/*
 * 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/. */

/*
 * Implementation of DOM Traversal's NodeIterator
 */

#ifndef mozilla_dom_NodeIterator_h
#define mozilla_dom_NodeIterator_h

#include "nsCycleCollectionParticipant.h"
#include "nsStubMutationObserver.h"
#include "nsTraversal.h"

class nsINode;

namespace mozilla::dom {

class NodeIterator final : public nsStubMutationObserver, public nsTraversal {
 public:
  NS_DECL_CYCLE_COLLECTING_ISUPPORTS_FINAL

  NodeIterator(nsINode* aRoot, uint32_t aWhatToShow, NodeFilter* aFilter);

  NS_DECL_NSIMUTATIONOBSERVER_CONTENTREMOVED

  NS_DECL_CYCLE_COLLECTION_CLASS(NodeIterator)

  // WebIDL API
  nsINode* Root() const { return mRoot; }
  nsINode* GetReferenceNode() const { return mPointer.mNode; }
  bool PointerBeforeReferenceNode() const { return mPointer.mBeforeNode; }
  uint32_t WhatToShow() const { return mWhatToShow; }
  NodeFilter* GetFilter() { return mFilter; }
  already_AddRefed<nsINode> NextNode(ErrorResult& aResult) {
    return NextOrPrevNode(&NodePointer::MoveToNext, aResult);
  }
  already_AddRefed<nsINode> PreviousNode(ErrorResult& aResult) {
    return NextOrPrevNode(&NodePointer::MoveToPrevious, aResult);
  }
  void Detach();

  bool WrapObject(JSContext* cx, JS::Handle<JSObject*> aGivenProto,
                  JS::MutableHandle<JSObject*> aReflector);

 private:
  ~NodeIterator();

  struct NodePointer {
    NodePointer() : mNode(nullptr), mBeforeNode(false) {}
    NodePointer(nsINode* aNode, bool aBeforeNode);

    typedef bool (NodePointer::*MoveToMethodType)(nsINode*);
    bool MoveToNext(nsINode* aRoot);
    bool MoveToPrevious(nsINode* aRoot);

    bool MoveForward(nsINode* aRoot, nsINode* aNode);
    void MoveBackward(nsINode* aParent, nsINode* aNode);

    void AdjustForRemoval(nsINode* aRoot, nsINode* aContainer,
                          nsIContent* aChild);

    void Clear() { mNode = nullptr; }

    nsINode* mNode;
    bool mBeforeNode;
  };

  // Have to return a strong ref, because the act of testing the node can
  // remove it from the DOM so we're holding the only ref to it.
  already_AddRefed<nsINode> NextOrPrevNode(NodePointer::MoveToMethodType aMove,
                                           ErrorResult& aResult);

  NodePointer mPointer;
  NodePointer mWorkingPointer;
};

}  // namespace mozilla::dom

#endif  // mozilla_dom_NodeIterator_h