#!/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.

"""GHOPTask (Model) query functions.

"""

__authors__ = [

    '"Madhusudan.C.S" <madhusudancs@gmail.com>',

    '"Daniel Hans" <daniel.m.hans@gmail.com>',

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

  ]

import datetime

from google.appengine.ext import db

from django.utils import simplejson

from django.utils.translation import ugettext

from soc.logic.models import base

from soc.logic import tags

from soc.modules.ghop.logic.models import comment as ghop_comment_logic

import soc.models.linkable

import soc.modules.ghop.logic.models.organization

import soc.modules.ghop.models.task

STATE_TRANSITIONS = {

    'Claimed': 'transitFromClaimed',

    'NeedsReview': 'transitFromNeedsReview',

    'ActionNeeded': 'transitFromActionNeeded',

    'NeedsWork': 'transitFromNeedsWork',

    }

TAG_NAMES = ['arbit_tag', 'difficulty', 'task_type']

class Logic(base.Logic):

  """Logic methods for the GHOPTask model.

  """

  DEF_ACTION_NEEDED_MSG = ugettext(

      '(The Melange Automated System has detected that the intial '

      'deadline has been passed and it has set the task status to '

      'ActionNeeded.)')

  DEF_NO_MORE_WORK_MSG = ugettext(

      '(The Melange Automated System has detected that the deadline '

      'has been passed and no more work can be submitted.)')

  DEF_REOPENED_MSG = ugettext(

      '(The Melange Automated System has detected that the final '

      'deadline has been passed and it has Reopened the task.)')

  def __init__(self, model=soc.modules.ghop.models.task.GHOPTask,

               base_model=soc.models.linkable.Linkable, 

               scope_logic=soc.modules.ghop.logic.models.organization):

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

    """

    self.tags_service = tags.TagsService(TAG_NAMES)

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

                                scope_logic=scope_logic)

  def updateEntityProperties(self, entity, entity_properties,

                             silent=False, store=True):

    """See base.Logic.updateEntityProperties().

    Also ensures that the history property of the task is updated in the same

    datastore operation.

    """

    from soc.logic.models import base as base_logic

    # TODO: History needs a proper test drive and perhaps a refactoring

    history = {}

    # we construct initial snapshot of the task when it is published

    # for the first time.

    if entity_properties and 'status' in entity_properties:

      if entity.status == 'Unpublished' or entity.status == 'Unapproved':

        if entity_properties['status'] == 'Open':

          history = {

              'title': entity.title,

              'description': entity.description,

              'difficulty': entity.difficulty[0].tag,

              'task_type': [type.tag for type in entity.task_type],

              'time_to_complete': entity.time_to_complete,

              'mentors': [m_key.name() for m_key in entity.mentors],

              'user': '',

              'student': '',

              'status': entity.status,

              'deadline': '',

              'created_by': entity.created_by.key().name(),

              'created_on': str(entity.created_on),

              'modified_on': str(entity.modified_on),

              }

          if entity.modified_by:

            history['modified_by'] = entity.modified_by.key().name()

          # initialize history

          task_history = {}

      # extract the existing json history from the entity to update it

    elif entity.history:

      task_history = simplejson.loads(entity.history)

    else:

      task_history = {}

      # we construct history for only changed entity properties

      if entity_properties:

        for property in entity_properties:

          changed_val = getattr(entity, property)

          if changed_val != entity_properties[property]:

            if property == 'deadline':

              history[property] = str(changed_val)

            else:

              history[property] = changed_val

    if history:

      # create a dictionary for the new history update with timestamp as key

      tstamp = str(datetime.datetime.now())

      new_history = {tstamp: history}

      # update existing history

      task_history.update(new_history)

      task_history_str = simplejson.dumps(task_history)

      # update the task's history property

      history_property = {

          'history': task_history_str

          }

      entity_properties.update(history_property)

    # call the base logic method to store the updated Task entity

    return super(Logic, self).updateEntityProperties(

        entity, entity_properties, silent=silent, store=store)

  def updateEntityPropertiesWithCWS(self, entity, entity_properties,

                                    comment_properties=None, 

                                    ws_properties=None, silent=False):

    """Updates the GHOPTask entity properties and creates a comment

    entity.

