// Copyright 2013 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "flutter/flow/stopwatch.h"
#include "fml/time/time_delta.h"
#include "gmock/gmock.h"  // IWYU pragma: keep
#include "gtest/gtest.h"

using testing::Return;

namespace flutter {
namespace testing {

class FakeRefreshRateUpdater : public Stopwatch::RefreshRateUpdater {
 public:
  fml::Milliseconds GetFrameBudget() const override { return budget_; }

  void SetFrameBudget(fml::Milliseconds budget) { budget_ = budget; }

 private:
  fml::Milliseconds budget_;
};

TEST(Instrumentation, GetDefaultFrameBudgetTest) {
  fml::Milliseconds frame_budget_60fps = fml::RefreshRateToFrameBudget(60);
  // The default constructor sets the frame_budget to 16.6667 (60 fps).
  FixedRefreshRateStopwatch stopwatch;
  fml::Milliseconds actual_frame_budget = stopwatch.GetFrameBudget();
  EXPECT_EQ(frame_budget_60fps, actual_frame_budget);
}

TEST(Instrumentation, GetOneShotFrameBudgetTest) {
  fml::Milliseconds frame_budget_90fps = fml::RefreshRateToFrameBudget(90);
  FixedRefreshRateStopwatch stopwatch(frame_budget_90fps);
  fml::Milliseconds actual_frame_budget = stopwatch.GetFrameBudget();
  EXPECT_EQ(frame_budget_90fps, actual_frame_budget);
}

TEST(Instrumentation, GetFrameBudgetFromUpdaterTest) {
  FakeRefreshRateUpdater updater;
  fml::Milliseconds frame_budget_90fps = fml::RefreshRateToFrameBudget(90);
  updater.SetFrameBudget(frame_budget_90fps);

  Stopwatch stopwatch(updater);
  fml::Milliseconds actual_frame_budget = stopwatch.GetFrameBudget();
  EXPECT_EQ(frame_budget_90fps, actual_frame_budget);
}

TEST(Instrumentation, GetLapByIndexTest) {
  fml::Milliseconds frame_budget_90fps = fml::RefreshRateToFrameBudget(90);
  FixedRefreshRateStopwatch stopwatch(frame_budget_90fps);
  stopwatch.SetLapTime(fml::TimeDelta::FromMilliseconds(10));
  EXPECT_EQ(stopwatch.GetLap(0), fml::TimeDelta::FromMilliseconds(10));
}

TEST(Instrumentation, GetCurrentSampleStartStopTest) {
  fml::Milliseconds frame_budget_90fps = fml::RefreshRateToFrameBudget(90);
  FixedRefreshRateStopwatch stopwatch(frame_budget_90fps);
  // Stopwatch starts primed to place the first sample in slot 0 when
  // the actual time is available.
  EXPECT_EQ(stopwatch.GetCurrentSample(), size_t(Stopwatch::kMaxSamples - 1u));
  stopwatch.Start();
  // CurrentSample still not updated because we are still measuring
  // this frame.
  EXPECT_EQ(stopwatch.GetCurrentSample(), size_t(Stopwatch::kMaxSamples - 1u));
  stopwatch.Stop();
  // The most current sample is placed in slot #0.
  EXPECT_EQ(stopwatch.GetCurrentSample(), size_t(0));
}

TEST(Instrumentation, GetCurrentSampleSetLapTimeTest) {
  fml::Milliseconds frame_budget_90fps = fml::RefreshRateToFrameBudget(90);
  FixedRefreshRateStopwatch stopwatch(frame_budget_90fps);
  // Stopwatch starts primed to place the first sample in slot 0 when
  // the actual time is available.
  EXPECT_EQ(stopwatch.GetCurrentSample(), size_t(Stopwatch::kMaxSamples - 1u));
  stopwatch.SetLapTime(fml::TimeDelta::FromMilliseconds(10));
  // The most current sample is placed in slot #0.
  EXPECT_EQ(stopwatch.GetCurrentSample(), size_t(0));
}

TEST(Instrumentation, GetLapsCount) {
  fml::Milliseconds frame_budget_90fps = fml::RefreshRateToFrameBudget(90);
  FixedRefreshRateStopwatch stopwatch(frame_budget_90fps);
  stopwatch.SetLapTime(fml::TimeDelta::FromMilliseconds(10));
  EXPECT_EQ(stopwatch.GetLapsCount(), size_t(120));
}

}  // namespace testing
}  // namespace flutter