/*
    * #%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.ArrayList;
  import java.util.List;
  
  import org.bitrepository.bitrepositoryelements.FileIDs;
  import org.bitrepository.bitrepositoryelements.ResponseCode;
  import org.bitrepository.bitrepositoryelements.ResponseInfo;
  import org.bitrepository.bitrepositorymessages.IdentifyPillarsForGetChecksumsRequest;
  import org.bitrepository.bitrepositorymessages.IdentifyPillarsForGetChecksumsResponse;
  import org.bitrepository.bitrepositorymessages.MessageResponse;
  import org.bitrepository.common.utils.TimeMeasurementUtils;
  import org.bitrepository.pillar.cache.ChecksumStore;
  import org.bitrepository.pillar.common.MessageHandlerContext;
  import org.bitrepository.service.exception.IdentifyContributorException;
  import org.bitrepository.service.exception.RequestHandlerException;
  
  /**
   * Class for handling the identification of this pillar for the purpose of performing the GetChecksums operation.
   */
  public class IdentifyPillarsForGetChecksumsRequestHandler
          extends ChecksumPillarMessageHandler<IdentifyPillarsForGetChecksumsRequest> {
      
      /**
       * Constructor.
       * @param context The context of the message handler.
       * @param refCache The cache for the checksum data.
       */
      public IdentifyPillarsForGetChecksumsRequestHandler(MessageHandlerContext context, ChecksumStore refCache) {
          super(context, refCache);
      }
  
      @Override
      public Class<IdentifyPillarsForGetChecksumsRequest> getRequestClass() {
          return IdentifyPillarsForGetChecksumsRequest.class;
      }
  
      @Override
      public void processRequest(IdentifyPillarsForGetChecksumsRequest message) throws RequestHandlerException {
          validateCollectionID(message);
          validateMessage(message);
          checkThatAllRequestedFilesAreAvailable(message);
          respondSuccesfullIdentification(message);
      }
  
      @Override
      public MessageResponse generateFailedResponse(IdentifyPillarsForGetChecksumsRequest message) {
          return createFinalResponse(message);
      }
      
      /**
       * Validates the identification message.
       * @param message The identify message to validate.
       */
      private void validateMessage(IdentifyPillarsForGetChecksumsRequest message) throws RequestHandlerException {
          validateChecksumSpec(message.getChecksumRequestForExistingFile(), message.getCollectionID());        
      }
      
      /**
       * Validates that all the requested files in the filelist are present. 
       * Otherwise an {@link IdentifyContributorException} with the appropriate errorcode is thrown.
       * @param message The message containing the list files. An empty filelist is expected 
       * when "AllFiles" or the parameter option is used.
       */
      public void checkThatAllRequestedFilesAreAvailable(IdentifyPillarsForGetChecksumsRequest message) 
              throws RequestHandlerException {
          FileIDs fileids = message.getFileIDs();
          validateFileID(message.getFileIDs().getFileID());
          
          List<String> missingFiles = new ArrayList<String>();
          String fileID = fileids.getFileID();
          if(fileID != null && !getCache().hasFile(fileID, message.getCollectionID())) {
              missingFiles.add(fileID);
          }
          
         // Throw exception if any files are missing.
         if(!missingFiles.isEmpty()) {
             ResponseInfo irInfo = new ResponseInfo();
             irInfo.setResponseCode(ResponseCode.FILE_NOT_FOUND_FAILURE);
             
             throw new IdentifyContributorException(irInfo, message.getCollectionID());
         }
     }
     
     /**
      * Method for making a successful response to the identification.
      * @param request The request to respond to.
      */
     private void respondSuccesfullIdentification(IdentifyPillarsForGetChecksumsRequest request) {
         IdentifyPillarsForGetChecksumsResponse response = createFinalResponse(request);
 
         response.setTimeToDeliver(TimeMeasurementUtils.getTimeMeasurementFromMiliseconds(
             getSettings().getReferenceSettings().getPillarSettings().getTimeToStartDeliver()));
         
         ResponseInfo irInfo = new ResponseInfo();
         irInfo.setResponseCode(ResponseCode.IDENTIFICATION_POSITIVE);
         response.setResponseInfo(irInfo);
 
         dispatchResponse(response, request);
     }
     
     /**
      * Creates a IdentifyPillarsForGetChecksumsResponse based on a 
      * IdentifyPillarsForGetFileRequest. The following fields are not inserted:
      * <br/> - TimeToDeliver
      * <br/> - AuditTrailInformation
      * <br/> - IdentifyResponseInfo
      * <br/> - PillarChecksumSpec
      * 
      * @param msg The IdentifyPillarsForGetFileRequest to base the response on.
      * @return The response to the request.
      */
     private IdentifyPillarsForGetChecksumsResponse createFinalResponse(
             IdentifyPillarsForGetChecksumsRequest msg) {
         IdentifyPillarsForGetChecksumsResponse res 
                 = new IdentifyPillarsForGetChecksumsResponse();
         res.setFileIDs(msg.getFileIDs());
         res.setChecksumRequestForExistingFile(msg.getChecksumRequestForExistingFile());
         res.setPillarID(getSettings().getReferenceSettings().getPillarSettings().getPillarID());
         res.setPillarChecksumSpec(getChecksumType());
         
         return res;
     }
 }