    Args:

      entity: a model entity

      entity_properties: keyword arguments that correspond to entity

          properties and their values

      comment_properties: keyword arguments that correspond to the

          GHOPTask's to be created comment entity

      silent: iff True does not call post store methods.

    """

    from soc.modules.ghop.logic.models.comment import logic as \

        ghop_comment_logic

    from soc.modules.ghop.logic.models.work_submission import logic as \

        ghop_work_submission_logic

    from soc.modules.ghop.models import comment as ghop_comment_model

    from soc.modules.ghop.models import work_submission as \

        ghop_work_submission_model

    if entity_properties:

      entity = self.updateEntityProperties(entity, entity_properties, 

                                           silent=silent, store=False)

    comment_entity = ghop_comment_model.GHOPComment(**comment_properties)

    ws_entity = None

    if ws_properties:

      ws_entity = ghop_work_submission_model.GHOPWorkSubmission(

          **ws_properties)

    def comment_create():

      """Method to be run in transaction that stores Task, Comment and

      WorkSubmission.

      """

      entity.put()

      if ws_entity:

        ws_entity.put()

        comment_entity.content = comment_entity.content % (

            ws_entity.key().id_or_name())

        comment_entity.put()

        return entity, comment_entity, ws_entity

      else:

        comment_entity.put()

        return entity, comment_entity, None

    entity, comment_entity, ws_entity = db.run_in_transaction(

        comment_create)

    if not silent:

      # call the _onCreate methods for the Comment and WorkSubmission

      if comment_entity:

        ghop_comment_logic._onCreate(comment_entity)

      if ws_entity:

        ghop_work_submission_logic._onCreate(ws_entity)

    return entity, comment_entity, ws_entity

  def updateOrCreateFromFields(self, properties, silent=False):

    """See base.Logic.updateOrCreateFromFields().

    """

    # TODO: History needs to be tested and perhaps refactored

    if properties['status'] == 'Open':

      history = {

          'title': properties['title'],

          'description': properties['description'],

          'difficulty': properties['difficulty']['tags'],

          'task_type': properties['type_tags'],

          'time_to_complete': properties['time_to_complete'],

          'mentors': [m_key.name() for m_key in properties['mentors']],

          'user': '',

          'student': '',

          'status': properties['status'],

          'deadline': '',

          'created_on': str(properties['created_on']),

          'modified_on': str(properties['modified_on']),

          }

      if 'created_by' in properties and properties['created_by']:

        history['created_by'] = properties['created_by'].key().name()

        history['modified_by'] = properties['modified_by'].key().name()

      # Constructs new history from the _constructNewHistory method, assigns

      # it as a value to the dictionary key with current timestamp and dumps

      # a JSON string.

      task_history_str = simplejson.dumps({

          str(datetime.datetime.now()): history,

          })

      # update the task's history property

      history_property = {

          'history': task_history_str

          }

      properties.update(history_property)

    entity = super(Logic, self).updateOrCreateFromFields(properties, silent)

    return entity

  def getFromKeyFieldsWithCWSOr404(self, fields):

    """Returns the Task, all Comments and all WorkSubmissions for the Task

    specified by the fields argument.

    For args see base.getFromKeyFieldsOr404().

    """

    from soc.modules.ghop.logic.models.comment import logic as \

        ghop_comment_logic

    from soc.modules.ghop.logic.models.work_submission import logic as \

        ghop_work_submission_logic

    entity = self.getFromKeyFieldsOr404(fields)

    comment_entities = ghop_comment_logic.getForFields(

        ancestors=[entity], order=['created_on'])

    ws_entities = ghop_work_submission_logic.getForFields(

        ancestors=[entity], order=['submitted_on'])

    return entity, comment_entities, ws_entities

  def updateTaskStatus(self, entity):

    """Method used to transit a task from a state to another state

    depending on the context. Whenever the deadline has passed.

