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

import java.util.HashSet;
import java.util.Iterator;
import java.util.Set;

import net.sourceforge.fenixedu.applicationTier.FenixService;
import net.sourceforge.fenixedu.domain.Attends;
import net.sourceforge.fenixedu.domain.CurricularCourse;
import net.sourceforge.fenixedu.domain.Enrolment;
import net.sourceforge.fenixedu.domain.ExecutionCourse;
import net.sourceforge.fenixedu.domain.Shift;
import net.sourceforge.fenixedu.domain.student.Registration;
import net.sourceforge.fenixedu.persistenceTier.ExcepcaoPersistencia;

import org.apache.commons.collections.CollectionUtils;
import org.apache.commons.collections.Predicate;

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

public class TransferCurricularCourse extends FenixService {

    @Checked("RolePredicates.MANAGER_PREDICATE")
    @Service
    public static void run(Integer sourceExecutionCourseId, final Integer curricularCourseId, Integer destinationExecutionCourseId) {

	final ExecutionCourse sourceExecutionCourse = rootDomainObject.readExecutionCourseByOID(sourceExecutionCourseId);
	final ExecutionCourse destinationExecutionCourse = rootDomainObject
		.readExecutionCourseByOID(destinationExecutionCourseId);

	CurricularCourse curricularCourse = null;
	for (final CurricularCourse curricularCourseOther : sourceExecutionCourse.getAssociatedCurricularCoursesSet()) {
	    if (curricularCourseOther.getIdInternal().equals(curricularCourseId)) {
		curricularCourse = curricularCourseOther;
		break;
	    }
	}

	deleteShiftStudents(sourceExecutionCourse, curricularCourse);

	Set<Integer> transferedStudents = new HashSet<Integer>();
	transferAttends(destinationExecutionCourseId, sourceExecutionCourse, destinationExecutionCourse, curricularCourse,
		transferedStudents);

	sourceExecutionCourse.removeAssociatedCurricularCourses(curricularCourse);
	destinationExecutionCourse.addAssociatedCurricularCourses(curricularCourse);
    }

    /**
     * @param destinationExecutionCourseId
     * @param sourceExecutionCourse
     * @param destinationExecutionCourse
     * @param curricularCourse
     * @param transferedStudents
     * @throws ExcepcaoPersistencia
     */
    private static void transferAttends(Integer destinationExecutionCourseId, ExecutionCourse sourceExecutionCourse,
	    ExecutionCourse destinationExecutionCourse, CurricularCourse curricularCourse, Set<Integer> transferedStudents) {
	for (Attends attend : sourceExecutionCourse.getAttends()) {
	    Enrolment enrollment = attend.getEnrolment();
	    final Registration registration = attend.getRegistration();
	    if (enrollment != null) {
		CurricularCourse associatedCurricularCourse = attend.getEnrolment().getCurricularCourse();
		if (curricularCourse == associatedCurricularCourse) {
		    Attends existingAttend = (Attends) CollectionUtils.find(destinationExecutionCourse.getAttends(),
			    new Predicate() {
				public boolean evaluate(Object arg0) {
				    Attends attendFromDestination = (Attends) arg0;
				    return (attendFromDestination.getRegistration() == registration);
				}
			    });
		    if (existingAttend != null) {
			existingAttend.setEnrolment(enrollment);
			attend.delete();
		    } else {
			attend.setDisciplinaExecucao(destinationExecutionCourse);
		    }

		    transferedStudents.add(registration.getIdInternal());
		}
	    }
	}
    }

    /**
     * @param sourceExecutionCourse
     * @param curricularCourse
     * @throws ExcepcaoPersistencia
     */
    private static void deleteShiftStudents(ExecutionCourse sourceExecutionCourse, CurricularCourse curricularCourse) {

	Set<Shift> shifts = sourceExecutionCourse.getAssociatedShifts();

	for (Shift shift : shifts) {
	    Iterator<Registration> iter = shift.getStudentsIterator();
	    while (iter.hasNext()) {
		Registration registration = iter.next();
		Attends attend = sourceExecutionCourse.getAttendsByStudent(registration);

		if (attend.getEnrolment() != null && attend.getEnrolment().getCurricularCourse() == curricularCourse) {
		    iter.remove();
		}
	    }
	}
    }

}