/*
    * #%L
    * bitrepository-access-client
    * *
    * $Id$
    * $HeadURL$
    * %%
    * Copyright (C) 2010 - 2011 The State and University Library, The Royal Library and The State Archives, Denmark
    * %%
   * This program 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 program 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 General Lesser Public License for more details.
   * 
   * You should have received a copy of the GNU General Lesser Public 
   * License along with this program.  If not, see
   * <http://www.gnu.org/licenses/lgpl-2.1.html>.
   * #L%
   */
  package org.bitrepository.pillar.checksumpillar.messagehandler;
  
  import java.util.Arrays;
  
  import org.bitrepository.bitrepositoryelements.ChecksumDataForFileTYPE;
  import org.bitrepository.bitrepositoryelements.ResponseCode;
  import org.bitrepository.bitrepositoryelements.ResponseInfo;
  import org.bitrepository.bitrepositorymessages.IdentifyPillarsForPutFileRequest;
  import org.bitrepository.bitrepositorymessages.IdentifyPillarsForPutFileResponse;
  import org.bitrepository.bitrepositorymessages.MessageResponse;
  import org.bitrepository.common.utils.Base16Utils;
  import org.bitrepository.common.utils.CalendarUtils;
  import org.bitrepository.common.utils.TimeMeasurementUtils;
  import org.bitrepository.pillar.cache.ChecksumEntry;
  import org.bitrepository.pillar.cache.ChecksumStore;
  import org.bitrepository.pillar.common.MessageHandlerContext;
  import org.bitrepository.protocol.utils.MessageUtils;
  import org.bitrepository.service.exception.RequestHandlerException;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * Class for handling the identification of this pillar for the purpose of performing the PutFile operation.
   */
  public class IdentifyPillarsForPutFileRequestHandler extends ChecksumPillarMessageHandler<IdentifyPillarsForPutFileRequest> {
  
      private Logger log = LoggerFactory.getLogger(getClass());
  
      /**
       * Constructor.
       * @param context The context of the message handler.
       * @param refCache The cache for the checksum data.
       */
      public IdentifyPillarsForPutFileRequestHandler(MessageHandlerContext context, ChecksumStore refCache) {
          super(context, refCache);
      }
  
      @Override
      public Class<IdentifyPillarsForPutFileRequest> getRequestClass() {
          return IdentifyPillarsForPutFileRequest.class;
      }
  
      @Override
      public void processRequest(IdentifyPillarsForPutFileRequest message) throws RequestHandlerException {
          validateCollectionID(message);
          if (!Arrays.asList(context.getPillarCollections()).contains(message.getCollectionID())) {
              return; // Irrelevant collection.
          }
          if(checkThatTheFileDoesNotAlreadyExist(message)) {
              respondDuplicateFile(message);
          } else {
              respondSuccesfullIdentification(message);
          }
          
      }
  
      @Override
      public MessageResponse generateFailedResponse(IdentifyPillarsForPutFileRequest message) {
          return createFinalResponse(message);
      }
  
      
      /**
       * Validates that the file is not already within the archive. 
       * @param message The request with the filename to validate.
       * @return Whether the file already exists.
       */
      private boolean checkThatTheFileDoesNotAlreadyExist(IdentifyPillarsForPutFileRequest message) 
              throws RequestHandlerException {
          if(message.getFileID() == null) {
              return false;
          }
          
          return getCache().hasFile(message.getFileID(), message.getCollectionID());
      }
     
     /**
      * Method for sending a response for 'DUPLICATE_FILE_FAILURE'.
      * @param message The request to base the response upon.
      */
     protected void respondDuplicateFile(IdentifyPillarsForPutFileRequest message) {
         log.debug("Creating DuplicateFile response for " + MessageUtils.createMessageIdentifier(message));
         IdentifyPillarsForPutFileResponse response = createFinalResponse(message);
 
         ChecksumEntry entry = getCache().getEntry(message.getFileID(), message.getCollectionID());
         ChecksumDataForFileTYPE checksumData = new ChecksumDataForFileTYPE();
         checksumData.setCalculationTimestamp(CalendarUtils.getXmlGregorianCalendar(entry.getCalculationDate()));
         checksumData.setChecksumSpec(getChecksumType());
         checksumData.setChecksumValue(Base16Utils.encodeBase16(entry.getChecksum()));
         response.setChecksumDataForExistingFile(checksumData);
         
         ResponseInfo irInfo = new ResponseInfo();
         irInfo.setResponseCode(ResponseCode.DUPLICATE_FILE_FAILURE);
         response.setResponseInfo(irInfo);
 
         getContext().getResponseDispatcher().dispatchResponse(response, message);
     }
     
     /**
      * Method for sending a positive response for putting this file.
      * @param request The request to respond to.
      */
     protected void respondSuccesfullIdentification(IdentifyPillarsForPutFileRequest request)  {
         IdentifyPillarsForPutFileResponse response = createFinalResponse(request);
         response.setTimeToDeliver(TimeMeasurementUtils.getTimeMeasurementFromMiliseconds(
                 getSettings().getReferenceSettings().getPillarSettings().getTimeToStartDeliver()));
         
         ResponseInfo irInfo = new ResponseInfo();
         irInfo.setResponseCode(ResponseCode.IDENTIFICATION_POSITIVE);
         irInfo.setResponseText(RESPONSE_FOR_POSITIVE_IDENTIFICATION);
         response.setResponseInfo(irInfo);
 
         getContext().getResponseDispatcher().dispatchResponse(response, request);
     }
     
     /**
      * Creates a IdentifyPillarsForPutFileResponse based on a 
      * IdentifyPillarsForPutFileRequest. The following fields are not inserted:
      * <br/> - TimeToDeliver
      * <br/> - AuditTrailInformation
      * <br/> - PillarChecksumSpec
      * <br/> - IdentifyResponseInfo
      * 
      * @param msg The IdentifyPillarsForPutFileRequest to base the response on.
      * @return A IdentifyPillarsForPutFileResponse from the request.
      */
     private IdentifyPillarsForPutFileResponse createFinalResponse(IdentifyPillarsForPutFileRequest msg) {
         IdentifyPillarsForPutFileResponse res
                 = new IdentifyPillarsForPutFileResponse();
         res.setPillarID(getSettings().getReferenceSettings().getPillarSettings().getPillarID());
         res.setPillarChecksumSpec(getChecksumType());
         return res;
     }
 }