Move fav notifications to model

bookwyrm/models/favorite.py

@@ -1,4 +1,5 @@
 ''' like/fav/star a status '''
+from django.apps import apps
 from django.db import models
 from django.utils import timezone
 
@@ -22,6 +23,35 @@ class Favorite(ActivityMixin, BookWyrmModel):
         self.user.save(broadcast=False)
         super().save(*args, **kwargs)
 
+        if self.status.user.local and self.status.user != self.user:
+            notification_model = apps.get_model(
+                'bookwyrm.Notification', require_ready=True)
+            if notification_model.objects.filter(
+                    user=self.status.user, related_user=self.user,
+                    related_status=self.status, notification_type='FAVORITE'
+                ).exists():
+                return
+            notification_model.objects.create(
+                user=self.status.user,
+                notification_type='FAVORITE',
+                related_user=self.user,
+                related_status=self.status
+            )
+
+    def delete(self, *args, **kwargs):
+        ''' delete and delete notifications '''
+        # check for notification
+        if self.status.user.local:
+            notification_model = apps.get_model(
+                'bookwyrm.Notification', require_ready=True)
+            notification = notification_model.objects.filter(
+                user=self.status.user, related_user=self.user,
+                related_status=self.status, notification_type='FAVORITE'
+            ).first()
+            if notification:
+                notification.delete()
+        super().delete(*args, **kwargs)
+
     class Meta:
         ''' can't fav things twice '''
         unique_together = ('user', 'status')