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):
    orders = Order.objects.filter(owner=user)

    amount = 0
    for order in orders:
        amount += order.one_time_price
        amount += order.recurring_price * order.count_used(when=timezone.now())

    return amount

@transaction.atomic
def get_balance_for_user(user):
    return get_payments_for_user(user) - get_spendings_for_user(user)