/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

/* This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "Hal.h"

#include "HalLog.h"

#include <dbus/dbus-glib.h>

#include <dbus/dbus-glib-lowlevel.h>

#include <mozilla/Attributes.h>

#include <mozilla/dom/battery/Constants.h>

#include "nsAutoRef.h"

#include <cmath>

/*

 * Helper that manages the destruction of glib objects as soon as they leave

 * the current scope.

 *

 * We are specializing nsAutoRef class.

 */

template <>

class nsAutoRefTraits<GHashTable> : public nsPointerRefTraits<GHashTable>

{

public:

  static void Release(GHashTable* ptr) { g_hash_table_unref(ptr); }

};

using namespace mozilla::dom::battery;

namespace mozilla {

namespace hal_impl {

/**

 * This is the declaration of UPowerClient class. This class is listening and

 * communicating to upower daemon through DBus.

 * There is no header file because this class shouldn't be public.

 */

class UPowerClient

{

public:

  static UPowerClient* GetInstance();

  void BeginListening();

  void StopListening();

  double GetLevel();

  bool   IsCharging();

  double GetRemainingTime();

  ~UPowerClient();

private:

  UPowerClient();

  enum States {

    eState_Unknown = 0,

    eState_Charging,

    eState_Discharging,

    eState_Empty,

    eState_FullyCharged,

    eState_PendingCharge,

    eState_PendingDischarge

  };

  /**

   * Update the currently tracked device.

   * @return whether everything went ok.

   */

  void UpdateTrackedDeviceSync();

  /**

   * Returns a hash table with the properties of aDevice.

   * Note: the caller has to unref the hash table.

   */

  GHashTable* GetDevicePropertiesSync(DBusGProxy* aProxy);

  void GetDevicePropertiesAsync(DBusGProxy* aProxy);

  static void GetDevicePropertiesCallback(DBusGProxy* aProxy,

                                          DBusGProxyCall* aCall,

                                          void* aData);

  /**

   * Using the device properties (aHashTable), this method updates the member

   * variable storing the values we care about.

   */

  void UpdateSavedInfo(GHashTable* aHashTable);

  /**

   * Callback used by 'DeviceChanged' signal.

   */

  static void DeviceChanged(DBusGProxy* aProxy, const gchar* aObjectPath,

                            UPowerClient* aListener);

  /**

   * Callback used by 'PropertiesChanged' signal.

   * This method is called when the the battery level changes.

   * (Only with upower >= 0.99)

   */

  static void PropertiesChanged(DBusGProxy* aProxy, const gchar*,

                                GHashTable*, char**,

                                UPowerClient* aListener);

  /**

   * Callback called when mDBusConnection gets a signal.

   */

  static DBusHandlerResult ConnectionSignalFilter(DBusConnection* aConnection,

                                                  DBusMessage* aMessage,

                                                  void* aData);

  // The DBus connection object.

  DBusGConnection* mDBusConnection;

  // The DBus proxy object to upower.

  DBusGProxy* mUPowerProxy;

  // The path of the tracked device.

  gchar* mTrackedDevice;

  // The DBusGProxy for the tracked device.

  DBusGProxy* mTrackedDeviceProxy;

  double mLevel;

  bool mCharging;

  double mRemainingTime;

  static UPowerClient* sInstance;

  static const guint sDeviceTypeBattery = 2;

  static const guint64 kUPowerUnknownRemainingTime = 0;

};

/*

 * Implementation of mozilla::hal_impl::EnableBatteryNotifications,

 *                   mozilla::hal_impl::DisableBatteryNotifications,

 *               and mozilla::hal_impl::GetCurrentBatteryInformation.

 */

void

EnableBatteryNotifications()

{

  UPowerClient::GetInstance()->BeginListening();

}

void

DisableBatteryNotifications()

{

  UPowerClient::GetInstance()->StopListening();

}

void

GetCurrentBatteryInformation(hal::BatteryInformation* aBatteryInfo)

{

  UPowerClient* upowerClient = UPowerClient::GetInstance();

  aBatteryInfo->level() = upowerClient->GetLevel();

  aBatteryInfo->charging() = upowerClient->IsCharging();

  aBatteryInfo->remainingTime() = upowerClient->GetRemainingTime();

}

/*

 * Following is the implementation of UPowerClient.

