fix: delete timeslots & schedule while deactivating a show

Closes: #180

program/models.py

@@ -26,6 +26,7 @@ from versatileimagefield.fields import PPOIField, VersatileImageField
 from django.contrib.auth.models import User
 from django.db import models
 from django.db.models import Q, QuerySet
+from django.utils import timezone
 from django.utils.translation import gettext_lazy as _
 from program.utils import parse_datetime
 from steering.settings import THUMBNAIL_SIZES
@@ -248,6 +249,20 @@ class Show(models.Model):
     def __str__(self):
         return self.name
 
+    def save(self, *args, **kwargs):
+        now = timezone.datetime.now()
+        today = now.date()
+
+        if self.pk and self.is_active is False:
+            # deactivating a show means:
+            # - **delete all* the timeslots that belong to a schedule of this show the after now
+            # - **update all** the schedules of this show have today as `last_date`
+            TimeSlot.objects.filter(schedule__show=self, start__gt=now).delete()
+            self.schedules.filter(Q(last_date__gt=today) | Q(last_date=None)).update(
+                last_date=today
+            )
+        super().save(*args, **kwargs)
+
 
 class ShowLink(Link):
     show = models.ForeignKey(Show, on_delete=models.CASCADE, related_name="links")