/**
 * Proof of concept for delta rd5's
 *
 * @author ab
 */
package btools.mapaccess;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.util.Arrays;

import btools.codec.DataBuffers;
import btools.codec.MicroCache;
import btools.codec.MicroCache2;
import btools.codec.StatCoderContext;
import btools.util.Crc32;

final public class Rd5DiffTool
{
  public static void main( String[] args ) throws Exception
  {
    if ( args[1].endsWith( ".rd5diff" ) )
    {
      if ( args[0].endsWith( ".rd5diff" ) )
      {
        addDeltas( new File( args[0] ),new File( args[1] ), new File( args[2] ) );
      }
      else
      {
        recoverFromDelta( new File( args[0] ),new File( args[1] ), new File( args[2] ) /*, new File( args[3] ) */ );
      }
    }
    else
    {
      diff2files( new File( args[0] ),new File( args[1] ), new File( args[2] ) );
    }
  }

  private static long[] readFileIndex( DataInputStream dis, DataOutputStream dos ) throws Exception
  {
    long[] fileIndex = new long[25];
    for( int i=0; i<25; i++ )
    {
      long lv = dis.readLong();
      fileIndex[i] = lv & 0xffffffffffffL;
      if ( dos != null )
      {
        dos.writeLong( lv );
      }
    }
    return fileIndex;
  }

  private static long getTileStart( long[] index, int tileIndex )
  {
    return tileIndex > 0 ? index[tileIndex - 1] : 200L;
  }

  private static long getTileEnd( long[] index, int tileIndex )
  {
    return index[tileIndex];
  }

  private static int[] readPosIndex( DataInputStream dis, DataOutputStream dos ) throws Exception
  {
    int[] posIndex = new int[1024];
    for( int i=0; i<1024; i++ )
    {
      int iv = dis.readInt();
      posIndex[i] = iv;
      if ( dos != null )
      {
        dos.writeInt( iv );
      }
    }
    return posIndex;
  }

  private static int getPosIdx( int[] posIdx, int idx )
  {
    return idx == -1 ? 4096 : posIdx[idx];
  }

  private static byte[] createMicroCache( int[] posIdx, int tileIdx, DataInputStream dis, boolean deltaMode ) throws Exception
  {
    if ( posIdx == null )
    {
      return null;
    }
    int size = getPosIdx( posIdx, tileIdx ) - getPosIdx( posIdx, tileIdx-1 );
    if ( size == 0 )
    {
      return null;
    }
    if ( deltaMode )
    {
      size = dis.readInt();
    }
    byte[] ab = new byte[size];
    dis.readFully( ab );
    return ab;
  }

  private static MicroCache createMicroCache( byte[] ab, DataBuffers dataBuffers ) throws Exception
  {
    if ( ab == null || ab.length == 0 )
    {
      return MicroCache.emptyCache();
    }
    StatCoderContext bc = new StatCoderContext( ab );
    return new MicroCache2( bc, dataBuffers, 0, 0, 32, null, null );
  }

  /**
   * Compute the delta between 2 RD5 files and
   * show statistics on the expected size of the delta file
   */
  public static void diff2files( File f1, File f2, File outFile ) throws Exception
  {
    byte[] abBuf1 = new byte[10 * 1024 * 1024];
    byte[] abBuf2 = new byte[10 * 1024 * 1024];
    
    int nodesDiff = 0;
    int diffedTiles = 0;
    
    long bytesDiff = 0L;

    DataInputStream dis1 = new DataInputStream( new BufferedInputStream( new FileInputStream( f1 ) ) );
    DataInputStream dis2 = new DataInputStream( new BufferedInputStream( new FileInputStream( f2 ) ) );
    DataOutputStream dos = new DataOutputStream( new BufferedOutputStream( new FileOutputStream( outFile ) ) );

