package net.sourceforge.fenixedu.presentationTier.Action;

import java.io.IOException;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.List;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import net.fortuna.ical4j.model.Calendar;
import net.sourceforge.fenixedu.domain.Attends;
import net.sourceforge.fenixedu.domain.ExecutionSemester;
import net.sourceforge.fenixedu.domain.Lesson;
import net.sourceforge.fenixedu.domain.Project;
import net.sourceforge.fenixedu.domain.Shift;
import net.sourceforge.fenixedu.domain.User;
import net.sourceforge.fenixedu.domain.WrittenEvaluation;
import net.sourceforge.fenixedu.domain.person.RoleType;
import net.sourceforge.fenixedu.domain.student.Registration;
import net.sourceforge.fenixedu.domain.util.icalendar.CalendarFactory;
import net.sourceforge.fenixedu.domain.util.icalendar.EventBean;
import net.sourceforge.fenixedu.presentationTier.Action.base.FenixDispatchAction;
import net.sourceforge.fenixedu.presentationTier.Action.exceptions.FenixActionException;
import net.sourceforge.fenixedu.presentationTier.Action.student.ICalStudentTimeTable;

import org.apache.commons.lang.CharEncoding;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;
import org.joda.time.DateTime;

import pt.ist.fenixWebFramework.struts.annotations.Mapping;

@Mapping(path = "/iCalendarSync", module = "external")
public class ICalendarSyncPoint extends FenixDispatchAction {

    private Calendar getClassCalendar(User user, DateTime validity, HttpServletRequest request) {
	ExecutionSemester currentExecutionSemester = ExecutionSemester.readActualExecutionSemester();

	List<EventBean> allEvents = new ArrayList<EventBean>();
	String scheme = request.getScheme();
	String serverName = request.getServerName();
	int serverPort = request.getServerPort();
	for (Registration registration : user.getPerson().getStudent().getRegistrations()) {
	    for (Shift shift : registration.getShiftsForCurrentExecutionPeriod()) {
		for (Lesson lesson : shift.getAssociatedLessons()) {
		    allEvents.addAll(lesson.getAllLessonsEvents(scheme, serverName, serverPort));
		}
	    }

	    for (Shift shift : registration.getShiftsFor(currentExecutionSemester.getPreviousExecutionPeriod())) {
		for (Lesson lesson : shift.getAssociatedLessons()) {
		    allEvents.addAll(lesson.getAllLessonsEvents(scheme, serverName, serverPort));
		}
	    }
	}
	String url = scheme + "://" + serverName + ((serverPort == 80 || serverPort == 443) ? "" : ":" + serverPort) + "/privado";
	EventBean event = new EventBean("Renovar a chave do calendario.", validity.minusMinutes(30), validity.plusMinutes(30),
		false, "Portal Fénix", url,
		"A sua chave de sincronização do calendario vai expirar. Diriga-se ao Portal Fénix para gerar nova chave");

	allEvents.add(event);

	return CalendarFactory.createCalendar(allEvents);

    }

    private Calendar getExamsCalendar(User user, DateTime validity, HttpServletRequest request) {
	ExecutionSemester currentExecutionSemester = ExecutionSemester.readActualExecutionSemester();
	List<EventBean> allEvents = new ArrayList<EventBean>();
	String scheme = request.getScheme();
	String serverName = request.getServerName();
	int serverPort = request.getServerPort();
	for (Registration registration : user.getPerson().getStudent().getRegistrations()) {
	    for (WrittenEvaluation writtenEvaluation : registration.getWrittenEvaluations(currentExecutionSemester)) {
		allEvents.addAll(writtenEvaluation.getAllEvents(registration, scheme, serverName, serverPort));
	    }

	    for (Attends attends : registration.getAttendsForExecutionPeriod(currentExecutionSemester)) {
		for (Project project : attends.getExecutionCourse().getAssociatedProjects()) {
		    allEvents.addAll(project.getAllEvents(attends.getExecutionCourse(), scheme, serverName, serverPort));
		}
	    }

