package org.jaudiotagger.audio.real;

 import org.jaudiotagger.audio.exceptions.CannotReadException;

 import org.jaudiotagger.audio.generic.AudioFileReader;

 import org.jaudiotagger.audio.generic.GenericAudioHeader;

 import org.jaudiotagger.audio.generic.GenericTag;

 import org.jaudiotagger.audio.generic.Utils;

 import org.jaudiotagger.tag.Tag;

 import java.io.DataInputStream;

 import java.io.IOException;

 import java.io.RandomAccessFile;

 /**

  * Real Media File Format: Major Chunks: .RMF PROP MDPR CONT DATA INDX

  */

 public class RealFileReader extends AudioFileReader

 {

     @Override

     protected GenericAudioHeader getEncodingInfo(RandomAccessFile raf) throws CannotReadException, IOException

     {

         final GenericAudioHeader rv = new GenericAudioHeader();

         final RealChunk prop = findPropChunk(raf);

         final DataInputStream dis = prop.getDataInputStream();

         final int objVersion = Utils.readUint16(dis);

         if (objVersion == 0)

         {

             final long maxBitRate = Utils.readUint32(dis) / 1000;

             final long avgBitRate = Utils.readUint32(dis) / 1000;

             final long maxPacketSize = Utils.readUint32(dis);

             final long avgPacketSize = Utils.readUint32(dis);

             final long packetCnt = Utils.readUint32(dis);

             final int duration = Utils.readUint32AsInt(dis) / 1000;

             final long preroll = Utils.readUint32(dis);

             final long indexOffset = Utils.readUint32(dis);

             final long dataOffset = Utils.readUint32(dis);

             final int numStreams = Utils.readUint16(dis);

             final int flags = Utils.readUint16(dis);

             rv.setBitrate((int) avgBitRate);

             rv.setLength(duration);

             rv.setVariableBitRate(maxBitRate != avgBitRate);

         }

         return rv;

     }

     private RealChunk findPropChunk(RandomAccessFile raf) throws IOException, CannotReadException

     {

         final RealChunk rmf = RealChunk.readChunk(raf);

         final RealChunk prop = RealChunk.readChunk(raf);

         return prop;

     }

     private RealChunk findContChunk(RandomAccessFile raf) throws IOException, CannotReadException

     {

         final RealChunk rmf = RealChunk.readChunk(raf);

         final RealChunk prop = RealChunk.readChunk(raf);

         RealChunk rv = RealChunk.readChunk(raf);

         while (!rv.isCONT()) rv = RealChunk.readChunk(raf);

         return rv;

     }

     @Override

     protected Tag getTag(RandomAccessFile raf) throws CannotReadException, IOException

     {

         final RealChunk cont = findContChunk(raf);

         final DataInputStream dis = cont.getDataInputStream();

         final String title = Utils.readString(dis, Utils.readUint16(dis));

         final String author = Utils.readString(dis, Utils.readUint16(dis));

         final String copyright = Utils.readString(dis, Utils.readUint16(dis));

         final String comment = Utils.readString(dis, Utils.readUint16(dis));

         final RealTag rv = new RealTag();

         // NOTE: frequently these fields are off-by-one, thus the crazy

         // logic below...

         rv.addTitle(title.length() == 0 ? author : title);

         rv.addArtist(title.length() == 0 ? copyright : author);

         rv.addComment(comment);

         return rv;

     }

 }