    // copy header to outfile
    long[] fileIndex1 = readFileIndex( dis1, null );
    long[] fileIndex2 = readFileIndex( dis2, dos );

    try
    {
      DataBuffers dataBuffers = new DataBuffers();
      for ( int subFileIdx = 0; subFileIdx < 25; subFileIdx++ )
      {
         boolean hasData1 = getTileStart( fileIndex1, subFileIdx ) < getTileEnd( fileIndex1, subFileIdx );
         boolean hasData2 = getTileStart( fileIndex2, subFileIdx ) < getTileEnd( fileIndex2, subFileIdx );

         int[] posIdx1 = hasData1 ? readPosIndex( dis1, null ) : null;
         int[] posIdx2 = hasData2 ? readPosIndex( dis2, dos ) : null;

         for ( int tileIdx = 0; tileIdx < 1024; tileIdx++ )
         {
           byte[] ab1 = createMicroCache( posIdx1, tileIdx, dis1, false );
           byte[] ab2 = createMicroCache( posIdx2, tileIdx, dis2, false );

           if ( ab2 == null )
           {
             continue; // empty target tile
           }
           MicroCache mc;
           if ( Arrays.equals( ab1, ab2 ) )
           {
             mc = MicroCache.emptyCache(); // empty diff
           }
           else // calc diff of the 2 tiles
           {
             MicroCache mc1 = createMicroCache( ab1, dataBuffers );
             MicroCache mc2 = createMicroCache( ab2, dataBuffers );
             mc = new MicroCache2( mc1.getSize() + mc2.getSize(), abBuf2, 0, 0, 32 );
             mc.calcDelta( mc1, mc2 );
           }
              
           if ( mc.getSize() == 0 )
           {
             dos.writeInt( 0 );
           }
           else
           {
             int len = mc.encodeMicroCache( abBuf1 );
             dos.writeInt( len );
             dos.write( abBuf1, 0, len );

                 // do some consistemcy checks on the encoding

                 byte[] bytes = new byte[len];
                 System.arraycopy( abBuf1, 0, bytes, 0, len );

                 bytesDiff += len;
                 nodesDiff += mc.getSize();
                 diffedTiles++;
                 
                 // cross-check the encoding: decode again
                 MicroCache mcCheck = new MicroCache2( new StatCoderContext( bytes ), new DataBuffers( null ), 0, 0, 32, null, null );
                 
                 // due to link-order ambiguity, for decoded we can only compare node-count and datasize
                 if ( mc.size() != mcCheck.size() )
                 {
                   throw new IllegalArgumentException( "re-decoded data-size mismatch!" );
                 }
                 if ( mc.getSize() != mcCheck.getSize() )
                 {
                   throw new IllegalArgumentException( "re-decoded node-count mismatch!" );
                 }
                 
                 // .... so re-encode again
                 int len2 = mcCheck.encodeMicroCache( abBuf1 );
                 byte[] bytes2 = new byte[len2];
                 System.arraycopy( abBuf1, 0, bytes2, 0, len2 );
                 
                 // and here we can compare byte-by-byte
                 if ( len != len2 )
                 {
                   throw new IllegalArgumentException( "decoded size mismatch!" );
                 }
                 for( int i=0; i<len; i++ )
                 {
                   if ( bytes[i] != bytes2[i] )
                   {
                     throw new IllegalArgumentException( "decoded data mismatch at i=" + i );
                   }
                 }
          }
        }
      }
      // write any remaining data to the output file
      for(;;)
      {
        int len = dis2.read( abBuf1 );
        if (len < 0)
        {
          break;
        }
        dos.write( abBuf1, 0, len );
      }
      System.out.println( "nodesDiff=" + nodesDiff + " bytesDiff=" + bytesDiff + " diffedTiles=" + diffedTiles );
    }
    finally
    {
      if ( dis1 != null )
      {
        try
        {
          dis1.close();
        }
        catch (Exception ee)
        {
        }
      }
      if ( dis2 != null )
      {
        try
        {
          dis2.close();
        }
        catch (Exception ee)
        {
        }
      }
      if ( dos != null )
      {
        try
        {
          dos.close();
        }
        catch (Exception ee)
        {
        }
      }
    }
  }


  public static void recoverFromDelta( File f1, File f2, File outFile /* , File cmpFile */ ) throws Exception
  {
    byte[] abBuf1 = new byte[10 * 1024 * 1024];
    byte[] abBuf2 = new byte[10 * 1024 * 1024];

