course.py

from wagtail.admin.panels import FieldPanel, InlinePanel, ObjectList, TabbedInterface
from wagtail.models import Page, Orderable, RevisionMixin
from wagtail.snippets.models import register_snippet
from modelcluster.fields import ParentalKey
## imports truncated so may not be 100% complete 


class CourseDepartment(Orderable):
    course = ParentalKey('core.CoursePage', related_name='coursedepartments', on_delete=models.CASCADE)
    department = models.ForeignKey('core.Department', related_name='coursedepartments', on_delete=models.CASCADE)

    panels = [
        FieldPanel('course'),
        FieldPanel('department'),
    ]

    class Meta:
        # The ordering will affect the API
        ordering = ['sort_order']


@register_snippet
class Department(RevisionMixin, models.Model):
    abbr = models.CharField(
        verbose_name='Department Abbreviation',
        max_length=100
    )
    name = models.CharField(
        verbose_name='Department Name',
        max_length=100
    )

    class Meta:
        verbose_name = 'Department'
        ordering = ['name']

    def __repr__(self):
        return "<Department: {} ({})>".format(self.name, self.abbr)
      
      
class CoursePage(Page):
    course_number = models.CharField(
        verbose_name='Course Number',
        max_length=256,
        help_text="Only the numeric part",
    )

    class Meta:
        verbose_name = 'Catalog Course'
        verbose_name_plural = 'Catalog Courses'
        
    content_panels = [
        FieldPanel('title'),
        InlinePanel('coursedepartments', label="Departments", min_num=1),
        FieldPanel('course_number'),
        CommentPanel()
    
    # We don't need the promote or publish tabs so combine everything into one content tab
    edit_handler = TabbedInterface([
        ObjectList(content_panels, heading='Content'),
    ])