from registrasion.exceptions import CartValidationError

from registrasion.models import commerce

from registrasion.models import conditions

from registrasion.models import inventory

from .category import CategoryController

from .discount import DiscountController

from .flag import FlagController

from .product import ProductController

def _modifies_cart(func):

                user=user,

                time_last_updated=timezone.now(),

                reservation_duration=datetime.timedelta(),

            )

        return cls(existing)

    # Marks the carts that are currently in batches

    _FOR_USER = {}

    _BATCH_COUNT = collections.defaultdict(int)

    _MODIFIED_CARTS = set()

    class _ModificationMarker(object):

        You need to call this after you've finished modifying the user's cart.

        This is normally done by wrapping a block of code using

        ``operations_batch``.

        '''

        self.cart.refresh_from_db()

        self._recalculate_discounts()

        self._autoextend_reservation()

        self.cart.revision += 1

        # Pre-annotate categories

        r = CategoryController.attach_user_remainders(self.cart.user, by_cat)

        with_remainders = dict((cat, cat) for cat in r)

        # Test each category limit here

        for category in by_cat:

            limit = with_remainders[category].remainder

            # Get the amount so far in the cart

            to_add = sum(i[1] for i in by_cat[category])

            if to_add > limit:

            user,

            products=products,

        )

        return set(i.category for i in available)

    @classmethod

    def attach_user_remainders(cls, user, categories):

        '''

        Return:

            queryset(inventory.Product): A queryset containing items from

from django.db.models import Case

from django.db.models import F, Q

from django.db.models import Sum

from django.db.models import Value

from django.db.models import When

from django.utils import timezone

from registrasion.models import commerce

from registrasion.models import conditions

_BIG_QUANTITY = 99999999  # A big quantity

class ConditionController(object):

        '''

        if filtered:

            if hasattr(self.condition, "remainder"):

                return self.condition.remainder

        # Mark self.condition with a remainder

        qs = type(self.condition).objects.filter(pk=self.condition.id)

        qs = self.pre_filter(qs, user)

        if len(qs) > 0:

            return qs[0].remainder

    @classmethod

    def available_discounts(cls, user, categories, products):

        ''' Returns all discounts available to this user for the given

        categories and products. The discounts also list the available quantity

        for this user, not including products that are pending purchase. '''

        filtered_clauses = cls._filtered_discounts(user, categories, products)

        discounts = []

        # Markers so that we don't need to evaluate given conditions

        # more than once

        out = list(passed_limits - failed_conditions)

        out.sort(key=lambda product: product.order)

        return out

    @classmethod

    def attach_user_remainders(cls, user, products):

        '''

        Return:

            queryset(inventory.Product): A queryset containing items from

    id_to_quantity = dict(i[:2] for i in quantities)

    pks = [i[0] for i in quantities]

    products = inventory.Product.objects.filter(

        id__in=pks,

    ).select_related("category")

    product_quantities = [

        (product, id_to_quantity[product.id]) for product in products

    ]

    field_names = dict(

        (i[0][0], i[1][2]) for i in zip(product_quantities, quantities)

    )