def grade_updated(**kwargs):
    """
    Emits the appropriate grade-related event after checking for which
    event-transaction is active.

    Emits a problem.submitted event only if there is no current event
    transaction type, i.e. we have not reached this point in the code via
    an outer event type (such as problem.rescored or score_overridden).
    """
    root_type = get_event_transaction_type()

    if not root_type:
        root_id = get_event_transaction_id()
        if not root_id:
            root_id = create_new_event_transaction_id()
        set_event_transaction_type(PROBLEM_SUBMITTED_EVENT_TYPE)
        tracker.emit(
            unicode(PROBLEM_SUBMITTED_EVENT_TYPE),
            {
                'user_id': unicode(kwargs['user_id']),
                'course_id': unicode(kwargs['course_id']),
                'problem_id': unicode(kwargs['usage_id']),
                'event_transaction_id': unicode(root_id),
                'event_transaction_type': unicode(PROBLEM_SUBMITTED_EVENT_TYPE),
                'weighted_earned': kwargs.get('weighted_earned'),
                'weighted_possible': kwargs.get('weighted_possible'),
            }
        )

    elif root_type in [GRADES_RESCORE_EVENT_TYPE, GRADES_OVERRIDE_EVENT_TYPE]:
        current_user = get_current_user()
        instructor_id = getattr(current_user, 'id', None)
        tracker.emit(
            unicode(root_type),
            {
                'course_id': unicode(kwargs['course_id']),
                'user_id': unicode(kwargs['user_id']),
                'problem_id': unicode(kwargs['usage_id']),
                'new_weighted_earned': kwargs.get('weighted_earned'),
                'new_weighted_possible': kwargs.get('weighted_possible'),
                'only_if_higher': kwargs.get('only_if_higher'),
                'instructor_id': unicode(instructor_id),
                'event_transaction_id': unicode(get_event_transaction_id()),
                'event_transaction_type': unicode(root_type),
            }
        )

    elif root_type in [SUBSECTION_OVERRIDE_EVENT_TYPE]:
        tracker.emit(
            unicode(root_type),
            {
                'course_id': unicode(kwargs['course_id']),
                'user_id': unicode(kwargs['user_id']),
                'problem_id': unicode(kwargs['usage_id']),
                'only_if_higher': kwargs.get('only_if_higher'),
                'override_deleted': kwargs.get('score_deleted', False),
                'event_transaction_id': unicode(get_event_transaction_id()),
                'event_transaction_type': unicode(root_type),
            }
        )

def subsection_grade_calculated(subsection_grade):
    """
    Emits an edx.grades.subsection.grade_calculated event
    with data from the passed subsection_grade.
    """
    event_name = SUBSECTION_GRADE_CALCULATED
    context = contexts.course_context_from_course_id(subsection_grade.course_id)
    # TODO (AN-6134): remove this context manager
    with tracker.get_tracker().context(event_name, context):
        tracker.emit(
            event_name,
            {
                'user_id': unicode(subsection_grade.user_id),
                'course_id': unicode(subsection_grade.course_id),
                'block_id': unicode(subsection_grade.usage_key),
                'course_version': unicode(subsection_grade.course_version),
                'weighted_total_earned': subsection_grade.earned_all,
                'weighted_total_possible': subsection_grade.possible_all,
                'weighted_graded_earned': subsection_grade.earned_graded,
                'weighted_graded_possible': subsection_grade.possible_graded,
                'first_attempted': unicode(subsection_grade.first_attempted),
                'subtree_edited_timestamp': unicode(subsection_grade.subtree_edited_timestamp),
                'event_transaction_id': unicode(get_event_transaction_id()),
                'event_transaction_type': unicode(get_event_transaction_type()),
                'visible_blocks_hash': unicode(subsection_grade.visible_blocks_id),
            }
        )