    DataInputStream dis1 = new DataInputStream( new BufferedInputStream( new FileInputStream( f1 ) ) );
    DataInputStream dis2 = new DataInputStream( new BufferedInputStream( new FileInputStream( f2 ) ) );
//    DataInputStream disCmp = new DataInputStream( new BufferedInputStream( new FileInputStream( cmpFile ) ) );
    DataOutputStream dos = new DataOutputStream( new BufferedOutputStream( new FileOutputStream( outFile ) ) );

    // copy header to outfile
    long[] fileIndex1 = readFileIndex( dis1, null );
    long[] fileIndex2 = readFileIndex( dis2, dos );
//    long[] fileIndexCmp = readFileIndex( disCmp, null );

    try
    {
      DataBuffers dataBuffers = new DataBuffers();
      for ( int subFileIdx = 0; subFileIdx < 25; subFileIdx++ )
      {
         boolean hasData1 = getTileStart( fileIndex1, subFileIdx ) < getTileEnd( fileIndex1, subFileIdx );
         boolean hasData2 = getTileStart( fileIndex2, subFileIdx ) < getTileEnd( fileIndex2, subFileIdx );

//         boolean hasDataCmp = getTileStart( fileIndexCmp, subFileIdx ) < getTileEnd( fileIndexCmp, subFileIdx );

         int[] posIdx1 = hasData1 ? readPosIndex( dis1, null ) : null;
         int[] posIdx2 = hasData2 ? readPosIndex( dis2, dos ) : null;

 //        int[] posIdxCmp = hasDataCmp ? readPosIndex( disCmp, null ) : null;

         for ( int tileIdx = 0; tileIdx < 1024; tileIdx++ )
         {
           byte[] ab1 = createMicroCache( posIdx1, tileIdx, dis1, false );
           byte[] ab2 = createMicroCache( posIdx2, tileIdx, dis2, true );
           if ( ab2 == null )
           {
             continue; // no target tile expected
           }

/*         int targetSizeCmp = getPosIdx( posIdxCmp, tileIdx ) - getPosIdx( posIdxCmp, tileIdx-1 );
           if ( targetSizeCmp != targetSize ) throw new IllegalArgumentException( "target size mismatch: "+ targetSize + "," + targetSizeCmp );
           byte[] abCmp = new byte[targetSizeCmp];
           disCmp.readFully( abCmp );
*/

           // no-delta shortcut: just copy base data
           if ( ab2.length == 0 )
           {
             if ( ab1 != null )
             {
               dos.write( ab1 );
             }
             continue;
           }

           // this is the real delta case (using decode->delta->encode )
           MicroCache mc1 = createMicroCache( ab1, dataBuffers );
           MicroCache mc2 = createMicroCache( ab2, dataBuffers );

           MicroCache mc = new MicroCache2( mc1.getSize() + mc2.getSize(), abBuf2, 0, 0, 32 );
           mc.addDelta( mc1, mc2, false );

           int len = mc.encodeMicroCache( abBuf1 );

/*           System.out.println( "comparing for subFileIdx=" + subFileIdx + " tileIdx=" + tileIdx );
           boolean isequal = true;
           for( int i=0; i<len;i++ )
           {
             if ( isequal && abCmp[i] != abBuf1[i] )
             {
               System.out.println( "data mismatch at i=" + i + " " + abCmp[i] + "!=" + abBuf1[i]  + " targetSize=" + targetSize );
               isequal = false;

