84 lines
2.4 KiB
Python
84 lines
2.4 KiB
Python
from registrasion.models import commerce
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from registrasion.models import inventory
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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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class AllProducts(object):
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pass
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class CategoryController(object):
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def __init__(self, category):
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self.category = category
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@classmethod
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def available_categories(cls, user, products=AllProducts):
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''' Returns the categories available to the user. Specify `products` if
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you want to restrict to just the categories that hold the specified
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products, otherwise it'll do all. '''
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# STOPGAP -- this needs to be elsewhere tbqh
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from product import ProductController
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if products is AllProducts:
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products = inventory.Product.objects.all().select_related(
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"category",
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)
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available = ProductController.available_products(
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user,
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products=products,
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)
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return set(i.category for i in available)
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@classmethod
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def attach_user_remainders(cls, user, categories):
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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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``categories``, with an extra attribute -- remainder = the amount
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of items from this category that is remaining.
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'''
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ids = [category.id for category in categories]
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categories = inventory.Category.objects.filter(id__in=ids)
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cart_filter = (
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Q(product__productitem__cart__user=user) &
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Q(product__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='product__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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categories = categories.annotate(remainder=remainder)
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return categories
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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.category])
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return with_remainders[0].remainder
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