// Copyright 2014 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.

#include "modules/netinfo/NetworkInformation.h"

#include "core/dom/ExecutionContext.h"
#include "core/events/Event.h"
#include "core/page/NetworkStateNotifier.h"
#include "modules/EventTargetModules.h"
#include "platform/RuntimeEnabledFeatures.h"
#include "wtf/text/WTFString.h"

namespace {

using namespace blink;

String connectionTypeToString(WebConnectionType type) {
  switch (type) {
    case WebConnectionTypeCellular2G:
    case WebConnectionTypeCellular3G:
    case WebConnectionTypeCellular4G:
      return "cellular";
    case WebConnectionTypeBluetooth:
      return "bluetooth";
    case WebConnectionTypeEthernet:
      return "ethernet";
    case WebConnectionTypeWifi:
      return "wifi";
    case WebConnectionTypeWimax:
      return "wimax";
    case WebConnectionTypeOther:
      return "other";
    case WebConnectionTypeNone:
      return "none";
    case WebConnectionTypeUnknown:
      return "unknown";
  }
  ASSERT_NOT_REACHED();
  return "none";
}

}  // namespace

namespace blink {

NetworkInformation* NetworkInformation::create(ExecutionContext* context) {
  NetworkInformation* connection = new NetworkInformation(context);
  connection->suspendIfNeeded();
  return connection;
}

NetworkInformation::~NetworkInformation() {
  ASSERT(!m_observing);
}

String NetworkInformation::type() const {
  // m_type is only updated when listening for events, so ask
  // networkStateNotifier if not listening (crbug.com/379841).
  if (!m_observing)
    return connectionTypeToString(networkStateNotifier().connectionType());

  // If observing, return m_type which changes when the event fires, per spec.
  return connectionTypeToString(m_type);
}

double NetworkInformation::downlinkMax() const {
  if (!m_observing)
    return networkStateNotifier().maxBandwidth();

  return m_downlinkMaxMbps;
}

void NetworkInformation::connectionChange(WebConnectionType type,
                                          double downlinkMaxMbps) {
  ASSERT(getExecutionContext()->isContextThread());

  // This can happen if the observer removes and then adds itself again
  // during notification.
  if (m_type == type && m_downlinkMaxMbps == downlinkMaxMbps)
    return;

  m_type = type;
  m_downlinkMaxMbps = downlinkMaxMbps;
  dispatchEvent(Event::create(EventTypeNames::typechange));

  if (RuntimeEnabledFeatures::netInfoDownlinkMaxEnabled())
    dispatchEvent(Event::create(EventTypeNames::change));
}

const AtomicString& NetworkInformation::interfaceName() const {
  return EventTargetNames::NetworkInformation;
}

ExecutionContext* NetworkInformation::getExecutionContext() const {
  return ActiveDOMObject::getExecutionContext();
}

void NetworkInformation::addedEventListener(
    const AtomicString& eventType,
    RegisteredEventListener& registeredListener) {
  EventTargetWithInlineData::addedEventListener(eventType, registeredListener);
  startObserving();
}

void NetworkInformation::removedEventListener(
    const AtomicString& eventType,
    const RegisteredEventListener& registeredListener) {
  EventTargetWithInlineData::removedEventListener(eventType,
                                                  registeredListener);
  if (!hasEventListeners())
    stopObserving();
}

void NetworkInformation::removeAllEventListeners() {
  EventTargetWithInlineData::removeAllEventListeners();
  ASSERT(!hasEventListeners());
  stopObserving();
}

bool NetworkInformation::hasPendingActivity() const {
  ASSERT(m_contextStopped || m_observing == hasEventListeners());

  // Prevent collection of this object when there are active listeners.
  return m_observing;
}

void NetworkInformation::stop() {
  m_contextStopped = true;
  stopObserving();
}

void NetworkInformation::startObserving() {
  if (!m_observing && !m_contextStopped) {
    m_type = networkStateNotifier().connectionType();
    networkStateNotifier().addObserver(this, getExecutionContext());
    m_observing = true;
  }
}

void NetworkInformation::stopObserving() {
  if (m_observing) {
    networkStateNotifier().removeObserver(this, getExecutionContext());
    m_observing = false;
  }
}

NetworkInformation::NetworkInformation(ExecutionContext* context)
    : ActiveScriptWrappable(this),
      ActiveDOMObject(context),
      m_type(networkStateNotifier().connectionType()),
      m_downlinkMaxMbps(networkStateNotifier().maxBandwidth()),
      m_observing(false),
      m_contextStopped(false) {}

DEFINE_TRACE(NetworkInformation) {
  EventTargetWithInlineData::trace(visitor);
  ActiveDOMObject::trace(visitor);
}

}  // namespace blink