inventory.Category.RENDER_TYPE_ITEM_QUANTITY: _ItemQuantityProductsForm,

class _ItemQuantityProductsForm(_ProductsForm):

    ''' Products entry form that allows users to select a product type, and

     enter a quantity of that product. This version _only_ allows a specific

     product type to be purchased.'''

    CHOICE_FIELD = "choice"

    QUANTITY_FIELD = "quantity"

    @classmethod

    def set_fields(cls, category, products):

        choices = []

        for product in products:

            choice_text = "%s -- $%d each" % (product.name, product.price)

            choices.append((product.id, choice_text))

        if not category.required:

            choices.append((0, "No selection"))

        cls.base_fields[cls.CHOICE_FIELD] = forms.TypedChoiceField(

            label=category.name,

            widget=forms.Select,

            choices=choices,

            empty_value=0,

            coerce=int,

        )

        cls.base_fields[cls.QUANTITY_FIELD] = forms.IntegerField(

            label="Quantity",  # TODO: internationalise

            min_value=0,

            max_value=500,  # Issue #19. We should figure out real limit.

        )

    @classmethod

    def initial_data(cls, product_quantities):

        initial = {}

        for product, quantity in product_quantities:

            if quantity > 0:

                initial[cls.CHOICE_FIELD] = product.id

                initial[cls.QUANTITY_FIELD] = quantity

                break

        return initial

    def product_quantities(self):

        our_choice = self.cleaned_data[self.CHOICE_FIELD]

        our_quantity = self.cleaned_data[self.QUANTITY_FIELD]

        choices = self.fields[self.CHOICE_FIELD].choices

        for choice_value, choice_display in choices:

            if choice_value == 0:

                continue

            yield (

                choice_value,

                our_quantity if our_choice == choice_value else 0,

                self.CHOICE_FIELD,

            )