// Copyright 2015 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CHROME_BROWSER_CHROMEOS_SYSTEM_SYSTEM_CLOCK_H_
#define CHROME_BROWSER_CHROMEOS_SYSTEM_SYSTEM_CLOCK_H_

#include "base/callback_list.h"
#include "base/i18n/time_formatting.h"
#include "base/macros.h"
#include "base/memory/scoped_ptr.h"
#include "chromeos/login/login_state.h"
#include "components/user_manager/user_manager.h"
#include "content/public/browser/notification_observer.h"
#include "content/public/browser/notification_registrar.h"

class Profile;
class PrefChangeRegistrar;

namespace user_manager {
class User;
}

namespace chromeos {
namespace system {

class SystemClockObserver;

// This is a global singleton (actually a member of BrowserProcessPlatformPart)
// that is responsible for correct time formatting. It listens to events that
// modify on-screen time representation (like ActiveUserChanged) and notifies
// observers.
//
// (Most of) this code used to be a part of ash::SystemTrayDelegate.
class SystemClock : public chromeos::LoginState::Observer,
                    public content::NotificationObserver,
                    public user_manager::UserManager::UserSessionStateObserver {
 public:
  SystemClock();
  ~SystemClock() override;

  void SetLastFocusedPodHourClockType(base::HourClockType hour_clock_type);

  void AddObserver(SystemClockObserver* observer);
  void RemoveObserver(SystemClockObserver* observer);

  bool ShouldUse24HourClock() const;

  // content::NotificationObserver implementation.
  void Observe(int type,
               const content::NotificationSource& source,
               const content::NotificationDetails& details) override;

  // user_manager::UserManager::UserSessionStateObserver overrides
  void ActiveUserChanged(const user_manager::User* user) override;

 private:
  // Should be the same as CrosSettings::ObserverSubscription.
  typedef base::CallbackList<void(void)>::Subscription
      CrosSettingsObserverSubscription;

  void OnActiveProfileChanged(Profile* profile);
  bool OnProfileDestroyed(Profile* profile);

  // LoginState::Observer overrides.
  void LoggedInStateChanged() override;

  void OnSystemPrefChanged();

  void UpdateClockType();

  bool user_pod_was_focused_;
  base::HourClockType last_focused_pod_hour_clock_type_;

  Profile* user_profile_;
  scoped_ptr<content::NotificationRegistrar> registrar_;
  scoped_ptr<PrefChangeRegistrar> user_pref_registrar_;

  base::ObserverList<SystemClockObserver> observer_list_;

  scoped_ptr<CrosSettingsObserverSubscription> device_settings_observer_;

  DISALLOW_COPY_AND_ASSIGN(SystemClock);
};

}  // namespace system
}  // namespace chromeos

#endif  // CHROME_BROWSER_CHROMEOS_SYSTEM_SYSTEM_CLOCK_H_