/*
    * 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.QName;
  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.Element;
  import org.w3c.dom.NamedNodeMap;
  import org.w3c.dom.Node;
  
  /**
   * An iterator of attributes of a DOM Node.
   *
   * @author Dmitri Plotnikov
   * @version $Revision: 652845 $ $Date: 2008-05-02 19:46:46 +0200 (Fr, 02 Mai 2008) $
   */
  public class DOMAttributeIterator implements NodeIterator {
      private NodePointer parent;
      private QName name;
      private List attributes;
      private int position = 0;
  
      /**
       * Create a new DOMAttributeIterator.
       * @param parent pointer
       * @param name to test
       */
      public DOMAttributeIterator(NodePointer parent, QName name) {
          this.parent = parent;
          this.name = name;
          attributes = new ArrayList();
          Node node = (Node) parent.getNode();
          if (node.getNodeType() == Node.ELEMENT_NODE) {
              String lname = name.getName();
              if (!lname.equals("*")) {
                  Attr attr = getAttribute((Element) node, name);
                  if (attr != null) {
                      attributes.add(attr);
                  }
              }
              else {
                  NamedNodeMap map = node.getAttributes();
                  int count = map.getLength();
                  for (int i = 0; i < count; i++) {
                      Attr attr = (Attr) map.item(i);
                      if (testAttr(attr)) {
                          attributes.add(attr);
                      }
                  }
              }
          }
      }
  
      /**
       * Test an attribute.
       * @param attr to test
       * @return whether test succeeded
       */
      private boolean testAttr(Attr attr) {
          String nodePrefix = DOMNodePointer.getPrefix(attr);
          String nodeLocalName = DOMNodePointer.getLocalName(attr);
  
          if (nodePrefix != null && nodePrefix.equals("xmlns")) {
              return false;
          }
  
          if (nodePrefix == null && nodeLocalName.equals("xmlns")) {
              return false;
          }
  
          String testLocalName = name.getName();
          if (testLocalName.equals("*") || testLocalName.equals(nodeLocalName)) {
              String testPrefix = name.getPrefix();
  
              if (testPrefix == null || equalStrings(testPrefix, nodePrefix)) {
                  return true;
              }
              if (nodePrefix == null) {
                  return false;
              }
             return equalStrings(parent.getNamespaceURI(testPrefix), parent
                     .getNamespaceURI(nodePrefix));
         }
         return false;
     }
 
     /**
      * Test whether two strings are == or .equals()
      * @param s1 first string
      * @param s2 second string
      * @return boolean
      */
     private static boolean equalStrings(String s1, String s2) {
         return s1 == s2 || s1 != null && s1.equals(s2);
     }
 
     /**
      * Get the named attribute.
      * @param element to search
      * @param name to match
      * @return Attr found
      */
     private Attr getAttribute(Element element, QName name) {
         String testPrefix = name.getPrefix();
         String testNS = null;
 
         if (testPrefix != null) {
             testNS = parent.getNamespaceResolver().getNamespaceURI(testPrefix);
         }
 
         if (testNS != null) {
             Attr attr = element.getAttributeNodeNS(testNS, name.getName());
             if (attr != null) {
                 return attr;
             }
 
             // This may mean that the parser does not support NS for
             // attributes, example - the version of Crimson bundled
             // with JDK 1.4.0
             NamedNodeMap nnm = element.getAttributes();
             for (int i = 0; i < nnm.getLength(); i++) {
                 attr = (Attr) nnm.item(i);
                 if (testAttr(attr)) {
                     return attr;
                 }
             }
             return null;
         }
         return element.getAttributeNode(name.getName());
     }
 
     public NodePointer getNodePointer() {
         if (position == 0) {
             if (!setPosition(1)) {
                 return null;
             }
             position = 0;
         }
         int index = position - 1;
         if (index < 0) {
             index = 0;
         }
         return new DOMAttributePointer(parent, (Attr) attributes.get(index));
     }
 
     public int getPosition() {
         return position;
     }
 
     public boolean setPosition(int position) {
         this.position = position;
         return position >= 1 && position <= attributes.size();
     }
 }