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",)

class Restaurant(Place):

    serves_hot_dogs = models.BooleanField(default=False)

    serves_pizza = models.BooleanField(default=False)

class ItalianRestaurant(Restaurant):

    serves_gnocchi = models.BooleanField(default=False)

class ParkingLot(Place):

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

    parent = models.OneToOneField(

        Place, models.CASCADE, primary_key=True, parent_link=True

    )

    capacity = models.IntegerField()

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, models.CASCADE, parent_link=True)

class ParkingLot4(models.Model):

    # Test parent_link connector can be discovered in abstract classes.

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

    class Meta:

        abstract = True

class ParkingLot4A(ParkingLot4, Place):

    pass

class ParkingLot4B(Place, ParkingLot4):

    pass

class Supplier(models.Model):

    name = models.CharField(max_length=50)

    restaurant = models.ForeignKey(Restaurant, models.CASCADE)

class Wholesaler(Supplier):

    retailer = models.ForeignKey(

        Supplier, models.CASCADE, 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", models.SET_NULL, 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")

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)

class DerivedM(BaseM):

    customPK = models.IntegerField(primary_key=True)

    derived_name = models.CharField(max_length=100)

class AuditBase(models.Model):

    planned_date = models.DateField()

    class Meta:

        abstract = True

        verbose_name_plural = "Audits"

class CertificationAudit(AuditBase):

    class Meta(AuditBase.Meta):

        abstract = True

class InternalCertificationAudit(CertificationAudit):

    auditing_dept = models.CharField(max_length=20)

# Abstract classes don't get m2m tables autocreated.

class Person(models.Model):

    name = models.CharField(max_length=100)

    class Meta:

        ordering = ("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",)

class BirthdayParty(AbstractEvent):

    pass

class BachelorParty(AbstractEvent):

    pass

class MessyBachelorParty(BachelorParty):

    pass

# Check concrete -> abstract -> concrete inheritance

class SearchableLocation(models.Model):

    keywords = models.CharField(max_length=255)

class Station(SearchableLocation):

    name = models.CharField(max_length=128)

    class Meta:

        abstract = True

class BusStation(Station):

    inbound = models.BooleanField(default=False)

class TrainStation(Station):

    zone = models.IntegerField()

class User(models.Model):

    username = models.CharField(max_length=30, unique=True)

class Profile(User):

    profile_id = models.AutoField(primary_key=True)

    extra = models.CharField(max_length=30, blank=True)

# Check concrete + concrete -> concrete -> concrete

class Politician(models.Model):

    politician_id = models.AutoField(primary_key=True)

    title = models.CharField(max_length=50)

class Congressman(Person, Politician):

    state = models.CharField(max_length=2)

class Senator(Congressman):

    pass