package org.jscsi.target.connection.stage.fullfeature;
   
   
   import static org.jscsi.target.storage.IStorageModule.VIRTUAL_BLOCK_SIZE;
   
   import java.io.IOException;
   import java.security.DigestException;
   
   import org.jscsi.exception.InternetSCSIException;
  import org.jscsi.parser.BasicHeaderSegment;
  import org.jscsi.parser.ProtocolDataUnit;
  import org.jscsi.parser.scsi.SCSICommandParser;
  import org.jscsi.target.connection.phase.TargetFullFeaturePhase;
  import org.jscsi.target.scsi.cdb.ModeSense6Cdb;
  import org.jscsi.target.scsi.modeSense.CachingModePage;
  import org.jscsi.target.scsi.modeSense.HeaderType;
  import org.jscsi.target.scsi.modeSense.InformationExceptionsControlModePage;
  import org.jscsi.target.scsi.modeSense.ModePage;
  import org.jscsi.target.scsi.modeSense.ModePageCode;
  import org.jscsi.target.scsi.modeSense.ModeParameterList;
  import org.jscsi.target.scsi.modeSense.ModeParameterListBuilder;
  import org.jscsi.target.scsi.modeSense.ShortLogicalBlockDescriptor;
  import org.jscsi.target.settings.SettingsException;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  
  /**
   * A stage for processing <code>MODE SENSE (6)</code> SCSI commands.
   * 
   * @author Andreas Ergenzinger
   */
  public final class ModeSenseStage extends TargetFullFeatureStage {
  
      private static final Logger LOGGER = LoggerFactory.getLogger(ModeSenseStage.class);
  
      public ModeSenseStage (TargetFullFeaturePhase targetFullFeaturePhase) {
          super(targetFullFeaturePhase);
      }
  
      @Override
      public void execute (final ProtocolDataUnit pdu) throws IOException , InterruptedException , InternetSCSIException , DigestException , SettingsException {
  
          final BasicHeaderSegment bhs = pdu.getBasicHeaderSegment();
          final SCSICommandParser parser = (SCSICommandParser) bhs.getParser();
          final ModeSense6Cdb cdb = new ModeSense6Cdb(parser.getCDB());
  
          if (LOGGER.isDebugEnabled()) {
              LOGGER.debug(Boolean.toString(cdb.getDisableBlockDescriptors()));
              LOGGER.debug(cdb.getPageControl().toString());
              LOGGER.debug(Integer.toString(cdb.getPageCode()));
              LOGGER.debug(Integer.toString(cdb.getSubpageCode()));
              LOGGER.debug("cdb.getAllocationLength() = " + cdb.getAllocationLength());
              // LOGGER.debug(cdb.getModePage());
          }
  
          // final PageControl pageControl = cdb.getPageControl();//see 8 lines
          // below
          final ModePageCode modePageCode = cdb.getModePage();
  
          // ModeParameterList and ModeParameterListBuilder common to
          // all supported ModePage requests
  
          ModePage[] modePages = null;
          if (modePageCode == ModePageCode.INFORMATIONAL_EXCEPTIONS_CONTROL_MODE_PAGE) {
              // TODO this should to be made dynamic wrt. cdb.getPageControl();
  
              modePages = new ModePage[] { getInformationExceptionsControlModePage() };
  
          } else if (modePageCode == ModePageCode.CACHING_MODE_PAGE) {
  
              modePages = new ModePage[] { getCachingModePage() };
  
          } else if (modePageCode == ModePageCode.RETURN_ALL_MODE_PAGES_ONLY) {
  
              modePages = new ModePage[] { getInformationExceptionsControlModePage(), getCachingModePage() };
  
          }// else modeParameterList stays null
  
          // create and send response PDU
          if (modePages != null) {
  
              // create ModeParameterList
              final ModeParameterListBuilder builder = new ModeParameterListBuilder(HeaderType.MODE_PARAMETER_HEADER_6);
              builder.setLogicalBlockDescriptors(new ShortLogicalBlockDescriptor(session.getStorageModule().getSizeInBlocks(),// numberOfLogicalBlocks
              VIRTUAL_BLOCK_SIZE));// logicalBlockLength
              builder.setModePages(modePages);
              ModeParameterList modeParameterList = ModeParameterList.build(builder);
  
              // send response
              sendResponse(bhs.getInitiatorTaskTag(),// initiatorTaskTag,
                      parser.getExpectedDataTransferLength(),// expectedDataTransferLength,
                      modeParameterList);// responseData
  
          } else {
              /*
               * The initiator has requested a mode sense page which the jSCSI Target cannot provide. This could be
               * answered with an Illegal field in CDB message but, there is no good way to identify the exact field at
               * fault.
              */
             throw new InternetSCSIException();
         }
 
     }
 
     private static final InformationExceptionsControlModePage getInformationExceptionsControlModePage () {
         return new InformationExceptionsControlModePage(false,// parametersSaveable
         false,// performance
         false,// enableBackgroundFunction
         false,// enableWarning
         true,// disableExceptionControl
         false,// test
         false,// logErrors
         0x0,// methodOfReportingInformationalExceptionConditions
         0,// intervalTimer
         0);// reportCount
     }
 
     private static final CachingModePage getCachingModePage () {
         return new CachingModePage(false,// parametersSaveable
         false,// initiatorControl
         true,// abortPrefetch
         false,// cachingAnalysisPermitted
         false,// discontinuity
         true,// sizeEnable
         false,// writebackCacheEnable
         false,// multiplicationFactor
         true,// readCacheDisable
         0x0,// demandReadRetentionPriority
         0x0,// writeRetentionPriority
         0,// disablePrefetchTransferLength
         0,// minimumPrefetch
         65535,// maximumPrefetch
         65535,// maximumPrefetchCeiling
         true,// forceSequentialWrite
         false,// logicalBlockCacheSegmentSize
         false,// disableReadAhead
         false,// nonVolatileCacheDisabled
         20,// numberOfCacheSegments
         0);// cacheSegmentSize
     }
 
     public boolean canHandle (final ProtocolDataUnit pdu) {
         final BasicHeaderSegment bhs = pdu.getBasicHeaderSegment();
         final SCSICommandParser parser = (SCSICommandParser) bhs.getParser();
         final ModeSense6Cdb cdb = new ModeSense6Cdb(parser.getCDB());
         final ModePageCode modePageCode = cdb.getModePage();
         if (modePageCode == ModePageCode.INFORMATIONAL_EXCEPTIONS_CONTROL_MODE_PAGE) {
             return true;
         } else if (modePageCode == ModePageCode.CACHING_MODE_PAGE) {
             return true;
         } else if (modePageCode == ModePageCode.RETURN_ALL_MODE_PAGES_ONLY) {
             return true;
         } else {
             return false;
         }
     }
 
 }