#!/usr/bin/python2.5

#

# Copyright 2009 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 functions for updating different kinds of Expando models.

"""

__authors__ = [

  '"Lennard de Rijk" <ljvderijk@gmail.com>',

  ]

from soc.logic.models import base

class Logic(base.Logic):

  """Base logic for Expando entity classes.

  """

  def __init__(self, model, base_model=None, scope_logic=None,

               name=None, skip_properties=None, id_based=False):

    """Defines the name, key_name and model for this entity.

    """

    super(Logic, self).__init__(model=model, base_model=base_model,

                                scope_logic=scope_logic, name=name,

                                skip_properties=skip_properties,

                                id_based=id_based)

  def updateEntityProperties(self, entity, entity_properties, silent=False,

                             store=True):

    """Update existing entity using supplied properties.

    Overwrites base because of Expando properties.

    Args:

      entity: a model entity

      entity_properties: keyword arguments that correspond to entity

        properties and their values

      silent: iff True does not call _onUpdate method

      store: iff True updated entity is actually stored in the data model 

    Returns:

      The original entity with any supplied properties changed.

    """

    if not entity:

      raise NoEntityError

    if not entity_properties:

      raise InvalidArgumentError

    for name, value in entity_properties.iteritems():

      # if the property is not to be updated, skip it

      if name in self._skip_properties:

        continue

      if self._updateField(entity, entity_properties, name):

        setattr(entity, name, value)

    if store:

      entity.put()

    # call the _onUpdate method

    if not silent:

      self._onUpdate(entity)

    return entity