package ptolemy.plot.servlet;

import ptolemy.plot.Plot;
import ptolemy.plot.plotml.PlotMLParser;
import com.microstar.xml.XmlException;

import javax.servlet.http.*;
import javax.servlet.ServletException;
import java.io.*;

import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGImageEncoder;
import com.sun.image.codec.jpeg.JPEGEncodeParam;
import java.awt.image.BufferedImage;
import java.awt.Graphics2D;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.Color;

/**
 * Takes the parameters file, w, h and returs and jpeg image with the
 * ptplot graph generated from the PlotML file.
 *
 * the file mustbe located in the same directory or a subdirectory of the
 * servlet.
 *
 * Use in your html as:
 * <img src="/servlet/ptolemy/plot/servlet/PlotServlet?file=Bin.xml&w=500&h=500"/>
 * <img src="/servlet/ptolemy/plot/servlet/PlotServlet?file=HighLowSmall.xml&w=500&h=500"/>
 *
 * No waranties given in any respect! Have fun.
 * @author A. Gobbi
 * @version 1.0
 */

public class PlotServlet extends HttpServlet
{  public void doGet(HttpServletRequest request, HttpServletResponse response)
           throws ServletException, IOException
    {  doPost(request, response);
    }


    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException
    {  String fName = request.getParameter("file");
    if (fName == null)
        throw new ServletException("No filename given!");

    if (fName.indexOf("..") >= 0)
        throw new ServletException("Security problem with filename: " + fName);

    InputStream fileStream = this.getClass().getClassLoader()
        .getResourceAsStream("ptolemy/plot/servlet/" + fName);

    Plot ptPlot;
    try
        {
            if (fileStream == null)
                throw new ServletException("Could not find: " + fName);


            ptPlot = new Plot();
            int h = 200;
            int w = 300;
            String dummy = request.getParameter("h");
            if (dummy != null) h = Integer.parseInt(dummy);
            dummy = request.getParameter("w");
            if (dummy != null) w = Integer.parseInt(dummy);
            ptPlot.setSize(w,h);

            read(ptPlot, fileStream);
        }finally
            {  fileStream.close();
            }

    response.setContentType("image/jpeg");

    OutputStream out = response.getOutputStream();
    writeAsJPEG(out, ptPlot);
    out.close();
    }




    /**
     * Write the jpeg image of the Component cnt to the OutPutStream.
     *
     * If the component is a penal with subpanels you might need to call
     * {@link JPanel#addNotify} and {@link JPanel#doLayout}.
     * If the server is running on Unix you will need to use java 1.4 and specify
     * -Djava.awt.headless=true on the command Line or for tomcat:
     *    edit catalina.sh in the $CATALINA_HOME/bin directory and add a line
     *    CATALINA_OPTS='-Djava.awt.headless=true'
     */
    static public void writeAsJPEG(OutputStream out, Component cnt) throws IOException
    {  Dimension s = cnt.getSize();
    BufferedImage bufferedImage =
        new BufferedImage((int)s.getWidth(), (int)s.getHeight(),
                BufferedImage.TYPE_3BYTE_BGR );
    Graphics2D graphics = bufferedImage.createGraphics();
    graphics.setColor(Color.white);
    //graphics.fillRect(0, 0, (int)s.getWidth(), (int)s.getHeight());

    cnt.print(graphics);
    JPEGImageEncoder jpegEncoder = JPEGCodec.createJPEGEncoder(out);
    JPEGEncodeParam encodeParam =  JPEGCodec.getDefaultJPEGEncodeParam(bufferedImage);
    encodeParam.setQuality((float)0.9, true);
    jpegEncoder.encode(bufferedImage, encodeParam);
    graphics.dispose();
    bufferedImage.flush();
    }

    /**
     * Parse PlotML file into plot.
     */
    private static void read(Plot plot, InputStream in) throws IOException
    {
        PlotMLParser parser;
        parser = new PlotMLParser(plot);
        try
            {  parser.parse(null, in);
            } catch (Exception ex)
                {
                    String msg;
                    if (ex instanceof XmlException)
                        {   XmlException xmlex = (XmlException)ex;
                        msg =
                            "PlotMLFrame: failed to parse PlotML data:\n"
                            + "line: " + xmlex.getLine()
                            + ", column: " + xmlex.getColumn()
                            + "\nIn entity: " + xmlex.getSystemId()
                            + "\n";
                        } else
                            {   msg = "PlotMLFrame: failed to parse PlotML data:\n";
                            }
                    throw new IOException(msg);
                }
    }
}