/*

 * All Sigmah code is released under the GNU General Public License v3

 * See COPYRIGHT.txt and LICENSE.txt.

 */



package org.sigmah.server.endpoint.kml;



import com.google.inject.Inject;

import com.google.inject.Injector;

import com.google.inject.Singleton;

import org.apache.commons.codec.binary.Base64;

import org.sigmah.server.auth.Authenticator;

import org.sigmah.server.domain.DomainFilters;

import org.sigmah.server.domain.SiteData;

import org.sigmah.server.report.generator.SiteDataBinder;

import org.sigmah.server.report.util.HtmlWriter;

import org.sigmah.server.util.KMLNamespace;

import org.sigmah.server.util.XmlBuilder;

import org.sigmah.shared.command.GetSchema;

import org.sigmah.shared.command.handler.GetSchemaHandler;

import org.sigmah.shared.dao.*;

import org.sigmah.shared.domain.User;

import org.sigmah.shared.dto.ActivityDTO;

import org.sigmah.shared.dto.IndicatorDTO;

import org.sigmah.shared.dto.SchemaDTO;

import org.sigmah.shared.exception.CommandException;

import org.xml.sax.SAXException;



import javax.persistence.EntityManager;

import javax.persistence.NoResultException;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import javax.xml.transform.TransformerConfigurationException;

import javax.xml.transform.stream.StreamResult;

import java.io.IOException;

import java.io.PrintWriter;

import java.nio.charset.Charset;

import java.util.ArrayList;

import java.util.List;



/**

 * Serves a KML (Google Earth) file containing the locations of all activities

 * that are visible to the user.

 * <p/>

 * Users are authenticated using Basic HTTP authentication, and will see a prompt

 * for their username (email) and password when they access from Google Earth.

 *

 * @author Alex Bertram

 */

@Singleton

public class KmlDataServlet extends javax.servlet.http.HttpServlet {



    @Inject

    private Injector injector;



    public void doGet(HttpServletRequest req, HttpServletResponse res)

            throws ServletException, IOException {

        PrintWriter out = res.getWriter();



        // Get Authorization header

        String auth = req.getHeader("Authorization");



        // Do we allow that user?



        User user = authenticate(auth);

        if (user == null) {

            // Not allowed, or no password provided so report unauthorized

            res.setHeader("WWW-Authenticate", "BASIC realm=\"Utilisateurs authorises\"");

            res.sendError(HttpServletResponse.SC_UNAUTHORIZED);

            return;

        }





        res.setContentType("application/vnd.google-earth.kml+xml");



        try {

            writeDocument(user, res.getWriter());



        } catch (TransformerConfigurationException e) {

            e.printStackTrace();

        } catch (SAXException e) {

            e.printStackTrace();

        } catch (CommandException e) {

            e.printStackTrace();

        }



    }



    // This method checks the user information sent in the Authorization

    // header against the database of users maintained in the users Hashtable.



    protected User authenticate(String auth) throws IOException {

        if (auth == null) {

            return null;

        }// no auth



        if (!auth.toUpperCase().startsWith("BASIC ")) {

            return null;

        }// we only do BASIC



        // Get encoded user and password, comes after "BASIC "

        String emailpassEncoded = auth.substring(6);



        // Decode it, using any base 64 decoder



        byte[] emailpassDecodedBytes = Base64.decodeBase64(emailpassEncoded.getBytes());

        String emailpassDecoded = new String(emailpassDecodedBytes, Charset.defaultCharset());

        String[] emailPass = emailpassDecoded.split(":");



        if (emailPass.length != 2) {

            return null;

        }



        // look up the user in the database

        UserDAO userDAO = injector.getInstance(UserDAO.class);

        User user = null; 

        try {

        	userDAO.findUserByEmail(emailPass[0]);

        } catch (NoResultException e) {

        	return null;

        }

        

        Authenticator checker = injector.getInstance(Authenticator.class);

        if (!checker.check(user, emailPass[1])) {

            return null;

        }

        return user;