 def _emit_grade_calculated_event(grade):
     """
     Emits an edx.grades.subsection.grade_calculated event
     with data from the passed grade.
     """
     # TODO: remove this context manager after completion of AN-6134
     event_name = u'edx.grades.subsection.grade_calculated'
     context = contexts.course_context_from_course_id(grade.course_id)
     with tracker.get_tracker().context(event_name, context):
         tracker.emit(
             event_name,
             {
                 'user_id': unicode(grade.user_id),
                 'course_id': unicode(grade.course_id),
                 'block_id': unicode(grade.usage_key),
                 'course_version': unicode(grade.course_version),
                 'weighted_total_earned': grade.earned_all,
                 'weighted_total_possible': grade.possible_all,
                 'weighted_graded_earned': grade.earned_graded,
                 'weighted_graded_possible': grade.possible_graded,
                 'first_attempted': unicode(grade.first_attempted),
                 'subtree_edited_timestamp': unicode(grade.subtree_edited_timestamp),
                 'event_transaction_id': unicode(get_event_transaction_id()),
                 'event_transaction_type': unicode(get_event_transaction_type()),
                 'visible_blocks_hash': unicode(grade.visible_blocks_id),
             }
         )

    def _create_override(self, request_user, subsection_grade_model, **override_data):
        """
        Helper method to create a `PersistentSubsectionGradeOverride` object
        and send a `SUBSECTION_OVERRIDE_CHANGED` signal.
        """
        override = PersistentSubsectionGradeOverride.update_or_create_override(
            requesting_user=request_user,
            subsection_grade_model=subsection_grade_model,
            feature=grades_constants.GradeOverrideFeatureEnum.gradebook,
            **override_data
        )

        set_event_transaction_type(grades_events.SUBSECTION_GRADE_CALCULATED)
        create_new_event_transaction_id()

        recalculate_subsection_grade_v3.apply(
            kwargs=dict(
                user_id=subsection_grade_model.user_id,
                anonymous_user_id=None,
                course_id=text_type(subsection_grade_model.course_id),
                usage_id=text_type(subsection_grade_model.usage_key),
                only_if_higher=False,
                expected_modified_time=to_timestamp(override.modified),
                score_deleted=False,
                event_transaction_id=six.text_type(get_event_transaction_id()),
                event_transaction_type=six.text_type(get_event_transaction_type()),
                score_db_table=grades_constants.ScoreDatabaseTableEnum.overrides,
                force_update_subsections=True,
            )
        )
        # Emit events to let our tracking system to know we updated subsection grade
        grades_events.subsection_grade_calculated(subsection_grade_model)
        return override

def _retry_recalculate_subsection_grade(
        user_id,
        course_id,
        usage_id,
        only_if_higher,
        expected_modified_time,
        score_deleted,
        exc=None,
):
    """
    Calls retry for the recalculate_subsection_grade task with the
    given inputs.
    """
    recalculate_subsection_grade_v2.retry(
        kwargs=dict(
            user_id=user_id,
            course_id=course_id,
            usage_id=usage_id,
            only_if_higher=only_if_higher,
            expected_modified_time=expected_modified_time,
            score_deleted=score_deleted,
            event_transaction_id=unicode(get_event_transaction_id()),
            event_transaction_type=unicode(get_event_transaction_type()),
        ),
        exc=exc,
    )

def _emit_event(kwargs):
    """
    Emits a problem submitted event only if there is no current event
    transaction type, i.e. we have not reached this point in the code via a
    rescore or student state deletion.

    If the event transaction type has already been set and the transacation is
    a rescore, emits a problem rescored event.
    """
    root_type = get_event_transaction_type()

    if not root_type:
        root_id = get_event_transaction_id()
        if not root_id:
            root_id = create_new_event_transaction_id()
        set_event_transaction_type(PROBLEM_SUBMITTED_EVENT_TYPE)
        tracker.emit(
            unicode(PROBLEM_SUBMITTED_EVENT_TYPE),
            {
                'user_id': unicode(kwargs['user_id']),
                'course_id': unicode(kwargs['course_id']),
                'problem_id': unicode(kwargs['usage_id']),
                'event_transaction_id': unicode(root_id),
                'event_transaction_type': unicode(PROBLEM_SUBMITTED_EVENT_TYPE),
                'weighted_earned': kwargs.get('weighted_earned'),
                'weighted_possible': kwargs.get('weighted_possible'),
            }
        )

    if root_type in [GRADES_RESCORE_EVENT_TYPE, GRADES_OVERRIDE_EVENT_TYPE]:
        current_user = get_current_user()
        instructor_id = getattr(current_user, 'id', None)
        tracker.emit(
            unicode(GRADES_RESCORE_EVENT_TYPE),
            {
                'course_id': unicode(kwargs['course_id']),
                'user_id': unicode(kwargs['user_id']),
                'problem_id': unicode(kwargs['usage_id']),
                'new_weighted_earned': kwargs.get('weighted_earned'),
                'new_weighted_possible': kwargs.get('weighted_possible'),
                'only_if_higher': kwargs.get('only_if_higher'),
                'instructor_id': unicode(instructor_id),
                'event_transaction_id': unicode(get_event_transaction_id()),
                'event_transaction_type': unicode(root_type),
            }
        )

