models.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.
"""

from django.db import models
from django.contrib.auth.models import User
from django.utils.timezone import now
from django.core.urlresolvers import reverse
from django.core.exceptions import ValidationError, ObjectDoesNotExist
from django.utils.translation import ugettext_lazy as _
from django.utils.translation import pgettext

from course.constants import (  # noqa
        user_status, USER_STATUS_CHOICES,
        participation_role, PARTICIPATION_ROLE_CHOICES,
        participation_status, PARTICIPATION_STATUS_CHOICES,
        flow_permission, FLOW_PERMISSION_CHOICES,
        flow_session_expiration_mode, FLOW_SESSION_EXPIRATION_MODE_CHOICES,
        grade_aggregation_strategy, GRADE_AGGREGATION_STRATEGY_CHOICES,
        grade_state_change_types, GRADE_STATE_CHANGE_CHOICES,
        flow_rule_kind, FLOW_RULE_KIND_CHOICES,
        )


from jsonfield import JSONField
from yamlfield.fields import YAMLField


# {{{ facility

class Facility(models.Model):
    """Data about a facility from where content may be accessed."""

    # Translators: for identifier in  Facility class
    identifier = models.CharField(max_length=50, unique=True,
            help_text= _("Format is lower-case-with-hyphens. " 
                                  "Do not use spaces."),
            verbose_name = _("Facility ID"))
    description = models.CharField(max_length=100,
            verbose_name = _("Facility description"))

    class Meta:
        verbose_name = _("Facility")
        # Translators: plural form of facility
        verbose_name_plural = _("Facilities")

    def __unicode__(self):
        return self.identifier


class FacilityIPRange(models.Model):
    """Network data about a facility from where content may be accessed."""

    facility = models.ForeignKey(Facility, related_name="ip_ranges")

    ip_range = models.CharField(
            max_length=200,
            verbose_name = _("IP Range"))

    description = models.CharField(max_length=100,)

    class Meta:
        verbose_name = _("Facility IP Range")

    def clean(self):
        import ipaddr
        try:
            ipaddr.IPNetwork(self.ip_range)
        except Exception as e:
            raise ValidationError({"ip_range": str(e)})

# }}}


# {{{ user status

def get_user_status(user):
    try:
        return user.user_status
    except AttributeError:
        ustatus = UserStatus()
        ustatus.user = user
        ustatus.status = user_status.unconfirmed
        ustatus.save()

        return ustatus


class UserStatus(models.Model):
    user = models.OneToOneField(User, db_index=True, related_name="user_status")
    status = models.CharField(max_length=50,
            choices=USER_STATUS_CHOICES)
    sign_in_key = models.CharField(max_length=50,
            null=True, unique=True, db_index=True, blank=True)
    key_time = models.DateTimeField(default=now)

    editor_mode = models.CharField(max_length=20,
            # Translators: the text editor used by participants
            choices=(
                ("default", _("Default")),
                ("sublime", "Sublime text"),
                ("emacs", "Emacs"),
                ("vim", "Vim"),
                ),
            default="default",
            verbose_name = _("Editor mode"))

    class Meta:
        verbose_name = _("User status")
        verbose_name_plural = _("User statuses")
        ordering = ("key_time",)

    def __unicode__(self):
        return _("User status for %(user)s") % {'user':self.user}

# }}}


# {{{ course

class Course(models.Model):
    identifier = models.CharField(max_length=200, unique=True,
            help_text=_("A course identifier. Alphanumeric with dashes, "
            "no spaces. This is visible in URLs and determines the location "
            "on your file system where the course's git repository lives."),
            verbose_name = _('Course ID'),
            db_index=True)

    hidden = models.BooleanField(
            default=True,
            help_text=_("Is the course only accessible to course staff?"),
            verbose_name = _('Hidden to student'))
    listed = models.BooleanField(
            default=True,
            help_text=_("Should the course be listed on the main page?"),
            verbose_name = _('Listed in main page'))
    accepts_enrollment = models.BooleanField(
            default=True, verbose_name = _('Accepts enrollment'))
    valid = models.BooleanField(
            default=True,
            help_text=_("Whether the course content has passed validation."),
            verbose_name = _('Valid'))

    git_source = models.CharField(max_length=200, blank=True,
            help_text=_("A Git URL from which to pull course updates. "
            "If you're just starting out, enter "
            "<tt>git://github.com/inducer/relate-sample</tt> "
            "to get some sample content."),
            verbose_name = _('git source'))
    ssh_private_key = models.TextField(blank=True,
            help_text=_("An SSH private key to use for Git authentication. "
            "Not needed for the sample URL above."),
            verbose_name = _('SSH private key'))

    course_file = models.CharField(max_length=200,
            default="course.yml",
            help_text=_("Name of a YAML file in the git repository that contains "
            "the root course descriptor."),
            verbose_name = _('Course file'))
    events_file = models.CharField(max_length=200,
            default="events.yml",
            help_text=_("Name of a YAML file in the git repository that contains "
            "calendar information."),
            verbose_name = _('Events file'))

    enrollment_approval_required = models.BooleanField(
            default=False,
            help_text=_("If set, each enrolling student must be "
                        "individually approved."),
            verbose_name = _('Enrollment approval required'))
    enrollment_required_email_suffix = models.CharField(
            max_length=200, blank=True, null=True,
            help_text=_("Enrollee's email addresses must end in the "
            "specified suffix, such as '@illinois.edu'."),
            verbose_name = _('Enrollment required email suffix'))

    from_email = models.EmailField(
            help_text=_("This email address will be used in the 'From' line "