/*
Below is the copyright agreement for the Ptolemy II system.

Copyright (c) 2002-2009 The Regents of the University of California.
All rights reserved.

Permission is hereby granted, without written agreement and without
license or royalty fees, to use, copy, modify, and distribute this
software and its documentation for any purpose, provided that the above
copyright notice and the following two paragraphs appear in all copies
of this software.

IN NO EVENT SHALL THE UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY
FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF
THE UNIVERSITY OF CALIFORNIA HAS BEEN ADVISED OF THE POSSIBILITY OF
SUCH DAMAGE.

THE UNIVERSITY OF CALIFORNIA SPECIFICALLY DISCLAIMS ANY WARRANTIES,
INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE
PROVIDED HEREUNDER IS ON AN "AS IS" BASIS, AND THE UNIVERSITY OF
CALIFORNIA HAS NO OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT, UPDATES,
ENHANCEMENTS, OR MODIFICATIONS.
*/
package ptolemy.plot.servlet;

import ptolemy.plot.Plot;
import ptolemy.plot.plotml.PlotMLParser;

import com.microstar.xml.XmlException;
import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGEncodeParam;
import com.sun.image.codec.jpeg.JPEGImageEncoder;

import java.awt.Color;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.*;

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


/**
 * Takes the parameters file, w, h and returs and jpeg image with the
 * ptplot graph generated from the PlotML file.
 *
 * The file must be located in the same directory or a subdirectory of the
 * servlet.
 *
 * <p>Use in your html as:
 * <pre>
 * <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"/>
 * </pre>
 *
 * No waranties given in any respect! Have fun.
 * @author A. Gobbi
 * @version $Id$
 */
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);
        }
    }
}