package com.c2kernel.utils;

//Java
import java.io.IOException;
import java.io.StringReader;
import java.io.StringWriter;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.HashSet;
import java.util.Properties;
import java.util.StringTokenizer;

import org.exolab.castor.mapping.Mapping;
import org.exolab.castor.mapping.MappingException;
import org.exolab.castor.xml.MarshalException;
import org.exolab.castor.xml.Marshaller;
import org.exolab.castor.xml.Unmarshaller;
import org.exolab.castor.xml.ValidationException;
import org.exolab.castor.xml.XMLContext;

import com.c2kernel.common.InvalidDataException;
import com.c2kernel.persistency.outcome.Outcome;
import com.c2kernel.process.resource.ResourceLoader;


/**************************************************************************
 * Loads all mapfiles, and wraps marshalling/unmarshalling
 *
 * @author $Author: abranson $ $Date: 2004/10/20 14:10:21 $
 * @version $Revision: 1.12 $
 **************************************************************************/
public class CastorXMLUtility{
	
	public static final String  CASTOR_XML_SERIALIZER_FACTORY = "org.exolab.castor.xml.serializer.factory";
	
    private XMLContext pCastorContext;
    
	/**
	 * Looks for a file called 'index.xml' at the given URL, and loads every
	 * file listed in there by relative path
	 * 
	 * @param aResourceLoader
	 *            the resource loader able to return the right class loader
	 * @param aAppProperties
	 *            the application properties containint optionnal castor
	 *            configuration
	 * @param aMapsSubPath
	 *            the map root sub path (in the kernel path)
	 * @throws InvalidDataException
	 */
	public CastorXMLUtility(final ResourceLoader aResourceLoader,
			final Properties aAppProperties, final String aMapsSubPath)
			throws InvalidDataException {

		// build base url 
    	URL wMapsURL ;
		try {
			wMapsURL = aResourceLoader.getKernelResourceURL(aMapsSubPath);
		} catch (MalformedURLException e) {
			throw new InvalidDataException(String.format(
					"Invalid Resource Location [%s]. Cause:%s", aMapsSubPath,
					e.getLocalizedMessage()));
		}
    	
        // load index
        Logger.msg(3,String.format( "CastorXMLUtility.<init> Loading maps from [%s]",wMapsURL));
        String index;
        try {
            index = FileStringUtility.url2String( new URL(wMapsURL, "index") );
        } catch (Exception e) {
           throw new InvalidDataException(String.format("Could not load map index from [%s]",wMapsURL));
        }
        
        // retrieve the class loader of the class "CastorXMLUtility" 
		ClassLoader wKernelClassLoader = aResourceLoader
				.getClassLoader(CastorXMLUtility.class.getName());

		Logger.msg(3, String.format(
				"CastorXMLUtility.<init>: iuse KernelClassLoader=[%s]",
				wKernelClassLoader));

		
        StringTokenizer sTokenizer = new StringTokenizer(index);
		int wNbMap = sTokenizer.countTokens();

        // init the castor mapping using the classloader of the class "CastorXMLUtility" 
        Mapping wCastorMapping = new Mapping(wKernelClassLoader);
        HashSet<URL> loadedMapURLs = new HashSet<URL>();
        try { 
        	int wMapIdx=0;
        	while( sTokenizer.hasMoreTokens() ) {
	            String wCurrentMap = sTokenizer.nextToken();
	            URL wCurrentMapURL = new URL(wMapsURL, wCurrentMap);
	            wMapIdx++;
	            if( !loadedMapURLs.contains(wCurrentMapURL) ) {
					Logger.msg(
							3,
							String.format(
									"CastorXMLUtility.<init>: Adding mapping file (%d/%d):[%s]",
									wMapIdx, wNbMap, wCurrentMapURL));
	                wCastorMapping.loadMapping( wCurrentMapURL );
	                loadedMapURLs.add( wCurrentMapURL );
	            }
	            else {
	                Logger.msg(3,"Map file already loaded:"+wCurrentMapURL);
	            }
	        }
	        
			pCastorContext = new XMLContext();

			pCastorContext.setClassLoader(wKernelClassLoader);

			// if the aAppProperties contains castor properties then
			if (aAppProperties.contains(CASTOR_XML_SERIALIZER_FACTORY)) {

				pCastorContext.setProperty(CASTOR_XML_SERIALIZER_FACTORY,
						aAppProperties
								.getProperty(CASTOR_XML_SERIALIZER_FACTORY));

				Logger.msg(3, String.format(
						"CastorXMLUtility.<init>: castor prop: %s=[%s]",
						CASTOR_XML_SERIALIZER_FACTORY, pCastorContext
								.getProperty(CASTOR_XML_SERIALIZER_FACTORY)));

			}
    			
			pCastorContext.addMapping(wCastorMapping);
		} catch (MappingException ex) {
			Logger.error(ex);
			throw new InvalidDataException("XML Mapping files are not valid: "+ex.getMessage(), "");
		} catch (MalformedURLException ex) {
			Logger.error(ex);
			throw new InvalidDataException("Mapping file location invalid: "+ex.getMessage(), "");
		} catch (IOException ex) {
			Logger.error(ex);
			throw new InvalidDataException("Could not read XML mapping files: "+ex.getMessage(), "");
		}
        
        Logger.msg(1, String.format("Loaded [%d] maps from [%s]",loadedMapURLs.size(),wMapsURL));
    }

   /**************************************************************************
    * Marshalls a mapped object to string. The mapping must be loaded before.
    * See updateMapping().
    **************************************************************************/
    public String marshall( Object obj )
        throws IOException,
               MappingException,
               MarshalException,
               ValidationException
    {
        if (obj == null) return "<NULL/>";
        if (obj instanceof Outcome)
            return ((Outcome)obj).getData();
        StringWriter sWriter    = new StringWriter();
        Marshaller   marshaller = pCastorContext.createMarshaller();
        
        marshaller.setWriter(sWriter);
        marshaller.setMarshalAsDocument( false );
        marshaller.marshal( obj );

        return sWriter.toString();
    }

   /**************************************************************************
    * Unmarshalls a mapped object from string. The mapping must be loaded before.
    * See updateMapping().
    **************************************************************************/
    public Object unmarshall( String data )
        throws IOException,
               MappingException,
               MarshalException,
               ValidationException
    {
        if (data.equals("<NULL/>")) return null;
        StringReader sReader      = new StringReader( data );
        Unmarshaller unmarshaller = pCastorContext.createUnmarshaller();
        return unmarshaller.unmarshal( sReader );
    }
}