#!/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.

"""Role (Model) query functions.

"""

__authors__ = [

  '"Sverre Rabbelier" <sverre@rabbelier.nl>',

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

  ]

from soc.cache import sidebar

from soc.logic.models import base

import soc.models.role

DEF_LAST_RESIGN_ERROR_FMT = "This user can't be " \

    "resigned, please make sure it's not the last %(name)s."

ROLE_LOGICS = {}

def registerRoleLogic(role_logic):

  """Adds the specified Role Logic to the known ones.

  Args:

    role_logic: Instance of or subclass from Role Logic

  """

  global ROLE_LOGICS

  name = role_logic.role_name

  ROLE_LOGICS[name] = role_logic

class Logic(base.Logic):

  """Logic methods for the Role model.

  """

  def __init__(self, model=soc.models.role.Role,

               base_model=None, scope_logic=None, role_name=None,

               disallow_last_resign=False):

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

    Args:

      role_name: The name of this role used for instance for Requests

      dissallow_last_resign: Iff True and a given role entity is the last of

        its kind in its scope then this role can not be resigned.

    """

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

                                scope_logic=scope_logic)

    self.role_name = role_name

    registerRoleLogic(self)

    self.disallow_last_resign = disallow_last_resign

  def getGroupEntityFromScopePath(self, group_logic, scope_path):

    """Returns a group entity by using the given scope_path.

    Args:

      group_logic: logic for the group which should be retrieved

      scope_path : the scope path of the entity

    """

    group_key_fields = scope_path.rsplit('/', 1)

    if len(group_key_fields) == 1:

      # there is only a link_id

      fields = {'link_id' : group_key_fields[0]}

    else:

      # there is a scope_path and link_id

      fields = {'scope_path' : group_key_fields[0],

                'link_id' : group_key_fields[1]}

    group = group_logic.getForFields(fields, unique=True)

    return group

  def _updateField(self, entity, entity_properties, name):

    """Special logic for role. If status changes to active we flush the sidebar.

    """

    value = entity_properties[name]

    if (name == 'status') and (entity.status != value) and value == 'active':

      # in case the status of the role changes to active we flush the sidebar

      # cache. Other changes will be visible after the retention time expires.

      sidebar.flush(entity.user.account)

    return True

  def _onCreate(self, entity):

    """Flush the sidebar cache when a new active role entity has been created.

    """

    if entity.status == 'active':

      sidebar.flush(entity.user.account)

    super(Logic, self)._onCreate(entity)

  def canResign(self, entity):

    """Checks if the current entity is allowed to be resigned.

    Args:

      entity: a Role entity

    Returns:

      - None if the entity is allowed to resign.

      - Error message otherwise.

    """

    if self.disallow_last_resign:

      # check if this is the last active role for it's scope

      fields = {'scope': entity.scope,

          'status': 'active'}

      roles = self.getForFields(fields, limit=2)

      # if this it the last one return error message

      if len(roles) <= 1:

        return DEF_LAST_RESIGN_ERROR_FMT

    # resignation is possible

    return None

  def getRoleLogicsToNotifyUponNewRequest(self):

    """Returns a list with subclasses of Role Logic which should be notified

    when a new request to obtain this Role arrives.

    Returns:

      A list with all Role Logics to notify

    """

    return []

logic = Logic()