X-Git-Url: http://git.ithinksw.org/philo.git/blobdiff_plain/82b08f79564159d7acbcaf255ed1ac1fb4882e64..d19e216035b14d8f60b24dda0c0670e6997f16ce:/philo/admin/forms/attributes.py

diff --git a/philo/admin/forms/attributes.py b/philo/admin/forms/attributes.py
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index 0000000..fc77d0f
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+++ b/philo/admin/forms/attributes.py
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+from django.contrib.contenttypes.generic import BaseGenericInlineFormSet
+from django.contrib.contenttypes.models import ContentType
+from django.forms.models import ModelForm
+from philo.models import Attribute
+
+
+__all__ = ('AttributeForm', 'AttributeInlineFormSet')
+
+
+class AttributeForm(ModelForm):
+	"""
+	This class handles an attribute's fields as well as the fields for its value (if there is one.)
+	The fields defined will vary depending on the value type, but the fields for defining the value
+	(i.e. value_content_type and value_object_id) will always be defined. Except that value_object_id
+	will never be defined. BLARGH!
+	"""
+	def __init__(self, *args, **kwargs):
+		super(AttributeForm, self).__init__(*args, **kwargs)
+		
+		# This is necessary because model forms store changes to self.instance in their clean method.
+		# Mutter mutter.
+		value = self.instance.value
+		self._cached_value_ct = self.instance.value_content_type
+		self._cached_value = value
+		
+		# If there is a value, pull in its fields.
+		if value is not None:
+			self.value_fields = value.value_formfields()
+			self.fields.update(self.value_fields)
+	
+	def save(self, *args, **kwargs):
+		# At this point, the cleaned_data has already been stored on self.instance.
+		
+		if self.instance.value_content_type != self._cached_value_ct:
+			# The value content type has changed. Clear the old value, if there was one.
+			if self._cached_value:
+				self._cached_value.delete()
+			
+			# Clear the submitted value, if any.
+			self.cleaned_data.pop('value', None)
+			
+			# Now create a new value instance so that on next instantiation, the form will
+			# know what fields to add.
+			if self.instance.value_content_type is not None:
+				self.instance.value = self.instance.value_content_type.model_class().objects.create()
+		elif self.instance.value is not None:
+			# The value content type is the same, but one of the value fields has changed.
+			
+			# Use construct_instance to apply the changes from the cleaned_data to the value instance.
+			fields = self.value_fields.keys()
+			if set(fields) & set(self.changed_data):
+				self.instance.value.construct_instance(**dict([(key, self.cleaned_data[key]) for key in fields]))
+				self.instance.value.save()
+		
+		return super(AttributeForm, self).save(*args, **kwargs)
+	
+	class Meta:
+		model = Attribute
+
+
+class AttributeInlineFormSet(BaseGenericInlineFormSet):
+	"Necessary to force the GenericInlineFormset to use the form's save method for new objects."
+	def save_new(self, form, commit):
+		setattr(form.instance, self.ct_field.get_attname(), ContentType.objects.get_for_model(self.instance).pk)
+		setattr(form.instance, self.ct_fk_field.get_attname(), self.instance.pk)
+		return form.save()
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