#!/usr/bin/python2.5

#

# Copyright 2008 the Melange authors.

#

# Licensed under the Apache License, Version 2.0 (the "License");

# you may not use this file except in compliance with the License.

# You may obtain a copy of the License at

#

#   http://www.apache.org/licenses/LICENSE-2.0

#

# Unless required by applicable law or agreed to in writing, software

# distributed under the License is distributed on an "AS IS" BASIS,

# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

# See the License for the specific language governing permissions and

# limitations under the License.

"""Helpers used to display various views that are forms.

"""

__authors__ = [

  '"Todd Larsen" <tlarsen@google.com>',

  ]

from google.appengine.ext.db import djangoforms

class DbModelForm(djangoforms.ModelForm):

  """Subclass of Django ModelForm that fixes some label and help_text issues.

  The default behavior of ModelForm is to use the verbose_name in all

  lowercase, capitalizing only the first character, as the displayed field

  label.  This class uses verbose_name unaltered as the visible field label

  instead.

  The Property classes used by the App Engine Datastore do not have a

  help_text parameter to their constructor.  In a Model class, a help_text

  attribute *can* be added to the property after it is created, but the

  help text will not be automatically passed along to the Django ModelForm.

  This class detects the presence of a help_text attribute and adds it to

  the corresponding form field object.

  ugettext_lazy() proxies used for internationalization in the Model will

  still work correctly with this new behavior, as long as the original

  strings are used as the translation keys.

  """

  def __init__(self, *args, **kwargs):

    """Fixes label and help_text issues after parent initialization.

    Args:

      *args, **kwargs:  passed through to parent __init__() constructor

    """

    super(DbModelForm, self).__init__(*args, **kwargs)

    for field_name in self.fields.iterkeys():

      # Since fields can be added only to the ModelForm subclass, check to

      # see if the Model has a corresponding field first.

      if hasattr(self.Meta.model, field_name):

        model_prop = getattr(self.Meta.model, field_name)

        # Check if the Model property defined verbose_name, and copy that

        # verbatim to the corresponding field label.

        if hasattr(model_prop, 'verbose_name'):

          self.fields[field_name].label = model_prop.verbose_name

        # Check if the Model property added help_text, and copy that verbatim

        # to the corresponding field help_text.

        if hasattr(model_prop, 'help_text'):

          self.fields[field_name].help_text = model_prop.help_text