/*
 * Copyright 2012  Research Studios Austria Forschungsges.m.b.H.
 *
 *    Licensed under the Apache License, Version 2.0 (the "License");
 *    you may not use this file except in compliance with the License.
 *    You may obtain a copy of the License at
 *
 *        http://www.apache.org/licenses/LICENSE-2.0
 *
 *    Unless required by applicable law or agreed to in writing, software
 *    distributed under the License is distributed on an "AS IS" BASIS,
 *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *    See the License for the specific language governing permissions and
 *    limitations under the License.
 */

package won.protocol.message.processor.camel;

import org.apache.camel.Exchange;
import org.apache.camel.Processor;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.transaction.annotation.Isolation;
import org.springframework.transaction.annotation.Propagation;
import org.springframework.transaction.annotation.Transactional;
import won.protocol.message.WonMessage;
import won.protocol.message.processor.exception.MissingMessagePropertyException;
import won.protocol.message.processor.exception.WonMessageProcessingException;
import won.protocol.model.Connection;
import won.protocol.repository.ConnectionRepository;
import won.protocol.util.WonRdfUtils;
import won.protocol.vocabulary.WONMSG;

import java.net.URI;

/**
 * Extracts the facet looking into the 'wonConnectionURI' header and looking up the connection in the db
 */
public class FacetExtractingCamelProcessor implements Processor{
  @Autowired
  ConnectionRepository connectionRepository;

  @Override
  @Transactional(propagation = Propagation.SUPPORTS, isolation = Isolation.READ_COMMITTED)
  public void process(Exchange exchange) throws Exception {
    URI facetType = null;
    //first, try to extract the facet from the message
    WonMessage wonMessage = (WonMessage) exchange.getIn().getHeader(WonCamelConstants.MESSAGE_HEADER);
    facetType = WonRdfUtils.FacetUtils.getFacet(wonMessage);
    if (facetType == null) {
      //not found.. look into the database. For that, we need to know the connection in question:
      URI conUri = (URI) exchange.getIn().getHeader(WonCamelConstants.CONNECTION_URI_HEADER);
      if (conUri == null)
        throw new MissingMessagePropertyException(URI.create(WONMSG.RECEIVER_PROPERTY.getURI().toString()));
      Connection con = connectionRepository.findOneByConnectionURI(conUri);
      facetType = con.getTypeURI();
    }
    if (facetType == null){
      throw new WonMessageProcessingException(String.format("Failed to determine connection " +
        "facet for message %s", wonMessage.getMessageURI()));
    }
    exchange.getIn().setHeader(WonCamelConstants.FACET_TYPE_HEADER, facetType);
  }
}