from django.utils import timezone from django.db import transaction from .models import * def get_payments_for_user(user): payments = [ payment.amount for payment in Payment.objects.filter(owner=user) ] return sum(payments) def get_spendings_for_user(user): bills = Bill.objects.filter(owner=user) amount = 0 for bill in bills: amount += bill.sum return amount @transaction.atomic def get_balance_for_user(user): return get_payments_for_user(user) - get_spendings_for_user(user) @transaction.atomic def has_enough_balance(user, due_amount): balance = get_balance_for_user(user) if balance >= due_amount: return True return False def get_billing_address_for_user(user): return BillingAddress.objects.filter(owner=user, active=True).first()