package bristol;

import com.megginson.sax.DataWriter;
import java.io.IOException;
import java.io.PrintWriter;
import java.io.StringWriter;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.postgis.Geometry;
import org.postgis.LineString;
import org.postgis.MultiLineString;
import org.postgis.PGbox2d;
import org.postgis.PGbox3d;
import org.postgis.PGgeometry;
import org.postgis.Point;
import org.xml.sax.SAXException;

public class GoogleMapsServlet extends HttpServlet {

    java.sql.Connection conn;

    /** Processes requests for both HTTP <code>GET</code> and <code>POST</code> methods.
     * @param request servlet request
     * @param response servlet response
     */
    protected void processRequest(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
        response.setContentType("text/xml;charset=UTF-8");
        PrintWriter out = response.getWriter();

        String longitude_west = request.getParameter("longitude_west");
        String latitude_south = request.getParameter("latitude_south");
        String longitude_east = request.getParameter("longitude_east");
        String latitude_north = request.getParameter("latitude_north");

        // llb            78.84196025356454 29.74739718007597
        // urt            78.96069820510147 29.82851883423195

        if (longitude_west == null){ longitude_west = "78.84196025356454";};
        if (latitude_south == null){ latitude_south = "29.74739718007597";};
        if (longitude_east == null){ longitude_east = "78.96069820510147";};
        if (latitude_north == null){ latitude_north = "29.82851883423195";};

        String url = "EchoServlet?" +
                "longitude_west=" + longitude_west +
                "&latitude_south=" + latitude_south +
                "&longitude_east=" + longitude_east +
                "&latitude_north=" + latitude_north;


        try {
            StringWriter sw = new StringWriter();
            DataWriter w = new DataWriter(sw);

            /*
            <gml:boundedBy>
    <gml:Box>
      <gml:coord><gml:X>77.07738000000001</gml:X><gml:Y>28.1704</gml:Y></gml:coord>
      <gml:coord><gml:X>80.73318</gml:X><gml:Y>31.4303</gml:Y></gml:coord>
    </gml:Box>
  </gml:boundedBy>
             */

            w.startElement("gml:boundedBy");
            w.startElement("gml:Box");

            w.startElement("gml:coord");
            w.dataElement("gml:X", longitude_west + "");
            w.dataElement("gml:Y", latitude_south + "");

            w.endElement("gml:coord");

            w.startElement("gml:coord");
            w.dataElement("gml:X", longitude_east + "");
            w.dataElement("gml:Y", latitude_north + "");
            w.endElement("gml:coord");

            w.endElement("gml:Box");
            w.endElement("gml:boundedBy");


            /*
             * Load the JDBC driver and establish a connection.
             */
            Class.forName("org.postgresql.Driver");

            String dburl = "jdbc:postgresql://localhost:5432/postgis";

            conn = DriverManager.getConnection(dburl, "postgres", "postgres");

            /*
             * Add the geometry types to the connection. Note that you
             * must cast the connection to the pgsql-specific connection
             * implementation before calling the addDataType() method.
             */
            ((org.postgresql.PGConnection) conn).addDataType("geometry",
                    PGgeometry.class);
            ((org.postgresql.PGConnection) conn).addDataType("box3d",
                    PGbox3d.class);
            ((org.postgresql.PGConnection) conn).addDataType("box2d",
                    PGbox2d.class);


            /*
             * Create a statement and execute a select query.
             */
            Statement s = conn.createStatement();

            // llb            78.84196025356454 29.74739718007597
            // urt            78.96069820510147 29.82851883423195
            String llb = longitude_west + " " + latitude_south;
            //"78.84196025356454 29.74739718007597";
            // lower left bottom

            String ult = longitude_west + " " + latitude_north;
            //"78.84196025356454 29.82851883423195";
            // upper left top

            String urt = longitude_east + " " + latitude_north;
            //"78.96069820510147 29.82851883423195";
            // upper right top

            String lrb = longitude_east + " " + latitude_south;
            //"78.96069820510147 29.74739718007597";
            // lower botton right

            String query = "SELECT intersection(wkb_geometry, GeometryFromText('POLYGON((" +
                    llb + "," +
                    ult + "," +
                    urt + "," +
                    lrb + "," +
                    llb +
                    "))', -1)) AS GEOM, ogc_fid FROM roads WHERE" +
                    " wkb_geometry && SetSRID('BOX3D(" + llb + "," + urt +  ")'::box3d,-1)";

            //System.out.println(query);

            ResultSet r = s.executeQuery(query);

            while (r.next()) {

                /*
                 * Retrieve the geometry as an object then cast it to the geometry type.
                 * Print things out.
                 */

                PGgeometry geom = (PGgeometry) r.getObject(1);

                if (geom.getGeoType() == Geometry.LINESTRING){
                    LineString ls = (LineString) geom.getGeometry();
                    w = printLineString(ls, w);
                }

                if (geom.getGeoType() == Geometry.MULTILINESTRING){
                    MultiLineString mls = (MultiLineString) geom.getGeometry() ;
                    LineString [] lineStrings = mls.getLines();
                    for(int i=0;i<lineStrings.length;i++){
                        w = printLineString(lineStrings[i], w);
                    }
                }
            }

            s.close();
            conn.close();

            String startDocument = "<?xml version=\"1.0\" encoding=\"utf-8\" ?>" +
                    "\n<ogr:FeatureCollection" +
                    "\n     xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\"" +
                    "\n     xsi:schemaLocation=\"http://ogr.maptools.org/ roads.xsd\"" +
                    "\n     xmlns:ogr=\"http://ogr.maptools.org/\"" +
                    "\n     xmlns:gml=\"http://www.opengis.net/gml\">\n";
            String endDocument = "\n</ogr:FeatureCollection>";

            out.println(startDocument + sw.toString() + endDocument);

        } catch (Exception e) {
            e.printStackTrace();
        }
        out.close();
    }

    private static DataWriter printLineString(LineString ls, DataWriter w) throws SAXException{
        w.startElement("gml:featureMember");
        w.startElement("ogr:roads");
        w.startElement("ogr:geometryProperty");
        w.startElement("gml:LineString");
        Point [] points = ls.getPoints();
        // <coord><X>324.1</X><Y>219.7</Y></coord>
        for(int i=0;i<points.length;i++){
            w.startElement("gml:coord");
            w.dataElement("gml:X", points[i].x + "");
            w.dataElement("gml:Y", points[i].y + "");
            w.endElement("gml:coord");
        }
        w.endElement("gml:LineString");
        w.endElement("ogr:geometryProperty");
        w.endElement("ogr:roads");
        w.endElement("gml:featureMember");

        return w;
    }

    // <editor-fold defaultstate="collapsed" desc="HttpServlet methods. Click on the + sign on the left to edit the code.">
    /** Handles the HTTP <code>GET</code> method.
     * @param request servlet request
     * @param response servlet response
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
        processRequest(request, response);
    }

    /** Handles the HTTP <code>POST</code> method.
     * @param request servlet request
     * @param response servlet response
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
        processRequest(request, response);
    }

    /** Returns a short description of the servlet.
     */
    public String getServletInfo() {
        return "Short description";
    }
    // </editor-fold>
}