/*

  * Licensed to the Apache Software Foundation (ASF) under one

  * or more contributor license agreements. See the NOTICE file

  * distributed with this work for additional information

  * regarding copyright ownership. The ASF licenses this file

  * to you under the Apache License, Version 2.0 (the

  * "License"); you may not use this file except in compliance

  * with the License. You may obtain a copy of the License at

  *

  * http://www.apache.org/licenses/LICENSE-2.0

  *

  * Unless required by applicable law or agreed to in writing,

  * software distributed under the License is distributed on an

  * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY

  * KIND, either express or implied. See the License for the

  * specific language governing permissions and limitations

  * under the License.

  */

 package org.apache.johnzon.jaxrs.xml;

 import org.w3c.dom.Document;

 import org.w3c.dom.NamedNodeMap;

 import org.w3c.dom.Node;

 import org.w3c.dom.NodeList;

 import javax.json.Json;

 import javax.json.JsonArrayBuilder;

 import javax.json.JsonBuilderFactory;

 import javax.json.JsonObjectBuilder;

 import javax.xml.stream.XMLStreamException;

 import java.util.Collection;

 import java.util.Collections;

 import java.util.LinkedHashMap;

 import java.util.LinkedList;

 import java.util.Map;

 public class WadlDocumentToJson {

     private final JsonBuilderFactory builderFactory = Json.createBuilderFactory(Collections.<String, Object>emptyMap());

     public String convert(final Document doc) throws XMLStreamException {

         final JsonObjectBuilder builder = builderFactory.createObjectBuilder();

         if (doc.getChildNodes().getLength() != 1) {

             return "{}";

         }

         final Node item = doc.getChildNodes().item(0);

         return builder.add(item.getNodeName(), createNode(item)).build().toString();

     }

     private void addChildrens(/*final String nodeName, */final JsonObjectBuilder builder, final NodeList children) {

         final Map<String, Collection<Node>> nodesByName = new LinkedHashMap<String, Collection<Node>>();

         for (int i = 0; i < children.getLength(); i++) {

             final Node node = children.item(i);

             if ("#text".equals(node.getNodeName())) {

                 continue;

             }

             final String name = node.getNodeName();

             Collection<Node> nodes = nodesByName.get(name);

             if (nodes == null) {

                 nodes = new LinkedList<Node>();

                 nodesByName.put(name, nodes);

             }

             nodes.add(node);

         }

         for (final Map.Entry<String, Collection<Node>> entry : nodesByName.entrySet()) {

             final JsonArrayBuilder arrayBuilder = builderFactory.createArrayBuilder();

             for (final Node n : entry.getValue()) {

                 final JsonObjectBuilder jsonObjectBuilder = createNode(n);

                 if (jsonObjectBuilder != null) {

                     arrayBuilder.add(jsonObjectBuilder);

                 }

             }

             builder.add(entry.getKey(), arrayBuilder);

         }

     }

     private JsonObjectBuilder createNode(final Node node) {

         JsonObjectBuilder childBuilder = null;

         if (node.hasAttributes()) {

             childBuilder = builderFactory.createObjectBuilder();

             final NamedNodeMap attributes = node.getAttributes();

             for (int j = 0; j < attributes.getLength(); j++) {

                 final Node namedItem = attributes.item(j);

                 childBuilder.add(namedItem.getNodeName(), namedItem.getNodeValue());

             }

         }

         if (node.hasChildNodes()) {

             if (childBuilder == null) {

                 childBuilder = builderFactory.createObjectBuilder();

             }

             addChildrens(/*node.getNodeName(),*/ childBuilder, node.getChildNodes());

         }

         return childBuilder;

     }

 }