// Copyright 2020 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "cc/metrics/frame_sequence_tracker_collection.h"

#include <utility>
#include <vector>

#include "base/containers/contains.h"
#include "base/memory/ptr_util.h"
#include "base/time/time.h"
#include "cc/metrics/compositor_frame_reporting_controller.h"
#include "cc/metrics/frame_info.h"
#include "cc/metrics/frame_sequence_metrics.h"
#include "cc/metrics/frame_sequence_tracker.h"
#include "cc/metrics/ukm_dropped_frames_data.h"

namespace cc {

namespace {

using ThreadType = FrameInfo::SmoothEffectDrivingThread;

bool IsScrollType(FrameSequenceTrackerType type) {
  return type == FrameSequenceTrackerType::kTouchScroll ||
         type == FrameSequenceTrackerType::kWheelScroll ||
         type == FrameSequenceTrackerType::kScrollbarScroll;
}

}  // namespace

FrameSequenceTrackerCollection::FrameSequenceTrackerCollection(
    bool is_single_threaded)
    : is_single_threaded_(is_single_threaded) {}

FrameSequenceTrackerCollection::~FrameSequenceTrackerCollection() {
  CleanUp();
  frame_trackers_.clear();
  removal_trackers_.clear();
  custom_frame_trackers_.clear();
  accumulated_metrics_.clear();
}

void FrameSequenceTrackerCollection::SetScrollingThread(
    FrameInfo::SmoothEffectDrivingThread thread) {
  auto current_scrolling_thread = scrolling_thread_;
  base::TimeTicks set_time = base::TimeTicks::Now();

  // Assign the thread.
  scrolling_thread_ = thread;

  // keep the history for the last 3 seconds.
  if (!scroll_thread_history_.empty()) {
    auto expired_scrolling_thread =
        scroll_thread_history_.lower_bound(set_time - base::Seconds(3));
    scroll_thread_history_.erase(scroll_thread_history_.begin(),
                                 expired_scrolling_thread);
  }

  // Only traces the history if there is a change in scrolling_thread
  if (current_scrolling_thread != scrolling_thread_) {
    scroll_thread_history_.insert(
        std::make_pair(set_time, current_scrolling_thread));
  }
}

FrameInfo::SmoothThread FrameSequenceTrackerCollection::GetSmoothThread()
    const {
  if (main_thread_driving_smoothness_) {
    return compositor_thread_driving_smoothness_
               ? FrameInfo::SmoothThread::kSmoothBoth
               : FrameInfo::SmoothThread::kSmoothMain;
  }
  if (raster_thread_driving_smoothness_) {
    return FrameInfo::SmoothThread::kSmoothRaster;
  }
  return compositor_thread_driving_smoothness_
             ? FrameInfo::SmoothThread::kSmoothCompositor
             : FrameInfo::SmoothThread::kSmoothNone;
}

void FrameSequenceTrackerCollection::UpdateSmoothThreadHistory(
    FrameInfo::SmoothEffectDrivingThread thread_type,
    int modifier) {
  auto current_smooth_thread = GetSmoothThread();
  base::TimeTicks set_time = base::TimeTicks::Now();

  // Update smooth effect thread tracking count based on the type of
  // tracker being created or destroyed.
  if (thread_type == FrameInfo::SmoothEffectDrivingThread::kCompositor) {
    compositor_thread_driving_smoothness_ += modifier;
  } else if (thread_type == FrameInfo::SmoothEffectDrivingThread::kRaster) {
    raster_thread_driving_smoothness_ += modifier;
  } else {
    DCHECK_EQ(thread_type, FrameInfo::SmoothEffectDrivingThread::kMain);
    main_thread_driving_smoothness_ += modifier;
  }

  // Only called if there is a change in smooth_thread_
  if (current_smooth_thread != GetSmoothThread()) {
    // Keep the history for the last 3 seconds.
    if (!smooth_thread_history_.empty()) {
      auto expired_smooth_thread =
          smooth_thread_history_.lower_bound(set_time - base::Seconds(3));
      smooth_thread_history_.erase(smooth_thread_history_.begin(),
                                   expired_smooth_thread);
    }
    smooth_thread_history_.insert(
        std::make_pair(set_time, current_smooth_thread));
  }
}

