/*
    * Splitter.java
    *
    * Created on August 31, 2001, 5:47 PM
    *
    * Modified June 15, 2002 N.A. Graf
    * Output file names are now derived from input file names.
    * Trap normal EOF exceptions.
    * Added usage hints.
   *
   */
  package org.lcsim.util.stdhep;
  
  import java.io.*;
  import java.util.StringTokenizer;
  import hep.io.stdhep.*;
  
  /**
   * @author tonyj
   */
  public class Splitter
  {
  	/**
  	* @param args the command line arguments
  	*/
  	public static void main(String args[]) throws Exception
  	{
  		// remind user of correct usage
  		if(args.length<1) usage();
  		if(args.length==1 && args[0].equals("-h")) usage();
  		
  		// get input file
  		String inputFile = args[0];                
  
  		// does it exist?
  		File f = new File(inputFile);
  		if (!f.exists())
  		{
  			System.out.println("\n\n  File "+f + " does not exist!");	
  			System.exit(1);
  		}
  
  		// set up the output file names
  		String outputFile = null;
  		StringTokenizer st = new StringTokenizer(inputFile, ".");
  		if(st.hasMoreTokens()) outputFile = st.nextToken();
  		if (outputFile==null)
  		{
  			System.out.println("\n\n  Problem parsing input file name");
  			System.out.println(" \n\n File name should be in file.stdhep format");
  			System.exit(1);
  		}
  
  		// get number of events to put into each split output file
  		// default is 100
  		int nevts = 100;
  		if ( args.length > 1 ) nevts = Integer.parseInt(args[1]);
  		
  		StdhepReader in = null;
  		try
  		{
  		  in = new StdhepReader(inputFile);
  		}
  		catch(IOException ex)
  		{
  			System.out.println("Problem opening "+inputFile+" !");
  			System.exit(1);
  		}
  		
  		int readEvents = 0;
  		int r=0;
  		try
  		{
  			for (r = 0;;r++)
  			{
  				int n = 0;
  				StdhepWriter out = null;
                  try
                  {
                     for(;;)
      					{
  	    					StdhepRecord record = in.nextRecord();
  	    					if (record instanceof StdhepEvent)
  	    					{
  	    						if (out == null)
  	    						{
      								String name = outputFile+"-"+r+"-"+nevts+".stdhep";
  	    							System.out.println("Writing "+name);
  	    							out = new StdhepWriter(name,"title","comment",nevts);
  	    						}
  	    						out.writeRecord(record);
  	    						readEvents++;
  	    						if (++n == nevts) break;
      						}
      					}
      			}
                  finally
                  {
                     if (out != null) out.close();
 				}
          	}
 		}
 		catch( EOFException ex)
 		{
 			System.out.println("\n\n Read "+readEvents+" events and created "+r +" output files.");
 		}	  
 		finally
 		{
 			in.close();
 		}
 	}
 
 	public static void usage()
 	{
 		System.out.println("Splitter: an application to split input stdhep files into smaller files.\n");
 		System.out.println("Usage: \n\n >> java Splitter filename.stdhep [nevents] \n");
 		System.out.println(" Where \n  filename is a file in stdhep format \n  nevents is the number of events in each output file [ default is 100 ]");
 		System.out.println("  Output files will be named filename-nnn-nevents.stdhep");
 		System.exit(0);
 	}
 
 }