/*
    * 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.jdom;
  
  import java.util.ArrayList;
  import java.util.HashSet;
  import java.util.List;
  import java.util.Set;
  
  import org.apache.commons.jxpath.ri.model.NodeIterator;
  import org.apache.commons.jxpath.ri.model.NodePointer;
  import org.jdom.Document;
  import org.jdom.Element;
  import org.jdom.Namespace;
  
  /**
   * An iterator of namespaces of a DOM Node.
   */
  public class JDOMNamespaceIterator implements NodeIterator {
  
      private final NodePointer parent;
      private List<Namespace> namespaces;
      private Set<String> prefixes;
      private int position;
  
      /**
       * Constructs a new JDOMNamespaceIterator.
       *
       * @param parent the parent NodePointer.
       */
      public JDOMNamespaceIterator(final NodePointer parent) {
          this.parent = parent;
          Object node = parent.getNode();
          if (node instanceof Document) {
              node = ((Document) node).getRootElement();
          }
          if (node instanceof Element) {
              namespaces = new ArrayList<>();
              prefixes = new HashSet<>();
              collectNamespaces((Element) node);
          }
      }
  
      /**
       * Collect the namespaces from a JDOM Element.
       *
       * @param element the source Element
       */
      private void collectNamespaces(final Element element) {
          Namespace ns = element.getNamespace();
          if (ns != null && !prefixes.contains(ns.getPrefix())) {
              namespaces.add(ns);
              prefixes.add(ns.getPrefix());
          }
          final List others = element.getAdditionalNamespaces();
          for (final Object other : others) {
              ns = (Namespace) other;
              if (ns != null && !prefixes.contains(ns.getPrefix())) {
                  namespaces.add(ns);
                  prefixes.add(ns.getPrefix());
              }
          }
          final Object elementParent = element.getParent();
          if (elementParent instanceof Element) {
              collectNamespaces((Element) elementParent);
          }
      }
  
      @Override
      public NodePointer getNodePointer() {
          if (position == 0) {
              if (!setPosition(1)) {
                  return null;
              }
              position = 0;
          }
          int index = position - 1;
          if (index < 0) {
              index = 0;
          }
          final Namespace ns = namespaces.get(index);
          return new JDOMNamespacePointer(parent, ns.getPrefix(), ns.getURI());
      }
  
     @Override
     public int getPosition() {
         return position;
     }
 
     @Override
     public boolean setPosition(final int position) {
         if (namespaces == null) {
             return false;
         }
         this.position = position;
         return position >= 1 && position <= namespaces.size();
     }
 }