"""

One-to-one relationships

To define a one-to-one relationship, use ``OneToOneField()``.

In this example, a ``Place`` optionally can be a ``Restaurant``.

"""

from django.db import models

class Place(models.Model):

    name = models.CharField(max_length=50)

    address = models.CharField(max_length=80)

    def __str__(self):

        return "%s the place" % self.name

class Restaurant(models.Model):

    place = models.OneToOneField(Place, models.CASCADE, primary_key=True)

    serves_hot_dogs = models.BooleanField(default=False)

    serves_pizza = models.BooleanField(default=False)

    def __str__(self):

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

class Bar(models.Model):

    place = models.OneToOneField(Place, models.CASCADE)

    serves_cocktails = models.BooleanField(default=True)

class UndergroundBar(models.Model):

    place = models.OneToOneField(Place, models.SET_NULL, null=True)

    serves_cocktails = models.BooleanField(default=True)

class Waiter(models.Model):

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

    name = models.CharField(max_length=50)

    def __str__(self):

        return "%s the waiter at %s" % (self.name, self.restaurant)

class Favorites(models.Model):

    name = models.CharField(max_length=50)

    restaurants = models.ManyToManyField(Restaurant)

class ManualPrimaryKey(models.Model):

    primary_key = models.CharField(max_length=10, primary_key=True)

    name = models.CharField(max_length=50)

class RelatedModel(models.Model):

    link = models.OneToOneField(ManualPrimaryKey, models.CASCADE)

    name = models.CharField(max_length=50)

class MultiModel(models.Model):

    link1 = models.OneToOneField(Place, models.CASCADE)

    link2 = models.OneToOneField(ManualPrimaryKey, models.CASCADE)

    name = models.CharField(max_length=50)

    def __str__(self):

        return "Multimodel %s" % self.name

class Target(models.Model):

    name = models.CharField(max_length=50, unique=True)

class Pointer(models.Model):

    other = models.OneToOneField(Target, models.CASCADE, primary_key=True)

class Pointer2(models.Model):

    other = models.OneToOneField(Target, models.CASCADE, related_name="second_pointer")

class HiddenPointer(models.Model):

    target = models.OneToOneField(Target, models.CASCADE, related_name="hidden+")

class ToFieldPointer(models.Model):

    target = models.OneToOneField(

        Target, models.CASCADE, to_field="name", primary_key=True

    )

# Test related objects visibility.

class SchoolManager(models.Manager):

    def get_queryset(self):

        return super().get_queryset().filter(is_public=True)

class School(models.Model):

    is_public = models.BooleanField(default=False)

    objects = SchoolManager()

class DirectorManager(models.Manager):

    def get_queryset(self):

        return super().get_queryset().filter(is_temp=False)

class Director(models.Model):

    is_temp = models.BooleanField(default=False)

    school = models.OneToOneField(School, models.CASCADE)

    objects = DirectorManager()