from django.core.management.base import BaseCommand
from uncloud_auth.models import User
from uncloud_pay.models import Order, Bill
from uncloud_pay.helpers import get_balance_for, get_payment_method_for

from datetime import timedelta
from django.utils import timezone

class Command(BaseCommand):
    help = 'Generate bills and charge customers if necessary.'

    def add_arguments(self, parser):
        pass

    def handle(self, *args, **options):
        users = User.objects.all()
        print("Processing {} users.".format(users.count()))
        for user in users:
            balance = get_balance_for(user)
            if balance < 0:
                print("User {} has negative balance ({}), checking for overdue bills."
                        .format(user.username, balance))

                # Get bills DESCENDING by creation date (= latest at top).
                bills = Bill.objects.filter(
                        owner=user,
                        due_date__lt=timezone.now()
                        ).order_by('-creation_date')
                overdue_balance = abs(balance)
                overdue_bills = []
                for bill in bills:
                    if  overdue_balance < 0:
                        break # XXX: I'm (fnux) not fond of breaks!

                    overdue_balance -= bill.amount
                    overdue_bills.append(bill)

                for bill in overdue_bills:
                    print("/!\ Overdue bill for {}, {} with amount {}"
                            .format(user.username, bill.uuid, bill.amount))
                    # TODO: take action?

        print("=> Done.")