Files
timetracker/games/signals.py
T

90 lines
3.0 KiB
Python

import logging
from datetime import timedelta
from django.db.models import F, Sum
from django.db.models.signals import (
m2m_changed,
post_delete,
post_save,
pre_delete,
pre_save,
)
from django.dispatch import receiver
from django.utils.timezone import now
from games.models import Game, GameStatusChange, Purchase, Session
logger = logging.getLogger("games")
@receiver(m2m_changed, sender=Purchase.games.through)
def update_num_purchases(sender, instance, action, reverse, **kwargs):
if not reverse and action.startswith("post_"):
instance.num_purchases = instance.games.count()
instance.updated_at = now()
instance.save(update_fields=["num_purchases", "updated_at"])
@receiver(pre_delete, sender=Game)
def update_purchase_counts_on_game_delete(sender, instance, **kwargs):
"""
Update num_purchases on related Purchase objects when a Game is deleted.
m2m_changed is not fired when a related object is deleted.
"""
for purchase in instance.purchases.all():
if purchase.num_purchases > 0:
purchase.num_purchases -= 1
if purchase.num_purchases == 0:
purchase.delete()
else:
purchase.updated_at = now()
purchase.save(update_fields=["num_purchases", "updated_at"])
@receiver([post_save, post_delete], sender=Session)
def update_game_playtime(sender, instance, **kwargs):
# During cascade deletes the related Game may already have been removed.
# Use the FK id to look up the Game safely and bail out if it no longer exists.
game_pk = getattr(instance, "game_id", None)
if not game_pk:
return
game = Game.objects.filter(pk=game_pk).first()
if not game:
return
total_playtime = game.sessions.aggregate(
total_playtime=Sum(F("duration_calculated") + F("duration_manual"))
)["total_playtime"]
game.playtime = total_playtime if total_playtime else timedelta(0)
game.save(update_fields=["playtime"])
@receiver(pre_save, sender=Game)
def game_status_changed(sender, instance, **kwargs):
"""
Signal handler to create a GameStatusChange record whenever a Game's status is updated.
"""
try:
old_instance = sender.objects.get(pk=instance.pk)
old_status = old_instance.status
logger.info("[game_status_changed]: Previous status exists.")
except sender.DoesNotExist:
# Handle the case where the instance was deleted before the signal was sent
logger.info("[game_status_changed]: Previous status does not exist.")
return
if old_status != instance.status:
logger.info(
"[game_status_changed]: Status changed from {} to {}".format(
old_status, instance.status
)
)
GameStatusChange.objects.create(
game=instance,
old_status=old_status,
new_status=instance.status,
timestamp=now(),
)
else:
logger.info("[game_status_changed]: Status has not changed")