// Copyright 2017 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 ASH_TRAY_ACTION_TRAY_ACTION_H_
#define ASH_TRAY_ACTION_TRAY_ACTION_H_

#include <memory>

#include "ash/ash_export.h"
#include "ash/public/mojom/tray_action.mojom.h"
#include "base/macros.h"
#include "base/observer_list.h"
#include "base/scoped_observer.h"
#include "mojo/public/cpp/bindings/pending_receiver.h"
#include "mojo/public/cpp/bindings/pending_remote.h"
#include "mojo/public/cpp/bindings/receiver_set.h"
#include "mojo/public/cpp/bindings/remote.h"
#include "ui/events/devices/device_data_manager.h"
#include "ui/events/devices/input_device_event_observer.h"

namespace ui {
enum class StylusState;
}  // namespace ui

namespace ash {

class BacklightsForcedOffSetter;
class LockScreenNoteDisplayStateHandler;
class TrayActionObserver;

// Controller that ash can use to request a predefined set of actions to be
// performed by clients.
// The controller provides an interface to:
//  * Send a request to the client to handle an action.
//  * Observe the state of support for an action as reported by the current ash
//    client.
// Currently, only single action is supported - creating new note on the lock
// screen - Chrome handles this action by launching an app (if any) that is
// registered as a lock screen enabled action handler for the new note action.
class ASH_EXPORT TrayAction : public mojom::TrayAction,
                              public ui::InputDeviceEventObserver {
 public:
  explicit TrayAction(BacklightsForcedOffSetter* backlights_forced_off_setter);
  ~TrayAction() override;

  LockScreenNoteDisplayStateHandler*
  lock_screen_note_display_state_handler_for_test() {
    return lock_screen_note_display_state_handler_.get();
  }

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

  void BindReceiver(mojo::PendingReceiver<mojom::TrayAction> receiver);

  // Gets last known handler state for the lock screen note action.
  // It will return kNotAvailable if an action handler has not been set using
  // |SetClient|.
  mojom::TrayActionState GetLockScreenNoteState() const;

  // Helper method for determining if lock screen not action is in active state.
  bool IsLockScreenNoteActive() const;

  // If the client is set, sends it a request to handle the lock screen note
  // action.
  void RequestNewLockScreenNote(mojom::LockScreenNoteOrigin origin);

  // If the client is set, sends a request to close the lock screen note.
  void CloseLockScreenNote(mojom::CloseLockScreenNoteReason reason);

  // mojom::TrayAction:
  void SetClient(mojo::PendingRemote<mojom::TrayActionClient> action_handler,
                 mojom::TrayActionState lock_screen_note_state) override;
  void UpdateLockScreenNoteState(mojom::TrayActionState state) override;

  // ui::InputDeviceEventObserver:
  void OnStylusStateChanged(ui::StylusState state) override;

  void FlushMojoForTesting();

 private:
  // Notifies the observers that state for the lock screen note action has been
  // updated.
  void NotifyLockScreenNoteStateChanged();

  BacklightsForcedOffSetter* const backlights_forced_off_setter_;

  // Last known state for lock screen note action.
  mojom::TrayActionState lock_screen_note_state_ =
      mojom::TrayActionState::kNotAvailable;

  std::unique_ptr<LockScreenNoteDisplayStateHandler>
      lock_screen_note_display_state_handler_;

  base::ObserverList<TrayActionObserver>::Unchecked observers_;

  // Receivers for users of the mojo interface.
  mojo::ReceiverSet<mojom::TrayAction> receivers_;

  mojo::Remote<mojom::TrayActionClient> tray_action_client_;

  ScopedObserver<ui::DeviceDataManager, ui::InputDeviceEventObserver>
      stylus_observer_{this};

  DISALLOW_COPY_AND_ASSIGN(TrayAction);
};

}  // namespace ash

#endif  // ASH_TRAY_ACTION_TRAY_ACTION_H_