import datetime

from django.db import DJANGO_VERSION_PICKLE_KEY, models

from django.utils.translation import gettext_lazy as _

def standalone_number():

    return 1

class Numbers:

    @staticmethod

    def get_static_number():

        return 2

class PreviousDjangoVersionQuerySet(models.QuerySet):

    def __getstate__(self):

        state = super().__getstate__()

        state[DJANGO_VERSION_PICKLE_KEY] = "1.0"

        return state

class MissingDjangoVersionQuerySet(models.QuerySet):

    def __getstate__(self):

        state = super().__getstate__()

        del state[DJANGO_VERSION_PICKLE_KEY]

        return state

class Group(models.Model):

    name = models.CharField(_("name"), max_length=100)

    objects = models.Manager()

    previous_django_version_objects = PreviousDjangoVersionQuerySet.as_manager()

    missing_django_version_objects = MissingDjangoVersionQuerySet.as_manager()

class Event(models.Model):

    title = models.CharField(max_length=100)

    group = models.ForeignKey(Group, models.CASCADE, limit_choices_to=models.Q())

class Happening(models.Model):

    when = models.DateTimeField(blank=True, default=datetime.datetime.now)

    name = models.CharField(blank=True, max_length=100, default="test")

    number1 = models.IntegerField(blank=True, default=standalone_number)

    number2 = models.IntegerField(blank=True, default=Numbers.get_static_number)

    event = models.OneToOneField(Event, models.CASCADE, null=True)

class BinaryFieldModel(models.Model):

    data = models.BinaryField(null=True)

class Container:

    # To test pickling we need a class that isn't defined on module, but

    # is still available from app-cache. So, the Container class moves

    # SomeModel outside of module level

    class SomeModel(models.Model):

        somefield = models.IntegerField()

class M2MModel(models.Model):

    added = models.DateField(default=datetime.date.today)

    groups = models.ManyToManyField(Group)

class AbstractEvent(Event):

    class Meta:

        abstract = True

        ordering = ["title"]

class MyEvent(AbstractEvent):

    pass

class Edition(models.Model):

    event = models.ForeignKey("MyEvent", on_delete=models.CASCADE)