    }



    protected void writeDocument(User user, PrintWriter out) throws TransformerConfigurationException, SAXException, CommandException {



        // TODO: rewrite using FreeMarker



        EntityManager em = injector.getInstance(EntityManager.class);

        DomainFilters.applyUserFilter(user, em);



        XmlBuilder xml = new XmlBuilder(new StreamResult(out));



        GetSchemaHandler schemaHandler = injector.getInstance(GetSchemaHandler.class);

        SchemaDTO schema = (SchemaDTO) schemaHandler.execute(new GetSchema(), user);



        List<SiteData> sites = querySites(user, schema);



        xml.startDocument();



        KMLNamespace kml = new KMLNamespace(xml);



        kml.startKml();



        kml.startDocument();

        kml.name("ActivityInfo");

        kml.open(true);



        int lastDatabaseId = -1;

        int lastActivityId = -1;

        ActivityDTO activity = null;



        for (SiteData pm : sites) {



            if (pm.hasLatLong()) {



                if (pm.getActivityId() != lastActivityId && lastActivityId != -1) {

                    xml.close();

                }



                if (pm.getDatabaseId() != lastDatabaseId) {

                    if (lastDatabaseId != -1) {

                        xml.close();

                    }

                    kml.startFolder();

                    kml.name(schema.getDatabaseById(pm.getDatabaseId()).getName());

                    kml.open(true);

                    lastDatabaseId = pm.getDatabaseId();

                }



                if (pm.getActivityId() != lastActivityId) {

                    kml.startFolder();

                    kml.name(schema.getActivityById(pm.getActivityId()).getName());

                    kml.open(false);



                    activity = schema.getActivityById(pm.getActivityId());

                    lastActivityId = activity.getId();

                }



                kml.startPlaceMark();

                kml.name(pm.getLocationName());



                kml.startSnippet();

                xml.cdata(renderSnippet(activity, pm));

                xml.close(); // Snippet



                kml.startDescription();

                xml.cdata(renderDescription(activity, pm));

                xml.close();  // Description



                kml.startTimeSpan();

                kml.begin(pm.getDate1());

                kml.end(pm.getDate2());

                xml.close(); // Timespan



                kml.startPoint();

                kml.coordinates(pm.getLongitude(), pm.getLatitude());

                xml.close();  // Point



                xml.close();  // Placemark

            }

        }



        if (lastActivityId != -1) {

            xml.close();

        }

        if (lastDatabaseId != -1) {

            xml.close();

        }



        xml.close(); // Document

        xml.close(); // kml

        xml.endDocument();





    }



    private String renderSnippet(ActivityDTO activity, SiteData pm) {

        return activity.getName() + " ?  " + pm.getLocationName() + " (" + pm.getPartnerName() + ")";

    }



    private List<SiteData> querySites(User user, SchemaDTO schema) {



        List<SiteOrder> order = new ArrayList<SiteOrder>();

        order.add(SiteOrder.ascendingOn(SiteTableColumn.database_name.property()));

        order.add(SiteOrder.ascendingOn(SiteTableColumn.activity_name.property()));

        order.add(SiteOrder.ascendingOn(SiteTableColumn.date2.property()));



        SiteTableDAO siteDAO = injector.getInstance(SiteTableDAO.class);

        return siteDAO.query(user, new Filter(), order, new SiteDataBinder(), SiteTableDAO.RETRIEVE_ALL, 0, -1);



    }



    private String renderDescription(ActivityDTO activity, SiteData data) {

        HtmlWriter html = new HtmlWriter();



        html.startTable();



        for (IndicatorDTO indicator : activity.getIndicators()) {

            if (data.getIndicatorValue(indicator.getId()) != null) {

                html.startTableRow();



                html.tableCell(indicator.getName());

                html.tableCell(Double.toString(data.getIndicatorValue(indicator.getId())));

                html.tableCell(indicator.getUnits());



                html.endTableRow();

            }

        }



        html.endTable();

        return html.toString();

    }



}