// 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 "ash/wm/overview/overview_session_metrics_recorder.h"

#include "ash/shell.h"
#include "ash/wm/desks/desks_controller.h"
#include "ash/wm/desks/overview_desk_bar_view.h"
#include "ash/wm/overview/overview_controller.h"
#include "ash/wm/overview/overview_grid.h"
#include "ash/wm/overview/overview_session.h"
#include "ash/wm/overview/overview_types.h"
#include "base/check.h"
#include "base/metrics/histogram_functions.h"
#include "base/trace_event/named_trigger.h"
#include "base/trace_event/trace_event.h"
#include "third_party/perfetto/include/perfetto/tracing/track.h"
#include "ui/compositor/layer.h"
#include "ui/compositor/presentation_time_recorder.h"

namespace ash {

OverviewSessionMetricsRecorder::OverviewSessionMetricsRecorder(
    OverviewStartAction start_action,
    OverviewController* controller)
    : start_action_(start_action) {
  RecordOverviewStartAction(start_action);
  controller_observation_.Observe(controller);
}

OverviewSessionMetricsRecorder::~OverviewSessionMetricsRecorder() {
  // Corner case: If an overview session is started while one is in progress,
  // then the recorder for the first session is destroyed before the
  // `OnOverviewModeEndingAnimationComplete()` notification is received. This
  // case needs to be checked explicitly.
  if (!has_finished_exit_overview_trace_event_) {
    OnOverviewModeEndingAnimationComplete(/*canceled=*/true);
  }
}

void OverviewSessionMetricsRecorder::OnOverviewSessionInitializing() {
  overview_start_time_ = base::Time::Now();
  // We're only interested in chrometto traces where the user definitely intends
  // to see an overview of their windows. These two are the most common use
  // cases in the field, accounting for a combined 85% of overview sessions in
  // stable channel as of 8/29/24.
  if (start_action_ == OverviewStartAction::kAccelerator ||
      start_action_ == OverviewStartAction::kDragWindowFromShelf) {
    base::trace_event::EmitNamedTrigger("ash-overview-start");
  }
  TRACE_EVENT_BEGIN(
      "ui", "OverviewController::EnterOverview",
      perfetto::NamedTrack::FromPointer("ash::OverviewSession", this));

  auto enter_presentation_time_recorder =
      CreatePresentationTimeHistogramRecorder(
          Shell::GetPrimaryRootWindow()->layer()->GetCompositor(),
          GetOverviewEnterPresentationTimeMetricName(start_action_), "",
          GetOverviewPresentationTimeBucketParams(),
          /*emit_trace_event=*/true);
  enter_presentation_time_recorder->RequestNext();

  base::UmaHistogramCounts100("Ash.Overview.DeskCount",
                              DesksController::Get()->desks().size());
}

void OverviewSessionMetricsRecorder::OnOverviewSessionInitialized(
    OverviewSession* session) {
  session_ = session;
  CHECK(session_);
  desk_bar_shown_immediately_ = IsDeskBarOpen();
}

void OverviewSessionMetricsRecorder::OnOverviewSessionEnding() {
  RecordOverviewEndAction(session_->overview_end_action());

  TRACE_EVENT_BEGIN(
      "ui", "OverviewController::ExitOverview",
      perfetto::NamedTrack::FromPointer("ash::OverviewSession", this));

  const DeskBarVisibility desk_bar_visibility =
      desk_bar_shown_immediately_
          ? DeskBarVisibility::kShownImmediately
          : (IsDeskBarOpen() ? DeskBarVisibility::kShownAfterFirstFrame
                             : DeskBarVisibility::kNotShown);
  base::UmaHistogramEnumeration("Ash.Overview.DeskBarVisibility",
                                desk_bar_visibility);

  auto exit_presentation_time_recorder =
      CreatePresentationTimeHistogramRecorder(
          Shell::GetPrimaryRootWindow()->layer()->GetCompositor(),
          kExitOverviewPresentationHistogram, "",
          GetOverviewPresentationTimeBucketParams(),
          /*emit_trace_event=*/true);
  exit_presentation_time_recorder->RequestNext();

  CHECK(!overview_start_time_.is_null());
  base::UmaHistogramMediumTimes("Ash.Overview.TimeInOverview",
                                base::Time::Now() - overview_start_time_);
  // Prevents dangling raw_ptr failures.
  session_ = nullptr;
}

void OverviewSessionMetricsRecorder::OnOverviewModeStartingAnimationComplete(
    bool canceled) {
  TRACE_EVENT_END(
      "ui", /* OverviewController::EnterOverview */
      perfetto::NamedTrack::FromPointer("ash::OverviewSession", this),
      "canceled", canceled);
}

void OverviewSessionMetricsRecorder::OnOverviewModeEndingAnimationComplete(
    bool canceled) {
  has_finished_exit_overview_trace_event_ = true;
  TRACE_EVENT_END(
      "ui", /* OverviewController::ExitOverview */
      perfetto::NamedTrack::FromPointer("ash::OverviewSession", this),
      "canceled", canceled);
}

bool OverviewSessionMetricsRecorder::IsDeskBarOpen() const {
  CHECK(session_);
  // Note an overview grid for the primary root window may not exist in some
  // corner cases (see http://crbug.com/378501600).
  for (const auto& root_window : Shell::GetAllRootWindows()) {
    auto* const overview_grid = session_->GetGridWithRootWindow(root_window);
    if (overview_grid && overview_grid->desks_bar_view()) {
      return true;
    }
  }
  return false;
}

}  // namespace ash