Adds “CategoryForm” to forms.py. It’s about to replace the existing ProductItem form

registrasion/forms.py

@@ -3,11 +3,46 @@ import models as rego
 from django import forms
 
 
-class ProductItemForm(forms.Form):
-    product = forms.ModelChoiceField(queryset=None, empty_label=None)
-    quantity = forms.IntegerField()
+def CategoryForm(category):
 
-    def __init__(self, category, *a, **k):
-        super(ProductItemForm, self).__init__(*a, **k)
-        products = rego.Product.objects.filter(category=category)
-        self.fields['product'].queryset = products
+    PREFIX = "product_"
+
+    def field_name(product):
+        return PREFIX + ("%d" % product.id)
+
+    class _CategoryForm(forms.Form):
+
+        @staticmethod
+        def initial_data(product_quantities):
+            ''' Prepares initial data for an instance of this form.
+            product_quantities is a sequence of (product,quantity) tuples '''
+            initial = {}
+            for product, quantity in product_quantities:
+                initial[field_name(product)] = quantity
+
+            return initial
+
+        def product_quantities(self):
+            ''' Yields a sequence of (product, quantity) tuples from the
+            cleaned form data. '''
+            for name, value in self.cleaned_data.items():
+                if name.startswith(PREFIX):
+                    product_id = int(name[len(PREFIX):])
+                    yield (product_id, value, name)
+
+        def disable_product(self, product):
+            ''' Removes a given product from this form. '''
+            del self.fields[field_name(product)]
+
+    products = rego.Product.objects.filter(category=category).order_by("order")
+    for product in products:
+
+        help_text = "$%d -- %s" % (product.price, product.description)
+
+        field = forms.IntegerField(
+            label=product.name,
+            help_text=help_text,
+        )
+        _CategoryForm.base_fields[field_name(product)] = field
+
+    return _CategoryForm

registrasion/templates/product_category.html

@@ -9,12 +9,14 @@
 
   <form method="post" action="">
     {% csrf_token %}
+
     <table>
-        {{ formset }}
+        {{ form }}
     </table>
 
     <input type="submit">
 
   </form>
 
+
 {% endblock %}

registrasion/views.py

@@ -6,11 +6,10 @@ from registrasion.controllers.product import ProductController
 
 from django.contrib.auth.decorators import login_required
 from django.core.exceptions import ObjectDoesNotExist
+from django.core.exceptions import ValidationError
 from django.db import transaction
-from django.forms import formset_factory
 from django.shortcuts import redirect
 from django.shortcuts import render
-from functools import partial, wraps
 
 
 @login_required
@@ -20,50 +19,61 @@ def product_category(request, category_id):
     category_id = int(category_id)  # Routing is [0-9]+
     category = rego.Category.objects.get(pk=category_id)
 
-    ProductItemFormForCategory = (
-        wraps(forms.ProductItemForm)
-        (partial(forms.ProductItemForm, category=category)))
-    ProductItemFormSet = formset_factory(ProductItemFormForCategory, extra=0)
+    CategoryForm = forms.CategoryForm(category)
+
+    products = rego.Product.objects.filter(category=category)
+    products = products.order_by("order")
 
     if request.method == "POST":
-        formset = ProductItemFormSet(request.POST, request.FILES)
-        if formset.is_valid():
+        cat_form = CategoryForm(request.POST, request.FILES)
+        if cat_form.is_valid():
             current_cart = CartController.for_user(request.user)
-            with transaction.atomic():
-                for form in formset.forms:
-                    data = form.cleaned_data
-                    # TODO set form error instead of failing completely
-                    current_cart.set_quantity(
-                        data["product"], data["quantity"], batched=True)
-                current_cart.end_batch()
+            try:
+                with transaction.atomic():
+                    for product_id, quantity, field_name \
+                            in cat_form.product_quantities():
+                        product = rego.Product.objects.get(pk=product_id)
+                        try:
+                            current_cart.set_quantity(
+                                product, quantity, batched=True)
+                        except ValidationError as ve:
+                            cat_form.add_error(field_name, ve)
+                    if cat_form.errors:
+                        raise ValidationError("Cannot add that stuff")
+                    current_cart.end_batch()
+            except ValidationError as ve:
+                pass
+
     else:
         # Create initial data for each of products in category
-        initial = []
-        products = rego.Product.objects.filter(category=category)
         items = rego.ProductItem.objects.filter(product__category=category)
-        products = products.order_by("order")
+        quantities = []
         for product in products:
             # Only add items that are enabled.
             prod = ProductController(product)
-            if not prod.can_add_with_enabling_conditions(request.user, 0):
-                continue
-
             try:
                 quantity = items.get(product=product).quantity
             except ObjectDoesNotExist:
                 quantity = 0
-            data = {"product": product, "quantity": quantity}
-            initial.append(data)
+            quantities.append((product, quantity))
 
-        formset = ProductItemFormSet(initial=initial)
+        initial = CategoryForm.initial_data(quantities)
+        cat_form = CategoryForm(initial=initial)
+
+    for product in products:
+        # Remove fields that do not have an enabling condition.
+        prod = ProductController(product)
+        if not prod.can_add_with_enabling_conditions(request.user, 0):
+            cat_form.disable_product(product)
 
     data = {
         "category": category,
-        "formset": formset,
+        "form": cat_form,
     }
 
     return render(request, "product_category.html", data)
 
+
 @login_required
 def checkout(request):
     ''' Runs checkout for the current cart of items, ideally generating an