/*

  * Entagged Audio Tag library

  * Copyright (c) 2003-2005 Rapha�l Slinckx <raphael@slinckx.net>

  * 

  * This library 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 library 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

  * Lesser General Public License for more details.

  * 

  * You should have received a copy of the GNU Lesser General Public

  * License along with this library; if not, write to the Free Software

  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

  */

 package org.jaudiotagger.tag.vorbiscomment;

 import org.jaudiotagger.audio.generic.AbstractTagCreator;

 import org.jaudiotagger.audio.generic.Utils;

 import org.jaudiotagger.tag.Tag;

 import org.jaudiotagger.tag.TagField;

 import java.io.ByteArrayOutputStream;

 import java.io.IOException;

 import java.io.UnsupportedEncodingException;

 import java.nio.ByteBuffer;

 import java.util.Iterator;

 /**

  * Create the raw packet data for a Vorbis Comment Tag

  */

 public class VorbisCommentCreator extends AbstractTagCreator

 {

     /**

      * Convert tagdata to rawdata ready for writing to file

      *

      * @param tag

      * @param padding

      * @return

      * @throws UnsupportedEncodingException

      */

     //TODO padding parameter currently ignored

     public ByteBuffer convert(Tag tag, int padding) throws UnsupportedEncodingException

     {

         try

         {

             ByteArrayOutputStream baos = new ByteArrayOutputStream();

             //Vendor

             String vendorString = ((VorbisCommentTag) tag).getVendor();

             int vendorLength = Utils.getUTF8Bytes(vendorString).length;

             baos.write(Utils.getSizeLEInt32(vendorLength));

             baos.write(Utils.getUTF8Bytes(vendorString));

             //User Comment List

             int listLength = tag.getFieldCount() - 1; //Remove Vendor from count         

             baos.write(Utils.getSizeLEInt32(listLength));

             //Add metadata raw content

             Iterator<TagField> it = tag.getFields();

             while (it.hasNext())

             {

                 TagField frame = it.next();

                 if (frame.getId().equals(VorbisCommentFieldKey.VENDOR.name()))

                 {

                     //this is always stored above so ignore                    

                 }

                 else

                 {

                     baos.write(frame.getRawContent());

                 }

             }

             //Put into ByteBuffer

             ByteBuffer buf = ByteBuffer.wrap(baos.toByteArray());

             buf.rewind();

             return buf;

         }

         catch (IOException ioe)

         {

             //Should never happen as not writing to file at this point

             throw new RuntimeException(ioe);

         }

     }

 }