics {
 public:
  Diagnostics();

  void RecordPaintTimes(const PaintTiming& aPaintTimes);
  void RecordUpdateTime(float aValue) { mUpdateMs.Add(aValue); }
  void RecordPrepareTime(float aValue) { mPrepareMs.Add(aValue); }
  void RecordCompositeTime(float aValue) { mCompositeMs.Add(aValue); }
  void AddTxnFrame() { mTransactionFps.AddFrame(TimeStamp::Now()); }

  std::string GetFrameOverlayString(const GPUStats& aStats);

  class Record {
   public:
    explicit Record(TimeStamp aStart = TimeStamp()) {
      if (StaticPrefs::layers_acceleration_draw_fps()) {
        mStart = aStart.IsNull() ? TimeStamp::Now() : aStart;
      }
    }
    bool Recording() const { return !mStart.IsNull(); }
    float Duration() const {
      return (TimeStamp::Now() - mStart).ToMilliseconds();
    }

   private:
    TimeStamp mStart;
  };

 private:
  FPSCounter mCompositeFps;
  FPSCounter mTransactionFps;
  TimedMetric mDlbMs;
  TimedMetric mDlb2Ms;
  TimedMetric mFlbMs;
  TimedMetric mRasterMs;
  TimedMetric mSerializeMs;
  TimedMetric mSendMs;
  TimedMetric mUpdateMs;
  TimedMetric mPrepareMs;
  TimedMetric mCompositeMs;
  TimedMetric mGPUDrawMs;
};

}  // namespace layers
}  // namespace mozilla

#endif  // mozilla_gfx_layers_composite_Diagnostics_h