package dk.thoerup.traininfoservice.banedk;


import java.io.IOException;
import java.io.StringWriter;
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 org.simpleframework.xml.Serializer;
import org.simpleframework.xml.core.Persister;

import dk.thoerup.android.traininfo.common.MetroBean;
import dk.thoerup.circuitbreaker.CircuitBreakerException;





@WebServlet(urlPatterns={"/MetroServlet"})
public class MetroServlet extends HttpServlet {

	private static final long serialVersionUID = 1L;

	Logger logger = Logger.getLogger(MetroServlet.class.getName());
	
	MetroFetcher fetcher = new MetroFetcher();

	protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		
		if (req.getParameter("station") == null || req.getParameter("station").equals("") ) {
			resp.sendError(400, "not enough parameters");
			return;
		}			
		
		//TODO: How should statistics be handled for the metro
		//Statistics.getInstance().incrementDepartureLookups(); 
		
		int station = Integer.parseInt( req.getParameter("station") );


		MetroBean bean;		

		try {
			
			bean = fetcher.cachedLookupMetroDepartures(station);
			String xml = formatXml(bean);
			
			resp.setDateHeader("Expires", 0);
			resp.setHeader("Cache-Control", "no-cache, must-revalidate");
			resp.setContentType("text/xml");
			resp.getWriter().print(xml);
			
		} catch (java.io.IOException ioe) {
			logger.warning("Metro read failed, station="+station + ". " + ioe.getMessage() );
			//Statistics.getInstance().incrementDepartureErrors();
			resp.sendError(500);
			return;
		} catch (CircuitBreakerException cbe) {
			logger.warning("Circuitbreaker - failing fast");
			//Statistics.getInstance().incrementDepartureErrors();
			resp.sendError(500);
			return;
		} catch (Exception e) {			
			logger.log(Level.WARNING, "Unknown exception, metro-station=" +station, e);
			//Statistics.getInstance().incrementDepartureErrors();
			resp.sendError(500);
			return;
		}
		
		
	}
	
	String formatXml(MetroBean metro) throws ServletException {
		
		Serializer serializer = new Persister();

		StringWriter out = new StringWriter();

		try {
			serializer.write(metro, out);
		} catch (Exception e) {
			throw new ServletException(e);
		}
		
		return out.toString();
	}
	
}