/*
 * Created on 27/Ago/2003
 *
 */

package net.sourceforge.fenixedu.applicationTier.Servico.student;

import pt.ist.fenixWebFramework.services.Service;

import pt.ist.fenixWebFramework.security.accessControl.Checked;

import java.util.List;

import net.sourceforge.fenixedu.applicationTier.FenixService;
import net.sourceforge.fenixedu.applicationTier.Servico.exceptions.FenixServiceException;
import net.sourceforge.fenixedu.applicationTier.Servico.exceptions.InvalidArgumentsServiceException;
import net.sourceforge.fenixedu.applicationTier.Servico.exceptions.InvalidSituationServiceException;
import net.sourceforge.fenixedu.applicationTier.Servico.exceptions.NotAuthorizedException;
import net.sourceforge.fenixedu.applicationTier.strategy.groupEnrolment.strategys.GroupEnrolmentStrategyFactory;
import net.sourceforge.fenixedu.applicationTier.strategy.groupEnrolment.strategys.IGroupEnrolmentStrategy;
import net.sourceforge.fenixedu.applicationTier.strategy.groupEnrolment.strategys.IGroupEnrolmentStrategyFactory;
import net.sourceforge.fenixedu.domain.Attends;
import net.sourceforge.fenixedu.domain.ExecutionCourse;
import net.sourceforge.fenixedu.domain.Grouping;
import net.sourceforge.fenixedu.domain.StudentGroup;
import net.sourceforge.fenixedu.domain.student.Registration;

import org.apache.struts.util.MessageResources;

/**
 * @author asnr and scpo
 * 
 */
public class GroupStudentEnrolment extends FenixService {

    private static final MessageResources messages = MessageResources.getMessageResources("resources/GlobalResources");

    @Checked("RolePredicates.STUDENT_PREDICATE")
    @Service
    public static Boolean run(Integer studentGroupCode, String username) throws FenixServiceException {

	final StudentGroup studentGroup = rootDomainObject.readStudentGroupByOID(studentGroupCode);
	if (studentGroup == null) {
	    throw new InvalidArgumentsServiceException();
	}
	final Registration registration = Registration.readByUsername(username);
	if (registration == null) {
	    throw new InvalidArgumentsServiceException();
	}

	final Grouping grouping = studentGroup.getGrouping();
	final Attends studentAttend = grouping.getStudentAttend(registration);
	if (studentAttend == null) {
	    throw new NotAuthorizedException();
	}
	if (studentGroup.getAttends().contains(studentAttend)) {
	    throw new InvalidSituationServiceException();
	}

	final IGroupEnrolmentStrategyFactory enrolmentGroupPolicyStrategyFactory = GroupEnrolmentStrategyFactory.getInstance();
	final IGroupEnrolmentStrategy strategy = enrolmentGroupPolicyStrategyFactory.getGroupEnrolmentStrategyInstance(grouping);

	boolean result = strategy.checkPossibleToEnrolInExistingGroup(grouping, studentGroup);
	if (!result) {
	    throw new InvalidArgumentsServiceException();
	}

	checkIfStudentIsNotEnrolledInOtherGroups(grouping.getStudentGroups(), studentGroup, studentAttend);

	studentGroup.addAttends(studentAttend);

	informStudents(studentGroup, registration, grouping);

	return Boolean.TRUE;
    }

    private static void informStudents(final StudentGroup studentGroup, final Registration registration, final Grouping grouping) {

	final StringBuilder executionCourseNames = new StringBuilder();
	for (final ExecutionCourse executionCourse : grouping.getExecutionCourses()) {
	    if (executionCourseNames.length() > 0) {
		executionCourseNames.append(", ");
	    }
	    executionCourseNames.append(executionCourse.getNome());
	}
    }

    private static void checkIfStudentIsNotEnrolledInOtherGroups(final List<StudentGroup> studentGroups,
	    final StudentGroup studentGroupEnrolled, final Attends studentAttend) throws InvalidSituationServiceException {

	for (final StudentGroup studentGroup : studentGroups) {
	    if (studentGroup != studentGroupEnrolled && studentGroup.getAttends().contains(studentAttend)) {
		throw new InvalidSituationServiceException();
	    }
	}
    }
}