/*
 * The Apache Software License, Version 1.1
 *
 *
 * Copyright (c) 1999 The Apache Software Foundation.  All rights 
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer. 
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:  
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Xalan" and "Apache Software Foundation" must
 *    not be used to endorse or promote products derived from this
 *    software without prior written permission. For written 
 *    permission, please contact apache@apache.org.
 *
 * 5. Products derived from this software may not be called "Apache",
 *    nor may "Apache" appear in their name, without prior written
 *    permission of the Apache Software Foundation.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation and was
 * originally based on software copyright (c) 1999, Lotus
 * Development Corporation., http://www.lotus.com.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 */
package org.apache.xml.utils;

import org.w3c.dom.*;

import org.xml.sax.*;
import org.xml.sax.ext.LexicalHandler;

import org.apache.xpath.DOM2Helper;
import org.apache.xpath.DOMHelper;
import org.apache.xml.utils.NodeConsumer;

/**
 * <meta name="usage" content="advanced"/>
 * This class does a pre-order walk of the DOM tree, calling a ContentHandler
 * interface as it goes.
 */
public class TreeWalker
{

  /** Local reference to a ContentHandler          */
  private ContentHandler m_contentHandler = null;

  // ARGHH!!  JAXP Uses Xerces without setting the namespace processing to ON!
  // DOM2Helper m_dh = new DOM2Helper();

  /** DomHelper for this TreeWalker          */
  protected DOMHelper m_dh;

  /**
   * Get the ContentHandler used for the tree walk.
   *
   * @return the ContentHandler used for the tree walk
   */
  public ContentHandler getContentHandler()
  {
    return m_contentHandler;
  }

  /**
   * Get the ContentHandler used for the tree walk.
   *
   * @return the ContentHandler used for the tree walk
   */
  public void setContentHandler(ContentHandler ch)
  {
    m_contentHandler = ch;
  }

  /**
   * Constructor.
   * @param   contentHandler The implemention of the
   * contentHandler operation (toXMLString, digest, ...)
   */
  public TreeWalker(ContentHandler contentHandler, DOMHelper dh)
  {
    this.m_contentHandler = contentHandler;
    m_dh = dh;
  }
  
  /**
   * Constructor.
   * @param   contentHandler The implemention of the
   * contentHandler operation (toXMLString, digest, ...)
   */
  public TreeWalker(ContentHandler contentHandler)
  {
    this.m_contentHandler = contentHandler;
    m_dh = new org.apache.xpath.DOM2Helper();
  }

  /**
   * Perform a pre-order traversal non-recursive style.
   *
   * @param pos Node in the tree where to start traversal
   *
   * @throws TransformerException
   */
  public void traverse(Node pos) throws org.xml.sax.SAXException
  {

    Node top = pos;

    while (null != pos)
    {
      startNode(pos);

      Node nextNode = pos.getFirstChild();

      while (null == nextNode)
      {
        endNode(pos);

        if (top.equals(pos))
          break;

        nextNode = pos.getNextSibling();

        if (null == nextNode)
        {
          pos = pos.getParentNode();

          if ((null == pos) || (top.equals(pos)))
          {
            if (null != pos)
              endNode(pos);

            nextNode = null;

            break;
          }
        }
      }

      pos = nextNode;
    }
  }

  /**
   * Perform a pre-order traversal non-recursive style.
   *
   * @param pos Node in the tree where to start traversal
   * @param top Node in the tree where to end traversal
   *
   * @throws TransformerException
   */
  public void traverse(Node pos, Node top) throws org.xml.sax.SAXException
  {

    while (null != pos)
    {
      startNode(pos);

      Node nextNode = pos.getFirstChild();

      while (null == nextNode)
      {
        endNode(pos);

        if ((null != top) && top.equals(pos))
          break;

        nextNode = pos.getNextSibling();

        if (null == nextNode)
        {
          pos = pos.getParentNode();

          if ((null == pos) || ((null != top) && top.equals(pos)))
          {
            nextNode = null;

            break;
          }
        }
      }

      pos = nextNode;
    }
  }

  /** Flag indicating whether following text to be processed is raw text          */
  boolean nextIsRaw = false;
  
  /**
   * Optimized dispatch of characters.
   */
  private final void dispatachChars(Node node)
     throws org.xml.sax.SAXException
  {
    String data = ((Text) node).getData();
    this.m_contentHandler.characters(data.toCharArray(), 0, data.length());
  }

  /**
   * Start processing given node
   *
   *
   * @param node Node to process
   *
   * @throws org.xml.sax.SAXException
   */
  protected void startNode(Node node) throws org.xml.sax.SAXException
  {

    if (m_contentHandler instanceof NodeConsumer)
    {
      ((NodeConsumer) m_contentHandler).setOriginatingNode(node);
    }

    switch (node.getNodeType())
    {
    case Node.COMMENT_NODE :
    {
      String data = ((Comment) node).getData();

      if (m_contentHandler instanceof LexicalHandler)
      {
        LexicalHandler lh = ((LexicalHandler) this.m_contentHandler);

        lh.comment(data.toCharArray(), 0, data.length());
      }
    }
    break;
    case Node.DOCUMENT_FRAGMENT_NODE :

