/*
    * Copyright 2005-2010 the original author or authors.
    *
    * Licensed 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.springframework.ws.soap.saaj.support;
  
  import java.util.LinkedHashMap;
  import java.util.Map;
  import javax.xml.soap.Name;
  import javax.xml.soap.SOAPElement;
  import javax.xml.soap.SOAPEnvelope;
  import javax.xml.soap.SOAPException;
  
  import org.springframework.util.Assert;
  import org.springframework.util.StringUtils;
  
  import org.xml.sax.Attributes;
  import org.xml.sax.ContentHandler;
  import org.xml.sax.Locator;
  import org.xml.sax.SAXException;
  
  /**
   * SAX <code>ContentHandler</code> that transforms callback calls to the creation of SAAJ <code>Node</code>s and
   * <code>SOAPElement</code>s.
   *
   * @author Arjen Poutsma
   * @see javax.xml.soap.Node
   * @see javax.xml.soap.SOAPElement
   * @since 1.0.0
   */
  public class SaajContentHandler implements ContentHandler {
  
      private SOAPElement element;
  
      private final SOAPEnvelope envelope;
  
      private Map<String, String> namespaces = new LinkedHashMap<String, String>();
  
      /**
       * Constructs a new instance of the <code>SaajContentHandler</code> that creates children of the given
       * <code>SOAPElement</code>.
       *
       * @param element the element to write to
       */
      public SaajContentHandler(SOAPElement element) {
          Assert.notNull(element, "element must not be null");
          if (element instanceof SOAPEnvelope) {
              envelope = (SOAPEnvelope) element;
          }
          else {
              envelope = SaajUtils.getEnvelope(element);
          }
          this.element = element;
      }
  
      public void characters(char ch[], int start, int length) throws SAXException {
          try {
              String text = new String(ch, start, length);
              element.addTextNode(text);
          }
          catch (SOAPException ex) {
              throw new SAXException(ex);
          }
      }
  
      public void startElement(String uri, String localName, String qName, Attributes atts) throws SAXException {
          try {
              String childPrefix = getPrefix(qName);
              SOAPElement child = element.addChildElement(localName, childPrefix, uri);
              for (int i = 0; i < atts.getLength(); i++) {
                  if (StringUtils.hasLength(atts.getLocalName(i))) {
                      String attributePrefix = getPrefix(atts.getQName(i));
                      if (!"xmlns".equals(atts.getLocalName(i)) && !"xmlns".equals(attributePrefix)) {
                          Name attributeName = envelope.createName(atts.getLocalName(i), attributePrefix, atts.getURI(i));
                          child.addAttribute(attributeName, atts.getValue(i));
                      }
                  }
              }
              for (String namespacePrefix : namespaces.keySet()) {
                  String namespaceUri = namespaces.get(namespacePrefix);
                  if (!findParentNamespaceDeclaration(child, namespacePrefix, namespaceUri)) {
                      child.addNamespaceDeclaration(namespacePrefix, namespaceUri);
                  }
              }
              element = child;
          }
          catch (SOAPException ex) {
             throw new SAXException(ex);
         }
     }
 
     private boolean findParentNamespaceDeclaration(SOAPElement element, String prefix, String namespaceUri) {
         String result = element.getNamespaceURI(prefix);
         if (namespaceUri.equals(result)) {
             return true;
         }
         else {
             try {
                 SOAPElement parent = element.getParentElement();
                 if (parent != null) {
                     return findParentNamespaceDeclaration(parent, prefix, namespaceUri);
                 }
             }
             catch (UnsupportedOperationException ex) {
                 // ignore
             }
             return false;
         }
     }
 
     public void endElement(String uri, String localName, String qName) throws SAXException {
         Assert.isTrue(localName.equals(element.getElementName().getLocalName()), "Invalid element on stack");
         Assert.isTrue(uri.equals(element.getElementName().getURI()), "Invalid element on stack");
         element = element.getParentElement();
     }
 
     public void startPrefixMapping(String prefix, String uri) throws SAXException {
         namespaces.put(prefix, uri);
     }
 
     public void endPrefixMapping(String prefix) throws SAXException {
         namespaces.remove(prefix);
     }
 
     public void setDocumentLocator(Locator locator) {
     }
 
     public void startDocument() throws SAXException {
     }
 
     public void endDocument() throws SAXException {
     }
 
     public void ignorableWhitespace(char ch[], int start, int length) throws SAXException {
     }
 
     public void processingInstruction(String target, String data) throws SAXException {
     }
 
     public void skippedEntity(String name) throws SAXException {
     }
 
     private String getPrefix(String qName) {
         int idx = qName.indexOf(':');
         if (idx != -1) {
             return qName.substring(0, idx);
         }
         else {
             return null;
         }
     }
 }