/*
    * 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.commons.jxpath.ri.model.dom;
  
  import java.util.ArrayList;
  import java.util.List;
  
  import org.apache.commons.jxpath.ri.model.NodeIterator;
  import org.apache.commons.jxpath.ri.model.NodePointer;
  import org.w3c.dom.Attr;
  import org.w3c.dom.Document;
  import org.w3c.dom.NamedNodeMap;
  import org.w3c.dom.Node;
  
  /**
   * An iterator of namespaces of a DOM Node.
   */
  public class DOMNamespaceIterator implements NodeIterator {
  
      private final NodePointer parent;
      private final List<Attr> attributes;
      private int position;
  
      /**
       * Constructs a new DOMNamespaceIterator.
       *
       * @param parent parent pointer
       */
      public DOMNamespaceIterator(final NodePointer parent) {
          this.parent = parent;
          attributes = new ArrayList<>();
          collectNamespaces(attributes, (Node) parent.getNode());
      }
  
      /**
       * Collect namespaces from attribute nodes.
       *
       * @param attributes attribute list
       * @param node       target node
       */
      private void collectNamespaces(final List<Attr> attributes, Node node) {
          final Node parent = node.getParentNode();
          if (parent != null) {
              collectNamespaces(attributes, parent);
          }
          if (node.getNodeType() == Node.DOCUMENT_NODE) {
              node = ((Document) node).getDocumentElement();
          }
          if (node.getNodeType() == Node.ELEMENT_NODE) {
              final NamedNodeMap map = node.getAttributes();
              final int count = map.getLength();
              for (int i = 0; i < count; i++) {
                  final Attr attr = (Attr) map.item(i);
                  final String prefix = DOMNodePointer.getPrefix(attr);
                  final String name = DOMNodePointer.getLocalName(attr);
                  if (prefix != null && prefix.equals("xmlns") || prefix == null && name.equals("xmlns")) {
                      attributes.add(attr);
                  }
              }
          }
      }
  
      @Override
      public NodePointer getNodePointer() {
          if (position == 0) {
              if (!setPosition(1)) {
                  return null;
              }
              position = 0;
          }
          int index = position - 1;
          if (index < 0) {
              index = 0;
          }
          String prefix = "";
          final Attr attr = attributes.get(index);
          final String name = attr.getPrefix();
          if (name != null && name.equals("xmlns")) {
              prefix = DOMNodePointer.getLocalName(attr);
          }
          return new NamespacePointer(parent, prefix, attr.getValue());
      }
  
      @Override
     public int getPosition() {
         return position;
     }
 
     @Override
     public boolean setPosition(final int position) {
         this.position = position;
         return position >= 1 && position <= attributes.size();
     }
 }