package org.jaudiotagger.tag.datatype;

 import org.jaudiotagger.tag.InvalidDataTypeException;

 import org.jaudiotagger.tag.TagOptionSingleton;

 import org.jaudiotagger.tag.id3.AbstractTagFrameBody;

 import org.jaudiotagger.tag.id3.valuepair.TextEncoding;

 import java.nio.ByteBuffer;

 import java.nio.CharBuffer;

 import java.nio.charset.*;

 import java.util.ArrayList;

 import java.util.Arrays;

 import java.util.List;

 /**

  * Represents a String which is not delimited by null character.

  * <p/>

  * This type of String will usually only be used when it is the last field within a frame, when reading the remainder of

  * the byte array will be read, when writing the frame will be accomodate the required size for the String. The String

  * will be encoded based upon the text encoding of the frame that it belongs to.

  * <p/>

  * All TextInformation frames support multiple strings, stored as a null separated list, where null is represented by

  * the termination code for the character encoding. This functionality is only officially support in ID3v24.  Itunes

  * write null terminators characters after the String even though it only writes a single value.

  */

 public class TextEncodedStringSizeTerminated extends AbstractString

 {

     /**

      * Creates a new empty TextEncodedStringSizeTerminated datatype.

      *

      * @param identifier identifies the frame type

      * @param frameBody

      */

     public TextEncodedStringSizeTerminated(String identifier, AbstractTagFrameBody frameBody)

     {

         super(identifier, frameBody);

     }

     /**

      * Copy constructor

      *

      * @param object

      */

     public TextEncodedStringSizeTerminated(TextEncodedStringSizeTerminated object)

     {

         super(object);

     }

     public boolean equals(Object obj)

     {

         return obj instanceof TextEncodedStringSizeTerminated && super.equals(obj);

     }

     /**

      * Read a 'n' bytes from buffer into a String where n is the framesize - offset

      * so thefore cannot use this if there are other objects after it because it has no

      * delimiter.

      * <p/>

      * Must take into account the text encoding defined in the Encoding Object

      * ID3 Text Frames often allow multiple strings seperated by the null char

      * appropriate for the encoding.

      *

      * @param arr    this is the buffer for the frame

      * @param offset this is where to start reading in the buffer for this field

      * @throws NullPointerException

      * @throws IndexOutOfBoundsException

      */

     public void readByteArray(byte[] arr, int offset) throws InvalidDataTypeException

     {

         logger.finest("Reading from array from offset:" + offset);

         //Get the Specified Decoder

         String charSetName = getTextEncodingCharSet();

         CharsetDecoder decoder = Charset.forName(charSetName).newDecoder();

         //Decode sliced inBuffer

         ByteBuffer inBuffer = ByteBuffer.wrap(arr, offset, arr.length - offset).slice();

         CharBuffer outBuffer = CharBuffer.allocate(arr.length - offset);

         decoder.reset();

         CoderResult coderResult = decoder.decode(inBuffer, outBuffer, true);

         if (coderResult.isError())

         {

             logger.warning("Decoding error:" + coderResult.toString());

         }

         decoder.flush(outBuffer);

         outBuffer.flip();

         //Store value

         value = outBuffer.toString();

         //SetSize, important this is correct for finding the next datatype

         setSize(arr.length - offset);

         logger.info("Read SizeTerminatedString:" + value + " size:" + size);

     }

     /**

      * Write String into byte array

      * <p/>

      * It will remove a trailing null terminator if exists if the option

      * RemoveTrailingTerminatorOnWrite has been set.

      *

      * @return the data as a byte array in format to write to file

      */

     public byte[] writeByteArray()

     {

         byte[] data;

         //Try and write to buffer using the CharSet defined by getTextEncodingCharSet()

         try

         {

             if (TagOptionSingleton.getInstance().isRemoveTrailingTerminatorOnWrite())

             {

                 String stringValue = (String) value;

                 if (stringValue.length() > 0)

                 {

                     if (stringValue.charAt(stringValue.length() - 1) == '\0')

                     {

                         stringValue = (stringValue).substring(0, stringValue.length() - 1);

                         value = stringValue;

                     }

                 }

             }

             String charSetName = getTextEncodingCharSet();

             if (charSetName.equals(TextEncoding.CHARSET_UTF_16))

             {

                 charSetName = TextEncoding.CHARSET_UTF_16_ENCODING_FORMAT;

                 CharsetEncoder encoder = Charset.forName(charSetName).newEncoder();

                 //Note remember LE BOM is ff fe but tis is handled by encoder Unicode char is fe ff

                 ByteBuffer bb = encoder.encode(CharBuffer.wrap('\ufeff' + (String) value));

                 data = new byte[bb.limit()];

                 bb.get(data, 0, bb.limit());

             }

             else

             {

                 CharsetEncoder encoder = Charset.forName(charSetName).newEncoder();

                 ByteBuffer bb = encoder.encode(CharBuffer.wrap((String) value));

                 data = new byte[bb.limit()];

                 bb.get(data, 0, bb.limit());

             }

         }

         //Should never happen so if does throw a RuntimeException

         catch (CharacterCodingException ce)

         {

             logger.severe(ce.getMessage());

             throw new RuntimeException(ce);

         }

         setSize(data.length);

         return data;

     }

     /**

      * Get the text encoding being used.

      * <p/>

      * The text encoding is defined by the frame body that the text field belongs to.

      *

      * @return the text encoding charset

      */

     protected String getTextEncodingCharSet()

     {

         byte textEncoding = this.getBody().getTextEncoding();

         String charSetName = TextEncoding.getInstanceOf().getValueForId(textEncoding);

         logger.finest("text encoding:" + textEncoding + " charset:" + charSetName);

         return charSetName;

     }

     /**

      * Split the values seperated by null character

      *

      * @param value the raw value

      * @return list of values, guaranteed to be at least one value

      */

     private static List splitByNullSeperator(String value)

     {

         String[] valuesarray = value.split("\\u0000");

         List values = Arrays.asList(valuesarray);

         //Read only list so if empty have to create new list

         if (values.size() == 0)

         {

             values = new ArrayList(1);

             values.add("");

         }

         return values;

     }

     /**

      * Add an additional String to the current String value

      *

      * @param value

      */

     public void addValue(String value)

     {

         setValue(this.value + "\u0000" + value);

     }

     /**

      * How many values are held, each value is seperated by a null terminator

      *

      * @return number of values held, usually this will be one.

      */

     public int getNumberOfValues()

     {

         return splitByNullSeperator(((String) value)).size();

     }

     /**

      * Get the nth value

      *

      * @param index

      * @return the nth value

      * @throws IndexOutOfBoundsException if value does not exist

      */

     public String getValueAtIndex(int index)

     {

         //Split String into seperate components

         List values = splitByNullSeperator((String) value);

         return (String) values.get(index);

     }

 }