package dk.thoerup.traininfoservice.banedk;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.IOException;
import java.util.logging.Level;
import java.util.logging.Logger;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import javax.xml.transform.Source;
import javax.xml.transform.Templates;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.stream.StreamResult;
import javax.xml.transform.stream.StreamSource;

import org.simpleframework.xml.Serializer;
import org.simpleframework.xml.core.Persister;

import dk.thoerup.android.traininfo.common.DepartureBean;
import dk.thoerup.circuitbreaker.CircuitBreakerException;
import dk.thoerup.traininfoservice.StationDAO;
import dk.thoerup.traininfoservice.Statistics;

/**
 * Servlet implementation class DepartureServlet
 */
@WebServlet(urlPatterns={"/DepartureServlet"})
public class DepartureServlet extends HttpServlet {
	private static final long serialVersionUID = 1L;
	
	Logger logger = Logger.getLogger( DepartureServlet.class.getName() );

	DepartureFetcher fetcher;


	
	TransformerFactory xslTransFact;
	Templates xslTemplate;
	

	@Override
	public void init() throws ServletException {
		super.init();

		boolean useAzureSite =  Boolean.parseBoolean( getServletContext().getInitParameter("useazuresite") );
		int cacheTimeout =  Integer.parseInt( getServletContext().getInitParameter("cache_timeout") );
		int replyTimeout =  Integer.parseInt( getServletContext().getInitParameter("reply_timeout") ); 
		logger.info( "DepartureServlet, use azure site=" + useAzureSite + ", cache=" + cacheTimeout);
		fetcher = new DepartureFetcher(useAzureSite, cacheTimeout, replyTimeout);
		
		xslTransFact = TransformerFactory.newInstance();
		
		String xslPath = getServletContext().getRealPath("/departures.xsl");
		Source stylesheet = new StreamSource( new File(xslPath) );
		
		try {
			xslTemplate = xslTransFact.newTemplates(stylesheet);
		} catch (Exception e) {
			throw new ServletException(e);
		}
	}

	@Override
	protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {		
		if (req.getParameter("station") == null) {
			resp.sendError(400, "not enough parameters");
			return;
		}
		
		boolean arrival = false;
		try {
			arrival = Integer.parseInt( req.getParameter("arrival")) != 0;
		} catch (Exception e) {}
		
		Statistics.getInstance().incrementDepartureLookups();
		
		int station = Integer.parseInt( req.getParameter("station") );
		String format = req.getParameter("format");

		DepartureBean beans;		

		try {
			beans = fetcher.cachedLookupDepartures(station, arrival);
			beans.arrival = arrival;
		} catch (java.io.IOException ioe) {
			logger.warning("Read failed, station="+station + ". " + ioe.getMessage() );
			Statistics.getInstance().incrementDepartureErrors();
			resp.sendError(500);
			return;
		} catch (CircuitBreakerException cbe) {
			logger.warning("Circuitbreaker - failing fast, station=" +station);
			Statistics.getInstance().incrementDepartureErrors();
			resp.sendError(500);
			return;
		} catch (StationDAO.NostationException nse) {
			logger.log(Level.WARNING, "Station not in Database, station=" +station);
			Statistics.getInstance().incrementDepartureErrors();
			resp.sendError(400, "invalid station ID");
			return;			
		} catch (Exception e) {			
			logger.log(Level.WARNING, "Unknown exception, station=" +station, e);
			Statistics.getInstance().incrementDepartureErrors();
			resp.sendError(500);
			return;
		}
		
		resp.setDateHeader("Expires", 0);
		resp.setHeader("Cache-Control", "no-cache, must-revalidate");
		
		if (format.equalsIgnoreCase("xml")) {
			resp.setContentType("text/xml");
			resp.getWriter().print( formatXml(beans) );
		} else if (format.equalsIgnoreCase("html")) {
			/*
			String advStr = req.getParameter("advanced");
			boolean advanced = advStr != null ? Boolean.parseBoolean(advStr) : false;
			
			req.setAttribute("advanced", advanced);
			req.setAttribute("departurebeans", beans);
			req.setAttribute("stationID", station );
			getServletContext().getRequestDispatcher("/ViewDepartures.jsp").forward(req,resp);*/
			resp.setContentType("text/html");
			resp.getWriter().print(  xmlToHtml(formatXml(beans))  );
		} else {
			resp.sendError(400, "Unknown format");			
		}

	}

	protected String formatXml(DepartureBean beans) throws ServletException{
		
		Serializer serializer = new Persister();

		ByteArrayOutputStream out = new ByteArrayOutputStream();

		try {
			serializer.write(beans, out);
		} catch (Exception e) {
			throw new ServletException(e);
		}
		
		return out.toString();
	}
	
	protected String xmlToHtml(String input) throws ServletException {

		try {					
			Transformer trans = xslTemplate.newTransformer();			
		
			Source xml = new StreamSource( new ByteArrayInputStream(input.getBytes() ));
			ByteArrayOutputStream out = new ByteArrayOutputStream();
			trans.transform(xml, new StreamResult(out));		
		
			return out.toString();
		} catch (Exception e) {
			throw new ServletException(e);
		}
	}

}