/*
 * Copyright (C) 2014, 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.
 * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
 *     its contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE 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 OR ITS CONTRIBUTORS BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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 */

#ifndef AXObjectCacheImpl_h
#define AXObjectCacheImpl_h

#include "core/dom/AXObjectCache.h"
#include "modules/ModulesExport.h"
#include "modules/accessibility/AXObject.h"
#include "platform/Timer.h"
#include "wtf/Forward.h"
#include "wtf/HashMap.h"
#include "wtf/HashSet.h"
#include <memory>

namespace blink {

class AbstractInlineTextBox;
class HTMLAreaElement;
class FrameView;

// This class should only be used from inside the accessibility directory.
class MODULES_EXPORT AXObjectCacheImpl : public AXObjectCache {
  WTF_MAKE_NONCOPYABLE(AXObjectCacheImpl);

 public:
  static AXObjectCache* create(Document&);

  explicit AXObjectCacheImpl(Document&);
  ~AXObjectCacheImpl();
  DECLARE_VIRTUAL_TRACE();

  AXObject* focusedObject();

  void dispose() override;

  void selectionChanged(Node*) override;
  void childrenChanged(Node*) override;
  void childrenChanged(LayoutObject*) override;
  void checkedStateChanged(Node*) override;
  virtual void listboxOptionStateChanged(HTMLOptionElement*);
  virtual void listboxSelectedChildrenChanged(HTMLSelectElement*);
  virtual void listboxActiveIndexChanged(HTMLSelectElement*);
  virtual void radiobuttonRemovedFromGroup(HTMLInputElement*);

  void remove(LayoutObject*) override;
  void remove(Node*) override;
  void remove(AbstractInlineTextBox*) override;

  const Element* rootAXEditableElement(const Node*) override;

  // Called by a node when text or a text equivalent (e.g. alt) attribute is
  // changed.
  void textChanged(LayoutObject*) override;
  // Called when a node has just been attached, so we can make sure we have the
  // right subclass of AXObject.
  void updateCacheAfterNodeIsAttached(Node*) override;

  void handleAttributeChanged(const QualifiedName& attrName, Element*) override;
  void handleFocusedUIElementChanged(Node* oldFocusedNode,
                                     Node* newFocusedNode) override;
  void handleInitialFocus() override;
  void handleTextFormControlChanged(Node*) override;
  void handleEditableTextContentChanged(Node*) override;
  void handleValueChanged(Node*) override;
  void handleUpdateActiveMenuOption(LayoutMenuList*, int optionIndex) override;
  void didShowMenuListPopup(LayoutMenuList*) override;
  void didHideMenuListPopup(LayoutMenuList*) override;
  void handleLoadComplete(Document*) override;
  void handleLayoutComplete(Document*) override;
  void handleClicked(Node*) override;

  void setCanvasObjectBounds(HTMLCanvasElement*,
                             Element*,
                             const LayoutRect&) override;

  void inlineTextBoxesUpdated(LineLayoutItem) override;

  // Called when the scroll offset changes.
  void handleScrollPositionChanged(FrameView*) override;
  void handleScrollPositionChanged(LayoutObject*) override;

  // Called when scroll bars are added / removed (as the view resizes).
  void handleLayoutComplete(LayoutObject*) override;
  void handleScrolledToAnchor(const Node* anchorNode) override;

  const AtomicString& computedRoleForNode(Node*) override;
  String computedNameForNode(Node*) override;

  void onTouchAccessibilityHover(const IntPoint&) override;

  // Returns the root object for the entire document.
  AXObject* rootObject();

  AXObject* objectFromAXID(AXID id) const { return m_objects.get(id); }
  AXObject* root();

  // used for objects without backing elements
  AXObject* getOrCreate(AccessibilityRole);
  AXObject* getOrCreate(LayoutObject*);
  AXObject* getOrCreate(Node*);
  AXObject* getOrCreate(AbstractInlineTextBox*);

  // will only return the AXObject if it already exists
  AXObject* get(Node*);
  AXObject* get(LayoutObject*);
  AXObject* get(AbstractInlineTextBox*);

  AXObject* firstAccessibleObjectFromNode(const Node*);

  void remove(AXID);

  void childrenChanged(AXObject*);

  void handleActiveDescendantChanged(Node*);
  void handleAriaRoleChanged(Node*);
  void handleAriaExpandedChange(Node*);
  void handleAriaSelectedChanged(Node*);

  bool accessibilityEnabled();
  bool inlineTextBoxAccessibilityEnabled();

  void removeAXID(AXObject*);

  AXID platformGenerateAXID() const;