    def set_up_course(self, enable_persistent_grades=True, create_multiple_subsections=False):
        """
        Configures the course for this test.
        """
        # pylint: disable=attribute-defined-outside-init,no-member
        self.course = CourseFactory.create(
            org='edx',
            name='course',
            run='run',
        )
        if not enable_persistent_grades:
            PersistentGradesEnabledFlag.objects.create(enabled=False)

        self.chapter = ItemFactory.create(parent=self.course, category="chapter", display_name="Chapter")
        self.sequential = ItemFactory.create(parent=self.chapter, category='sequential', display_name="Sequential1")
        self.problem = ItemFactory.create(parent=self.sequential, category='problem', display_name='Problem')

        if create_multiple_subsections:
            seq2 = ItemFactory.create(parent=self.chapter, category='sequential')
            ItemFactory.create(parent=seq2, category='problem')

        self.frozen_now_datetime = datetime.now().replace(tzinfo=pytz.UTC)
        self.frozen_now_timestamp = to_timestamp(self.frozen_now_datetime)

        self.problem_weighted_score_changed_kwargs = OrderedDict([
            ('weighted_earned', 1.0),
            ('weighted_possible', 2.0),
            ('user_id', self.user.id),
            ('anonymous_user_id', 5),
            ('course_id', unicode(self.course.id)),
            ('usage_id', unicode(self.problem.location)),
            ('only_if_higher', None),
            ('modified', self.frozen_now_datetime),
            ('score_db_table', ScoreDatabaseTableEnum.courseware_student_module),
        ])

        create_new_event_transaction_id()

        self.recalculate_subsection_grade_kwargs = OrderedDict([
            ('user_id', self.user.id),
            ('course_id', unicode(self.course.id)),
            ('usage_id', unicode(self.problem.location)),
            ('anonymous_user_id', 5),
            ('only_if_higher', None),
            ('expected_modified_time', self.frozen_now_timestamp),
            ('score_deleted', False),
            ('event_transaction_id', unicode(get_event_transaction_id())),
            ('event_transaction_type', u'edx.grades.problem.submitted'),
            ('score_db_table', ScoreDatabaseTableEnum.courseware_student_module),
        ])

        # this call caches the anonymous id on the user object, saving 4 queries in all happy path tests
        _ = anonymous_id_for_user(self.user, self.course.id)

def handle_grading_policy_changed(sender, **kwargs):
    # pylint: disable=unused-argument
    """
    Receives signal and kicks off celery task to recalculate grades
    """
    kwargs = {
        'course_key': unicode(kwargs.get('course_key')),
        'event_transaction_id': unicode(get_event_transaction_id()),
        'event_transaction_type': unicode(get_event_transaction_type()),
    }
    result = compute_all_grades_for_course.apply_async(kwargs=kwargs)
    log.info("Grades: Created {task_name}[{task_id}] with arguments {kwargs}".format(
        task_name=compute_all_grades_for_course.name,
        task_id=result.task_id,
        kwargs=kwargs,
    ))

    def _run_command_and_check_output(self, task_mock, score_db_table, include_anonymous_id=False):
        self.command.handle(modified_start='2016-08-25 16:42', modified_end='2018-08-25 16:44')
        kwargs = {
            "user_id": "ID",
            "course_id": u'x/y/z',
            "usage_id": u'abc',
            "only_if_higher": False,
            "expected_modified_time": to_timestamp(utc.localize(datetime.strptime('2016-08-23 16:43', DATE_FORMAT))),
            "score_deleted": False,
            "event_transaction_id": unicode(get_event_transaction_id()),
            "event_transaction_type": u'edx.grades.problem.submitted',
            "score_db_table": score_db_table,
        }

        if include_anonymous_id:
            kwargs['anonymous_user_id'] = 'anonymousID'

        task_mock.apply_async.assert_called_with(kwargs=kwargs)

