// Copyright 2024 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "ui/gl/vsync_provider_win_dcomp.h"

#include "base/logging.h"
#include "base/trace_event/trace_event.h"
#include "ui/gl/direct_composition_support.h"

namespace gl {

VSyncProviderWinDComp::VSyncProviderWinDComp() = default;

VSyncProviderWinDComp::~VSyncProviderWinDComp() = default;

void VSyncProviderWinDComp::GetVSyncParameters(UpdateVSyncCallback callback) {
  base::TimeTicks timebase;
  base::TimeDelta interval;
  if (GetVSyncParametersIfAvailable(&timebase, &interval)) {
    std::move(callback).Run(timebase, interval);
  }
}

// Use the compositor clock to determine vsync interval (as opposed
// to algining with primary monitor) to more optimally align vsync
// interval to video FPS in multi-display mixed refresh rate or VRR configs.
bool VSyncProviderWinDComp::GetVSyncParametersIfAvailable(
    base::TimeTicks* out_timebase,
    base::TimeDelta* out_interval) {
  TRACE_EVENT0("gpu", "VSyncProviderWinDComp::GetVSyncParametersIfAvailable");
  HRESULT hr = S_OK;

  COMPOSITION_FRAME_ID frame_id;
  hr = gl::DCompositionGetFrameId(COMPOSITION_FRAME_ID_COMPLETED, &frame_id);
  CHECK_EQ(S_OK, hr);

  // DCompositionGetStatistics may fail in situations such as switching
  // to a remote session. Cache the previous frame stats in case of failure.
  COMPOSITION_FRAME_STATS stats;
  hr = gl::DCompositionGetStatistics(frame_id, &stats, 0, nullptr, nullptr);
  if (FAILED(hr)) {
    DLOG(ERROR) << "DCompositionGetStatistics failed: "
                << logging::SystemErrorCodeToString(hr);
    if (prev_frame_stats_.has_value()) {
      stats = prev_frame_stats_.value();
      *out_interval = base::TimeDelta::FromQPCValue(stats.framePeriod);
      *out_timebase =
          base::TimeTicks::Now().SnappedToNextTick(
              base::TimeTicks::FromQPCValue(stats.startTime), *out_interval) -
          *out_interval;
      return true;
    }
    return false;
  }

  prev_frame_stats_ = stats;

  *out_timebase = base::TimeTicks::FromQPCValue(stats.startTime);
  *out_interval = base::TimeDelta::FromQPCValue(stats.framePeriod);
  return true;
}

bool VSyncProviderWinDComp::SupportGetVSyncParametersIfAvailable() const {
  return true;
}

bool VSyncProviderWinDComp::IsHWClock() const {
  return true;
}

}  // namespace gl