package net.sourceforge.fenixedu.domain;

import java.math.BigDecimal;
import java.math.RoundingMode;
import java.util.Comparator;

import net.sourceforge.fenixedu.domain.exceptions.DomainException;
import net.sourceforge.fenixedu.domain.space.AllocatableSpace;
import net.sourceforge.fenixedu.domain.space.LessonInstanceSpaceOccupation;
import net.sourceforge.fenixedu.util.DiaSemana;
import net.sourceforge.fenixedu.util.HourMinuteSecond;

import org.joda.time.DateTime;
import org.joda.time.Minutes;
import org.joda.time.YearMonthDay;

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

public class LessonInstance extends LessonInstance_Base {

    public static final Comparator<LessonInstance> COMPARATOR_BY_BEGIN_DATE_TIME = new Comparator<LessonInstance>() {

	@Override
	public int compare(LessonInstance o1, LessonInstance o2) {
	    final int c = o1.getBeginDateTime().compareTo(o2.getBeginDateTime());
	    return c == 0 ? DomainObject.COMPARATOR_BY_ID.compare(o1, o2) : c;
	}

    };

    @Checked("ResourceAllocationRolePredicates.checkPermissionsToManageLessonInstancesWithTeacherCheck")
    public LessonInstance(Summary summary, Lesson lesson) {

	super();

	if (summary == null) {
	    throw new DomainException("error.LessonInstance.empty.summary");
	}

	if (lesson == null) {
	    throw new DomainException("error.LessonInstance.empty.lesson");
	}

	YearMonthDay day = summary.getSummaryDateYearMonthDay();

	LessonInstance lessonInstance = lesson.getLessonInstanceFor(day);
	if (lessonInstance != null) {
	    throw new DomainException("error.lessonInstance.already.exist");
	}

	AllocatableSpace room = lesson.getSala();

	HourMinuteSecond beginTime = lesson.getBeginHourMinuteSecond();
	HourMinuteSecond endTime = lesson.getEndHourMinuteSecond();
	DateTime beginDateTime = new DateTime(day.getYear(), day.getMonthOfYear(), day.getDayOfMonth(), beginTime.getHour(),
		beginTime.getMinuteOfHour(), beginTime.getSecondOfMinute(), 0);
	DateTime endDateTime = new DateTime(day.getYear(), day.getMonthOfYear(), day.getDayOfMonth(), endTime.getHour(), endTime
		.getMinuteOfHour(), endTime.getSecondOfMinute(), 0);

	setRootDomainObject(RootDomainObject.getInstance());
	setBeginDateTime(beginDateTime);
	setEndDateTime(endDateTime);
	setLesson(lesson);

	summaryAndCourseLoadManagement(summary, lesson);
	lesson.refreshPeriodAndInstancesInSummaryCreation(day.plusDays(1));
	lessonInstanceSpaceOccupationManagement(room);
    }

    @Checked("ResourceAllocationRolePredicates.checkPermissionsToManageLessonInstancesWithTeacherCheck")
    public LessonInstance(Lesson lesson, YearMonthDay day) {

	super();

	if (day == null) {
	    throw new DomainException("error.LessonInstance.empty.day");
	}

	if (lesson == null) {
	    throw new DomainException("error.LessonInstance.empty.Lesson");
	}

	LessonInstance lessonInstance = lesson.getLessonInstanceFor(day);
	if (lessonInstance != null) {
	    throw new DomainException("error.lessonInstance.already.exist");
	}

	AllocatableSpace room = lesson.getSala();

	HourMinuteSecond beginTime = lesson.getBeginHourMinuteSecond();
	HourMinuteSecond endTime = lesson.getEndHourMinuteSecond();
	DateTime beginDateTime = new DateTime(day.getYear(), day.getMonthOfYear(), day.getDayOfMonth(), beginTime.getHour(),
		beginTime.getMinuteOfHour(), beginTime.getSecondOfMinute(), 0);
	DateTime endDateTime = new DateTime(day.getYear(), day.getMonthOfYear(), day.getDayOfMonth(), endTime.getHour(), endTime
		.getMinuteOfHour(), endTime.getSecondOfMinute(), 0);

	setRootDomainObject(RootDomainObject.getInstance());
	setBeginDateTime(beginDateTime);
	setEndDateTime(endDateTime);
	setLesson(lesson);

	lessonInstanceSpaceOccupationManagement(room);
    }

    @Checked("ResourceAllocationRolePredicates.checkPermissionsToManageLessonInstances")
    public void delete() {

	if (!canBeDeleted()) {
	    throw new DomainException("error.LessonInstance.cannot.be.deleted");
	}

