Factors _QuantityBoxForm out of _ProductsForm

registrasion/forms.py

@@ -3,51 +3,83 @@ import models as rego
 from django import forms
 
 
+# Products forms -- none of these have any fields: they are to be subclassed
+# and the fields added as needs be.
+
+class _ProductsForm(forms.Form):
+
+    PRODUCT_PREFIX = "product_"
+
+    ''' Base class for product entry forms. '''
+    def __init__(self, *a, **k):
+        if "product_quantities" in k:
+            initial = self.initial_data(k["product_quantities"])
+            k["initial"] = initial
+            del k["product_quantities"]
+        super(_ProductsForm, self).__init__(*a, **k)
+
+    @classmethod
+    def field_name(cls, product):
+        return cls.PRODUCT_PREFIX + ("%d" % product.id)
+
+    @classmethod
+    def set_fields(cls, products):
+        ''' Sets the base_fields on this _ProductsForm to allow selecting
+        from the provided products. '''
+        pass
+
+    @classmethod
+    def initial_data(cls, product_quantites):
+        ''' Prepares initial data for an instance of this form.
+        product_quantities is a sequence of (product,quantity) tuples '''
+        return {}
+
+    def product_quantities(self):
+        ''' Yields a sequence of (product, quantity) tuples from the
+        cleaned form data. '''
+        return iter([])
+
+
+class _QuantityBoxProductsForm(_ProductsForm):
+    ''' Products entry form that allows users to enter quantities
+    of desired products. '''
+
+    @classmethod
+    def set_fields(cls, products):
+        for product in products:
+            help_text = "$%d -- %s" % (product.price, product.description)
+
+            field = forms.IntegerField(
+                label=product.name,
+                help_text=help_text,
+            )
+            cls.base_fields[cls.field_name(product)] = field
+
+    @classmethod
+    def initial_data(cls, product_quantities):
+        initial = {}
+        for product, quantity in product_quantities:
+            initial[cls.field_name(product)] = quantity
+
+        return initial
+
+    def product_quantities(self):
+        for name, value in self.cleaned_data.items():
+            if name.startswith(self.PRODUCT_PREFIX):
+                product_id = int(name[len(self.PRODUCT_PREFIX):])
+                yield (product_id, value, name)
+
+
 def ProductsForm(products):
+    ''' Produces an appropriate _ProductsForm subclass for the given render
+    type. '''
 
-    PREFIX = "product_"
+    if True:
+        class ProductsForm(_QuantityBoxProductsForm):
+            pass
 
-    def field_name(product):
-        return PREFIX + ("%d" % product.id)
-
-    class _ProductsForm(forms.Form):
-
-        def __init__(self, *a, **k):
-            if "product_quantities" in k:
-                initial = _ProductsForm.initial_data(k["product_quantities"])
-                k["initial"] = initial
-                del k["product_quantities"]
-            super(_ProductsForm, self).__init__(*a, **k)
-
-        @classmethod
-        def initial_data(cls, 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)
-
-    for product in products:
-
-        help_text = "$%d -- %s" % (product.price, product.description)
-
-        field = forms.IntegerField(
-            label=product.name,
-            help_text=help_text,
-        )
-        _ProductsForm.base_fields[field_name(product)] = field
-
-    return _ProductsForm
+    ProductsForm.set_fields(products)
+    return ProductsForm
 
 
 class ProfileForm(forms.ModelForm):