choice_value,

                1 if ours == choice_value else 0,

                self.FIELD,

            )

def ProductsForm(category, products):

    ''' Produces an appropriate _ProductsForm subclass for the given render

    type. '''

    # Each Category.RENDER_TYPE value has a subclass here.

    RENDER_TYPES = {

    }

    # Produce a subclass of _ProductsForm which we can alter the base_fields on

    class ProductsForm(RENDER_TYPES[category.render_type]):

        pass

    ProductsForm.set_fields(category, products)

    return ProductsForm

class ProfileForm(forms.ModelForm):

    ''' A form for requesting badge and profile information. '''

from registrasion import models as rego

from collections import namedtuple

from django import template

from django.db.models import Sum

register = template.Library()

ProductAndQuantity = namedtuple("ProductAndQuantity", ["product", "quantity"])

@register.assignment_tag(takes_context=True)

def available_categories(context):

    ''' Returns all of the available product categories '''

    return rego.Category.objects.all()

@register.assignment_tag(takes_context=True)

def invoices(context):

    ''' Returns all of the invoices that this user has. '''

    return rego.Invoice.objects.filter(cart__user=context.request.user)

@register.assignment_tag(takes_context=True)

def items_pending(context):

    ''' Returns all of the items that this user has in their current cart,

    and is awaiting payment. '''

    all_items = rego.ProductItem.objects.filter(

        cart__user=context.request.user,

        cart__active=True,

    )

    return all_items

@register.assignment_tag(takes_context=True)

def items_purchased(context):

    ''' Returns all of the items that this user has purchased '''

    all_items = rego.ProductItem.objects.filter(

        cart__user=context.request.user,

        cart__active=False,

    )

    products = set(item.product for item in all_items)

    out = []

    for product in products:

            )

            if len(items) == 0:

                products_form.add_error(

                    None,

                    "You must have at least one item from this category",

                )

    handled = False if products_form.errors else True

    discounts = discount.available_discounts(request.user, [], products)

    return products_form, discounts, handled

@transaction.atomic

def set_quantities_from_products_form(products_form, current_cart):

    for product_id, quantity, field_name in products_form.product_quantities():

        product = rego.Product.objects.get(pk=product_id)

        try:

            current_cart.set_quantity(product, quantity, batched=True)

        except ValidationError as ve:

            products_form.add_error(field_name, ve)

    if products_form.errors:

        raise ValidationError("Cannot add that stuff")

    current_cart.end_batch()

def handle_voucher(request, prefix):

    ''' Handles a voucher form in the given request. Returns the voucher

    form instance, and whether the voucher code was handled. '''

    voucher_form = forms.VoucherForm(request.POST or None, prefix=prefix)

    current_cart = CartController.for_user(request.user)

    if (voucher_form.is_valid() and

            voucher_form.cleaned_data["voucher"].strip()):

        voucher = voucher_form.cleaned_data["voucher"]

        voucher = rego.Voucher.normalise_code(voucher)

            handled = False

        else:

            try:

                current_cart.apply_voucher(voucher)

            except Exception as e:

                voucher_form.add_error("voucher", e)

            handled = True

    else:

        handled = False

    return (voucher_form, handled)

@login_required

def checkout(request):

    ''' Runs checkout for the current cart of items, ideally generating an

    invoice. '''

    current_cart = CartController.for_user(request.user)

    current_invoice = InvoiceController.for_cart(current_cart.cart)

    return redirect("invoice", current_invoice.invoice.id)

@login_required