#!/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.

"""Mentor (Model) query functions.

"""

__authors__ = [

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

  ]

from google.appengine.ext import db

from soc.logic.models import role

from soc.logic.models import organization as org_logic

import soc.models.mentor

import soc.models.role

DEF_ALREADY_MENTORING_RPOJECT_MSG = "This Mentor is mentoring a Student "\

    "Project and can therefore not be resigned. Please assign another Mentor."

DEF_ALREADY_MENTORING_PROPOSAL_MSG = "This Mentor is mentoring a Student "\

    "Proposal and can therefore not be resigned. Please assign another Mentor."

class Logic(role.Logic):

  """Logic methods for the Mentor model.

  """

  def __init__(self, model=soc.models.mentor.Mentor,

               base_model=soc.models.role.Role, scope_logic=org_logic,

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

    """

                                disallow_last_resign=disallow_last_resign)

  def canResign(self, entity):

    """Checks if the Mentor is able to resign.

    Checks if there are no Student Proposals or Student Projects that

    have this mentor assigned to it.

    Args:

      entity: a Mentor entity

    """

    from soc.logic.models.student_project import logic as \

        student_project_logic

    from soc.logic.models.student_proposal import logic as \

        student_proposal_logic

    fields = {'mentor': entity}

    student_project_entity = student_project_logic.getForFields(fields,

                                                                unique=True)

    if student_project_entity:

      return DEF_ALREADY_MENTORING_RPOJECT_MSG

    student_proposal_entity = student_proposal_logic.getForFields(fields,

                                                                  unique=True)

    if student_proposal_entity:

      return DEF_ALREADY_MENTORING_PROPOSAL_MSG

    return super(Logic, self).canResign(entity)

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

    """Called when the fields of the mentor are updated

      When status is changed to invalid, removes the Mentor from all Student

      Proposals possible mentor lists.

    """

    from soc.logic.models.student_proposal import logic \

        as student_proposal_logic

    value = entity_properties[name]

    if name == 'status' and value != entity.status and value == 'invalid':

      fields = {'org': entity.scope}

      # TODO make this work for more then 1000 entities

      proposals_query = student_proposal_logic.getQueryForFields(fields)

      # store all updated proposals

      changed = []

      for proposal in proposals_query:

        if proposal.possible_mentors.count(entity.key()):

          # remove from list and add to changed

          proposal.possible_mentors.remove(entity.key())

          changed.append(proposal)

      # store all changed proposals

      db.put(changed)

    return super(Logic, self)._updateField(entity, entity_properties, name)

logic = Logic()