/*
 * Copyright (C) 2011, Google Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
 * DAMAGE.
 */

#include "modules/gamepad/NavigatorGamepad.h"

#include "core/dom/Document.h"
#include "core/frame/LocalFrame.h"
#include "core/frame/Navigator.h"
#include "core/page/Page.h"
#include "modules/gamepad/GamepadDispatcher.h"
#include "modules/gamepad/GamepadEvent.h"
#include "modules/gamepad/GamepadList.h"

namespace blink {

template <typename T>
static void sampleGamepad(unsigned index,
                          T& gamepad,
                          const WebGamepad& webGamepad) {
  gamepad.setId(webGamepad.id);
  gamepad.setIndex(index);
  gamepad.setConnected(webGamepad.connected);
  gamepad.setTimestamp(webGamepad.timestamp);
  gamepad.setMapping(webGamepad.mapping);
  gamepad.setAxes(webGamepad.axesLength, webGamepad.axes);
  gamepad.setButtons(webGamepad.buttonsLength, webGamepad.buttons);
  gamepad.setPose(webGamepad.pose);
  gamepad.setHand(webGamepad.hand);
  gamepad.setDisplayId(webGamepad.displayId);
}

template <typename GamepadType, typename ListType>
static void sampleGamepads(ListType* into) {
  WebGamepads gamepads;

  GamepadDispatcher::instance().sampleGamepads(gamepads);

  for (unsigned i = 0; i < WebGamepads::itemsLengthCap; ++i) {
    WebGamepad& webGamepad = gamepads.items[i];
    if (i < gamepads.length && webGamepad.connected) {
      GamepadType* gamepad = into->item(i);
      if (!gamepad)
        gamepad = GamepadType::create();
      sampleGamepad(i, *gamepad, webGamepad);
      into->set(i, gamepad);
    } else {
      into->set(i, 0);
    }
  }
}

NavigatorGamepad* NavigatorGamepad::from(Document& document) {
  if (!document.frame() || !document.frame()->domWindow())
    return 0;
  Navigator& navigator = *document.frame()->domWindow()->navigator();
  return &from(navigator);
}

NavigatorGamepad& NavigatorGamepad::from(Navigator& navigator) {
  NavigatorGamepad* supplement = static_cast<NavigatorGamepad*>(
      Supplement<Navigator>::from(navigator, supplementName()));
  if (!supplement) {
    supplement = new NavigatorGamepad(navigator.frame());
    provideTo(navigator, supplementName(), supplement);
  }
  return *supplement;
}

GamepadList* NavigatorGamepad::getGamepads(Navigator& navigator) {
  return NavigatorGamepad::from(navigator).gamepads();
}

GamepadList* NavigatorGamepad::gamepads() {
  if (!m_gamepads)
    m_gamepads = GamepadList::create();
  if (startUpdatingIfAttached())
    sampleGamepads<Gamepad>(m_gamepads.get());
  return m_gamepads.get();
}

DEFINE_TRACE(NavigatorGamepad) {
  visitor->trace(m_gamepads);
  visitor->trace(m_pendingEvents);
  visitor->trace(m_dispatchOneEventRunner);
  Supplement<Navigator>::trace(visitor);
  ContextLifecycleObserver::trace(visitor);
  PlatformEventController::trace(visitor);
}

bool NavigatorGamepad::startUpdatingIfAttached() {
  Document* document = static_cast<Document*>(getExecutionContext());
  // The frame must be attached to start updating.
  if (document && document->frame()) {
    startUpdating();
    return true;
  }
  return false;
}

void NavigatorGamepad::didUpdateData() {
  // We should stop listening once we detached.
  Document* document = static_cast<Document*>(getExecutionContext());
  DCHECK(document->frame());
  DCHECK(document->frame()->domWindow());

  // We register to the dispatcher before sampling gamepads so we need to check
  // if we actually have an event listener.
  if (!m_hasEventListener)
    return;

  if (document->activeDOMObjectsAreStopped() ||
      document->activeDOMObjectsAreSuspended())
    return;

  const GamepadDispatcher::ConnectionChange& change =
      GamepadDispatcher::instance().latestConnectionChange();

  if (!m_gamepads)
    m_gamepads = GamepadList::create();

  Gamepad* gamepad = m_gamepads->item(change.index);
  if (!gamepad)
    gamepad = Gamepad::create();
  sampleGamepad(change.index, *gamepad, change.pad);
  m_gamepads->set(change.index, gamepad);

  m_pendingEvents.append(gamepad);
  m_dispatchOneEventRunner->runAsync();
}

void NavigatorGamepad::dispatchOneEvent() {
  Document* document = static_cast<Document*>(getExecutionContext());
  DCHECK(document->frame());
  DCHECK(document->frame()->domWindow());
  DCHECK(!m_pendingEvents.isEmpty());