 def _assert_tracker_emitted_event(self, tracker_mock, grade):
     """
     Helper function to ensure that the mocked event tracker
     was called with the expected info based on the passed grade.
     """
     tracker_mock.emit.assert_called_with(
         u'edx.grades.course.grade_calculated',
         {
             'user_id': unicode(grade.user_id),
             'course_id': unicode(grade.course_id),
             'course_version': unicode(grade.course_version),
             'percent_grade': grade.percent_grade,
             'letter_grade': unicode(grade.letter_grade),
             'course_edited_timestamp': unicode(grade.course_edited_timestamp),
             'event_transaction_id': unicode(get_event_transaction_id()),
             'event_transaction_type': unicode(get_event_transaction_type()),
             'grading_policy_hash': unicode(grade.grading_policy_hash),
         }
     )

def enqueue_subsection_update(sender, **kwargs):  # pylint: disable=unused-argument
    """
    Handles the PROBLEM_WEIGHTED_SCORE_CHANGED or SUBSECTION_OVERRIDE_CHANGED signals by
    enqueueing a subsection update operation to occur asynchronously.
    """
    events.grade_updated(**kwargs)
    recalculate_subsection_grade_v3.apply_async(
        kwargs=dict(
            user_id=kwargs['user_id'],
            anonymous_user_id=kwargs.get('anonymous_user_id'),
            course_id=kwargs['course_id'],
            usage_id=kwargs['usage_id'],
            only_if_higher=kwargs.get('only_if_higher'),
            expected_modified_time=to_timestamp(kwargs['modified']),
            score_deleted=kwargs.get('score_deleted', False),
            event_transaction_id=unicode(get_event_transaction_id()),
            event_transaction_type=unicode(get_event_transaction_type()),
            score_db_table=kwargs['score_db_table'],
        ),
        countdown=RECALCULATE_GRADE_DELAY_SECONDS,
    )

def course_grade_calculated(course_grade):
    """
    Emits an edx.grades.course.grade_calculated event
    with data from the passed course_grade.
    """
    event_name = COURSE_GRADE_CALCULATED
    context = contexts.course_context_from_course_id(course_grade.course_id)
    # TODO (AN-6134): remove this context manager
    with tracker.get_tracker().context(event_name, context):
        tracker.emit(
            event_name,
            {
                'user_id': unicode(course_grade.user_id),
                'course_id': unicode(course_grade.course_id),
                'course_version': unicode(course_grade.course_version),
                'percent_grade': course_grade.percent_grade,
                'letter_grade': unicode(course_grade.letter_grade),
                'course_edited_timestamp': unicode(course_grade.course_edited_timestamp),
                'event_transaction_id': unicode(get_event_transaction_id()),
                'event_transaction_type': unicode(get_event_transaction_type()),
                'grading_policy_hash': unicode(course_grade.grading_policy_hash),
            }
        )

    def _create_override(self, request_user, subsection_grade_model, **override_data):
        """
        Helper method to create a `PersistentSubsectionGradeOverride` object
        and send a `SUBSECTION_OVERRIDE_CHANGED` signal.
        """
        override, _ = PersistentSubsectionGradeOverride.objects.update_or_create(
            grade=subsection_grade_model,
            defaults=self._clean_override_data(override_data),
        )

        _ = PersistentSubsectionGradeOverrideHistory.objects.create(
            override_id=override.id,
            user=request_user,
            feature=PersistentSubsectionGradeOverrideHistory.GRADEBOOK,
            action=PersistentSubsectionGradeOverrideHistory.CREATE_OR_UPDATE,
        )

        set_event_transaction_type(SUBSECTION_GRADE_CALCULATED)
        create_new_event_transaction_id()

        recalculate_subsection_grade_v3.apply(
            kwargs=dict(
                user_id=subsection_grade_model.user_id,
                anonymous_user_id=None,
                course_id=text_type(subsection_grade_model.course_id),
                usage_id=text_type(subsection_grade_model.usage_key),
                only_if_higher=False,
                expected_modified_time=to_timestamp(override.modified),
                score_deleted=False,
                event_transaction_id=unicode(get_event_transaction_id()),
                event_transaction_type=unicode(get_event_transaction_type()),
                score_db_table=ScoreDatabaseTableEnum.overrides,
                force_update_subsections=True,
            )
        )
        # Emit events to let our tracking system to know we updated subsection grade
        subsection_grade_calculated(subsection_grade_model)