	    for (WrittenEvaluation writtenEvaluation : registration.getWrittenEvaluations(currentExecutionSemester
		    .getPreviousExecutionPeriod())) {
		allEvents.addAll(writtenEvaluation.getAllEvents(registration, scheme, serverName, serverPort));
	    }

	    for (Attends attends : registration.getAttendsForExecutionPeriod(currentExecutionSemester
		    .getPreviousExecutionPeriod())) {
		for (Project project : attends.getExecutionCourse().getAssociatedProjects()) {
		    allEvents.addAll(project.getAllEvents(attends.getExecutionCourse(), scheme, serverName, serverPort));
		}
	    }
	}

	String url = scheme + "://" + serverName + ((serverPort == 80 || serverPort == 443) ? "" : ":" + serverPort) + "/privado";
	EventBean event = new EventBean("Renovar a chave do calendario.", validity.minusMinutes(30), validity.plusMinutes(30),
		false, "Portal Fénix", url,
		"A sua chave de sincronização do calendario vai expirar. Diriga-se ao Portal Fénix para gerar nova chave");

	allEvents.add(event);

	return CalendarFactory.createCalendar(allEvents);

    }

    private Calendar getCalendar(String method, User user, DateTime validity, HttpServletRequest request)
	    throws FenixActionException {
	if (method == "syncClasses") {
	    return getClassCalendar(user, validity, request);
	} else if (method == "syncExams") {
	    return getExamsCalendar(user, validity, request);
	} else {
	    throw new FenixActionException("unexpected.syncing.method");
	}
    }

    private void sync(HttpServletRequest request, final HttpServletResponse httpServletResponse, String method)
	    throws FenixActionException, Exception {
	String userId = request.getParameter("user");
	String payload = request.getParameter("payload");
	String regId = request.getParameter("registrationID");

	if (userId == null || payload == null || regId == null) {
	    throw new FenixActionException("error.expecting.parameter.not.found");
	}

	User user = User.readUserByUserUId(userId);
	Registration registration = rootDomainObject.readRegistrationByOID(Integer.valueOf(regId));

	if (user.getPrivateKeyValidity() != null) {
	    if (payload.equals(ICalStudentTimeTable.calculatePayload(method, registration, user))) {
		if (user.getPrivateKeyValidity().isBeforeNow()) {
		    returnError(httpServletResponse, "private.key.validity.expired");
		} else {
		    if (user.getPerson().hasRole(RoleType.STUDENT)) {

			encodeAndTransmitResponse(httpServletResponse, getCalendar(method, user, user.getPrivateKeyValidity(),
				request));

		    } else {
			returnError(httpServletResponse, "user.is.not.student");
		    }
		}
	    } else {
		returnError(httpServletResponse, "payload.checksum.doesnt.match");
	    }
	} else {
	    returnError(httpServletResponse, "key.not.found");
	}
    }

    public ActionForward syncExams(ActionMapping mapping, ActionForm actionForm, HttpServletRequest request,
	    final HttpServletResponse httpServletResponse) throws Exception {
	sync(request, httpServletResponse, "syncExams");
	return null;
    }

    public ActionForward syncClasses(ActionMapping mapping, ActionForm actionForm, HttpServletRequest request,
	    final HttpServletResponse httpServletResponse) throws Exception {
	sync(request, httpServletResponse, "syncClasses");
	return null;
    }

    @SuppressWarnings("deprecation")
    private void returnError(HttpServletResponse httpServletResponse, String error) throws IOException {
	httpServletResponse.setStatus(500, error);
	httpServletResponse.getWriter().write("");
    }

    private void encodeAndTransmitResponse(HttpServletResponse httpServletResponse, Calendar calendar) throws Exception {
	httpServletResponse.setHeader("Content-Type", "text/calendar; charset=" + CharEncoding.UTF_8);

	final OutputStream outputStream = httpServletResponse.getOutputStream();
	outputStream.write(calendar.toString().getBytes(CharEncoding.UTF_8));
	outputStream.close();
    }
}