utils.py

# -*- coding: utf-8 -*-

from __future__ import division

__copyright__ = "Copyright (C) 2014 Andreas Kloeckner"

__license__ = """
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
"""

import six
import datetime  # noqa

from typing import cast

from django.shortcuts import (  # noqa
        render, get_object_or_404)
from django import http
from django.core.exceptions import ObjectDoesNotExist
from django.utils.translation import (
        ugettext as _, string_concat, pgettext_lazy)

from course.content import (
        get_course_repo, get_flow_desc,
        parse_date_spec, get_course_commit_sha)
from course.constants import (
        flow_permission, flow_rule_kind)
import dulwich.repo
from course.content import (  # noqa
        FlowDesc,
        FlowPageDesc,
        FlowSessionAccessRuleDesc
        )
from course.page.base import (  # noqa
        PageBase,
        PageContext,
        )

# {{{ mypy

if False:
    from typing import Tuple, List, Text, Iterable, Any, Optional, Union  # noqa
    from relate.utils import Repo_ish  # noqa
    from course.models import (  # noqa
            Course,
            Participation,
            ExamTicket,
            FlowSession,
            FlowPageData,
            )

# }}}


def getattr_with_fallback(aggregates, attr_name, default=None):
    # type: (Iterable[Any], Text, Any) -> Any
    for agg in aggregates:
        result = getattr(agg, attr_name, None)
        if result is not None:
            return result

    return default


# {{{ flow permissions

class FlowSessionRuleBase(object):
    pass


class FlowSessionStartRule(FlowSessionRuleBase):
    def __init__(
            self,
            tag_session=None,  # type: Optional[Text]
            may_start_new_session=None,  # type: Optional[bool]
            may_list_existing_sessions=None,  # type: Optional[bool]
            default_expiration_mode=None,  # type: Optional[Text]
            ):
        # type: (...) -> None
        self.tag_session = tag_session
        self.may_start_new_session = may_start_new_session
        self.may_list_existing_sessions = may_list_existing_sessions
        self.default_expiration_mode = default_expiration_mode


class FlowSessionAccessRule(FlowSessionRuleBase):
    def __init__(
            self,
            permissions,  # type: frozenset[Text]
            message=None,  # type: Optional[Text]
            ):
        # type: (...) -> None
        self.permissions = permissions
        self.message = message

    def human_readable_permissions(self):
        from course.models import FLOW_PERMISSION_CHOICES
        permission_dict = dict(FLOW_PERMISSION_CHOICES)
        return [permission_dict[p] for p in self.permissions]


class FlowSessionGradingRule(FlowSessionRuleBase):
    def __init__(
            self,
            grade_identifier,  # type: Optional[Text]
            grade_aggregation_strategy,  # type: Text
            due,  # type: Optional[datetime.datetime]
            generates_grade,  # type: bool
            description=None,  # type: Optional[Text]
            credit_percent=None,  # type: Optional[float]
            use_last_activity_as_completion_time=None,  # type: Optional[bool]
            max_points=None,  # type: Optional[float]
            max_points_enforced_cap=None,  # type: Optional[float]
            bonus_points=None,  # type: Optional[float]
            ):
        # type: (...) -> None

        self.grade_identifier = grade_identifier
        self.grade_aggregation_strategy = grade_aggregation_strategy
        self.due = due
        self.generates_grade = generates_grade
        self.description = description
        self.credit_percent = credit_percent
        self.use_last_activity_as_completion_time = \
                use_last_activity_as_completion_time
        self.max_points = max_points
        self.max_points_enforced_cap = max_points_enforced_cap
        self.bonus_points = bonus_points


def _eval_generic_conditions(
        rule,  # type: Any
        course,  # type: Course
        participation,  # type: Optional[Participation]
        now_datetime,  # type: datetime.datetime
        flow_id,  # type: Text
        login_exam_ticket,  # type: Optional[ExamTicket]
        ):
    # type: (...) -> bool

    if hasattr(rule, "if_before"):
        ds = parse_date_spec(course, rule.if_before)
        if not (now_datetime <= ds):
            return False

    if hasattr(rule, "if_after"):
        ds = parse_date_spec(course, rule.if_after)
        if not (now_datetime >= ds):
            return False

    if hasattr(rule, "if_has_role"):
        from course.enrollment import get_participation_role_identifiers
        roles = get_participation_role_identifiers(course, participation)
        if all(role not in rule.if_has_role for role in roles):
            return False

    if (hasattr(rule, "if_signed_in_with_matching_exam_ticket")
            and rule.if_signed_in_with_matching_exam_ticket):
        if login_exam_ticket is None:
            return False
        if login_exam_ticket is None:
            return False
        if login_exam_ticket.exam.flow_id != flow_id:
            return False

    return True


def _eval_generic_session_conditions(
        rule,  # type: Any
        session,  # type: FlowSession
        now_datetime,  # type: datetime.datetime
        ):
    # type: (...) -> bool

    if hasattr(rule, "if_has_tag"):
        if session.access_rules_tag != rule.if_has_tag:
            return False

    if hasattr(rule, "if_started_before"):
        ds = parse_date_spec(session.course, rule.if_started_before)
        if not session.start_time < ds:
            return False