FrameInfo::SmoothThread FrameSequenceTrackerCollection::GetSmoothThreadAtTime(
    base::TimeTicks timestamp) const {
  auto last_smooth_thread = smooth_thread_history_.lower_bound(timestamp);
  if (last_smooth_thread == smooth_thread_history_.end()) {
    return GetSmoothThread();
  }
  return last_smooth_thread->second;
}

FrameInfo::SmoothEffectDrivingThread
FrameSequenceTrackerCollection::GetScrollThreadAtTime(
    base::TimeTicks timestamp) const {
  auto last_scroll_thread = scroll_thread_history_.lower_bound(timestamp);
  if (last_scroll_thread == scroll_thread_history_.end()) {
    return scrolling_thread_;
  }
  return last_scroll_thread->second;
}

FrameInfo::SmoothEffectDrivingThread
FrameSequenceTrackerCollection::GetScrollingThread() const {
  return scrolling_thread_;
}

FrameSequenceTracker* FrameSequenceTrackerCollection::StartSequenceInternal(
    FrameSequenceTrackerType type,
    FrameInfo::SmoothEffectDrivingThread scrolling_thread) {
  DCHECK_NE(FrameSequenceTrackerType::kCustom, type);
  if (is_single_threaded_)
    return nullptr;
  auto key = std::make_pair(type, scrolling_thread);
  auto [frame_tracker_it, inserted] = frame_trackers_.try_emplace(key, nullptr);
  if (!inserted) {
    // If the tracker already exists, we should return it.
    return frame_tracker_it->second.get();
  }

  auto& tracker = frame_tracker_it->second;
  tracker = base::WrapUnique(new FrameSequenceTracker(type));

  active_trackers_.set(static_cast<size_t>(type));

  auto* metrics = tracker->metrics();
  if (auto it = accumulated_metrics_.find(key);
      it != accumulated_metrics_.end()) {
    metrics->AdoptTrace(it->second.get());
  }
  if (IsScrollType(type)) {
    DCHECK_NE(scrolling_thread, ThreadType::kUnknown);
    metrics->SetScrollingThread(scrolling_thread);
    SetScrollingThread(scrolling_thread);
  }

  if (metrics->GetEffectiveThread() == ThreadType::kCompositor) {
    UpdateSmoothThreadHistory(ThreadType::kCompositor, /*modifier=*/1);
  } else if (metrics->GetEffectiveThread() == ThreadType::kRaster) {
    UpdateSmoothThreadHistory(ThreadType::kRaster, /*modifier=*/1);
  } else {
    DCHECK_EQ(metrics->GetEffectiveThread(), ThreadType::kMain);
    UpdateSmoothThreadHistory(ThreadType::kMain, /*modifier=*/1);
  }
  return tracker.get();
}

ActiveTrackers FrameSequenceTrackerCollection::GetActiveTrackers() const {
  return active_trackers_;
}

FrameSequenceTracker* FrameSequenceTrackerCollection::StartSequence(
    FrameSequenceTrackerType type) {
  DCHECK(!IsScrollType(type));
  return StartSequenceInternal(type, ThreadType::kUnknown);
}

FrameSequenceTracker* FrameSequenceTrackerCollection::StartScrollSequence(
    FrameSequenceTrackerType type,
    FrameInfo::SmoothEffectDrivingThread scrolling_thread) {
  DCHECK(IsScrollType(type));
  return StartSequenceInternal(type, scrolling_thread);
}

void FrameSequenceTrackerCollection::CleanUp() {
  for (auto& tracker : frame_trackers_)
    tracker.second->CleanUp();
  for (auto& tracker : custom_frame_trackers_)
    tracker.second->CleanUp();
  for (auto& tracker : removal_trackers_)
    tracker->CleanUp();
  for (auto& metric : accumulated_metrics_)
    metric.second->ReportLeftoverData();
}

void FrameSequenceTrackerCollection::StopSequence(
    FrameSequenceTrackerType type) {
  DCHECK_NE(FrameSequenceTrackerType::kCustom, type);

  auto key = std::make_pair(type, ThreadType::kUnknown);
  if (IsScrollType(type)) {
    SetScrollingThread(ThreadType::kUnknown);
    key = std::make_pair(type, ThreadType::kCompositor);
    if (!frame_trackers_.contains(key))
      key = std::make_pair(type, ThreadType::kMain);
    if (!frame_trackers_.contains(key)) {
      key = std::make_pair(type, ThreadType::kRaster);
    }
  }

  auto tracker_it = frame_trackers_.find(key);
  if (tracker_it == frame_trackers_.end()) {
    return;
  }

