views.py

"""
Student Views
"""
import datetime
import json
import logging
import re
import urllib
import uuid
import time
from collections import defaultdict
from pytz import UTC

from django.conf import settings
from django.contrib.auth import logout, authenticate, login
from django.contrib.auth.models import User, AnonymousUser
from django.contrib.auth.decorators import login_required
from django.contrib.auth.views import password_reset_confirm
from django.core.cache import cache
from django.core.context_processors import csrf
from django.core.mail import send_mail
from django.core.urlresolvers import reverse
from django.core.validators import validate_email, validate_slug, ValidationError
from django.db import IntegrityError, transaction
from django.http import (HttpResponse, HttpResponseBadRequest, HttpResponseForbidden,
                         Http404)
from django.shortcuts import redirect
from django_future.csrf import ensure_csrf_cookie
from django.utils.http import cookie_date, base36_to_int
from django.utils.translation import ugettext as _
from django.views.decorators.http import require_POST, require_GET

from ratelimitbackend.exceptions import RateLimitException

from edxmako.shortcuts import render_to_response, render_to_string

from course_modes.models import CourseMode
from student.models import (
    Registration, UserProfile, PendingNameChange,
    PendingEmailChange, CourseEnrollment, unique_id_for_user,
    CourseEnrollmentAllowed, UserStanding, LoginFailures
)
from student.forms import PasswordResetFormNoActive
from student.firebase_token_generator import create_token

from verify_student.models import SoftwareSecurePhotoVerification, MidcourseReverificationWindow
from certificates.models import CertificateStatuses, certificate_status_for_student
from dark_lang.models import DarkLangConfig

from xmodule.course_module import CourseDescriptor
from xmodule.modulestore.exceptions import ItemNotFoundError
from xmodule.modulestore.django import modulestore
from xmodule.modulestore import XML_MODULESTORE_TYPE, Location

from collections import namedtuple

from courseware.courses import get_courses, sort_by_announcement
from courseware.access import has_access

from external_auth.models import ExternalAuthMap
import external_auth.views

from bulk_email.models import Optout, CourseAuthorization
import shoppingcart
from user_api.models import UserPreference
from lang_pref import LANGUAGE_KEY

import track.views

from dogapi import dog_stats_api

from util.json_request import JsonResponse

from microsite_configuration.middleware import MicrositeConfiguration

from util.password_policy_validators import (
    validate_password_length, validate_password_complexity,
    validate_password_dictionary
)

log = logging.getLogger("edx.student")
AUDIT_LOG = logging.getLogger("audit")

Article = namedtuple('Article', 'title url author image deck publication publish_date')
ReverifyInfo = namedtuple('ReverifyInfo', 'course_id course_name course_number date status display')  # pylint: disable=C0103


def csrf_token(context):
    """A csrf token that can be included in a form."""
    csrf_token = context.get('csrf_token', '')
    if csrf_token == 'NOTPROVIDED':
        return ''
    return (u'<div style="display:none"><input type="hidden"'
            ' name="csrfmiddlewaretoken" value="%s" /></div>' % (csrf_token))


# NOTE: This view is not linked to directly--it is called from
# branding/views.py:index(), which is cached for anonymous users.
# This means that it should always return the same thing for anon
# users. (in particular, no switching based on query params allowed)
def index(request, extra_context={}, user=AnonymousUser()):
    """
    Render the edX main page.

    extra_context is used to allow immediate display of certain modal windows, eg signup,
    as used by external_auth.
    """

    # The course selection work is done in courseware.courses.
    domain = settings.FEATURES.get('FORCE_UNIVERSITY_DOMAIN')  # normally False
    # do explicit check, because domain=None is valid
    if domain is False:
        domain = request.META.get('HTTP_HOST')

    courses = get_courses(user, domain=domain)
    courses = sort_by_announcement(courses)

    context = {'courses': courses}

    context.update(extra_context)
    return render_to_response('index.html', context)


def course_from_id(course_id):
    """Return the CourseDescriptor corresponding to this course_id"""
    course_loc = CourseDescriptor.id_to_location(course_id)
    return modulestore().get_instance(course_id, course_loc)

day_pattern = re.compile(r'\s\d+,\s')
multimonth_pattern = re.compile(r'\s?\-\s?\S+\s')


def _get_date_for_press(publish_date):
    # strip off extra months, and just use the first:
    date = re.sub(multimonth_pattern, ", ", publish_date)
    if re.search(day_pattern, date):
        date = datetime.datetime.strptime(date, "%B %d, %Y").replace(tzinfo=UTC)
    else:
        date = datetime.datetime.strptime(date, "%B, %Y").replace(tzinfo=UTC)
    return date


def press(request):
    json_articles = cache.get("student_press_json_articles")
    if json_articles is None:
        if hasattr(settings, 'RSS_URL'):
            content = urllib.urlopen(settings.PRESS_URL).read()
            json_articles = json.loads(content)
        else:
            content = open(settings.PROJECT_ROOT / "templates" / "press.json").read()
            json_articles = json.loads(content)
        cache.set("student_press_json_articles", json_articles)
    articles = [Article(**article) for article in json_articles]
    articles.sort(key=lambda item: _get_date_for_press(item.publish_date), reverse=True)
    return render_to_response('static_templates/press.html', {'articles': articles})


def process_survey_link(survey_link, user):
    """
    If {UNIQUE_ID} appears in the link, replace it with a unique id for the user.
    Currently, this is sha1(user.username).  Otherwise, return survey_link.
    """
    return survey_link.format(UNIQUE_ID=unique_id_for_user(user))


def cert_info(user, course):
    """
    Get the certificate info needed to render the dashboard section for the given
    student and course.  Returns a dictionary with keys:

    'status': one of 'generating', 'ready', 'notpassing', 'processing', 'restricted'
    'show_download_url': bool
    'download_url': url, only present if show_download_url is True
    'show_disabled_download_button': bool -- true if state is 'generating'
    'show_survey_button': bool
    'survey_url': url, only if show_survey_button is True
    'grade': if status is not 'processing'
    """
    if not course.has_ended():
        return {}

    return _cert_info(user, course, certificate_status_for_student(user, course.id))


def reverification_info(course_enrollment_pairs, user, statuses):
    """
    Returns reverification-related information for *all* of user's enrollments whose
    reverification status is in status_list

    Args:
        course_enrollment_pairs (list): list of (course, enrollment) tuples
        user (User): the user whose information we want
        statuses (list): a list of reverification statuses we want information for
            example: ["must_reverify", "denied"]

    Returns:
        dictionary of lists: dictionary with one key per status, e.g.
            dict["must_reverify"] = []
            dict["must_reverify"] = [some information]
    """