    Args:

      entity: The GHOPTask entity

    Returns:

      Task entity and a Comment entity if the occurring transit created one.

    """

    from soc.modules.ghop.tasks import task_update

    if entity.deadline and datetime.datetime.now() > entity.deadline:

      # calls a specific method to make a transition depending on the

      # task's current state

      transit_func = getattr(self, STATE_TRANSITIONS[entity.status])

      update_dict = transit_func(entity)

      comment_properties = {

          'parent': entity,

          'scope_path': entity.key().name(),

          'created_by': None,

          'content': update_dict['content'],

          'changes': update_dict['changes'],

          }

      entity, comment_entity, _ = self.updateEntityPropertiesWithCWS(

          entity, update_dict['properties'], comment_properties)

      if entity.deadline:

        # only if there is a deadline set we should schedule another task

        task_update.spawnUpdateTask(entity)

    else:

      comment_entity=None

    return entity, comment_entity

  def transitFromClaimed(self, entity):

    """Makes a state transition of a GHOP Task from Claimed state

    to a relevant state.

    Args:

      entity: The GHOPTask entity

    """

    # deadline is extended by 24 hours.

    deadline = entity.deadline + datetime.timedelta(

        hours=24)

    properties = {

        'status': 'ActionNeeded',

        'deadline': deadline,

        }

    changes = [ugettext('User-MelangeAutomatic'),

               ugettext('Action-Warned for action'),

               ugettext('Status-%s' % (properties['status']))]

    content = self.DEF_ACTION_NEEDED_MSG

    update_dict = {

        'properties': properties,

        'changes': changes,

        'content': content,

        }

    return update_dict

  def transitFromNeedsReview(self, entity):

    """Makes a state transition of a GHOP Task from NeedsReview state

    to a relevant state.

    Args:

      entity: The GHOPTask entity

    """

    properties = {

        'deadline': None,

        }

    changes = [ugettext('User-MelangeAutomatic'),

               ugettext('Action-Deadline passed'),

               ugettext('Status-%s' % (entity.status))]

    content = self.DEF_NO_MORE_WORK_MSG

    update_dict = {

        'properties': properties,

        'changes': changes,

        'content': content,

        }

    return update_dict

  def transitFromActionNeeded(self, entity):

    """Makes a state transition of a GHOP Task from ActionNeeded state

    to a relevant state.

    Args:

      entity: The GHOPTask entity

    """

    properties = {

        'user': None,

        'student': None,

        'status': 'Reopened',

        'deadline': None,

        }

    changes = [ugettext('User-MelangeAutomatic'),

               ugettext('Action-Forcibly reopened'),

               ugettext('Status-Reopened')]

    content = self.DEF_REOPENED_MSG

    update_dict = {

        'properties': properties,

        'changes': changes,

        'content': content,

        }

    return update_dict

  def transitFromNeedsWork(self, entity):

    """Makes a state transition of a GHOP Task from NeedsWork state

    to a relevant state.

    Args:

      entity: The GHOPTask entity

    """

    properties = {

        'user': None,

        'student': None,

        'status': 'Reopened',

        'deadline': None,

        }

    changes = [ugettext('User-MelangeAutomatic'),

               ugettext('Action-Forcibly reopened'),

               ugettext('Status-Reopened')]

    update_dict = {

        'properties': properties,

        'changes': changes,

        'content': None,

        }

    return update_dict

  def delete(self, entity):

    """Delete existing entity from datastore.

    """

    def task_delete_txn(entity):

      """Performs all necessary operations in a single transaction when a task

      is deleted.

      """

      to_delete = []    

      to_delete += ghop_comment_logic.logic.getForFields(ancestors=[entity])

      to_delete += [entity]

      db.delete(to_delete)

    self.tags_service.removeAllTagsForEntity(entity)

    db.run_in_transaction(task_delete_txn, entity)

logic = Logic()