               MicroCache.debug = true;
               System.out.println( "**** decoding original cache ****" );
               createMicroCache( abCmp, dataBuffers );
               System.out.println( "**** decoding reconstructed cache ****" );
               createMicroCache( abBuf1, dataBuffers );
               System.exit(1);
             }
           }
*/
           dos.write( abBuf1, 0, len );
           dos.writeInt( Crc32.crc( abBuf1, 0, len ) ^ 2 );
        }
      }
      // write any remaining data to the output file
      for(;;)
      {
        int len = dis2.read( abBuf1 );
        if (len < 0)
        {
          break;
        }
        dos.write( abBuf1, 0, len );
      }
    }
    finally
    {
      if ( dis1 != null )
      {
        try
        {
          dis1.close();
        }
        catch (Exception ee)
        {
        }
      }
      if ( dis2 != null )
      {
        try
        {
          dis2.close();
        }
        catch (Exception ee)
        {
        }
      }
      if ( dos != null )
      {
        try
        {
          dos.close();
        }
        catch (Exception ee)
        {
        }
      }
    }
  }

  public static void addDeltas( File f1, File f2, File outFile ) throws Exception
  {
    byte[] abBuf1 = new byte[10 * 1024 * 1024];
    byte[] abBuf2 = new byte[10 * 1024 * 1024];

    DataInputStream dis1 = new DataInputStream( new BufferedInputStream( new FileInputStream( f1 ) ) );
    DataInputStream dis2 = new DataInputStream( new BufferedInputStream( new FileInputStream( f2 ) ) );
    DataOutputStream dos = new DataOutputStream( new BufferedOutputStream( new FileOutputStream( outFile ) ) );

    // copy header to outfile
    long[] fileIndex1 = readFileIndex( dis1, null );
    long[] fileIndex2 = readFileIndex( dis2, dos );

    try
    {
      DataBuffers dataBuffers = new DataBuffers();
      for ( int subFileIdx = 0; subFileIdx < 25; subFileIdx++ )
      {
         boolean hasData1 = getTileStart( fileIndex1, subFileIdx ) < getTileEnd( fileIndex1, subFileIdx );
         boolean hasData2 = getTileStart( fileIndex2, subFileIdx ) < getTileEnd( fileIndex2, subFileIdx );

         int[] posIdx1 = hasData1 ? readPosIndex( dis1, null ) : null;
         int[] posIdx2 = hasData2 ? readPosIndex( dis2, dos ) : null;

         for ( int tileIdx = 0; tileIdx < 1024; tileIdx++ )
         {
           byte[] ab1 = createMicroCache( posIdx1, tileIdx, dis1, true );
           byte[] ab2 = createMicroCache( posIdx2, tileIdx, dis2, true );
           if ( ab2 == null )
           {
             continue; // no target tile expected
           }

           // no-delta shortcut: just copy base data
           if ( ab2.length == 0 )
           {
             if ( ab1 == null )
             {
               dos.writeInt( 0 );
             }
             else
             {
               dos.writeInt( ab1.length );
               dos.write( ab1 );
             }
             continue;
           }

           // this is the real delta case (using decode->add->encode )
           MicroCache mc1 = createMicroCache( ab1, dataBuffers );
           MicroCache mc2 = createMicroCache( ab2, dataBuffers );

           MicroCache mc = new MicroCache2( mc1.getSize() + mc2.getSize(), abBuf2, 0, 0, 32 );
           mc.addDelta( mc1, mc2, true );

           int len = mc.encodeMicroCache( abBuf1 );

           dos.writeInt( len+4 );
           dos.write( abBuf1, 0, len );
           dos.writeInt( Crc32.crc( abBuf1, 0, len ) ^ 2 );
        }
      }
      // write any remaining data to the output file
      for(;;)
      {
        int len = dis2.read( abBuf1 );
        if (len < 0)
        {
          break;
        }
        dos.write( abBuf1, 0, len );
      }
    }
    finally
    {
      if ( dis1 != null )
      {
        try
        {
          dis1.close();
        }
        catch (Exception ee)
        {
        }
      }
      if ( dis2 != null )
      {
        try
        {
          dis2.close();
        }
        catch (Exception ee)
        {
        }
      }
      if ( dos != null )
      {
        try
        {
          dos.close();
        }
        catch (Exception ee)
        {
        }
      }
    }
  }
}