package org.opensync.engine.server;
   
   import org.opensync.engine.server.OpenSync;
   import org.opensync.engine.util.FileHelper;
   
   import java.io.*;
   import java.net.*;
   import javax.xml.transform.*;
   import javax.xml.transform.stream.*;
  import org.xml.sax.SAXException;
  import org.xml.sax.SAXParseException;
  
  /***
   * This class is used to to transform a business view to an other.
   * It begins by creating the xsl sheet from the xml mapping file and
   * finish by apply it on the xml view.
   */
  
  public class Mapper implements ErrorListener {
  
    /***
     * The xslt transfomer use to produice the xsl sheet
     *
     */
    protected Transformer genMappingTransformer;
    /***
     * The transformer factory
     *
     *
     */
    protected TransformerFactory transformerFactory = TransformerFactory.newInstance();
  
    /***
     * Consruct a <code>Mapper</code> object
     *
     */
    public Mapper() {
      try {
        String fileSeparator = System.getProperty("file.separator");
        Templates templates = transformerFactory.newTemplates(
          new StreamSource(new StringReader(
              FileHelper.fileToString(
                OpenSync.getInstance().getFilePath("etc"+fileSeparator+"gen_mapping.xsl", true)
              )
            )
          )
        );
        genMappingTransformer = templates.newTransformer();
        genMappingTransformer.setErrorListener(this);
      }
      catch (Exception ex) {
        throw new RuntimeException(ex.getMessage());
      }
    }
  
    // Receive notification of a recoverable error.
    public void error(TransformerException exception) throws TransformerException {
      throw exception;
    }
  
    // Receive notification of a non-recoverable error.
    public void fatalError(TransformerException exception) throws TransformerException {
      throw exception;
    }
  
    public void warning(TransformerException exception) throws TransformerException {
      throw exception;
    }
  
    /***
     * Generate the xsl sheet from the xml mapping
     *
     * @param	xmlMapping the xml mapping to transform the view
     * @exception	TransformerException
     * @exception	FileNotFoundException
     */
    private String generateXslMapping(String xmlMapping)throws FileNotFoundException, TransformerException{
      StringWriter resultWriter = new StringWriter();
      genMappingTransformer.transform(
        new StreamSource(new StringReader(xmlMapping)),
        new StreamResult(resultWriter)
      );
  
      return resultWriter.getBuffer().toString();
    }
  
    /***
     * Generate the xsl sheet from the xml mapping file
     *
     * @param	xmlMappingFile the xml mapping file to transform the view
     * @exception	TransformerException
     * @exception	FileNotFoundException
     */
    public String generateXslMapping(File xmlMappingFile)throws OpenSyncException, SAXException, FileNotFoundException, TransformerException, MalformedURLException{
      StringWriter resultWriter = new StringWriter();
      // xmlMappingFile.toURL().toExternalForm() to handle external files
      // used in the mapping file such as the mapping.dtd file !
  
      try {
       genMappingTransformer.transform(
 	  new StreamSource(xmlMappingFile.toURL().toExternalForm()),
 	  new StreamResult(resultWriter)
       );
     } catch (TransformerException tex) {
       SAXParseException spex = (SAXParseException)tex.getException();
       String message = "\r\nError at line "+spex.getLineNumber()+", column "+spex.getColumnNumber()+" in the file "+spex.getSystemId()+": "+spex.getLocalizedMessage();
       throw new OpenSyncException(message);
     }
 
     return resultWriter.getBuffer().toString();
   }
 
   /***
    * Transform the view from the xml mapping
    *
    * @param	xmlMapping the xml mapping
    * @param	xmlView the view in xml format
    * @exception	TransformerException
    * @exception	IOException
    */
   synchronized public String map(String xmlMapping,String xmlView)
   throws TransformerException, IOException {
     //System.err.println("****************");
     //System.err.println(xmlMapping);
     //System.err.println("****************");
     //System.err.println(xmlView);
     //System.err.println("****************");
     String xslMapping = generateXslMapping(xmlMapping);
     //System.err.println(xslMapping);
     //System.err.println("****************");
 
     Templates templates = transformerFactory.newTemplates(
       new StreamSource(new StringReader(xslMapping))
     );
 
     Transformer transformer = templates.newTransformer();
     transformer.setErrorListener(this);
     StringWriter resultWriter = new StringWriter();
     String fileSeparator = System.getProperty("file.separator");
     String home_etc = OpenSync.getInstance().getFilePath("etc"+fileSeparator, false);
     String uriXmlView = new File(home_etc).toURL().toExternalForm();
     transformer.transform(
       new StreamSource(new StringReader(xmlView), uriXmlView),
       new StreamResult(resultWriter)
     );
     return resultWriter.getBuffer().toString();
   }
 
   /***
    * Transform the view from the xml mapping
    *
    * @param	xmlMapping the xml mapping
    * @param	xmlView the view in xml format
    * @exception	TransformerException
    * @exception	IOException
    */
   synchronized public String map(File xmlMappingFile,String xmlView)
   throws TransformerException, OpenSyncException, IOException, SAXException {
     //System.err.println("****************");
     //System.err.println(xmlMapping);
     //System.err.println("****************");
     //System.err.println(xmlView);
     //System.err.println("****************");
     String xslMapping = generateXslMapping(xmlMappingFile);
     if (org.opensync.tools.Utils.debug) OpenSync.getInstance().getLog().debug(Log.ROOT,"xslMapping :" +xslMapping);
     //System.err.println("xslMapping :" +xslMapping);
     //System.err.println("****************");
 
     Templates templates = transformerFactory.newTemplates(
       new StreamSource(new StringReader(xslMapping))
     );
 
     Transformer transformer = templates.newTransformer();
     transformer.setErrorListener(this);
     StringWriter resultWriter = new StringWriter();
     StreamSource xmlViewSource = new StreamSource(new StringReader(xmlView));
 
     //System.out.println(xmlView);
     String fileSeparator = System.getProperty("file.separator");
     String home_etc = OpenSync.getInstance().getFilePath("etc"+fileSeparator, false);
     String uriXmlView = new File(home_etc).toURL().toExternalForm();
     xmlViewSource.setSystemId(uriXmlView);
 
     /*transformer.transform(
       new StreamSource(new StringReader(xmlView), uriXmlView),
       new StreamResult(resultWriter)
     );
     */
 
     try {
     transformer.transform(  xmlViewSource,
                             new StreamResult(resultWriter));
     }
     catch (TransformerConfigurationException tce) {
       try {
 	this.fatalError(tce);
       }
       catch (TransformerException ex) {
 	throw ex;
       }
     }
     catch (TransformerException te) {
       try {
 	this.error(te);
       }
       catch (TransformerException ex) {
 	throw ex;
       }
     }
 
 /*
         throw new OpenSyncException(
           "error.transformer.transform",
           new Object[]{te});
 */
     return resultWriter.getBuffer().toString();
   }
 
 }