 */

UPowerClient* UPowerClient::sInstance = nullptr;

/* static */ UPowerClient*

UPowerClient::GetInstance()

{

  if (!sInstance) {

    sInstance = new UPowerClient();

  }

  return sInstance;

}

UPowerClient::UPowerClient()

  : mDBusConnection(nullptr)

  , mUPowerProxy(nullptr)

  , mTrackedDevice(nullptr)

  , mTrackedDeviceProxy(nullptr)

  , mLevel(kDefaultLevel)

  , mCharging(kDefaultCharging)

  , mRemainingTime(kDefaultRemainingTime)

{

}

UPowerClient::~UPowerClient()

{

  NS_ASSERTION(!mDBusConnection && !mUPowerProxy && !mTrackedDevice && !mTrackedDeviceProxy,

               "The observers have not been correctly removed! "

               "(StopListening should have been called)");

}

void

UPowerClient::BeginListening()

{

  GError* error = nullptr;

  mDBusConnection = dbus_g_bus_get(DBUS_BUS_SYSTEM, &error);

  if (!mDBusConnection) {

    HAL_LOG("Failed to open connection to bus: %s\n", error->message);

    g_error_free(error);

    return;

  }

  DBusConnection* dbusConnection =

    dbus_g_connection_get_connection(mDBusConnection);

  // Make sure we do not exit the entire program if DBus connection get lost.

  dbus_connection_set_exit_on_disconnect(dbusConnection, false);

  // Listening to signals the DBus connection is going to get so we will know

  // when it is lost and we will be able to disconnect cleanly.

  dbus_connection_add_filter(dbusConnection, ConnectionSignalFilter, this,

                             nullptr);

  mUPowerProxy = dbus_g_proxy_new_for_name(mDBusConnection,

                                           "org.freedesktop.UPower",

                                           "/org/freedesktop/UPower",

                                           "org.freedesktop.UPower");

  UpdateTrackedDeviceSync();

  /*

   * TODO: we should probably listen to DeviceAdded and DeviceRemoved signals.

   * If we do that, we would have to disconnect from those in StopListening.

   * It's not yet implemented because it requires testing hot plugging and

   * removal of a battery.

   */

  dbus_g_proxy_add_signal(mUPowerProxy, "DeviceChanged", G_TYPE_STRING,

                          G_TYPE_INVALID);

  dbus_g_proxy_connect_signal(mUPowerProxy, "DeviceChanged",

                              G_CALLBACK (DeviceChanged), this, nullptr);

}

void

UPowerClient::StopListening()

{

  // If mDBusConnection isn't initialized, that means we are not really listening.

  if (!mDBusConnection) {

    return;

  }

  dbus_connection_remove_filter(

      dbus_g_connection_get_connection(mDBusConnection),

      ConnectionSignalFilter, this);

  dbus_g_proxy_disconnect_signal(mUPowerProxy, "DeviceChanged",

                                 G_CALLBACK (DeviceChanged), this);

  g_free(mTrackedDevice);

  mTrackedDevice = nullptr;

  if (mTrackedDeviceProxy) {

    dbus_g_proxy_disconnect_signal(mTrackedDeviceProxy, "PropertiesChanged",

                                   G_CALLBACK (PropertiesChanged), this);

    g_object_unref(mTrackedDeviceProxy);

    mTrackedDeviceProxy = nullptr;

  }

  g_object_unref(mUPowerProxy);

  mUPowerProxy = nullptr;

  dbus_g_connection_unref(mDBusConnection);

  mDBusConnection = nullptr;

  // We should now show the default values, not the latest we got.

  mLevel = kDefaultLevel;

  mCharging = kDefaultCharging;

  mRemainingTime = kDefaultRemainingTime;

}

void

UPowerClient::UpdateTrackedDeviceSync()

{

  GType typeGPtrArray = dbus_g_type_get_collection("GPtrArray",

                                                   DBUS_TYPE_G_OBJECT_PATH);

  GPtrArray* devices = nullptr;

  GError* error = nullptr;

  // Reset the current tracked device:

  g_free(mTrackedDevice);

  mTrackedDevice = nullptr;

