/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

/* vim: set ts=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/. */

#ifndef _nsAccessiblePivot_H_

#define _nsAccessiblePivot_H_

#include "nsIAccessiblePivot.h"

#include "Accessible-inl.h"

#include "nsTObserverArray.h"

#include "nsCycleCollectionParticipant.h"

#include "mozilla/Attributes.h"

class RuleCache;

/**

 * Class represents an accessible pivot.

 */

class nsAccessiblePivot final : public nsIAccessiblePivot

{

public:

  typedef mozilla::a11y::Accessible Accessible;

  explicit nsAccessiblePivot(Accessible* aRoot);

  NS_DECL_CYCLE_COLLECTING_ISUPPORTS

  NS_DECL_CYCLE_COLLECTION_CLASS_AMBIGUOUS(nsAccessiblePivot, nsIAccessiblePivot)

  NS_DECL_NSIACCESSIBLEPIVOT

  /*

   * A simple getter for the pivot's position.

   */

  Accessible* Position() { return mPosition; }

  int32_t StartOffset() { return mStartOffset; }

  int32_t EndOffset() { return mEndOffset; }

private:

  ~nsAccessiblePivot();

  nsAccessiblePivot() = delete;

  nsAccessiblePivot(const nsAccessiblePivot&) = delete;

  void operator = (const nsAccessiblePivot&) = delete;

  /*

   * Notify all observers on a pivot change. Return true if it has changed and

   * observers have been notified.

   */

  bool NotifyOfPivotChange(Accessible* aOldAccessible,

                           int32_t aOldStart, int32_t aOldEnd,

                           PivotMoveReason aReason,

                           TextBoundaryType aBoundaryType,

                           bool aIsFromUserInput);

  /*

   * Check to see that the given accessible is a descendant of given ancestor

   */

  bool IsDescendantOf(Accessible* aAccessible, Accessible* aAncestor);

  /*

   * Search in preorder for the first accessible to match the rule.

   */

  Accessible* SearchForward(Accessible* aAccessible,

                            nsIAccessibleTraversalRule* aRule,

                            bool aSearchCurrent,

                            nsresult* aResult);

  /*

   * Reverse search in preorder for the first accessible to match the rule.

   */

  Accessible* SearchBackward(Accessible* aAccessible,

                             nsIAccessibleTraversalRule* aRule,

                             bool aSearchCurrent,

                             nsresult* aResult);

  /*

   * Search in preorder for the first text accessible.

   */

  mozilla::a11y::HyperTextAccessible* SearchForText(Accessible* aAccessible,

                                                    bool aBackward);

  /*

   * Get the effective root for this pivot, either the true root or modal root.

   */

  Accessible* GetActiveRoot() const

  {

    if (mModalRoot) {

      NS_ENSURE_FALSE(mModalRoot->IsDefunct(), mRoot);

      return mModalRoot;

    }

    return mRoot;

  }

  /*

   * Update the pivot, and notify observers. Return true if it moved.

   */

  bool MovePivotInternal(Accessible* aPosition, PivotMoveReason aReason,

                         bool aIsFromUserInput);

  /*

   * Get initial node we should start a search from with a given rule.

   *

   * When we do a move operation from one position to another,

   * the initial position can be inside of a subtree that is ignored by

   * the given rule. We need to step out of the ignored subtree and start

   * the search from there.

   *

   */

  Accessible* AdjustStartPosition(Accessible* aAccessible, RuleCache& aCache,

                                  uint16_t* aFilterResult, nsresult* aResult);

  /*

   * The root accessible.

   */

  RefPtr<Accessible> mRoot;

  /*

   * The temporary modal root accessible.

   */

  RefPtr<Accessible> mModalRoot;

  /*

   * The current pivot position.

   */

  RefPtr<Accessible> mPosition;

  /*

   * The text start offset ofthe pivot.

   */

  int32_t mStartOffset;

  /*

   * The text end offset ofthe pivot.

   */

  int32_t mEndOffset;

  /*

   * The list of pivot-changed observers.

   */

  nsTObserverArray<nsCOMPtr<nsIAccessiblePivotObserver> > mObservers;

};

#endif