/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=2 sw=2 et 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/. */

#ifndef mozilla_IMEContentObserver_h_
#define mozilla_IMEContentObserver_h_

#include "mozilla/Attributes.h"
#include "nsCOMPtr.h"
#include "nsCycleCollectionParticipant.h"
#include "nsIDocShell.h" // XXX Why does only this need to be included here?
#include "nsIReflowObserver.h"
#include "nsISelectionListener.h"
#include "nsIScrollObserver.h"
#include "nsIWidget.h" // for nsIMEUpdatePreference
#include "nsStubMutationObserver.h"
#include "nsWeakReference.h"

class nsIContent;
class nsINode;
class nsISelection;
class nsPresContext;

namespace mozilla {

class EventStateManager;

// IMEContentObserver notifies widget of any text and selection changes
// in the currently focused editor
class IMEContentObserver MOZ_FINAL : public nsISelectionListener,
                                     public nsStubMutationObserver,
                                     public nsIReflowObserver,
                                     public nsIScrollObserver,
                                     public nsSupportsWeakReference
{
public:
  IMEContentObserver();

  NS_DECL_CYCLE_COLLECTING_ISUPPORTS
  NS_DECL_CYCLE_COLLECTION_CLASS_AMBIGUOUS(IMEContentObserver,
                                           nsISelectionListener)
  NS_DECL_NSISELECTIONLISTENER
  NS_DECL_NSIMUTATIONOBSERVER_CHARACTERDATACHANGED
  NS_DECL_NSIMUTATIONOBSERVER_CONTENTAPPENDED
  NS_DECL_NSIMUTATIONOBSERVER_CONTENTINSERTED
  NS_DECL_NSIMUTATIONOBSERVER_CONTENTREMOVED
  NS_DECL_NSIMUTATIONOBSERVER_ATTRIBUTEWILLCHANGE
  NS_DECL_NSIMUTATIONOBSERVER_ATTRIBUTECHANGED
  NS_DECL_NSIREFLOWOBSERVER

  // nsIScrollObserver
  virtual void ScrollPositionChanged() MOZ_OVERRIDE;

  void Init(nsIWidget* aWidget, nsPresContext* aPresContext,
            nsIContent* aContent);
  void Destroy();
  /**
   * IMEContentObserver is stored by EventStateManager during observing.
   * DisconnectFromEventStateManager() is called when EventStateManager stops
   * storing the instance.
   */
  void DisconnectFromEventStateManager();
  bool IsManaging(nsPresContext* aPresContext, nsIContent* aContent);
  bool IsEditorHandlingEventForComposition() const;
  bool KeepAliveDuringDeactive() const
  {
    return mUpdatePreference.WantDuringDeactive();
  }
  nsIWidget* GetWidget() const { return mWidget; }
  nsresult GetSelectionAndRoot(nsISelection** aSelection,
                               nsIContent** aRoot) const;

private:
  void NotifyContentAdded(nsINode* aContainer, int32_t aStart, int32_t aEnd);
  void ObserveEditableNode();

  nsCOMPtr<nsIWidget> mWidget;
  nsCOMPtr<nsISelection> mSelection;
  nsCOMPtr<nsIContent> mRootContent;
  nsCOMPtr<nsINode> mEditableNode;
  nsCOMPtr<nsIDocShell> mDocShell;

  EventStateManager* mESM;

  nsIMEUpdatePreference mUpdatePreference;
  uint32_t mPreAttrChangeLength;
};

} // namespace mozilla

#endif // mozilla_IMEContentObserver_h_