/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

/* vim: set ts=8 sts=2 et sw=2 tw=80: */

/* 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 <cmath>

#include <limits>

#include "BatteryManager.h"

#include "Constants.h"

#include "mozilla/DOMEventTargetHelper.h"

#include "mozilla/Hal.h"

#include "mozilla/dom/BatteryManagerBinding.h"

#include "mozilla/Preferences.h"

#include "nsContentUtils.h"

#include "nsIDocument.h"

/**

 * We have to use macros here because our leak analysis tool things we are

 * leaking strings when we have |static const nsString|. Sad :(

 */

#define LEVELCHANGE_EVENT_NAME           NS_LITERAL_STRING("levelchange")

#define CHARGINGCHANGE_EVENT_NAME        NS_LITERAL_STRING("chargingchange")

#define DISCHARGINGTIMECHANGE_EVENT_NAME NS_LITERAL_STRING("dischargingtimechange")

#define CHARGINGTIMECHANGE_EVENT_NAME    NS_LITERAL_STRING("chargingtimechange")

namespace mozilla {

namespace dom {

namespace battery {

BatteryManager::BatteryManager(nsPIDOMWindowInner* aWindow)

  : DOMEventTargetHelper(aWindow)

  , mLevel(kDefaultLevel)

  , mCharging(kDefaultCharging)

  , mRemainingTime(kDefaultRemainingTime)

{

}

void

BatteryManager::Init()

{

  hal::RegisterBatteryObserver(this);

  hal::BatteryInformation batteryInfo;

  hal::GetCurrentBatteryInformation(&batteryInfo);

  UpdateFromBatteryInfo(batteryInfo);

}

void

BatteryManager::Shutdown()

{

  hal::UnregisterBatteryObserver(this);

}

JSObject*

BatteryManager::WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto)

{

  return BatteryManager_Binding::Wrap(aCx, this, aGivenProto);

}

bool

BatteryManager::Charging() const

{

  MOZ_ASSERT(NS_IsMainThread());

  // For testing, unable to report the battery status information

  if (Preferences::GetBool("dom.battery.test.default", false)) {

    return true;

  }

  if (Preferences::GetBool("dom.battery.test.charging", false)) {

    return true;

  }

  if (Preferences::GetBool("dom.battery.test.discharging", false)) {

    return false;

  }

  return mCharging;

}

double

BatteryManager::DischargingTime() const

{

  MOZ_ASSERT(NS_IsMainThread());

  // For testing, unable to report the battery status information

  if (Preferences::GetBool("dom.battery.test.default", false)) {

    return std::numeric_limits<double>::infinity();

  }

  if (Preferences::GetBool("dom.battery.test.discharging", false)) {

    return 42.0;

  }

  if (Charging() || mRemainingTime == kUnknownRemainingTime) {

    return std::numeric_limits<double>::infinity();

  }

  return mRemainingTime;

}

double

BatteryManager::ChargingTime() const

{

  MOZ_ASSERT(NS_IsMainThread());

  // For testing, unable to report the battery status information

  if (Preferences::GetBool("dom.battery.test.default", false)) {

    return 0.0;

  }

  if (Preferences::GetBool("dom.battery.test.charging", false)) {

    return 42.0;

  }

  if (!Charging() || mRemainingTime == kUnknownRemainingTime) {

    return std::numeric_limits<double>::infinity();

  }

  return mRemainingTime;

}

double

BatteryManager::Level() const

{

  MOZ_ASSERT(NS_IsMainThread());

  // For testing, unable to report the battery status information

  if (Preferences::GetBool("dom.battery.test.default")) {

    return 1.0;

  }

  return mLevel;

}

void

BatteryManager::UpdateFromBatteryInfo(const hal::BatteryInformation& aBatteryInfo)

{

  mLevel = aBatteryInfo.level();

  // Round to the nearest ten percent for non-chrome.

  nsIDocument* doc = GetOwner() ? GetOwner()->GetDoc() : nullptr;

  mCharging = aBatteryInfo.charging();

  mRemainingTime = aBatteryInfo.remainingTime();

  if (!nsContentUtils::IsChromeDoc(doc))

  {

    mLevel = lround(mLevel * 10.0) / 10.0;

    if (mLevel == 1.0) {

      mRemainingTime = mCharging ? kDefaultRemainingTime : kUnknownRemainingTime;

    } else if (mRemainingTime != kUnknownRemainingTime) {

      // Round the remaining time to a multiple of 15 minutes and never zero

      const double MINUTES_15 = 15.0 * 60.0;

      mRemainingTime = fmax(lround(mRemainingTime / MINUTES_15) * MINUTES_15,

                            MINUTES_15);

    }

  }

  // Add some guards to make sure the values are coherent.

  if (mLevel == 1.0 && mCharging == true &&

      mRemainingTime != kDefaultRemainingTime) {

    mRemainingTime = kDefaultRemainingTime;

    NS_ERROR("Battery API: When charging and level at 1.0, remaining time "

             "should be 0. Please fix your backend!");

  }

}

void

BatteryManager::Notify(const hal::BatteryInformation& aBatteryInfo)

{

  double previousLevel = mLevel;

  bool previousCharging = mCharging;

  double previousRemainingTime = mRemainingTime;

  UpdateFromBatteryInfo(aBatteryInfo);

  if (previousCharging != mCharging) {

    DispatchTrustedEvent(CHARGINGCHANGE_EVENT_NAME);

  }

  if (previousLevel != mLevel) {

    DispatchTrustedEvent(LEVELCHANGE_EVENT_NAME);

  }

  /*

   * There are a few situations that could happen here:

   * 1. Charging state changed:

   *   a. Previous remaining time wasn't unkwonw, we have to fire an event for

   *      the change.

   *   b. New remaining time isn't unkwonw, we have to fire an event for it.

   * 2. Charging state didn't change but remainingTime did, we have to fire

   *    the event that correspond to the current charging state.

   */

  if (mCharging != previousCharging) {

    if (previousRemainingTime != kUnknownRemainingTime) {

      DispatchTrustedEvent(previousCharging ? CHARGINGTIMECHANGE_EVENT_NAME

                                            : DISCHARGINGTIMECHANGE_EVENT_NAME);

    }

    if (mRemainingTime != kUnknownRemainingTime) {

      DispatchTrustedEvent(mCharging ? CHARGINGTIMECHANGE_EVENT_NAME

                                     : DISCHARGINGTIMECHANGE_EVENT_NAME);

    }

  } else if (previousRemainingTime != mRemainingTime) {

    DispatchTrustedEvent(mCharging ? CHARGINGTIMECHANGE_EVENT_NAME

                                   : DISCHARGINGTIMECHANGE_EVENT_NAME);

  }

}

} // namespace battery

} // namespace dom

} // namespace mozilla