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/*
 Copyright 2013 Red Hat, Inc. and/or its affiliates.

 This file is part of lightblue.

 This program is free software: you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
 the Free Software Foundation, either version 3 of the License, or
 (at your option) any later version.

 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU General Public License for more details.

 You should have received a copy of the GNU General Public License
 along with this program.  If not, see .
 */
package com.redhat.lightblue.util;

import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.node.ArrayNode;
import com.fasterxml.jackson.databind.node.ObjectNode;

import java.util.Iterator;

/**
 * Note that parent() for JsonNode returns the grandparent of the current
 * JsonNode if it is not an ArrayNode or ObjectNode
 */
public final class JsonNodeCursor extends AbstractTreeCursor {

    private static final class ArrayElementCursor implements KeyValueCursor {
        private int index = -1;
        private final Iterator itr;
        private JsonNode node;

        public ArrayElementCursor(Iterator itr) {
            this.itr = itr;
        }

        @Override
        public boolean hasNext() {
            return itr.hasNext();
        }

        @Override
        public void next() {
            node = itr.next();
            index++;
        }

        @Override
        public String getCurrentKey() {
            return Integer.toString(index);
        }

        @Override
        public JsonNode getCurrentValue() {
            return node;
        }
    }

    public JsonNodeCursor(Path p, JsonNode start) {
        super(p.normalize(), start);
    }

    @Override
    protected KeyValueCursor getCursor(JsonNode node) {
        if (node instanceof ArrayNode) {
            return new ArrayElementCursor(((ArrayNode) node).elements());
        } else if (node instanceof ObjectNode) {
            return new KeyValueCursorIteratorAdapter<>(((ObjectNode) node).fields());
        } else {
            throw new IllegalArgumentException(node.getClass().getName());
        }
    }

    @Override
    protected boolean hasChildren(JsonNode node) {
        return node.isContainerNode() && node.size() > 0;
    }
}