/**
 *
 * 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.dci.restlet.server;

import org.qi4j.api.injection.scope.Service;
import org.qi4j.api.injection.scope.Structure;
import org.qi4j.api.mixin.InitializationException;
import org.qi4j.api.service.ServiceReference;
import org.qi4j.api.structure.Module;
import org.restlet.Request;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.List;
import java.util.ResourceBundle;

/**
 * Delegates to a list of potential readers. Register readers on startup.
 */
public class RequestReaderDelegator
        implements RequestReader
{
   private static final Object[] NULL_PARAMS = new Object[0];

   List<RequestReader> requestReaders = new ArrayList<RequestReader>();

   @Structure
   Module module;

   public void init(@Service Iterable<ServiceReference<RequestReader>> requestReaderReferences) throws InitializationException
   {
      Logger logger = LoggerFactory.getLogger(getClass());

      // Add custom readers first
      for (ServiceReference<RequestReader> requestReader : requestReaderReferences)
      {
         if (!requestReader.identity().equals("requestreaderdelegator"))
         {
            logger.info("Registered request reader:" + requestReader.identity());
            registerRequestReader(requestReader.get());
         }
      }

      // Add defaults
      ResourceBundle defaultRequestReaders = ResourceBundle.getBundle("commandquery");

      String requestReaderClasses = defaultRequestReaders.getString("requestreaders");
      logger.info("Using request readers:" + requestReaderClasses);
      for (String className : requestReaderClasses.split(","))
      {
         try
         {
            Class readerClass = module.classLoader().loadClass(className.trim());
            RequestReader writer = (RequestReader) module.objectBuilderFactory().newObject(readerClass);
            registerRequestReader(writer);
         } catch (ClassNotFoundException e)
         {
            logger.warn("Could not register request reader " + className, e);
         }
      }
   }

   public void registerRequestReader(RequestReader reader)
   {
      requestReaders.add(reader);
   }

   public Object[] readRequest(Request request, Method method)
   {
      if (method.getParameterTypes().length == 0)
         return NULL_PARAMS;

      for (RequestReader requestReader : requestReaders)
      {
         Object[] arguments = requestReader.readRequest(request, method);

         if (arguments != null)
            return arguments;
      }

      return null;
   }
}