/* 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/. */

#ifndef mozilla_DOMEventTargetHelper_h_
#define mozilla_DOMEventTargetHelper_h_

#include "mozilla/Attributes.h"
#include "mozilla/GlobalTeardownObserver.h"
#include "mozilla/RefPtr.h"
#include "mozilla/dom/EventTarget.h"
#include "nsAtom.h"
#include "nsCOMPtr.h"
#include "nsCycleCollectionParticipant.h"
#include "nsDebug.h"
#include "nsGkAtoms.h"
#include "nsID.h"
#include "nsIGlobalObject.h"
#include "nsISupports.h"
#include "nsPIDOMWindow.h"
#include "nsStringFwd.h"
#include "nsTArray.h"

class nsCycleCollectionTraversalCallback;

namespace mozilla {

class ErrorResult;
class EventChainPostVisitor;
class EventChainPreVisitor;
class EventListenerManager;

namespace dom {
class Document;
class Event;
enum class CallerType : uint32_t;
}  // namespace dom

#define NS_DOMEVENTTARGETHELPER_IID \
  {0xa28385c6, 0x9451, 0x4d7e, {0xa3, 0xdd, 0xf4, 0xb6, 0x87, 0x2f, 0xa4, 0x76}}

class DOMEventTargetHelper : public dom::EventTarget,
                             public GlobalTeardownObserver {
 public:
  DOMEventTargetHelper();
  explicit DOMEventTargetHelper(nsPIDOMWindowInner* aWindow);
  explicit DOMEventTargetHelper(nsIGlobalObject* aGlobalObject);
  explicit DOMEventTargetHelper(DOMEventTargetHelper* aOther);

  NS_DECL_ISUPPORTS_INHERITED
  NS_IMETHOD_(void) DeleteCycleCollectable() override;
  NS_DECL_CYCLE_COLLECTION_SKIPPABLE_WRAPPERCACHE_CLASS_AMBIGUOUS(
      DOMEventTargetHelper, dom::EventTarget)

  EventListenerManager* GetExistingListenerManager() const override;
  EventListenerManager* GetOrCreateListenerManager() override;

  bool ComputeDefaultWantsUntrusted(ErrorResult& aRv) override;

  using EventTarget::DispatchEvent;
  // TODO: Convert this to MOZ_CAN_RUN_SCRIPT (bug 1415230)
  MOZ_CAN_RUN_SCRIPT_BOUNDARY bool DispatchEvent(dom::Event& aEvent,
                                                 dom::CallerType aCallerType,
                                                 ErrorResult& aRv) override;

  void GetEventTargetParent(EventChainPreVisitor& aVisitor) override;

  nsresult PostHandleEvent(EventChainPostVisitor& aVisitor) override;

  NS_INLINE_DECL_STATIC_IID(NS_DOMEVENTTARGETHELPER_IID)

  nsIGlobalObject* GetRelevantGlobal() const override {
    return GlobalTeardownObserver::GetRelevantGlobal();
  }

  static DOMEventTargetHelper* FromSupports(nsISupports* aSupports) {
    dom::EventTarget* target = static_cast<dom::EventTarget*>(aSupports);
#ifdef DEBUG
    {
      nsCOMPtr<dom::EventTarget> target_qi = do_QueryInterface(aSupports);

      // If this assertion fires the QI implementation for the object in
      // question doesn't use the EventTarget pointer as the
      // nsISupports pointer. That must be fixed, or we'll crash...
      NS_ASSERTION(target_qi == target, "Uh, fix QI!");
    }
#endif

    return static_cast<DOMEventTargetHelper*>(target);
  }

  bool HasListenersFor(const nsAString& aType) const;

  bool HasListenersFor(nsAtom* aTypeWithOn) const;

  // Like GetOwner, but only returns non-null if the window being returned is
  // current (in the "current document" sense of the HTML spec).
  nsPIDOMWindowInner* GetWindowIfCurrent() const;
  // Returns the document associated with this event target, if that document is
  // the current document of its browsing context.  Will return null otherwise.
  mozilla::dom::Document* GetDocumentIfCurrent() const;

  void DisconnectFromOwner() override;
  using EventTarget::GetParentObject;

  void EventListenerAdded(nsAtom* aType) override;

  void EventListenerRemoved(nsAtom* aType) override;

  // Dispatch a trusted, non-cancellable and non-bubbling event to |this|.
  nsresult DispatchTrustedEvent(const nsAString& aEventName);

 protected:
  virtual ~DOMEventTargetHelper();

  nsresult WantsUntrusted(bool* aRetVal);

  void MaybeUpdateKeepAlive();
  void MaybeDontKeepAlive();

  // If this method returns true your object is kept alive until it returns
  // false. You can use this method instead using
  // NS_IMPL_CYCLE_COLLECTION_CAN_SKIP_BEGIN macro.
  virtual bool IsCertainlyAliveForCC() const { return mIsKeptAlive; }

  RefPtr<EventListenerManager> mListenerManager;
  // Make |event| trusted and dispatch |aEvent| to |this|.
  nsresult DispatchTrustedEvent(dom::Event* aEvent);

  virtual void LastRelease() {}

  void KeepAliveIfHasListenersFor(nsAtom* aType);

  void IgnoreKeepAliveIfHasListenersFor(nsAtom* aType);

 private:
  nsTArray<RefPtr<nsAtom>> mKeepingAliveTypes;

  bool mIsKeptAlive = false;
};

}  // namespace mozilla

// WebIDL event handlers
#define IMPL_EVENT_HANDLER(_event)                                          \
  inline mozilla::dom::EventHandlerNonNull* GetOn##_event() {               \
    return GetEventHandler(nsGkAtoms::on##_event);                          \
  }                                                                         \
  inline void SetOn##_event(mozilla::dom::EventHandlerNonNull* aCallback) { \
    SetEventHandler(nsGkAtoms::on##_event, aCallback);                      \
  }

#endif  // mozilla_DOMEventTargetHelper_h_