import java.io.*;

import javax.servlet.*;
import javax.servlet.http.*;


/**
 * This is a servlet to plot species on-the-fly using gnuplot
 */
public class GnuplotServlet extends HttpServlet {

   public void doGet( HttpServletRequest req, HttpServletResponse res )
   throws ServletException, IOException
   {
      Process p = null;
      Runtime r = null;
      ServletOutputStream out = res.getOutputStream();
   
      // get parameters
      String yAxis = req.getParameter( "yaxis" );
      if ( yAxis == null || yAxis.trim().length() == 0 
      || yAxis.indexOf( "." ) == -1 ) {
         throwError ( res, "GnuplotServlet Error: yAxis is " + yAxis );
         return;
      }

      String xAxis = req.getParameter( "xaxis" );
      if ( xAxis == null || xAxis.trim().length() == 0 
      || xAxis.indexOf( "." ) == -1 ) {
         throwError ( res, "GnuplotServlet Error: xAxis is " + xAxis );
         return;
      }

      String directorySufix = req.getParameter( "dirno" );
      if ( directorySufix == null || directorySufix.trim().length() == 0 ) {
         throwError ( res, "GnuplotServlet Error: directory sufix is " 
         + directorySufix );
         return;
      }

      int datasetNumber = 0;
      String dataset = req.getParameter( "dataset" );
      try {
         datasetNumber = Integer.parseInt( dataset );
      }
      catch( Exception e ) {
         System.err.println( "error in dataset number, using default 0" );
         datasetNumber = 0;
      }

      int yColumn = 0;
      int xColumn = 0;
      try {
         int yIndex = yAxis.indexOf( "." );
         int xIndex = xAxis.indexOf( "." );
         yColumn = Integer.parseInt( yAxis.substring( 0, yIndex ) );
         xColumn = Integer.parseInt( xAxis.substring( 0, xIndex ) );
         yAxis = yAxis.substring( yIndex + 1 );
         xAxis = xAxis.substring( xIndex + 1 );
      }
      catch( Exception e ) {
         throwError ( res, "GnuplotServlet Error: yAxis=[" + yAxis
         + "], xAxis=[" + xAxis + "]" );
         return;
      }

      // Create command file for gnuplot
      String plotIn = "tmp_gnuplot_" + Math.random();
      String plotOut = plotIn + ".pbm";
      String gifOut = plotIn + ".gif";
      try {
         PrintStream fileIn =
         new PrintStream ( new FileOutputStream ( new File( plotIn ) ) );
         fileIn.println( "set nokey" );
         fileIn.println( "set title '" + yAxis + " vs. " + xAxis + "'" );
         fileIn.println( "set ylabel '" + yAxis + "'" );
         fileIn.println( "set xlabel '" + xAxis + "'" );
         fileIn.println( "set terminal pbm" );
         fileIn.println( "set output \"" + plotOut + "\"" );
         fileIn.println( "plot '" + Environment.HTML_DIRECTORY + directorySufix 
         + File.separator + Environment.COLUMNS_DATA + datasetNumber 
         + "' using " + yColumn + ":" + xColumn );
         fileIn.println( "quit" );
         fileIn.close();
      } 
      catch( Exception e ) {
         e.printStackTrace();
         throwError ( res, "Gnuplot Error: Input file error" );
         return;
      }

      try {
         String[] command = { Environment.GNUPLOT, plotIn };
         r = Runtime.getRuntime();
         p = r.exec( command );
         p.waitFor();
         String[] command2 = { "/bin/sh", "-c", Environment.PBM2GIF + " <" 
         + plotOut + ">" + gifOut };
         p = r.exec( command2 );
         int status = p.waitFor();
         if( status != 0 ) {
System.err.println( "try: " + command2[ 0 ] + " " + command2[ 1 ] + " " +
command2[ 2 ] );
            throwError( res, "gnuplot error return: " + status );
//            String[] removeall = { "/bin/rm", "-f", plotIn, plotOut,
// gifOut };
//            p = r.exec( removeall );
            return;
         }
         // remove the files plotIn, plot.pbm
         String[] remove = { "/bin/rm", "-f", plotIn, plotOut };
         //String[] remove = { "/bin/rm", "-f", plotOut };
         p = r.exec(remove);
         p.waitFor();
      } 
      catch ( Exception e ) {
         throwError ( res, "Gnuplot Error: output file error" );
         return;
      }

      File f = new File ( gifOut );
      FileInputStream fileOut = null;
      try {
         fileOut = new FileInputStream ( f );
      } 
      catch ( Exception e ) {
         throwError ( res, "gif input file not found" );
         String[] removeall = { "/bin/rm", "-f", plotIn, plotOut, gifOut };
         p = r.exec( removeall );
         return;
      }
      long length = f.length();
     
      if ( length == 0 ) {
         throwError ( res, "No output" );
         String[] removeall = { "/bin/rm", "-f", plotIn, plotOut, gifOut };
         p = r.exec( removeall );
         return;
      }

      byte[] buffer = new byte[ (int) length];
      try {
         fileOut.read ( buffer );
      } 
      catch ( Exception e ) {
         throwError ( res, "gif input file error" );
         String[] removeall = { "/bin/rm", "-f", plotIn, plotOut, gifOut };
         p = r.exec( removeall );
         return;
      }
      res.setContentType( "image/gif" );
      try {
         out.write( buffer );
      } 
      catch ( Exception e ) {
         String[] removeall = { "/bin/rm", "-f", plotIn, plotOut, gifOut };
         p = r.exec( removeall );
         return;
      }
      out.close();
      try {
         // remove the files plot.gif
         String[] remove = { "/bin/rm", "-f", gifOut };
         p = r.exec( remove );
      } 
      catch ( Exception e ) {
      }

   }

   public String getServletInfo() 
   {
      return "The Gnuplot servlet";
   }

   private boolean notShellSafe ( String par ) 
   {
      if ( par.indexOf ( "shell" ) != -1 )
         return true;
      if ( par.indexOf ( '!' ) != -1 )
         return true;
      return false;
   }

   private void throwError (HttpServletResponse res, String errorMsg)
   throws IOException 
   {
      ServletOutputStream out = res.getOutputStream();
      res.setContentType( "text/html" );
      out.println( "<HEAD><TITLE>Gnuplot Error</TITLE></HEAD><BODY>" );
      out.println( "<h1>Gnuplot Servlet Error:</h1>" );
      out.println( "<P>" + errorMsg + "<hr>" );
      out.println( "</BODY>" );
      out.close();
   }
}