/**
 *
 * Copyright
 * 2009-2015 Jayway Products AB
 * 2016-2017 Föreningen Sambruk
 *
 * Licensed under AGPL, Version 3.0 (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.gnu.org/licenses/agpl.txt
 *
 * 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 se.streamsource.streamflow.web.infrastructure.database;

import org.qi4j.api.injection.scope.Structure;
import org.qi4j.api.service.ImportedServiceDescriptor;
import org.qi4j.api.service.ServiceImporter;
import org.qi4j.api.service.ServiceImporterException;
import org.qi4j.api.service.ServiceReference;
import org.qi4j.api.structure.Module;

/**
 * Use a registered service that implements ServiceImporter to do the actual
 * import. The service id of the service that this importer should delegate to must
 * be set as meta-info on this service. Example:
 * module.services(MyServiceImporterService.class).identifiedBy("someid");
 * module.importedServices(OtherService.class).importedBy(ServiceInstanceImporter.class).setMetaInfo("someid");
 */
public class ServiceInstanceImporter
        implements ServiceImporter
{
   @Structure
   Module module;

   ServiceImporter service;

   String serviceId;

   public Object importService(ImportedServiceDescriptor importedServiceDescriptor) throws ServiceImporterException
   {
      serviceId = importedServiceDescriptor.metaInfo(String.class);

      return getServiceImporter().importService(importedServiceDescriptor);
   }

   public boolean isActive(Object o)
   {
      return getServiceImporter().isActive(o);
   }

   public boolean isAvailable(Object instance)
   {
      return getServiceImporter().isAvailable(instance);
   }

   private ServiceImporter getServiceImporter()
   {
      if (service == null)
      {
         for (ServiceReference<ServiceImporter> reference : module.serviceFinder().<ServiceImporter>findServices(ServiceImporter.class))
         {
            if (reference.identity().equals(serviceId))
            {
               service = reference.get();
               break;
            }
         }
      }

      if (service == null)
         throw new ServiceImporterException("No service importer with id '" + serviceId + "' was found");

      return service;
   }
}