  // Reset the current tracked device proxy:

  if (mTrackedDeviceProxy) {

    dbus_g_proxy_disconnect_signal(mTrackedDeviceProxy, "PropertiesChanged",

                                   G_CALLBACK (PropertiesChanged), this);

    g_object_unref(mTrackedDeviceProxy);

    mTrackedDeviceProxy = nullptr;

  }

  // If that fails, that likely means upower isn't installed.

  if (!dbus_g_proxy_call(mUPowerProxy, "EnumerateDevices", &error, G_TYPE_INVALID,

                         typeGPtrArray, &devices, G_TYPE_INVALID)) {

    HAL_LOG("Error: %s\n", error->message);

    g_error_free(error);

    return;

  }

  /*

   * We are looking for the first device that is a battery.

   * TODO: we could try to combine more than one battery.

   */

  for (guint i=0; i<devices->len; ++i) {

    gchar* devicePath = static_cast<gchar*>(g_ptr_array_index(devices, i));

    DBusGProxy* proxy = dbus_g_proxy_new_from_proxy(mUPowerProxy,

                                                    "org.freedesktop.DBus.Properties",

                                                    devicePath);

    nsAutoRef<GHashTable> hashTable(GetDevicePropertiesSync(proxy));

    if (g_value_get_uint(static_cast<const GValue*>(g_hash_table_lookup(hashTable, "Type"))) == sDeviceTypeBattery) {

      UpdateSavedInfo(hashTable);

      mTrackedDevice = devicePath;

      mTrackedDeviceProxy = proxy;

      break;

    }

    g_object_unref(proxy);

    g_free(devicePath);

  }

  if (mTrackedDeviceProxy) {

    dbus_g_proxy_add_signal(mTrackedDeviceProxy, "PropertiesChanged",

                            G_TYPE_STRING,

                            dbus_g_type_get_map("GHashTable", G_TYPE_STRING,

                                                G_TYPE_VALUE),

                            G_TYPE_STRV, G_TYPE_INVALID);

    dbus_g_proxy_connect_signal(mTrackedDeviceProxy, "PropertiesChanged",

                                G_CALLBACK (PropertiesChanged), this, nullptr);

  }

  g_ptr_array_free(devices, true);

}

/* static */ void

UPowerClient::DeviceChanged(DBusGProxy* aProxy, const gchar* aObjectPath,

                            UPowerClient* aListener)

{

  if (!aListener->mTrackedDevice) {

    return;

  }

#if GLIB_MAJOR_VERSION >= 2 && GLIB_MINOR_VERSION >= 16

  if (g_strcmp0(aObjectPath, aListener->mTrackedDevice)) {

#else

  if (g_ascii_strcasecmp(aObjectPath, aListener->mTrackedDevice)) {

#endif

    return;

  }

  aListener->GetDevicePropertiesAsync(aListener->mTrackedDeviceProxy);

}

/* static */ void

UPowerClient::PropertiesChanged(DBusGProxy* aProxy, const gchar*, GHashTable*,

                                char**, UPowerClient* aListener)

{

  aListener->GetDevicePropertiesAsync(aListener->mTrackedDeviceProxy);

}

/* static */ DBusHandlerResult

UPowerClient::ConnectionSignalFilter(DBusConnection* aConnection,

                                     DBusMessage* aMessage, void* aData)

{

  if (dbus_message_is_signal(aMessage, DBUS_INTERFACE_LOCAL, "Disconnected")) {

    static_cast<UPowerClient*>(aData)->StopListening();

    // We do not return DBUS_HANDLER_RESULT_HANDLED here because the connection

    // might be shared and some other filters might want to do something.