	LessonInstanceSpaceOccupation occupation = getLessonInstanceSpaceOccupation();
	if (occupation != null) {
	    occupation.removeLessonInstances(this);
	    occupation.delete();
	}

	super.setCourseLoad(null);
	super.setLesson(null);
	removeRootDomainObject();
	deleteDomainObject();
    }

    @Checked("ResourceAllocationRolePredicates.checkPermissionsToManageLessonInstancesWithTeacherCheck")
    public void summaryAndCourseLoadManagement(Summary summary, Lesson lesson) {
	CourseLoad courseLoad = null;
	if (lesson != null && summary != null) {
	    courseLoad = lesson.getExecutionCourse().getCourseLoadByShiftType(summary.getSummaryType());
	}
	setSummary(summary);
	setCourseLoad(courseLoad);
    }

    private int getUnitMinutes() {
	return Minutes.minutesBetween(getStartTime(), getEndTime()).getMinutes();
    }

    public BigDecimal getInstanceDurationInHours() {
	return BigDecimal.valueOf(getUnitMinutes()).divide(BigDecimal.valueOf(Lesson.NUMBER_OF_MINUTES_IN_HOUR), 2,
		RoundingMode.HALF_UP);
    }

    private boolean canBeDeleted() {
	return !hasSummary();
    }

    @jvstm.cps.ConsistencyPredicate
    protected boolean checkDateTimeInterval() {
	final DateTime start = getBeginDateTime();
	final DateTime end = getEndDateTime();
	return start != null && end != null && start.isBefore(end);
    }

    private void lessonInstanceSpaceOccupationManagement(AllocatableSpace space) {
	if (space != null) {
	    LessonInstanceSpaceOccupation instanceSpaceOccupation = (LessonInstanceSpaceOccupation) space
		    .getFirstOccurrenceOfResourceAllocationByClass(LessonInstanceSpaceOccupation.class);

	    instanceSpaceOccupation = instanceSpaceOccupation == null ? new LessonInstanceSpaceOccupation(space)
		    : instanceSpaceOccupation;
	    instanceSpaceOccupation.edit(this);
	}
    }

    @Override
    public void setSummary(Summary summary) {
	if (summary == null) {
	    throw new DomainException("error.LessonInstance.empty.summary");
	}
	super.setSummary(summary);
    }

    @Override
    public void setCourseLoad(CourseLoad courseLoad) {
	if (courseLoad == null) {
	    throw new DomainException("error.lessonInstance.empty.courseLoad");
	}
	super.setCourseLoad(courseLoad);
    }

    @Override
    public void setLesson(Lesson lesson) {
	if (lesson == null) {
	    throw new DomainException("error.lessonInstance.empty.lesson");
	}
	super.setLesson(lesson);
    }

    public YearMonthDay getDay() {
	return getBeginDateTime().toYearMonthDay();
    }

    public HourMinuteSecond getStartTime() {
	return new HourMinuteSecond(getBeginDateTime().getHourOfDay(), getBeginDateTime().getMinuteOfHour(), getBeginDateTime()
		.getSecondOfMinute());
    }

    public HourMinuteSecond getEndTime() {
	return new HourMinuteSecond(getEndDateTime().getHourOfDay(), getEndDateTime().getMinuteOfHour(), getEndDateTime()
		.getSecondOfMinute());
    }

    public AllocatableSpace getRoom() {
	return hasLessonInstanceSpaceOccupation() ? getLessonInstanceSpaceOccupation().getRoom() : null;
    }

    public DiaSemana getDayOfweek() {
	return new DiaSemana(DiaSemana.getDiaSemana(getDay()));
    }

    public String prettyPrint() {
	final StringBuilder result = new StringBuilder();
	result.append(getDayOfweek().getDiaSemanaString()).append(" (");
	result.append(getStartTime().toString("HH:mm")).append(" - ");
	result.append(getEndDateTime().toString("HH:mm")).append(") ");
	result.append(getRoom() != null ? getRoom().getIdentification() : "");
	return result.toString();
    }

}