/*
 * Copyright (C) 2009 eXo Platform SAS.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */
package org.exoplatform.services.rest.impl.provider;

import org.exoplatform.commons.utils.SecurityHelper;
import org.exoplatform.services.rest.provider.EntityProvider;
import org.xml.sax.InputSource;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.lang.annotation.Annotation;
import java.lang.reflect.Type;
import java.security.PrivilegedActionException;
import java.security.PrivilegedExceptionAction;

import javax.ws.rs.Consumes;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.MultivaluedMap;
import javax.ws.rs.ext.Provider;
import javax.xml.transform.TransformerConfigurationException;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.TransformerFactoryConfigurationError;
import javax.xml.transform.sax.SAXSource;
import javax.xml.transform.stream.StreamResult;

/**
 * @author <a href="mailto:andrew00x@gmail.com">Andrey Parfonov</a>
 * @version $Id: $
 */
@Provider
@Consumes({MediaType.APPLICATION_XML, MediaType.TEXT_XML, MediaType.APPLICATION_XHTML_XML})
@Produces({MediaType.APPLICATION_XML, MediaType.TEXT_XML, MediaType.APPLICATION_XHTML_XML})
public class SAXSourceEntityProvider implements EntityProvider<SAXSource>
{

   /**
    * {@inheritDoc}
    */
   public boolean isReadable(Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType)
   {
      return type == SAXSource.class;
   }

   /**
    * {@inheritDoc}
    */
   public SAXSource readFrom(Class<SAXSource> type, Type genericType, Annotation[] annotations, MediaType mediaType,
      MultivaluedMap<String, String> httpHeaders, InputStream entityStream) throws IOException
   {
      return new SAXSource(new InputSource(entityStream));
   }

   /**
    * {@inheritDoc}
    */
   public long getSize(SAXSource t, Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType)
   {
      return -1;
   }

   /**
    * {@inheritDoc}
    */
   public boolean isWriteable(Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType)
   {
      return SAXSource.class.isAssignableFrom(type);
   }

   /**
    * {@inheritDoc}
    */
   public void writeTo(final SAXSource t, Class<?> type, Type genericType, Annotation[] annotations,
      MediaType mediaType,
      MultivaluedMap<String, Object> httpHeaders, OutputStream entityStream) throws IOException
   {
      final StreamResult out = new StreamResult(entityStream);
      try
      {
         SecurityHelper.doPrivilegedExceptionAction(new PrivilegedExceptionAction<Void>()
         {
            public Void run() throws Exception
            {
               TransformerFactory.newInstance().newTransformer().transform(t, out);
               return null;
            }
         });
      }
      catch (PrivilegedActionException pae)
      {
         Throwable cause = pae.getCause();
         if (cause instanceof TransformerConfigurationException)
         {
            throw new IOException("Can't write to output stream " + cause, cause);
         }
         else if (cause instanceof TransformerException)
         {
            throw new IOException("Can't write to output stream " + cause, cause);
         }
         else if (cause instanceof TransformerFactoryConfigurationError)
         {
            throw new IOException("Can't write to output stream " + cause, cause);
         }
         else if (cause instanceof RuntimeException)
         {
            throw (RuntimeException)cause;
         }
         else
         {
            throw new RuntimeException(cause);
         }
      }
   }
}
