import uuid
from django.db import models
from django.utils.text import gettext_lazy as _
from .models import Course, Instructor


class CourseTimeline(models.Model):
    id = models.UUIDField(
        _('id'),
        default=uuid.uuid4,
        primary_key=True,
        editable=False,
        unique=True
    )
    instructor = models.ForeignKey(Instructor, verbose_name=_('instructor'), related_name='courses', on_delete=models.CASCADE)
    course = models.ForeignKey(Course, verbose_name=_('course'), related_name='instructors', on_delete=models.CASCADE)
    start = models.DateField(_('start date of the course'))
    end = models.DateField(_('end date of the course'))

    class Meta:
        db_table = 'courses_timeline'

    def __str__(self):
        return '%s %s (%s-%s)'%(self.instructor, self.course, self.start, self.end)