      // ??;
      break;
    case Node.DOCUMENT_NODE :
      this.m_contentHandler.startDocument();
      break;
    case Node.ELEMENT_NODE :
      NamedNodeMap atts = ((Element) node).getAttributes();
      int nAttrs = atts.getLength();
      // System.out.println("TreeWalker#startNode: "+node.getNodeName());

      for (int i = 0; i < nAttrs; i++)
      {
        Node attr = atts.item(i);
        String attrName = attr.getNodeName();

        // System.out.println("TreeWalker#startNode: attr["+i+"] = "+attrName+", "+attr.getNodeValue());
        if (attrName.equals("xmlns") || attrName.startsWith("xmlns:"))
        {
          // System.out.println("TreeWalker#startNode: attr["+i+"] = "+attrName+", "+attr.getNodeValue());
          int index;
          // Use "" instead of null, as Xerces likes "" for the 
          // name of the default namespace.  Fix attributed 
          // to "Steven Murray" <smurray@ebt.com>.
          String prefix = (index = attrName.indexOf(":")) < 0
                          ? "" : attrName.substring(index + 1);

          this.m_contentHandler.startPrefixMapping(prefix,
                                                   attr.getNodeValue());
        }
        
      }

      // System.out.println("m_dh.getNamespaceOfNode(node): "+m_dh.getNamespaceOfNode(node));
      // System.out.println("m_dh.getLocalNameOfNode(node): "+m_dh.getLocalNameOfNode(node));
      String ns = m_dh.getNamespaceOfNode(node);
      if(null == ns)
        ns = "";
      this.m_contentHandler.startElement(ns,
                                         m_dh.getLocalNameOfNode(node),
                                         node.getNodeName(),
                                         new AttList(atts, m_dh));
      break;
    case Node.PROCESSING_INSTRUCTION_NODE :
    {
      ProcessingInstruction pi = (ProcessingInstruction) node;
      String name = pi.getNodeName();

      // String data = pi.getData();
      if (name.equals("xslt-next-is-raw"))
      {
        nextIsRaw = true;
      }
      else
      {
        this.m_contentHandler.processingInstruction(pi.getNodeName(),
                                                    pi.getData());
      }
    }
    break;
    case Node.CDATA_SECTION_NODE :
    {
      boolean isLexH = (m_contentHandler instanceof LexicalHandler);
      LexicalHandler lh = isLexH
                          ? ((LexicalHandler) this.m_contentHandler) : null;

      if (isLexH)
      {
        lh.startCDATA();
      }
      
      dispatachChars(node);

      {
        if (isLexH)
        {
          lh.endCDATA();
        }
      }
    }
    break;
    case Node.TEXT_NODE :
    {
      String data = ((Text) node).getData();

      if (nextIsRaw)
      {
        nextIsRaw = false;

        m_contentHandler.processingInstruction(javax.xml.transform.Result.PI_DISABLE_OUTPUT_ESCAPING, "");
        dispatachChars(node);
        m_contentHandler.processingInstruction(javax.xml.transform.Result.PI_ENABLE_OUTPUT_ESCAPING, "");
      }
      else
      {
        dispatachChars(node);
      }
    }
    break;
    case Node.ENTITY_REFERENCE_NODE :
    {
      EntityReference eref = (EntityReference) node;

      if (m_contentHandler instanceof LexicalHandler)
      {
        ((LexicalHandler) this.m_contentHandler).startEntity(
          eref.getNodeName());
      }
      else
      {

        // warning("Can not output entity to a pure SAX ContentHandler");
      }
    }
    break;
    default :
    }
  }

  /**
   * End processing of given node 
   *
   *
   * @param node Node we just finished processing
   *
   * @throws org.xml.sax.SAXException
   */
  protected void endNode(Node node) throws org.xml.sax.SAXException
  {

    switch (node.getNodeType())
    {
    case Node.DOCUMENT_NODE :
      this.m_contentHandler.endDocument();
      break;
    case Node.ELEMENT_NODE :
      String ns = m_dh.getNamespaceOfNode(node);
      if(null == ns)
        ns = "";
      this.m_contentHandler.endElement(ns,
                                         m_dh.getLocalNameOfNode(node),
                                         node.getNodeName());

      NamedNodeMap atts = ((Element) node).getAttributes();
      int nAttrs = atts.getLength();

      for (int i = 0; i < nAttrs; i++)
      {
        Node attr = atts.item(i);
        String attrName = attr.getNodeName();

        if (attrName.equals("xmlns") || attrName.startsWith("xmlns:"))
        {
          int index;
          // Use "" instead of null, as Xerces likes "" for the 
          // name of the default namespace.  Fix attributed 
          // to "Steven Murray" <smurray@ebt.com>.
          String prefix = (index = attrName.indexOf(":")) < 0
                          ? "" : attrName.substring(index + 1);

          this.m_contentHandler.endPrefixMapping(prefix);
        }
      }
      break;
    case Node.CDATA_SECTION_NODE :
      break;
    case Node.ENTITY_REFERENCE_NODE :
    {
      EntityReference eref = (EntityReference) node;

      if (m_contentHandler instanceof LexicalHandler)
      {
        LexicalHandler lh = ((LexicalHandler) this.m_contentHandler);

        lh.endEntity(eref.getNodeName());
      }
    }
    break;
    default :
    }
  }
}  //TreeWalker