/* -*- 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 "EventListenerService.h"
#include "mozilla/BasicEvents.h"
#include "mozilla/EventDispatcher.h"
#include "mozilla/EventListenerManager.h"
#include "mozilla/JSEventHandler.h"
#include "mozilla/Maybe.h"
#include "mozilla/dom/EventListenerBinding.h"
#include "mozilla/dom/ScriptSettings.h"
#include "nsArrayUtils.h"
#include "nsCOMArray.h"
#include "nsIXPConnect.h"
#include "nsJSUtils.h"
#include "nsMemory.h"
#include "nsServiceManagerUtils.h"
#include "nsArray.h"
#include "nsThreadUtils.h"

namespace mozilla {

using namespace dom;

/******************************************************************************
 * mozilla::EventListenerChange
 ******************************************************************************/

NS_IMPL_ISUPPORTS(EventListenerChange, nsIEventListenerChange)

EventListenerChange::~EventListenerChange()
{
}

EventListenerChange::EventListenerChange(EventTarget* aTarget) :
  mTarget(aTarget)
{
}

void
EventListenerChange::AddChangedListenerName(nsAtom* aEventName)
{
  mChangedListenerNames.AppendElement(aEventName);
}

NS_IMETHODIMP
EventListenerChange::GetTarget(EventTarget** aTarget)
{
  NS_ENSURE_ARG_POINTER(aTarget);
  NS_ADDREF(*aTarget = mTarget);
  return NS_OK;
}

NS_IMETHODIMP
EventListenerChange::GetCountOfEventListenerChangesAffectingAccessibility(
  uint32_t* aCount)
{
  *aCount = 0;

  size_t length = mChangedListenerNames.Length();
  for (size_t i = 0; i < length; i++) {
    RefPtr<nsAtom> listenerName = mChangedListenerNames[i];

    // These are the event listener changes which may make an element
    // accessible or inaccessible.
    if (listenerName == nsGkAtoms::onclick ||
        listenerName == nsGkAtoms::onmousedown ||
        listenerName == nsGkAtoms::onmouseup) {
      *aCount += 1;
    }
  }

  return NS_OK;
}

/******************************************************************************
 * mozilla::EventListenerInfo
 ******************************************************************************/

EventListenerInfo::EventListenerInfo(const nsAString& aType,
                                     JS::Handle<JSObject*> aScriptedListener,
                                     bool aCapturing,
                                     bool aAllowsUntrusted,
                                     bool aInSystemEventGroup)
  : mType(aType)
  , mScriptedListener(aScriptedListener)
  , mCapturing(aCapturing)
  , mAllowsUntrusted(aAllowsUntrusted)
  , mInSystemEventGroup(aInSystemEventGroup)
{
  HoldJSObjects(this);
}

EventListenerInfo::~EventListenerInfo()
{
  DropJSObjects(this);
}

NS_IMPL_CYCLE_COLLECTION_CLASS(EventListenerInfo)

NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(EventListenerInfo)
NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END

NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(EventListenerInfo)
  tmp->mScriptedListener = nullptr;
NS_IMPL_CYCLE_COLLECTION_UNLINK_END

NS_IMPL_CYCLE_COLLECTION_TRACE_BEGIN(EventListenerInfo)
  NS_IMPL_CYCLE_COLLECTION_TRACE_JS_MEMBER_CALLBACK(mScriptedListener)
NS_IMPL_CYCLE_COLLECTION_TRACE_END

NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(EventListenerInfo)
  NS_INTERFACE_MAP_ENTRY(nsIEventListenerInfo)
  NS_INTERFACE_MAP_ENTRY(nsISupports)
NS_INTERFACE_MAP_END

NS_IMPL_CYCLE_COLLECTING_ADDREF(EventListenerInfo)
NS_IMPL_CYCLE_COLLECTING_RELEASE(EventListenerInfo)

NS_IMETHODIMP
EventListenerInfo::GetType(nsAString& aType)
{
  aType = mType;
  return NS_OK;
}

NS_IMETHODIMP
EventListenerInfo::GetCapturing(bool* aCapturing)
{
  *aCapturing = mCapturing;
  return NS_OK;
}

NS_IMETHODIMP
EventListenerInfo::GetAllowsUntrusted(bool* aAllowsUntrusted)
{
  *aAllowsUntrusted = mAllowsUntrusted;
  return NS_OK;
}

NS_IMETHODIMP
EventListenerInfo::GetInSystemEventGroup(bool* aInSystemEventGroup)
{
  *aInSystemEventGroup = mInSystemEventGroup;
  return NS_OK;
}

NS_IMETHODIMP
EventListenerInfo::GetListenerObject(JSContext* aCx,
                                     JS::MutableHandle<JS::Value> aObject)
{
  Maybe<JSAutoCompartment> ac;
  GetJSVal(aCx, ac, aObject);
  return NS_OK;
}

/******************************************************************************
 * mozilla::EventListenerService
 ******************************************************************************/

