import datetime

from django.db import models

class Place(models.Model):

    name = models.CharField(max_length=50)

    address = models.CharField(max_length=80)

    class Meta:

        ordering = ('name',)

    def __unicode__(self):

        return u"%s the place" % self.name

class Restaurant(Place):

    serves_hot_dogs = models.BooleanField()

    serves_pizza = models.BooleanField()

    def __unicode__(self):

        return u"%s the restaurant" % self.name

class ItalianRestaurant(Restaurant):

    serves_gnocchi = models.BooleanField()

    def __unicode__(self):

        return u"%s the italian restaurant" % self.name

class ParkingLot(Place):

    # An explicit link to the parent (we can control the attribute name).

    parent = models.OneToOneField(Place, primary_key=True, parent_link=True)

    capacity = models.IntegerField()

    def __unicode__(self):

        return u"%s the parking lot" % self.name

class ParkingLot2(Place):

    # In lieu of any other connector, an existing OneToOneField will be

    # promoted to the primary key.

    parent = models.OneToOneField(Place)

class ParkingLot3(Place):

    # The parent_link connector need not be the pk on the model.

    primary_key = models.AutoField(primary_key=True)

    parent = models.OneToOneField(Place, parent_link=True)

class Supplier(models.Model):

    restaurant = models.ForeignKey(Restaurant)

class Wholesaler(Supplier):

    retailer = models.ForeignKey(Supplier,related_name='wholesale_supplier')

class Parent(models.Model):

    created = models.DateTimeField(default=datetime.datetime.now)

class Child(Parent):

    name = models.CharField(max_length=10)

class SelfRefParent(models.Model):

    parent_data = models.IntegerField()

    self_data = models.ForeignKey('self', null=True)

class SelfRefChild(SelfRefParent):

    child_data = models.IntegerField()

class Article(models.Model):

    headline = models.CharField(max_length=100)

    pub_date = models.DateTimeField()

    class Meta:

        ordering = ('-pub_date', 'headline')

    def __unicode__(self):

        return self.headline

class ArticleWithAuthor(Article):

    author = models.CharField(max_length=100)

class M2MBase(models.Model):

    articles = models.ManyToManyField(Article)

class M2MChild(M2MBase):

    name = models.CharField(max_length=50)

class Evaluation(Article):

    quality = models.IntegerField()

    class Meta:

        abstract = True

class QualityControl(Evaluation):

    assignee = models.CharField(max_length=50)

class BaseM(models.Model):

    base_name = models.CharField(max_length=100)

    def __unicode__(self):

        return self.base_name

class DerivedM(BaseM):

    customPK = models.IntegerField(primary_key=True)

    derived_name = models.CharField(max_length=100)

    def __unicode__(self):

        return "PK = %d, base_name = %s, derived_name = %s" \

                % (self.customPK, self.base_name, self.derived_name)

class AuditBase(models.Model):

    planned_date = models.DateField()

    class Meta:

        abstract = True

        verbose_name_plural = u'Audits'

class CertificationAudit(AuditBase):

    class Meta(AuditBase.Meta):

        abstract = True

class InternalCertificationAudit(CertificationAudit):

    auditing_dept = models.CharField(max_length=20)

# Check that abstract classes don't get m2m tables autocreated.

class Person(models.Model):

    name = models.CharField(max_length=100)

    class Meta:

        ordering = ('name',)

    def __unicode__(self):

        return self.name

class AbstractEvent(models.Model):

    name = models.CharField(max_length=100)

    attendees = models.ManyToManyField(Person, related_name="%(class)s_set")

    class Meta:

        abstract = True

        ordering = ('name',)

    def __unicode__(self):

        return self.name

class BirthdayParty(AbstractEvent):

    pass

class BachelorParty(AbstractEvent):

    pass

class MessyBachelorParty(BachelorParty):

    pass