package dk.thoerup.traininfoservice.banedk;

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.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.transform.OutputKeys;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;

import org.w3c.dom.DOMImplementation;
import org.w3c.dom.Document;
import org.w3c.dom.Element;

import dk.thoerup.circuitbreaker.CircuitBreakerException;
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 transformerFactory = TransformerFactory.newInstance();
	DocumentBuilderFactory docBuilderFactory = DocumentBuilderFactory.newInstance();
	

	@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 temp site=" + useAzureSite + ", cache=" + cacheTimeout);
		fetcher = new DepartureFetcher(useAzureSite, cacheTimeout, replyTimeout);
	}

	@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);
		} 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");
			Statistics.getInstance().incrementDepartureErrors();
			resp.sendError(500);
			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, arrival) );
		} 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);
		} else {
			resp.sendError(400, "Unknown format");			
		}

	}

	protected String formatXml(DepartureBean beans, boolean arrival) throws ServletException{
		String xml = "";
		try {
			DocumentBuilder builder = docBuilderFactory.newDocumentBuilder();
			DOMImplementation impl = builder.getDOMImplementation();

			
			Document doc = impl.createDocument(null,null,null);
	        Element root = doc.createElement("departureinfo");
	        root.setAttribute("station", beans.getStationName());
	        root.setAttribute("arrival", Boolean.toString(arrival) );
	        
	        for (String notif : beans.notifications) {
	        	Element notElem = doc.createElement("notification");
	        	notElem.setTextContent(notif);
	        	root.appendChild(notElem); 
	        }
	        
	        for (DepartureEntry departure : beans.departureEntries) {
	        	Element train = doc.createElement("train");
	        	
	        	Element time = doc.createElement("time");
	        	time.setTextContent( departure.getTime() );
	        	train.appendChild(time);
	        	
	        	Element updated = doc.createElement("updated");
	        	updated.setTextContent( String.valueOf(departure.getUpdated()) );
	        	train.appendChild(updated);
	        	
	        	Element trainNumber = doc.createElement("trainnumber");
	        	trainNumber.setTextContent( departure.getTrainNumber() );
	        	train.appendChild(trainNumber);
	        	
	        	Element destination = doc.createElement("destination");
	        	destination.setTextContent( departure.getDestination());
	        	train.appendChild(destination);
	        	
	        	Element origin = doc.createElement("origin");
	        	origin.setTextContent( departure.getOrigin() );
	        	train.appendChild(origin);
	        	
	        	Element location= doc.createElement("location");
	        	location.setTextContent( departure.getLocation() );
	        	train.appendChild(location);
	        	
	        	Element status = doc.createElement("status");
	        	status.setTextContent( departure.getStatus() );
	        	train.appendChild(status);
	        	
	        	Element note = doc.createElement("note");
	        	note.setTextContent( departure.getNote() );
	        	train.appendChild(note);
	        	
	        	Element type = doc.createElement("type");
	        	type.setTextContent( departure.getType() );
	        	train.appendChild(type);
	        	
	        	root.appendChild(train);
	        }
	        
	        doc.appendChild(root);
	        
	        
	        DOMSource domSource = new DOMSource(doc);

	        Transformer transformer = transformerFactory.newTransformer();
	        //transformer.setOutputProperty(OutputKeys.OMIT_XML_DECLARATION, "yes");
	        transformer.setOutputProperty(OutputKeys.METHOD, "xml");
	        transformer.setOutputProperty(OutputKeys.ENCODING,"ISO-8859-1");
	        transformer.setOutputProperty("{http://xml.apache.org/xslt}indent-amount", "1");
	        transformer.setOutputProperty(OutputKeys.INDENT, "yes");
	        java.io.StringWriter sw = new java.io.StringWriter();
	        StreamResult sr = new StreamResult(sw);
	        transformer.transform(domSource, sr);
	        xml = sw.toString();


		} catch (Exception e) {
			throw new ServletException(e);
		}
		return xml;
	}

}