// context for simple expression
// context means:
// - the local variables
// - the local variable names
// - the lookup-input variables

package btools.expressions;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.StringTokenizer;
import java.util.TreeMap;

import btools.util.BitCoderContext;
import btools.util.Crc32;


public final class BExpressionMetaData
{
  private  static final String CONTEXT_TAG = "---context:";
  private static final String VERSION_TAG = "---lookupversion:";
  private static final String MINOR_VERSION_TAG = "---minorversion:";
  private static final String VARLENGTH_TAG = "---readvarlength";

  public short lookupVersion = -1;
  public short lookupMinorVersion = -1;

  private HashMap<String,BExpressionContext> listeners = new HashMap<String,BExpressionContext>();
  
  public void registerListener( String context, BExpressionContext ctx )
  {
    listeners.put( context,  ctx );
  }
  
  public void readMetaData( File lookupsFile )
  {
   try
   {
    BufferedReader br = new BufferedReader( new FileReader( lookupsFile ) );
    
    BExpressionContext ctx = null;
    
    for(;;)
    {
      String line = br.readLine();
      if ( line == null ) break;
      line = line.trim();
      if ( line.length() == 0 || line.startsWith( "#" ) ) continue;
      if ( line.startsWith( CONTEXT_TAG ) )
      {
    	ctx = listeners.get( line.substring( CONTEXT_TAG.length() ) );
        continue;
      }
      if ( line.startsWith( VERSION_TAG ) )
      {
        lookupVersion = Short.parseShort( line.substring( VERSION_TAG.length() ) );
        continue;
      }
      if ( line.startsWith( MINOR_VERSION_TAG ) )
      {
        lookupMinorVersion = Short.parseShort( line.substring( MINOR_VERSION_TAG.length() ) );
        continue;
      }
      if ( line.startsWith( VARLENGTH_TAG ) ) // tag removed...
      {
        continue;
      }
      if ( ctx != null ) ctx.parseMetaLine( line );
    }
    br.close();
    
    for( BExpressionContext c : listeners.values() )
    {
    	c.finishMetaParsing();
    }
    
   }
   catch( Exception e )
   {
       throw new RuntimeException( e );
   }
  }
}