// Copyright 2013 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/display/display_configuration_observer.h"

#include "ash/constants/ash_switches.h"
#include "ash/display/display_prefs.h"
#include "ash/shell.h"
#include "ash/wm/tablet_mode/tablet_mode_controller.h"
#include "base/command_line.h"
#include "base/functional/bind.h"
#include "base/task/single_thread_task_runner.h"
#include "ui/display/manager/display_layout_store.h"
#include "ui/display/manager/display_manager.h"
#include "ui/display/tablet_state.h"

namespace ash {

DisplayConfigurationObserver::DisplayConfigurationObserver() {
  Shell::Get()->display_manager()->AddDisplayManagerObserver(this);
}

DisplayConfigurationObserver::~DisplayConfigurationObserver() {
  Shell::Get()->display_manager()->RemoveDisplayManagerObserver(this);
}

void DisplayConfigurationObserver::OnDisplaysInitialized() {
  // Update the display pref with the initial power state.
  base::CommandLine* command_line = base::CommandLine::ForCurrentProcess();
  if (command_line->HasSwitch(switches::kFirstExecAfterBoot))
    Shell::Get()->display_prefs()->MaybeStoreDisplayPrefs();
}

void DisplayConfigurationObserver::OnDidApplyDisplayChanges() {
  Shell::Get()->display_prefs()->MaybeStoreDisplayPrefs();
}

void DisplayConfigurationObserver::OnDisplayTabletStateChanged(
    display::TabletState state) {
  switch (state) {
    case display::TabletState::kEnteringTabletMode:
    case display::TabletState::kExitingTabletMode:
      // Do nothing when the tablet state is still in the process of transition.
      break;
    case display::TabletState::kInTabletMode:
      // Setting mirror mode may destroy the secondary SystemTray, so use
      // PostTask to set mirror mode in the next frame in case other
      // TabletModeObserver entries are owned by the SystemTray.
      base::SingleThreadTaskRunner::GetCurrentDefault()->PostTask(
          FROM_HERE,
          base::BindOnce(&DisplayConfigurationObserver::StartMirrorMode,
                         weak_ptr_factory_.GetWeakPtr()));
      break;
    case display::TabletState::kInClamshellMode:
      // See comment for kInTabletMode.
      base::SingleThreadTaskRunner::GetCurrentDefault()->PostTask(
          FROM_HERE,
          base::BindOnce(&DisplayConfigurationObserver::EndMirrorMode,
                         weak_ptr_factory_.GetWeakPtr()));
      break;
  }
}

void DisplayConfigurationObserver::StartMirrorMode() {
  // TODO(oshima): Tablet mode defaults to mirror mode until we figure out
  // how to handle this scenario, and we shouldn't save this state.
  // https://crbug.com/733092.
  display::DisplayManager* display_manager = Shell::Get()->display_manager();
  was_in_mirror_mode_ = display_manager->IsInMirrorMode();
  display_manager->layout_store()->set_forced_mirror_mode_for_tablet(true);
  display_manager->SetMirrorMode(display::MirrorMode::kNormal, std::nullopt);
}

void DisplayConfigurationObserver::EndMirrorMode() {
  if (!was_in_mirror_mode_) {
    Shell::Get()->display_manager()->SetMirrorMode(display::MirrorMode::kOff,
                                                   std::nullopt);
  }
  display::DisplayManager* display_manager = Shell::Get()->display_manager();
  display_manager->layout_store()->set_forced_mirror_mode_for_tablet(false);
}

}  // namespace ash