NS_IMPL_ISUPPORTS(EventListenerService, nsIEventListenerService)

bool
EventListenerInfo::GetJSVal(JSContext* aCx,
                            Maybe<JSAutoCompartment>& aAc,
                            JS::MutableHandle<JS::Value> aJSVal)
{
  if (mScriptedListener) {
    aJSVal.setObject(*mScriptedListener);
    aAc.emplace(aCx, mScriptedListener);
    return true;
  }

  aJSVal.setNull();
  return false;
}

NS_IMETHODIMP
EventListenerInfo::ToSource(nsAString& aResult)
{
  aResult.SetIsVoid(true);

  AutoSafeJSContext cx;
  Maybe<JSAutoCompartment> ac;
  JS::Rooted<JS::Value> v(cx);
  if (GetJSVal(cx, ac, &v)) {
    JSString* str = JS_ValueToSource(cx, v);
    if (str) {
      nsAutoJSString autoStr;
      if (autoStr.init(cx, str)) {
        aResult.Assign(autoStr);
      }
    }
  }
  return NS_OK;
}

EventListenerService*
EventListenerService::sInstance = nullptr;

EventListenerService::EventListenerService()
{
  MOZ_ASSERT(!sInstance);
  sInstance = this;
}

EventListenerService::~EventListenerService()
{
  MOZ_ASSERT(sInstance == this);
  sInstance = nullptr;
}

NS_IMETHODIMP
EventListenerService::GetListenerInfoFor(EventTarget* aEventTarget,
                                         uint32_t* aCount,
                                         nsIEventListenerInfo*** aOutArray)
{
  NS_ENSURE_ARG_POINTER(aEventTarget);
  *aCount = 0;
  *aOutArray = nullptr;
  nsCOMArray<nsIEventListenerInfo> listenerInfos;

  EventListenerManager* elm = aEventTarget->GetExistingListenerManager();
  if (elm) {
    elm->GetListenerInfo(&listenerInfos);
  }

  int32_t count = listenerInfos.Count();
  if (count == 0) {
    return NS_OK;
  }

  listenerInfos.Forget(aOutArray);
  *aCount = count;
  return NS_OK;
}

NS_IMETHODIMP
EventListenerService::GetEventTargetChainFor(EventTarget* aEventTarget,
                                             bool aComposed,
                                             uint32_t* aCount,
                                             EventTarget*** aOutArray)
{
  *aCount = 0;
  *aOutArray = nullptr;
  NS_ENSURE_ARG(aEventTarget);
  WidgetEvent event(true, eVoidEvent);
  event.SetComposed(aComposed);
  nsTArray<EventTarget*> targets;
  nsresult rv = EventDispatcher::Dispatch(aEventTarget, nullptr, &event,
                                          nullptr, nullptr, nullptr, &targets);
  NS_ENSURE_SUCCESS(rv, rv);
  int32_t count = targets.Length();
  if (count == 0) {
    return NS_OK;
  }

  *aOutArray =
    static_cast<EventTarget**>(
      moz_xmalloc(sizeof(EventTarget*) * count));
  NS_ENSURE_TRUE(*aOutArray, NS_ERROR_OUT_OF_MEMORY);

  for (int32_t i = 0; i < count; ++i) {
    NS_ADDREF((*aOutArray)[i] = targets[i]);
  }
  *aCount = count;

  return NS_OK;
}

NS_IMETHODIMP
EventListenerService::HasListenersFor(EventTarget* aEventTarget,
                                      const nsAString& aType,
                                      bool* aRetVal)
{
  NS_ENSURE_TRUE(aEventTarget, NS_ERROR_UNEXPECTED);

  EventListenerManager* elm = aEventTarget->GetExistingListenerManager();
  *aRetVal = elm && elm->HasListenersFor(aType);
  return NS_OK;
}

static already_AddRefed<EventListener>
ToEventListener(JSContext* aCx, JS::Handle<JS::Value> aValue)
{
  if (NS_WARN_IF(!aValue.isObject())) {
    return nullptr;
  }

  JS::Rooted<JSObject*> obj(aCx, &aValue.toObject());
  RefPtr<EventListener> listener =
    new EventListener(aCx, obj, GetIncumbentGlobal());
  return listener.forget();
}

NS_IMETHODIMP
EventListenerService::AddSystemEventListener(EventTarget *aTarget,
                                             const nsAString& aType,
                                             JS::Handle<JS::Value> aListener,
                                             bool aUseCapture,
                                             JSContext* aCx)
{
  MOZ_ASSERT(aTarget, "Missing target");

  NS_ENSURE_TRUE(aTarget, NS_ERROR_UNEXPECTED);

  RefPtr<EventListener> listener = ToEventListener(aCx, aListener);
  if (!listener) {
    return NS_ERROR_UNEXPECTED;
  }

  EventListenerManager* manager = aTarget->GetOrCreateListenerManager();
  NS_ENSURE_STATE(manager);

  EventListenerFlags flags =
    aUseCapture ? TrustedEventsAtSystemGroupCapture() :
                  TrustedEventsAtSystemGroupBubble();
  manager->AddEventListenerByType(listener, aType, flags);
  return NS_OK;
}

