104 lines
3.1 KiB
Python
104 lines
3.1 KiB
Python
import itertools
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from django.db.models import Case
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from django.db.models import F, Q
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from django.db.models import Sum
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from django.db.models import When
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from django.db.models import Value
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from registrasion.models import commerce
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from registrasion.models import inventory
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from .category import CategoryController
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from .flag import FlagController
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class ProductController(object):
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def __init__(self, product):
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self.product = product
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@classmethod
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def available_products(cls, user, category=None, products=None):
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''' Returns a list of all of the products that are available per
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flag conditions from the given categories. '''
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if category is None and products is None:
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raise ValueError("You must provide products or a category")
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if category is not None:
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all_products = inventory.Product.objects.filter(category=category)
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all_products = all_products.select_related("category")
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else:
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all_products = []
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if products is not None:
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all_products = set(itertools.chain(all_products, products))
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categories = set(product.category for product in all_products)
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r = CategoryController.attach_user_remainders(user, categories)
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cat_quants = dict((c, c) for c in r)
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r = ProductController.attach_user_remainders(user, all_products)
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prod_quants = dict((p, p) for p in r)
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passed_limits = set(
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product
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for product in all_products
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if cat_quants[product.category].remainder > 0
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if prod_quants[product].remainder > 0
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)
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failed_and_messages = FlagController.test_flags(
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user, products=passed_limits
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)
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failed_conditions = set(i[0] for i in failed_and_messages)
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out = list(passed_limits - failed_conditions)
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out.sort(key=lambda product: product.order)
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return out
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@classmethod
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def attach_user_remainders(cls, user, products):
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'''
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Return:
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queryset(inventory.Product): A queryset containing items from
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``product``, with an extra attribute -- remainder = the amount of
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this item that is remaining.
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'''
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ids = [product.id for product in products]
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products = inventory.Product.objects.filter(id__in=ids)
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cart_filter = (
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Q(productitem__cart__user=user) &
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Q(productitem__cart__status=commerce.Cart.STATUS_PAID)
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)
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quantity = When(
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cart_filter,
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then='productitem__quantity'
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)
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quantity_or_zero = Case(
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quantity,
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default=Value(0),
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)
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remainder = Case(
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When(limit_per_user=None, then=Value(99999999)),
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default=F('limit_per_user') - Sum(quantity_or_zero),
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)
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products = products.annotate(remainder=remainder)
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return products
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def user_quantity_remaining(self, user):
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''' Returns the quantity of this product that the user add in the
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current cart. '''
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with_remainders = self.attach_user_remainders(user, [self.product])
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return with_remainders[0].remainder
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