/*
 * Created on 20.11.2003
 *
 * (c) Stabsstelle IKT-Strategie des Bundes
 */
package at.gv.egovernment.moa.spss.slinterface.transformers;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;

import org.apache.xerces.dom.DocumentImpl;
import org.w3c.dom.Attr;
import org.w3c.dom.Element;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.w3c.dom.traversal.DocumentTraversal;
import org.w3c.dom.traversal.NodeFilter;
import org.w3c.dom.traversal.NodeIterator;

import at.gv.egovernment.moa.spss.slinterface.Constants;

/**
 * @author Gregor Karlinger (mailto:gregor.karlinger@cio.gv.at) 
 */
public class Utils
{
  /**
   * 
   * @param elem
   * @param prefixes
   * @param namespaces
   * @param names
   * 
   * @pre <code>elem</code> is backed by a <code>org.apache.xerces.dom.DocumentImpl</code>.
   */
  public static Element transformDeep(Element elem, Map prefixes, Map namespaces, Map names)
  {
    // Get node iterator for element
    DocumentTraversal docTraversal = (DocumentImpl) elem.getOwnerDocument();
    NodeIterator elemsIt = docTraversal.createNodeIterator(elem, NodeFilter.SHOW_ELEMENT, null, true);
    
    // Make iterator immutable
    List elemsList = new LinkedList();
    while (true)
    {
      Node currNode = elemsIt.nextNode();
      if (currNode == null) break;
      elemsList.add(currNode); 
    }
    
    Iterator elemsImmIt = elemsList.iterator();
    Element returnValue = null;
    while (elemsImmIt.hasNext())
    {
      Element currElem = (Element) elemsImmIt.next();

      String nsUri = currElem.getNamespaceURI();
      String localName = currElem.getLocalName();
      QName qName = new QName(nsUri, localName);

      // Check if element is in "names"
      QName newQName = (QName)names.get(qName);
      if (newQName != null)
      {
        Element transformedElem = transformElem(currElem, newQName, prefixes);
        if (returnValue == null) returnValue = transformedElem;
      }
      else
      {
        String newNamespace = (String)namespaces.get(nsUri);
        if (newNamespace != null)
        {
          newQName = new QName(newNamespace, localName);
          Element transformedElem = transformElem(currElem, newQName, prefixes);
          if (returnValue == null) returnValue = transformedElem;
        }
      }  
    }
    return returnValue;
  }
  
  /* ---------------------------------------------------------------------------------------------------- */

  private static Element transformElem(Element currElem, QName newQName, Map prefixes)
  {
    Element newElem = currElem.getOwnerDocument().createElementNS(newQName.nsUrl_, 
      (String) prefixes.get(newQName.nsUrl_) + ":" + newQName.localName_);
        
    currElem.getParentNode().replaceChild(newElem, currElem);
        
    // Treat attributes of currElem
    NamedNodeMap currAttrs = currElem.getAttributes(); 
    ArrayList currAttrsList = new ArrayList(currAttrs.getLength());
    for (int i = 0; i < currAttrs.getLength(); i++) currAttrsList.add(currAttrs.item(i));
    for (int i = 0; i < currAttrsList.size(); i++)
    {
      Attr currAttr = (Attr)currAttrsList.get(i);
      currAttr.getOwnerElement().removeAttributeNode(currAttr);
      
      // Workaround for bad Xerces behaviour: default attributes in the xml namespace are created without
      // the xml prefix
      if (Constants.NSURI_XML_.equals(currAttr.getNamespaceURI()) && "space".equals(currAttr.getLocalName()))
      {
        newElem.setAttributeNS(Constants.NSURI_XML_, "xml:space", currAttr.getValue());        
      }
      else
      {
        newElem.setAttributeNode(currAttr); 
      }
    }
        
    // Treat child nodes of currElem
    NodeList currChildren = currElem.getChildNodes();
    ArrayList currChildrenList = new ArrayList(currChildren.getLength());
    for (int i = 0; i < currChildren.getLength(); i++) currChildrenList.add(currChildren.item(i));
    for (int i = 0; i < currChildrenList.size(); i++)
    {
      Node currChild = (Node)currChildrenList.get(i);
      currElem.removeChild(currChild);
      newElem.appendChild(currChild);
    }
    
    return newElem;
  }
}