NS_IMETHODIMP
EventListenerService::RemoveSystemEventListener(EventTarget *aTarget,
                                                const nsAString& aType,
                                                JS::Handle<JS::Value> aListener,
                                                bool aUseCapture,
                                                JSContext* aCx)
{
  MOZ_ASSERT(aTarget, "Missing target");

  NS_ENSURE_TRUE(aTarget, NS_ERROR_UNEXPECTED);

  RefPtr<EventListener> listener = ToEventListener(aCx, aListener);
  if (!listener) {
    return NS_ERROR_UNEXPECTED;
  }

  EventListenerManager* manager = aTarget->GetExistingListenerManager();
  if (manager) {
    EventListenerFlags flags =
      aUseCapture ? TrustedEventsAtSystemGroupCapture() :
                    TrustedEventsAtSystemGroupBubble();
    manager->RemoveEventListenerByType(listener, aType, flags);
  }

  return NS_OK;
}

NS_IMETHODIMP
EventListenerService::AddListenerForAllEvents(EventTarget* aTarget,
                                              JS::Handle<JS::Value> aListener,
                                              bool aUseCapture,
                                              bool aWantsUntrusted,
                                              bool aSystemEventGroup,
                                              JSContext* aCx)
{
  NS_ENSURE_STATE(aTarget);

  RefPtr<EventListener> listener = ToEventListener(aCx, aListener);
  if (!listener) {
    return NS_ERROR_UNEXPECTED;
  }

  EventListenerManager* manager = aTarget->GetOrCreateListenerManager();
  NS_ENSURE_STATE(manager);
  manager->AddListenerForAllEvents(listener, aUseCapture, aWantsUntrusted,
                                   aSystemEventGroup);
  return NS_OK;
}

NS_IMETHODIMP
EventListenerService::RemoveListenerForAllEvents(EventTarget* aTarget,
                                                 JS::Handle<JS::Value> aListener,
                                                 bool aUseCapture,
                                                 bool aSystemEventGroup,
                                                 JSContext* aCx)
{
  NS_ENSURE_STATE(aTarget);

  RefPtr<EventListener> listener = ToEventListener(aCx, aListener);
  if (!listener) {
    return NS_ERROR_UNEXPECTED;
  }

  EventListenerManager* manager = aTarget->GetExistingListenerManager();
  if (manager) {
    manager->RemoveListenerForAllEvents(listener, aUseCapture, aSystemEventGroup);
  }
  return NS_OK;
}

NS_IMETHODIMP
EventListenerService::AddListenerChangeListener(nsIListenerChangeListener* aListener)
{
  if (!mChangeListeners.Contains(aListener)) {
    mChangeListeners.AppendElement(aListener);
  }
  return NS_OK;
};

NS_IMETHODIMP
EventListenerService::RemoveListenerChangeListener(nsIListenerChangeListener* aListener)
{
  mChangeListeners.RemoveElement(aListener);
  return NS_OK;
};

void
EventListenerService::NotifyAboutMainThreadListenerChangeInternal(dom::EventTarget* aTarget,
                                                                  nsAtom* aName)
{
  MOZ_ASSERT(NS_IsMainThread());
  MOZ_ASSERT(aTarget);
  if (mChangeListeners.IsEmpty()) {
    return;
  }

  if (!mPendingListenerChanges) {
    mPendingListenerChanges = nsArrayBase::Create();
    nsCOMPtr<nsIRunnable> runnable =
      NewRunnableMethod("EventListenerService::NotifyPendingChanges",
                        this, &EventListenerService::NotifyPendingChanges);
    if (nsCOMPtr<nsIGlobalObject> global = aTarget->GetOwnerGlobal()) {
      global->Dispatch(TaskCategory::Other, runnable.forget());
    } else if (nsCOMPtr<nsINode> node = do_QueryInterface(aTarget)) {
      node->OwnerDoc()->Dispatch(TaskCategory::Other, runnable.forget());
    } else {
      NS_DispatchToCurrentThread(runnable);
    }
  }

  RefPtr<EventListenerChange> changes =
    mPendingListenerChangesSet.LookupForAdd(aTarget).OrInsert(
      [this, aTarget] () {
        EventListenerChange* c = new EventListenerChange(aTarget);
        mPendingListenerChanges->AppendElement(c);
        return c;
      });
  changes->AddChangedListenerName(aName);
}

void
EventListenerService::NotifyPendingChanges()
{
  nsCOMPtr<nsIMutableArray> changes;
  mPendingListenerChanges.swap(changes);
  mPendingListenerChangesSet.Clear();

  nsTObserverArray<nsCOMPtr<nsIListenerChangeListener>>::EndLimitedIterator
    iter(mChangeListeners);
  while (iter.HasMore()) {
    nsCOMPtr<nsIListenerChangeListener> listener = iter.GetNext();
    listener->ListenersChanged(changes);
  }
}

} // namespace mozilla

nsresult
NS_NewEventListenerService(nsIEventListenerService** aResult)
{
  *aResult = new mozilla::EventListenerService();
  NS_ADDREF(*aResult);
  return NS_OK;
}