  }

  return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;

}

GHashTable*

UPowerClient::GetDevicePropertiesSync(DBusGProxy* aProxy)

{

  GError* error = nullptr;

  GHashTable* hashTable = nullptr;

  GType typeGHashTable = dbus_g_type_get_map("GHashTable", G_TYPE_STRING,

                                            G_TYPE_VALUE);

  if (!dbus_g_proxy_call(aProxy, "GetAll", &error, G_TYPE_STRING,

                         "org.freedesktop.UPower.Device", G_TYPE_INVALID,

                         typeGHashTable, &hashTable, G_TYPE_INVALID)) {

    HAL_LOG("Error: %s\n", error->message);

    g_error_free(error);

    return nullptr;

  }

  return hashTable;

}

/* static */ void

UPowerClient::GetDevicePropertiesCallback(DBusGProxy* aProxy,

                                          DBusGProxyCall* aCall, void* aData)

{

  GError* error = nullptr;

  GHashTable* hashTable = nullptr;

  GType typeGHashTable = dbus_g_type_get_map("GHashTable", G_TYPE_STRING,

                                             G_TYPE_VALUE);

  if (!dbus_g_proxy_end_call(aProxy, aCall, &error, typeGHashTable,

                             &hashTable, G_TYPE_INVALID)) {

    HAL_LOG("Error: %s\n", error->message);

    g_error_free(error);

  } else {

    sInstance->UpdateSavedInfo(hashTable);

    hal::NotifyBatteryChange(hal::BatteryInformation(sInstance->mLevel,

                                                     sInstance->mCharging,

                                                     sInstance->mRemainingTime));

    g_hash_table_unref(hashTable);

  }

}

void

UPowerClient::GetDevicePropertiesAsync(DBusGProxy* aProxy)

{

  dbus_g_proxy_begin_call(aProxy, "GetAll", GetDevicePropertiesCallback, nullptr,

                          nullptr, G_TYPE_STRING,

                          "org.freedesktop.UPower.Device", G_TYPE_INVALID);

}

void

UPowerClient::UpdateSavedInfo(GHashTable* aHashTable)

{

  bool isFull = false;

  /*

   * State values are confusing...

   * First of all, after looking at upower sources (0.9.13), it seems that

   * PendingDischarge and PendingCharge are not used.

   * In addition, FullyCharged and Empty states are not clear because we do not

   * know if the battery is actually charging or not. Those values come directly

   * from sysfs (in the Linux kernel) which have four states: "Empty", "Full",

   * "Charging" and "Discharging". In sysfs, "Empty" and "Full" are also only

   * related to the level, not to the charging state.

   * In this code, we are going to assume that Full means charging and Empty

   * means discharging because if that is not the case, the state should not

   * last a long time (actually, it should disappear at the following update).

   * It might be even very hard to see real cases where the state is Empty and

   * the battery is charging or the state is Full and the battery is discharging

   * given that plugging/unplugging the battery should have an impact on the

   * level.

   */

  switch (g_value_get_uint(static_cast<const GValue*>(g_hash_table_lookup(aHashTable, "State")))) {

    case eState_Unknown:

      mCharging = kDefaultCharging;

      break;

    case eState_FullyCharged:

      isFull = true;

      MOZ_FALLTHROUGH;

    case eState_Charging:

    case eState_PendingCharge:

      mCharging = true;

      break;

    case eState_Discharging:

    case eState_Empty:

    case eState_PendingDischarge:

      mCharging = false;

      break;

  }

  /*

   * The battery level might be very close to 100% (like 99%) without

   * increasing. It seems that upower sets the battery state as 'full' in that

   * case so we should trust it and not even try to get the value.

   */

  if (isFull) {

    mLevel = 1.0;

  } else {

    mLevel = round(g_value_get_double(static_cast<const GValue*>(g_hash_table_lookup(aHashTable, "Percentage"))))*0.01;

  }

  if (isFull) {

    mRemainingTime = 0;

  } else {

    mRemainingTime = mCharging ? g_value_get_int64(static_cast<const GValue*>(g_hash_table_lookup(aHashTable, "TimeToFull")))

                               : g_value_get_int64(static_cast<const GValue*>(g_hash_table_lookup(aHashTable, "TimeToEmpty")));

    if (mRemainingTime == kUPowerUnknownRemainingTime) {

      mRemainingTime = kUnknownRemainingTime;

    }

  }

}

double

UPowerClient::GetLevel()

{

  return mLevel;

}

bool

UPowerClient::IsCharging()

{

  return mCharging;

}

double

UPowerClient::GetRemainingTime()

{

  return mRemainingTime;

}

} // namespace hal_impl

} // namespace mozilla