#!/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.

"""Access control helper.

See soc.views.helper.access module.
"""

__authors__ = [
    '"Madhusudan.C.S" <madhusudancs@gmail.com>'
  ]


from django.utils.translation import ugettext

from soc.logic.helper import timeline as timeline_helper
from soc.logic.models import host as host_logic 
from soc.logic.models import user as user_logic
from soc.views import out_of_band
from soc.views.helper import access

from soc.modules.ghop.logic.models import mentor as ghop_mentor_logic
from soc.modules.ghop.logic.models import org_admin as ghop_org_admin_logic
from soc.modules.ghop.logic.models import task as ghop_task_logic


DEF_CANT_EDIT_MSG = ugettext(
    'This task cannot be edited since it has been claimed at least '
    'once before.')

DEF_MAX_TASKS_REACHED_MSG = ugettext(
    'You have reached the maximum number of Tasks allowed '
    'for your organization for this program.')

DEF_NEED_ROLE_MSG = ugettext(
    'You do not have the required role.')

DEF_NO_ACTIVE_ENTITY_MSG = ugettext(
    'There is no such active entity.')

DEF_NO_PUB_TASK_MSG = ugettext(
    'There is no such published task.')

DEF_PAGE_INACTIVE_MSG = ugettext(
    'This page is inactive at this time.')

DEF_SIGN_UP_AS_OA_MENTOR_MSG = ugettext(
    'You first need to sign up as an Org Admin or a Mentor.')


class GHOPChecker(access.Checker):
  """See soc.views.helper.access.Checker.
  """

  @access.allowDeveloper
  @access.denySidebar
  def checkCanOrgAdminOrMentorEdit(self, django_args, 
                                   key_location, check_limit):
    """Checks if the mentors can create task for this program,
    and obeys the task quota limit assigned for their org when check_limit is
    True.

    Args:
      django_args: a dictionary with django's arguments
      key_location: the key for django_args in which the key_name
                    from the mentor is stored
      check_limit: iff true checks if the organization reached the 
                   task quota limit for the given program.
    """

    self.checkIsUser(django_args)

    user_account = user_logic.logic.getForCurrentAccount()

    filter = {
        'user': user_account,
        'scope_path': django_args[key_location],
        'status': 'active'
        }

    role_entity = ghop_org_admin_logic.logic.getForFields(
        filter, unique=True) 
    if not role_entity:
      role_entity = ghop_mentor_logic.logic.getForFields(
          filter, unique=True)

    if not role_entity:
      raise out_of_band.AccessViolation(
        message_fmt=DEF_SIGN_UP_AS_OA_MENTOR_MSG)

    program_entity = role_entity.program

    if not timeline_helper.isActivePeriod(program_entity.timeline,
        'program'):
      raise out_of_band.AccessViolation(message_fmt=DEF_PAGE_INACTIVE_MSG)

    org_entity = role_entity.scope

    if check_limit:
      # count all tasks from this organization
      fields = {'scope': org_entity}
      task_query = ghop_task_logic.logic.getQueryForFields(fields)

      if task_query.count() >= org_entity.task_quota_limit:
        # too many tasks access denied
        raise out_of_band.AccessViolation(message_fmt=DEF_MAX_TASKS_REACHED)

    if 'link_id' in django_args:
      task_filter = {
          'link_id': django_args['link_id'],
          'scope_path': django_args['scope_path'],
          }
      task_entity = ghop_task_logic.logic.getFromKeyFields(task_filter)

      if task_entity.status not in ['Unapproved', 'Unpublished', 'Open']:
        # task is claimed at least once
        raise out_of_band.AccessViolation(message_fmt=DEF_CANT_EDIT_MSG)

    return

  @access.allowDeveloper
  @access.denySidebar
  def checkRoleAndStatusForTask(self, django_args, allowed_roles,
                                role_status, task_status):
    """Checks if the current user has access to the given task.

    Args:
      django_args: a dictionary with django's arguments
      allowed_roles: list with names for the roles allowed to pass access check
      role_status: list with states allowed for the role
      task_status: a list with states allowed for the task

     Raises:
       AccessViolationResponse:
         - If there is no task found
         - If the task is not in one of the required states.
         - If the user does not have any of the required roles
    """

    self.checkIsUser(django_args)

    if 'link_id' in django_args:
      # bail out with 404 if no task is found
      task_entity = ghop_task_logic.logic.getFromKeyFieldsOr404(django_args)

      if not task_entity.status in task_status:
        # this task can not be accessed at the moment
        raise out_of_band.AccessViolation(
            message_fmt=DEF_NO_ACTIVE_ENTITY_MSG)

    user_entity = self.user

    filter = {
        'user': user_entity,
        'status': role_status}

    if 'host' in allowed_roles:
      # check if the current user is a host for this proposal's program
      filter['scope'] =  task_entity.program

      if host_logic.logic.getForFields(filter, unique=True):
        return

    if 'ghop/org_admin' in allowed_roles:
      # check if the current user is an admin for this task's org
      filter['scope_path'] = django_args['scope_path']

      if ghop_org_admin_logic.logic.getForFields(filter, unique=True):
        return

    if 'ghop/mentor' in allowed_roles:
      # check if the current user is a mentor for this task's org
      filter['scope_path'] = django_args['scope_path']

      if ghop_mentor_logic.logic.getForFields(filter, unique=True):
        return

    if 'public' in allowed_roles:
      return

    # no roles found, access denied
    raise out_of_band.AccessViolation(
        message_fmt=DEF_NEED_ROLE_MSG)

  def checkStatusForTask(self, django_args):
    """Checks if the current user has access to the given task.

    Args:
      django_args: a dictionary with django's arguments

     Raises:
       AccessViolationResponse:
         - If there is no task found
         - If the task is not in one of the required states.
    """

    try:
      self.checkIsUser(django_args)
      user_entity = self.user

      filter = {
          'user': user_entity,
          'status': 'active',
          'scope_path': django_args['scope_path'],
          }

      if ghop_org_admin_logic.logic.getForFields(filter, unique=True):
        return

      if ghop_mentor_logic.logic.getForFields(filter, unique=True):
        return

    except out_of_band.Error:
      pass

    # bail out with 404 if no task is found
    task_entity = ghop_task_logic.logic.getFromKeyFieldsOr404(django_args)

    if task_entity.status  in ['Unapproved', 'Unpublished', 'Invalid']:
      # this proposal can not be task at the moment
      raise out_of_band.AccessViolation(
          message_fmt=DEF_NO_PUB_TASK_MSG)