package org.jaudiotagger.tag.mp4.field;

 import org.jaudiotagger.audio.mp4.atom.Mp4BoxHeader;

 import org.jaudiotagger.tag.FieldDataInvalidException;

 import org.jaudiotagger.tag.mp4.Mp4FieldKey;

 import org.jaudiotagger.tag.mp4.atom.Mp4DataBox;

 import java.io.UnsupportedEncodingException;

 import java.nio.ByteBuffer;

 import java.util.ArrayList;

 /**

  * Represents the Track No field

  * <p/>

  * <p>For some reason uses an array of four numbers, but only the middle two are of use for display purposes

  */

 public class Mp4TrackField extends Mp4TagTextNumberField

 {

     private static final int NONE_VALUE_INDEX = 0;

     private static final int TRACK_NO_INDEX = 1;

     private static final int TRACK_TOTAL_INDEX = 2;

     private static final int NONE_END_VALUE_INDEX = 3;

     /**

      * Create new Track Field parsing the String for the trackno/total

      *

      * @param trackValue

      */

     public Mp4TrackField(String trackValue) throws FieldDataInvalidException

     {

         super(Mp4FieldKey.TRACK.getFieldName(), trackValue);

         numbers = new ArrayList<Short>();

         numbers.add(new Short("0"));

         String values[] = trackValue.split("/");

         switch (values.length)

         {

             case 1:

                 try

                 {

                     numbers.add(Short.parseShort(values[0]));

                 }

                 catch (NumberFormatException nfe)

                 {

                     throw new FieldDataInvalidException("Value of:" + values[0] + " is invalid for field:" + id);

                 }

                 numbers.add(new Short("0"));

                 numbers.add(new Short("0"));

                 break;

             case 2:

                 try

                 {

                     numbers.add(Short.parseShort(values[0]));

                 }

                 catch (NumberFormatException nfe)

                 {

                     throw new FieldDataInvalidException("Value of:" + values[0] + " is invalid for field:" + id);

                 }

                 try

                 {

                     numbers.add(Short.parseShort(values[1]));

                 }

                 catch (NumberFormatException nfe)

                 {

                     throw new FieldDataInvalidException("Value of:" + values[1] + " is invalid for field:" + id);

                 }

                 numbers.add(new Short("0"));

                 break;

             default:

                 throw new FieldDataInvalidException("Value is invalid for field:" + id);

         }

     }

     /**

      * Create new Track Field with only track No

      *

      * @param trackNo

      */

     public Mp4TrackField(int trackNo)

     {

         super(Mp4FieldKey.TRACK.getFieldName(), String.valueOf(trackNo));

         numbers = new ArrayList<Short>();

         numbers.add(new Short("0"));

         numbers.add((short) trackNo);

         numbers.add(new Short("0"));

         numbers.add(new Short("0"));

     }

     /**

      * Create new Track Field with track No and total tracks

      *

      * @param trackNo

      * @param total

      */

     public Mp4TrackField(int trackNo, int total)

     {

         super(Mp4FieldKey.TRACK.getFieldName(), String.valueOf(trackNo));

         numbers = new ArrayList<Short>();

         numbers.add(new Short("0"));

         numbers.add((short) trackNo);

         numbers.add((short) total);

         numbers.add(new Short("0"));

     }

     /**

      * Construct from filedata

      *

      * @param id

      * @param data

      * @throws UnsupportedEncodingException

      */

     public Mp4TrackField(String id, ByteBuffer data) throws UnsupportedEncodingException

     {

         super(id, data);

     }

     protected void build(ByteBuffer data) throws UnsupportedEncodingException

     {

         //Data actually contains a 'Data' Box so process data using this

         Mp4BoxHeader header = new Mp4BoxHeader(data);

         Mp4DataBox databox = new Mp4DataBox(header, data);

         dataSize = header.getDataLength();

         numbers = databox.getNumbers();

         //Track number always hold three values, we can discard the first one, the second one is the track no

         //and the third is the total no of tracks so only use if not zero

         StringBuffer sb = new StringBuffer();

         sb.append(numbers.get(TRACK_NO_INDEX));

         if (numbers.get(TRACK_TOTAL_INDEX) > 0)

         {

             sb.append("/" + numbers.get(TRACK_TOTAL_INDEX));

         }

         content = sb.toString();

     }

     /**

      * @return

      */

     public Short getTrackNo()

     {

         return numbers.get(TRACK_NO_INDEX);

     }

     /**

      * @return

      */

     public Short getTrackTotal()

     {

         return numbers.get(TRACK_TOTAL_INDEX);

     }

 }