feat: improved product attribute views

backoffice/views/products.py

@@ -306,14 +306,38 @@ class ProductImageDeleteView(BackofficeCRUDMixin, BackofficeModalDeleteMixin, De
 
 # --- ProductVariant (nested under a product) ---
 
+VARIANT_FORM_FRAGMENT = 'backoffice/products/_variant_form_fragment.html'
 
-class ProductVariantCreateView(BackofficeCRUDMixin, BackofficeModalFormMixin, CreateView):
+
+class ProductVariantAttributesContextMixin:
+    """Agrupa los valores de atributo por atributo para pintarlos como tabla
+    (ver _variant_form_fragment.html) en vez del <ul> de checkboxes que genera
+    por defecto CheckboxSelectMultiple. Si el form viene con datos (reenvío
+    tras un error de validación, p.ej. combinación duplicada) se respeta lo
+    que el usuario había marcado en vez de lo que tuviera guardado la instancia."""
+
+    def get_context_data(self, **kwargs):
+        context = super().get_context_data(**kwargs)
+        form = context['form']
+
+        if form.is_bound:
+            selected_value_ids = {int(v) for v in form.data.getlist('attribute_values') if v.isdigit()}
+        else:
+            instance = getattr(self, 'object', None)
+            selected_value_ids = set(instance.attribute_values.values_list('pk', flat=True)) if instance and instance.pk else set()
+
+        context['attributes'] = ProductAttribute.objects.prefetch_related('values')
+        context['selected_value_ids'] = selected_value_ids
+        return context
+
+
+class ProductVariantCreateView(ProductVariantAttributesContextMixin, BackofficeCRUDMixin, BackofficeModalFormMixin, CreateView):
     model = ProductVariant
     form_class = ProductVariantForm
     permission_required = 'shop.add_productvariant'
     section = SECTION
-    template_name = 'backoffice/generic/form.html'
-    fragment_template_name = FORM_FRAGMENT
+    template_name = 'backoffice/products/variant_form.html'
+    fragment_template_name = VARIANT_FORM_FRAGMENT
 
     def get_product(self):
         return get_object_or_404(Product, pk=self.kwargs['product_pk'])
@@ -335,13 +359,13 @@ class ProductVariantCreateView(BackofficeCRUDMixin, BackofficeModalFormMixin, Cr
         return reverse_lazy('backoffice:product_detail', args=[self.object.product_id])
 
 
-class ProductVariantUpdateView(BackofficeCRUDMixin, BackofficeModalFormMixin, UpdateView):
+class ProductVariantUpdateView(ProductVariantAttributesContextMixin, BackofficeCRUDMixin, BackofficeModalFormMixin, UpdateView):
     model = ProductVariant
     form_class = ProductVariantForm
     permission_required = 'shop.change_productvariant'
     section = SECTION
-    template_name = 'backoffice/generic/form.html'
-    fragment_template_name = FORM_FRAGMENT
+    template_name = 'backoffice/products/variant_form.html'
+    fragment_template_name = VARIANT_FORM_FRAGMENT
 
     def get_context_data(self, **kwargs):
         context = super().get_context_data(**kwargs)