/*
    * 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 java.util.Objects;
  
  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.
   */
  public class DOMAttributeIterator implements NodeIterator {
  
      private final NodePointer parent;
      private final QName qName;
      private final List<Attr> attributes;
      private int position;
  
      /**
       * Constructs a new DOMAttributeIterator.
       *
       * @param parent pointer
       * @param qName   to test
       */
      public DOMAttributeIterator(final NodePointer parent, final QName qName) {
          this.parent = parent;
          this.qName = qName;
          attributes = new ArrayList<>();
          final Node node = (Node) parent.getNode();
          if (node.getNodeType() == Node.ELEMENT_NODE) {
              final String lname = qName.getName();
              if (!lname.equals("*")) {
                  final Attr attr = getAttribute((Element) node, qName);
                  if (attr != null) {
                      attributes.add(attr);
                  }
              } else {
                  final NamedNodeMap map = node.getAttributes();
                  final int count = map.getLength();
                  for (int i = 0; i < count; i++) {
                      final Attr attr = (Attr) map.item(i);
                      if (testAttr(attr)) {
                          attributes.add(attr);
                      }
                  }
              }
          }
      }
  
      /**
       * Gets the named attribute.
       *
       * @param element to search
       * @param qName    to match
       * @return Attr found
       */
      private Attr getAttribute(final Element element, final QName qName) {
          final String testPrefix = qName.getPrefix();
          String testNS = null;
          if (testPrefix != null) {
              testNS = parent.getNamespaceResolver().getNamespaceURI(testPrefix);
          }
          if (testNS != null) {
              Attr attr = element.getAttributeNodeNS(testNS, qName.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
              final 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(qName.getName());
     }
 
     @Override
     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, attributes.get(index));
     }
 
     @Override
     public int getPosition() {
         return position;
     }
 
     @Override
     public boolean setPosition(final int position) {
         this.position = position;
         return position >= 1 && position <= attributes.size();
     }
 
     /**
      * Test an attribute.
      *
      * @param attr to test
      * @return whether test succeeded
      */
     private boolean testAttr(final Attr attr) {
         final String nodePrefix = DOMNodePointer.getPrefix(attr);
         final String nodeLocalName = DOMNodePointer.getLocalName(attr);
         if (nodePrefix != null && nodePrefix.equals("xmlns")) {
             return false;
         }
         if (nodePrefix == null && nodeLocalName.equals("xmlns")) {
             return false;
         }
         final String testLocalName = qName.getName();
         if (testLocalName.equals("*") || testLocalName.equals(nodeLocalName)) {
             final String testPrefix = qName.getPrefix();
             if (testPrefix == null || Objects.equals(testPrefix, nodePrefix)) {
                 return true;
             }
             if (nodePrefix == null) {
                 return false;
             }
             return Objects.equals(parent.getNamespaceURI(testPrefix), parent.getNamespaceURI(nodePrefix));
         }
         return false;
     }
 }