"""
10. One-to-one relationships

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

In this example, a ``Place`` optionally can be a ``Restaurant``.
"""
from __future__ import unicode_literals

from django.db import models
from django.utils.encoding import python_2_unicode_compatible


@python_2_unicode_compatible
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


@python_2_unicode_compatible
class Restaurant(models.Model):
    place = models.OneToOneField(Place, 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, null=True)


@python_2_unicode_compatible
class Waiter(models.Model):
    restaurant = models.ForeignKey(Restaurant)
    name = models.CharField(max_length=50)

    def __str__(self):
        return "%s the waiter at %s" % (self.name, self.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)
    name = models.CharField(max_length=50)


@python_2_unicode_compatible
class MultiModel(models.Model):
    link1 = models.OneToOneField(Place)
    link2 = models.OneToOneField(ManualPrimaryKey)
    name = models.CharField(max_length=50)

    def __str__(self):
        return "Multimodel %s" % self.name