  auto tracker = std::move(tracker_it->second);
  active_trackers_.reset(static_cast<size_t>(tracker->type()));

  if (tracker->metrics()->GetEffectiveThread() == ThreadType::kCompositor) {
    DCHECK_GT(compositor_thread_driving_smoothness_, 0u);
    UpdateSmoothThreadHistory(ThreadType::kCompositor, /*modifier=*/-1);
  } else if (tracker->metrics()->GetEffectiveThread() == ThreadType::kRaster) {
    DCHECK_GT(raster_thread_driving_smoothness_, 0u);
    UpdateSmoothThreadHistory(ThreadType::kRaster, /*modifier=*/-1);
  } else {
    DCHECK_GT(main_thread_driving_smoothness_, 0u);
    UpdateSmoothThreadHistory(ThreadType::kMain, /*modifier=*/-1);
  }

  frame_trackers_.erase(tracker_it);
  tracker->ScheduleTerminate();
  removal_trackers_.push_back(std::move(tracker));
  DestroyTrackers();
}

void FrameSequenceTrackerCollection::StartCustomSequence(int sequence_id) {
  DCHECK(!base::Contains(custom_frame_trackers_, sequence_id));

  // base::Unretained() is safe here because |this| owns FrameSequenceTracker
  // and FrameSequenceMetrics.
  custom_frame_trackers_[sequence_id] =
      base::WrapUnique(new FrameSequenceTracker(
          sequence_id,
          base::BindOnce(
              &FrameSequenceTrackerCollection::AddCustomTrackerResult,
              base::Unretained(this), sequence_id)));
}

void FrameSequenceTrackerCollection::StopCustomSequence(int sequence_id) {
  auto it = custom_frame_trackers_.find(sequence_id);
  // This happens when an animation is aborted before starting.
  if (it == custom_frame_trackers_.end())
    return;

  std::unique_ptr<FrameSequenceTracker> tracker = std::move(it->second);
  custom_frame_trackers_.erase(it);
  tracker->ScheduleTerminate();
  removal_trackers_.push_back(std::move(tracker));
  DestroyTrackers();
}

void FrameSequenceTrackerCollection::ClearAll() {
  frame_trackers_.clear();
  custom_frame_trackers_.clear();
  removal_trackers_.clear();
}

void FrameSequenceTrackerCollection::NotifyBeginImplFrame(
    const viz::BeginFrameArgs& args) {
  RecreateTrackers(args);
  for (auto& tracker : frame_trackers_)
    tracker.second->ReportBeginImplFrame(args);
  for (auto& tracker : custom_frame_trackers_)
    tracker.second->ReportBeginImplFrame(args);
}

void FrameSequenceTrackerCollection::NotifyPauseFrameProduction() {
  for (auto& tracker : frame_trackers_)
    tracker.second->PauseFrameProduction();
  for (auto& tracker : custom_frame_trackers_)
    tracker.second->PauseFrameProduction();
}

void FrameSequenceTrackerCollection::NotifyFrameEnd(
    const viz::BeginFrameArgs& args,
    const viz::BeginFrameArgs& main_args) {
  for (auto& tracker : frame_trackers_)
    tracker.second->ReportFrameEnd(args, main_args);
  for (auto& tracker : custom_frame_trackers_)
    tracker.second->ReportFrameEnd(args, main_args);

  // Removal trackers continue to process any frames which they started
  // observing.
  for (auto& tracker : removal_trackers_)
    tracker->ReportFrameEnd(args, main_args);
  DestroyTrackers();
}

void FrameSequenceTrackerCollection::DestroyTrackers() {
  for (auto& tracker : removal_trackers_) {
    if (tracker->termination_status() ==
        FrameSequenceTracker::TerminationStatus::kReadyForTermination) {
      // The tracker is ready to be terminated.
      // For non kCustom typed trackers, take the metrics from the tracker.
      // merge with any outstanding metrics from previous trackers of the same
      // type. If there are enough frames to report the metrics, then report the
      // metrics and destroy it. Otherwise, retain it to be merged with
      // follow-up sequences.
      // For kCustom typed trackers, |metrics| invokes AddCustomTrackerResult
      // on its destruction, which add its data to |custom_tracker_results_|
      // to be picked up by caller.
      if (tracker->metrics() &&
          tracker->type() == FrameSequenceTrackerType::kCustom)
        continue;
      auto metrics = tracker->TakeMetrics();