  // Counts the number of times the document has been modified. Some attribute
  // values are cached as long as the modification count hasn't changed.
  int modificationCount() const { return m_modificationCount; }

  void postNotification(LayoutObject*, AXNotification);
  void postNotification(Node*, AXNotification);
  void postNotification(AXObject*, AXNotification);

  //
  // Aria-owns support.
  //

  // Returns true if the given object's position in the tree was due to
  // aria-owns.
  bool isAriaOwned(const AXObject*) const;

  // Returns the parent of the given object due to aria-owns.
  AXObject* getAriaOwnedParent(const AXObject*) const;

  // Given an object that has an aria-owns attributes, and a vector of ids from
  // the value of that attribute, updates the internal state to reflect the new
  // set of children owned by this object, returning the result in
  // |ownedChildren|. The result is validated - illegal, duplicate, or cyclical
  // references have been removed.
  //
  // If one or more ids aren't found, they're added to a lookup table so that if
  // an element with that id appears later, it can be added when you call
  // updateTreeIfElementIdIsAriaOwned.
  void updateAriaOwns(const AXObject* owner,
                      const Vector<String>& idVector,
                      HeapVector<Member<AXObject>>& ownedChildren);

  // Given an element in the DOM tree that was either just added or whose id
  // just changed, check to see if another object wants to be its parent due to
  // aria-owns. If so, update the tree by calling childrenChanged() on the
  // potential owner, possibly reparenting this element.
  void updateTreeIfElementIdIsAriaOwned(Element*);

 protected:
  void postPlatformNotification(AXObject*, AXNotification);
  void textChanged(AXObject*);
  void labelChanged(Element*);

  AXObject* createFromRenderer(LayoutObject*);
  AXObject* createFromNode(Node*);
  AXObject* createFromInlineTextBox(AbstractInlineTextBox*);

 private:
  Member<Document> m_document;
  HeapHashMap<AXID, Member<AXObject>> m_objects;
  // LayoutObject and AbstractInlineTextBox are not on the Oilpan heap so we
  // do not use HeapHashMap for those mappings.
  HashMap<LayoutObject*, AXID> m_layoutObjectMapping;
  HeapHashMap<Member<Node>, AXID> m_nodeObjectMapping;
  HashMap<AbstractInlineTextBox*, AXID> m_inlineTextBoxObjectMapping;
  int m_modificationCount;

  HashSet<AXID> m_idsInUse;

#if DCHECK_IS_ON()
  // Verified when finalizing.
  bool m_hasBeenDisposed = false;
#endif

  //
  // Aria-owns
  //

  // Map from the AXID of the owner to the AXIDs of the children.
  // This is a validated map, it doesn't contain illegal, duplicate,
  // or cyclical matches, or references to IDs that don't exist.
  HashMap<AXID, Vector<AXID>> m_ariaOwnerToChildrenMapping;

  // Map from the AXID of a child to the AXID of the parent that owns it.
  HashMap<AXID, AXID> m_ariaOwnedChildToOwnerMapping;

  // Map from the AXID of a child to the AXID of its real parent in the tree if
  // we ignored aria-owns. This is needed in case the owner no longer wants to
  // own it.
  HashMap<AXID, AXID> m_ariaOwnedChildToRealParentMapping;

  // Map from the AXID of any object with an aria-owns attribute to the set of
  // ids of its children. This is *unvalidated*, it includes ids that may not
  // currently exist in the tree.
  HashMap<AXID, HashSet<String>> m_ariaOwnerToIdsMapping;

  // Map from an ID (the ID attribute of a DOM element) to the set of elements
  // that want to own that ID. This is *unvalidated*, it includes possible
  // duplicates.  This is used so that when an element with an ID is added to
  // the tree or changes its ID, we can quickly determine if it affects an
  // aria-owns relationship.
  HashMap<String, std::unique_ptr<HashSet<AXID>>> m_idToAriaOwnersMapping;

  Timer<AXObjectCacheImpl> m_notificationPostTimer;
  HeapVector<std::pair<Member<AXObject>, AXNotification>> m_notificationsToPost;
  void notificationPostTimerFired(TimerBase*);

  AXObject* focusedImageMapUIElement(HTMLAreaElement*);

  AXID getAXID(AXObject*);

  void textChanged(Node*);
  bool nodeIsTextControl(const Node*);

  Settings* settings();
};

// This is the only subclass of AXObjectCache.
DEFINE_TYPE_CASTS(AXObjectCacheImpl, AXObjectCache, cache, true, true);

bool nodeHasRole(Node*, const String& role);
// This will let you know if aria-hidden was explicitly set to false.
bool isNodeAriaVisible(Node*);

}  // namespace blink

#endif