package org.treetank.filelistener.file.data;
   
   import java.io.DataInput;
   import java.io.DataOutput;
   import java.io.IOException;
   import java.util.Objects;
   
   import org.treetank.api.IMetaEntry;
   import org.treetank.api.IMetaEntryFactory;
  import org.treetank.exception.TTIOException;
  
  import com.google.common.hash.Funnel;
  import com.google.common.hash.PrimitiveSink;
  
  /**
   * This factory is used to give the treetank
   * system knowledge of the MetaEntries this interface module
   * uses to store the data.
   * 
   * @author Andreas Rain
   * 
   */
  public class FilelistenerMetaDataFactory implements IMetaEntryFactory {
  
      private final static int KEY = 1;
      private final static int VALUE = 2;
  
      @Override
      public IMetaEntry deserializeEntry(DataInput input) throws TTIOException {
          try {
              final int kind = input.readInt();
  
              switch (kind) {
              case KEY:
                  final int valSize = input.readInt();
                  final byte[] bytes = new byte[valSize];
                  input.readFully(bytes);
                  return new MetaKey(new String(bytes));
              case VALUE:
                  return new MetaValue(input.readLong());
              default:
                  throw new IllegalStateException("Kind not defined.");
              }
          } catch (final IOException exc) {
              throw new TTIOException(exc);
          }
      }
  
      /**
       * Key representing a relative path to the mount point.
       * 
       * @author Andreas Rain
       * 
       */
      public static class MetaKey implements IMetaEntry {
          /**
           * Enum for MetaKeyFunnel.
           * 
           * @author Sebastian Graf, University of Konstanz
           * 
           */
          enum MetaKeyFunnel implements Funnel<IMetaEntry> {
              INSTANCE;
              public void funnel(IMetaEntry from, PrimitiveSink into) {
                  MetaKey node = (MetaKey)from;
                  into.putString(node.mKey);
              }
          }
          
          /** Key Variable. */
          private final String mKey;
  
          /**
           * Constructor
           * 
           * @param pData
           *            setting the key
           */
          public MetaKey(final String pData) {
              mKey = pData;
          }
  
          /**
           * {@inheritDoc}
           */
          @Override
          public void serialize(final DataOutput output) throws TTIOException {
              try {
                  output.writeInt(KEY);
                  output.writeInt(mKey.getBytes().length);
                  output.write(mKey.getBytes());
              } catch (final IOException exc) {
                  throw new TTIOException(exc);
              }
          }
  
          public String getKey() {
              return this.mKey;
          }
 
         /**
          * {@inheritDoc}
          */
         @Override
         public int hashCode() {
             return Objects.hash(mKey);
         }
 
         /**
          * {@inheritDoc}
          */
         @Override
         public final boolean equals(final Object pObj) {
             return this.hashCode() == pObj.hashCode();
         }
         
         /**
          * {@inheritDoc}
          */
         @Override
         public Funnel<IMetaEntry> getFunnel() {
             return MetaKeyFunnel.INSTANCE;
         }
     }
 
     /**
      * Value which is basically the byte representation
      * of the header FileData
      * 
      * @author Andreas Rain
      * 
      */
     public static class MetaValue implements IMetaEntry {
         /**
          * Enum for MetaValueFunnel.
          * 
          * @author Sebastian Graf, University of Konstanz
          * 
          */
         enum MetaValueFunnel implements Funnel<IMetaEntry> {
             INSTANCE;
             public void funnel(IMetaEntry from, PrimitiveSink into) {
                 MetaValue node = (MetaValue)from;
                 into.putLong(node.mData);
             }
         }
         
         /** Value Variable. */
         private final long mData;
 
         /**
          * Constructor.
          * 
          * @param pData
          *            setting the value
          */
         public MetaValue(final long pData) {
             mData = pData;
         }
 
         /**
          * {@inheritDoc}
          */
         @Override
         public void serialize(final DataOutput output) throws TTIOException {
             try {
                 output.writeInt(VALUE);
                 output.writeLong(mData);
             } catch (final IOException exc) {
                 throw new TTIOException(exc);
             }
         }
 
         /**
          * {@inheritDoc}
          */
         @Override
         public int hashCode() {
             return Objects.hash(getData());
         }
 
         /**
          * {@inheritDoc}
          */
         @Override
         public final boolean equals(final Object pObj) {
             return this.hashCode() == pObj.hashCode();
         }
 
         public long getData() {
             return mData;
         }
         
         /**
          * {@inheritDoc}
          */
         @Override
         public Funnel<IMetaEntry> getFunnel() {
             return MetaValueFunnel.INSTANCE;
         }
 
     }
 
 }