symposion_app/pinaxcon/raffle/mixins.py

from functools import partial

from registrasion.models.commerce import Invoice, LineItem


def generate_ticket(prefix, length, num):
    return "%d-%0*d" % (prefix, length, num)


def create_ticket_numbers(item):
    quantity = item['quantity']
    length = len(str(quantity))
    ticket_func = partial(generate_ticket, item['id'], length)
    return map(ticket_func, range(1, quantity+1))


class RaffleMixin:
    @property
    def is_open(self):
        prizes = self.prizes.all()
        return len(prizes) and not all(p.locked for p in prizes)

    def draw(self, user):
        self.draws.create(drawn_by=user)

    def get_tickets(self, user=None):
        filters = {
            'invoice__status': Invoice.STATUS_PAID,
            'product__in': self.products.all()
        }

        if user is not None:
            filters['invoice__user'] = user

        for item in LineItem.objects.filter(**filters).values('id', 'quantity'):
            yield (item['id'], list(create_ticket_numbers(item)))


class PrizeMixin:
    @property
    def locked(self):
        return self._locked

    def unlock(self, user):
        self.audit_events.create(user=user, reason="Unlocked")
        self._locked = False

    def remove_winner(self, user):
        reason = "Removed winning ticket: {}".format(self.winning_ticket.id)
        self.audit_events.create(user=user, reason=reason)
        self.winning_ticket = None
        self.save(update_fields=('winning_ticket',))