right-tree/backend/right_tree/api/signals.py

from pathlib import Path
from shutil import rmtree

from django.db.models.signals import post_save, post_delete
from django.dispatch import receiver

from .models import Export, ActivationKey, ActivationKeySet, Questionnaire
from .resource_generation_utils import storage


@receiver(post_delete, sender=Export)
def delete_export(sender, instance, *args, **kwargs):
    """Clean up created files on the filesystem when an export is deleted"""
    path = storage.path(f"export_{instance.pk}")

    if Path(path).exists():
        rmtree(path)


@receiver(post_save, sender=ActivationKeySet)
def create_keys(sender, instance, created, *args, **kwargs):
    """Create n ActivationKey objects where n is the ActivationKeySet.size value"""
    if created:
        ActivationKey.objects.bulk_create([
            ActivationKey(key_set=instance, remaining_activations=instance.initial_activations)
            for _ in range(instance.size)
        ])


@receiver(post_save, sender=Questionnaire)
def activate_key(sender, instance, created, *args, **kwargs):
    """Consume one activation on the key associated with the created Questionnaire"""
    if created and (key := instance.key):
        key.remaining_activations -= 1
        key.activations += 1
        key.save()