// Copyright 2018 The Chromium OS 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 BLUETOOTH_DISPATCHER_SUSPEND_MANAGER_H_
#define BLUETOOTH_DISPATCHER_SUSPEND_MANAGER_H_

#include <memory>
#include <string>

#include <base/macros.h>
#include <base/memory/weak_ptr.h>
#include <dbus/bus.h>
#include <dbus/message.h>

#include "bluetooth/dispatcher/service_watcher.h"

namespace bluetooth {

// This class handles suspend/resume events and takes the necessary actions
// to pause or unpause discovery.
class SuspendManager {
 public:
  // Bluez's D-Bus object path representing the Bluetooth adapter.
  static const char kBluetoothAdapterObjectPath[];

  explicit SuspendManager(scoped_refptr<dbus::Bus> bus);
  ~SuspendManager();

  // Initializes the D-Bus operations.
  void Init();

 private:
  // Called when the power manager is initially available or restarted.
  void HandlePowerManagerAvailableOrRestarted(bool available);
  // Called when SuspendImminentSignal is received from power manager.
  void HandleSuspendImminentSignal(dbus::Signal* signal);
  // Called when SuspendDoneSignal is received from power manager.
  void HandleSuspendDoneSignal(dbus::Signal* signal);
  // Called when power manager's RegisterSuspendDelay method returns.
  void OnSuspendDelayRegistered(dbus::Response* response);

  // Called when BlueZ and NewBlue HandleSuspendImminent/
  // HandleSuspendDone method returns.
  void OnSuspendImminentHandled(dbus::Response* response);
  void OnSuspendDoneHandled(dbus::Response* response);

  // Initiates call to BlueZ or NewBlue HandleSuspendImminent/HandleSuspendDone.
  // These methods may or may not make the call to BlueZ depending on whether
  // there is a BlueZ HandleSuspendImminent/HandleSuspendDone call in progress.
  void HandleSuspendImminent(int new_suspend_id);
  void HandleSuspendDone();

  // Keeps the D-Bus connection. Mock/fake D-Bus can be injected through
  // constructor for unit testing without actual D-Bus IPC.
  scoped_refptr<dbus::Bus> bus_;

  // Proxy to power manager D-Bus service.
  dbus::ObjectProxy* power_manager_dbus_proxy_ = nullptr;
  // Proxy to dispatcher D-Bus service.
  dbus::ObjectProxy* btdispatch_dbus_proxy_ = nullptr;

  // If non-zero, that means we have registered a delay with power manager and
  // this variable keeps the delay id returned by power manager for later call
  // to HandleSuspendReadiness.
  // TODO(sonnysasaka): Migrate this to base::Optional when it's available.
  int suspend_delay_id_ = 0;

  // If non-zero, that means we are currently in a suspend imminent state and
  // this variable keeps its suspend id to be passed back to later
  // HandleSuspendReadiness.
  // TODO(sonnysasaka): Migrate this to base::Optional when it's available.
  int suspend_id_ = 0;

  // True if there is an in-progress BlueZ/NewBlue suspension call.
  // There can't be more than one call at a time. This flag is needed to
  // decide whether we can make the call immediately or "queued" after
  // the in-progress D-Bus call completes.
  bool is_suspend_operation_in_progress_ = false;

  // Watches powerd service availability.
  std::unique_ptr<ServiceWatcher> service_watcher_;

  // Must come last so that weak pointers will be invalidated before other
  // members are destroyed.
  base::WeakPtrFactory<SuspendManager> weak_ptr_factory_;

  DISALLOW_COPY_AND_ASSIGN(SuspendManager);
};

}  // namespace bluetooth

#endif  // BLUETOOTH_DISPATCHER_SUSPEND_MANAGER_H_