#!/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.

"""Tasks related to Grading Survey Groups.

"""

__authors__ = [

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

  ]

import datetime

import logging

from google.appengine.api.labs import taskqueue

from django import http

from soc.tasks.helper import error_handler

# batch size to use when going through StudentProjects

DEF_BATCH_SIZE = 10

def getDjangoURLPatterns():

  """Returns the URL patterns for the tasks in this module.

  """

  patterns = [(

      r'tasks/grading_survey_group/update_records$',

      'soc.tasks.grading_survey_group.updateOrCreateRecordsForSurveyGroup'),

              (

      r'tasks/grading_survey_group/update_projects$',

      'soc.tasks.grading_survey_group.updateProjectsForSurveyGroup')]

  return patterns

def updateOrCreateRecordsForSurveyGroup(request, *args, **kwargs):

  """Updates or creates GradingRecords for the given GradingSurveyGroup.

  Expects the following to be present in the POST dict:

    group_key: Specifies the GradingSurveyGroup key name.

    project_key: optional to specify which project was the last for which this

                 task was run

  Args:

    request: Django Request object

  """

  from soc.logic.models.grading_record import logic as grading_record_logic

  from soc.logic.models.grading_survey_group import logic as survey_group_logic

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

  post_dict = request.POST

  group_key = post_dict.get('group_key')

  if not group_key:

    # invalid task data, log and return OK

    return error_handler.logErrorAndReturnOK(

        'Invalid updateRecordForSurveyGroup data: %s' % post_dict)

  # get the GradingSurveyGroup for the given keyname

  survey_group_entity = survey_group_logic.getFromKeyName(group_key)

  if not survey_group_entity:

    # invalid GradingSurveyGroup specified, log and return OK

    return error_handler.logErrorAndReturnOK(

        'Invalid GradingSurveyGroup specified: %s' % group_key)

  # check and retrieve the project_key that has been done last

  if 'project_key' in post_dict:

    project_start_key = post_dict['project_key']

  else:

    project_start_key = None

  # get all valid StudentProjects from starting key

  fields = {'program': survey_group_entity.scope,

            'status': ['accepted', 'failed', 'completed', 'withdrawn']}

  if project_start_key:

    # retrieve the last project that was done

    project_start = student_project_logic.getFromKeyName(project_start_key)

    if not project_start:

      # invalid starting project key specified, log and return OK

      return error_handler.logErrorAndReturnOK(

          'Invalid Student Project Key specified: %s' %(project_start_key))

    fields['__key__ >'] = project_start.key()

  # get the first batch_size number of StudentProjects

  project_entities = student_project_logic.getForFields(fields,

                                                        limit=DEF_BATCH_SIZE)

  # update/create and batch put the new GradingRecords

  grading_record_logic.updateOrCreateRecordsFor(survey_group_entity,

                                                project_entities)

  if len(project_entities) == DEF_BATCH_SIZE:

    # spawn new task starting from the last

    new_project_start = project_entities[DEF_BATCH_SIZE-1].key().id_or_name()

    # pass along these params as POST to the new task

    task_params = {'group_key': group_key,

                   'project_key': new_project_start}

    task_url = '/tasks/grading_survey_group/update_records'

    new_task = taskqueue.Task(params=task_params, url=task_url)

    new_task.add()

  else:

    # task completed, update timestamp for last update complete

    fields = {'last_update_complete': datetime.datetime.now()}

    survey_group_logic.updateEntityProperties(survey_group_entity, fields)

  # task completed, return OK

  return http.HttpResponse('OK')

def updateProjectsForSurveyGroup(request, *args, **kwargs):

  """Updates each StudentProject for which a GradingRecord is found.

  Expects the following to be present in the POST dict:

    group_key: Specifies the GradingSurveyGroup key name.

  Args:

    request: Django Request object

  """

  # TODO(ljvderijk) implement this method

  return http.HttpResponse('OK')