/*

  * 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.Utils;

 import org.jaudiotagger.audio.ogg.util.VorbisHeader;

 import org.jaudiotagger.tag.TagField;

 import org.jaudiotagger.tag.TagTextField;

 import static org.jaudiotagger.tag.vorbiscomment.VorbisCommentFieldKey.*;

 import java.io.UnsupportedEncodingException;

 /**

  * This class represents the name and content of a tag entry in ogg-files.

  * <br>

  *

  * @author @author Raphael Slinckx (KiKiDonK)

  * @author Christian Laireiter (liree)

  */

 public class VorbisCommentTagField implements TagTextField

 {

     /**

      * If <code>true</code>, the id of the current encapsulated tag field is

      * specified as a common field. <br>

      * Example is "ARTIST" which should be interpreted by any application as the

      * artist of the media content. <br>

      * Will be set during construction with {@link #checkCommon()}.

      */

     private boolean common;

     /**

      * Stores the content of the tag field. <br>

      */

     private String content;

     /**

      * Stores the id (name) of the tag field. <br>

      */

     private String id;

     /**

      * Creates an instance.

      *

      * @param raw Raw byte data of the tagfield.

      * @throws UnsupportedEncodingException If the data doesn't conform "UTF-8" specification.

      */

     public VorbisCommentTagField(byte[] raw) throws UnsupportedEncodingException

     {

         String field = new String(raw, "UTF-8");

         int i = field.indexOf("=");

         if (i == -1)

         {

             //Beware that ogg ID, must be capitalized and contain no space..

             this.id = "ERRONEOUS";

             this.content = field;

         }

         else

         {

             this.id = field.substring(0, i).toUpperCase();

             if (field.length() > i)

             {

                 this.content = field.substring(i + 1);

             }

             else

             {

                 //We have "XXXXXX=" with nothing after the "="

                 this.content = "";

             }

         }

         checkCommon();

     }

     /**

      * Creates an instance.

      *

      * @param fieldId      ID (name) of the field.

      * @param fieldContent Content of the field.

      */

     public VorbisCommentTagField(String fieldId, String fieldContent)

     {

         this.id = fieldId.toUpperCase();

         this.content = fieldContent;

         checkCommon();

     }

     /**

      * This method examines the ID of the current field and modifies

      * {@link #common}in order to reflect if the tag id is a commonly used one.

      * <br>

      */

     private void checkCommon()

     {

         this.common = id.equals(TITLE.name()) || id.equals(ALBUM.name()) || id.equals(ARTIST.name()) || id.equals(GENRE.name()) || id.equals(TRACKNUMBER.name()) || id.equals(DATE.name()) || id.equals(DESCRIPTION.name()) || id.equals(COMMENT.name());

     }

     /**

      * This method will copy all bytes of <code>src</code> to <code>dst</code>

      * at the specified location.

      *

      * @param src       bytes to copy.

      * @param dst       where to copy to.

      * @param dstOffset at which position of <code>dst</code> the data should be

      *                  copied.

      */

     protected void copy(byte[] src, byte[] dst, int dstOffset)

     {

         //        for (int i = 0; i < src.length; i++)

         //            dst[i + dstOffset] = src[i];

         /*

          * Heared that this method is optimized and does its job very near of

          * the system.

          */

         System.arraycopy(src, 0, dst, dstOffset, src.length);

     }

     /**

      * @see TagField#copyContent(TagField)

      */

     public void copyContent(TagField field)

     {

         if (field instanceof TagTextField)

         {

             this.content = ((TagTextField) field).getContent();

         }

     }

     /**

      * This method will try to return the byte representation of the given

      * string after it has been converted to the given encoding. <br>

      *

      * @param s        The string whose converted bytes should be returned.

      * @param encoding The encoding type to which the string should be converted.

      * @return If <code>encoding</code> is supported the byte data of the

      *         given string is returned in that encoding.

      * @throws UnsupportedEncodingException If the requested encoding is not available.

      */

     protected byte[] getBytes(String s, String encoding) throws UnsupportedEncodingException

     {

         return s.getBytes(encoding);

     }

     /**

      * @see TagTextField#getContent()

      */

     public String getContent()

     {

         return content;

     }

     /**

      * @see TagTextField#getEncoding()

      */

     public String getEncoding()

     {

         return VorbisHeader.CHARSET_UTF_8;

     }

     /**

      * @see TagField#getId()

      */

     public String getId()

     {

         return this.id;

     }

     /**

      * @see TagField#getRawContent()

      */

     public byte[] getRawContent() throws UnsupportedEncodingException

     {

         byte[] size = new byte[VorbisCommentReader.FIELD_COMMENT_LENGTH_LENGTH];

         byte[] idBytes = Utils.getDefaultBytes(this.id, "ISO-8859-1");

         byte[] contentBytes = getBytes(this.content, "UTF-8");

         byte[] b = new byte[4 + idBytes.length + 1 + contentBytes.length];

         int length = idBytes.length + 1 + contentBytes.length;

         size[3] = (byte) ((length & 0xFF000000) >> 24);

         size[2] = (byte) ((length & 0x00FF0000) >> 16);

         size[1] = (byte) ((length & 0x0000FF00) >> 8);

         size[0] = (byte) (length & 0x000000FF);

         int offset = 0;

         copy(size, b, offset);

         offset += 4;

         copy(idBytes, b, offset);

         offset += idBytes.length;

         b[offset] = (byte) 0x3D;

         offset++;// "="

         copy(contentBytes, b, offset);

         return b;

     }

     /**

      * @see TagField#isBinary()

      */

     public boolean isBinary()

     {

         return false;

     }

     /**

      * @see TagField#isBinary(boolean)

      */

     public void isBinary(boolean b)

     {

         if (b)

         {

             // Only throw if binary = true requested.

             throw new UnsupportedOperationException("OggTagFields cannot be changed to binary.\n" + "binary data should be stored elsewhere" + " according to Vorbis_I_spec.");

         }

     }

     /**

      * @see TagField#isCommon()

      */

     public boolean isCommon()

     {

         return common;

     }

     /**

      * @see TagField#isEmpty()

      */

     public boolean isEmpty()

     {

         return this.content.equals("");

     }

     /**

      * @see TagTextField#setContent(String)

      */

     public void setContent(String s)

     {

         this.content = s;

     }

     /**

      * @see TagTextField#setEncoding(String)

      */

     public void setEncoding(String s)

     {

         if (s == null || !s.equalsIgnoreCase("UTF-8"))

         {

             throw new UnsupportedOperationException("The encoding of OggTagFields cannot be " + "changed.(specified to be UTF-8)");

         }

     }

     public String toString()

     {

         return getContent();

     }

 }