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

        queryset = queryset.exclude(in_released_carts)

        return queryset

class TimeOrStockLimitConditionController(

    ''' Common condition tests for TimeOrStockLimit Flag and

    Discount.'''

    @classmethod

    def pre_filter(self, queryset, user):

        ''' Returns all of the items from queryset where the date falls into

    @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

        if products is not None:

            all_products = set(itertools.chain(all_products, products))

        categories = set(product.category for product in all_products)

        r = CategoryController.attach_user_remainders(user, categories)

        r = ProductController.attach_user_remainders(user, all_products)

        passed_limits = set(

            product

            for product in all_products

            if cat_quants[product.category].remainder > 0

            if prod_quants[product].remainder > 0

        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

    Returns:

        [ProductAndQuantity, ...]: A list of product-quantity pairs,

            aggregating like products from across multiple invoices.

    '''

        Q(productitem__cart__user=context.request.user) &

        Q(productitem__cart__status=commerce.Cart.STATUS_PAID)

    )

    quantities_in_cart = When(

        in_cart,

    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)

    )