      auto key = std::make_pair(metrics->type(), metrics->GetEffectiveThread());
      auto accumulated_metrics_it = accumulated_metrics_.find(key);
      if (accumulated_metrics_it != accumulated_metrics_.end()) {
        metrics->Merge(std::move(accumulated_metrics_it->second));
        accumulated_metrics_.erase(accumulated_metrics_it);
      }

      if (metrics->HasEnoughDataForReporting()) {
        // This value is guaranteed to be positive by the
        // previous HasEnoughDataForReporting check.
        int percent_dropped_frames4 = metrics->ReportMetrics();
        CHECK_GE(percent_dropped_frames4, 0);
        if (ukm_dropped_frames_data_) {
          UkmDroppedFramesData dropped_frames_data;
          dropped_frames_data.percent_dropped_frames = percent_dropped_frames4;
          ukm_dropped_frames_data_->Write(dropped_frames_data);
        }
      }
      if (metrics->HasDataLeftForReporting()) {
        accumulated_metrics_.emplace(key, std::move(metrics));
      }
    }
  }

  std::erase_if(
      removal_trackers_,
      [](const std::unique_ptr<FrameSequenceTracker>& tracker) {
        return tracker->termination_status() ==
               FrameSequenceTracker::TerminationStatus::kReadyForTermination;
      });
}

void FrameSequenceTrackerCollection::RecreateTrackers(
    const viz::BeginFrameArgs& args) {
  std::vector<std::pair<FrameSequenceTrackerType, ThreadType>>
      recreate_trackers;
  for (const auto& tracker : frame_trackers_) {
    if (tracker.second->ShouldReportMetricsNow(args))
      recreate_trackers.push_back(tracker.first);
  }

  for (const auto& key : recreate_trackers) {
    DCHECK(frame_trackers_[key]);
    auto tracker_type = key.first;
    ThreadType thread_type = key.second;

    // StopSequence put the tracker in the |removal_trackers_|, which will
    // report its throughput data when its frame is presented.
    StopSequence(tracker_type);

    // The frame sequence is still active, so create a new tracker to keep
    // tracking this sequence.
    if (thread_type != FrameInfo::SmoothEffectDrivingThread::kUnknown) {
      DCHECK(IsScrollType(tracker_type));
      StartScrollSequence(tracker_type, thread_type);
    } else {
      StartSequence(tracker_type);
    }
  }
}

ActiveFrameSequenceTrackers
FrameSequenceTrackerCollection::FrameSequenceTrackerActiveTypes() const {
  ActiveFrameSequenceTrackers encoded_types = 0;
  for (const auto& key : frame_trackers_) {
    auto thread_type = key.first.first;
    encoded_types |= static_cast<ActiveFrameSequenceTrackers>(
        1 << static_cast<unsigned>(thread_type));
  }
  return encoded_types;
}

FrameSequenceTracker*
FrameSequenceTrackerCollection::GetRemovalTrackerForTesting(
    FrameSequenceTrackerType type) {
  for (const auto& tracker : removal_trackers_)
    if (tracker->type() == type)
      return tracker.get();
  return nullptr;
}

void FrameSequenceTrackerCollection::AddCustomTrackerResult(
    int custom_sequence_id,
    const FrameSequenceMetrics::CustomReportData& data) {
  DCHECK(custom_tracker_results_added_callback_);

  CustomTrackerResults results;
  results[custom_sequence_id] = data;
  custom_tracker_results_added_callback_.Run(results);
}

void FrameSequenceTrackerCollection::AddSortedFrame(
    const viz::BeginFrameArgs& args,
    const FrameInfo& frame_info) {
  for (auto& tracker : frame_trackers_)
    tracker.second->AddSortedFrame(args, frame_info);
  for (auto& tracker : custom_frame_trackers_)
    tracker.second->AddSortedFrame(args, frame_info);

  // Sorted frames could arrive after tracker are scheduled for termination.
  // Removal trackers continue to report metrics for frames which they started
  // observing.
  for (auto& tracker : removal_trackers_) {
    tracker->AddSortedFrame(args, frame_info);
  }

  DestroyTrackers();
}

void FrameSequenceTrackerCollection::SetUkmDroppedFramesDestination(
    UkmDroppedFramesDataShared* dropped_frames_data) {
  ukm_dropped_frames_data_ = dropped_frames_data;
}

}  // namespace cc