  Gamepad* gamepad = m_pendingEvents.takeFirst();
  const AtomicString& eventName = gamepad->connected()
                                      ? EventTypeNames::gamepadconnected
                                      : EventTypeNames::gamepaddisconnected;
  document->frame()->domWindow()->dispatchEvent(
      GamepadEvent::create(eventName, false, true, gamepad));

  if (!m_pendingEvents.isEmpty())
    m_dispatchOneEventRunner->runAsync();
}

NavigatorGamepad::NavigatorGamepad(LocalFrame* frame)
    : ContextLifecycleObserver(frame->document()),
      PlatformEventController(frame ? frame->page() : 0),
      m_dispatchOneEventRunner(AsyncMethodRunner<NavigatorGamepad>::create(
          this,
          &NavigatorGamepad::dispatchOneEvent)) {
  if (frame)
    frame->localDOMWindow()->registerEventListenerObserver(this);
}

NavigatorGamepad::~NavigatorGamepad() {}

const char* NavigatorGamepad::supplementName() {
  return "NavigatorGamepad";
}

void NavigatorGamepad::contextDestroyed() {
  stopUpdating();
}

void NavigatorGamepad::registerWithDispatcher() {
  GamepadDispatcher::instance().addController(this);
  m_dispatchOneEventRunner->resume();
}

void NavigatorGamepad::unregisterWithDispatcher() {
  m_dispatchOneEventRunner->suspend();
  GamepadDispatcher::instance().removeController(this);
}

bool NavigatorGamepad::hasLastData() {
  // Gamepad data is polled instead of pushed.
  return false;
}

static bool isGamepadEvent(const AtomicString& eventType) {
  return eventType == EventTypeNames::gamepadconnected ||
         eventType == EventTypeNames::gamepaddisconnected;
}

void NavigatorGamepad::didAddEventListener(LocalDOMWindow*,
                                           const AtomicString& eventType) {
  if (isGamepadEvent(eventType)) {
    if (page() && page()->isPageVisible())
      startUpdatingIfAttached();
    m_hasEventListener = true;
  }
}

void NavigatorGamepad::didRemoveEventListener(LocalDOMWindow* window,
                                              const AtomicString& eventType) {
  if (isGamepadEvent(eventType) &&
      !window->hasEventListeners(EventTypeNames::gamepadconnected) &&
      !window->hasEventListeners(EventTypeNames::gamepaddisconnected)) {
    didRemoveGamepadEventListeners();
  }
}

void NavigatorGamepad::didRemoveAllEventListeners(LocalDOMWindow*) {
  didRemoveGamepadEventListeners();
}

void NavigatorGamepad::didRemoveGamepadEventListeners() {
  m_hasEventListener = false;
  m_dispatchOneEventRunner->stop();
  m_pendingEvents.clear();
}

void NavigatorGamepad::pageVisibilityChanged() {
  // Inform the embedder whether it needs to provide gamepad data for us.
  bool visible = page()->isPageVisible();
  if (visible && (m_hasEventListener || m_gamepads))
    startUpdatingIfAttached();
  else
    stopUpdating();

  if (!visible || !m_hasEventListener)
    return;

  // Tell the page what has changed. m_gamepads contains the state before we
  // became hidden.  We create a new snapshot and compare them.
  GamepadList* oldGamepads = m_gamepads.release();
  gamepads();
  GamepadList* newGamepads = m_gamepads.get();
  DCHECK(newGamepads);

  for (unsigned i = 0; i < WebGamepads::itemsLengthCap; ++i) {
    Gamepad* oldGamepad = oldGamepads ? oldGamepads->item(i) : 0;
    Gamepad* newGamepad = newGamepads->item(i);
    bool oldWasConnected = oldGamepad && oldGamepad->connected();
    bool newIsConnected = newGamepad && newGamepad->connected();
    bool connectedGamepadChanged = oldWasConnected && newIsConnected &&
                                   oldGamepad->id() != newGamepad->id();
    if (connectedGamepadChanged || (oldWasConnected && !newIsConnected)) {
      oldGamepad->setConnected(false);
      m_pendingEvents.append(oldGamepad);
    }
    if (connectedGamepadChanged || (!oldWasConnected && newIsConnected)) {
      m_pendingEvents.append(newGamepad);
    }
  }

  if (!m_pendingEvents.isEmpty())
    m_dispatchOneEventRunner->runAsync();
}

}  // namespace blink