"""
37. Fixtures.

Fixtures are a way of loading data into the database in bulk. Fixure data
can be stored in any serializable format (including JSON and XML). Fixtures
are identified by name, and are stored in either a directory named 'fixtures'
in the application directory, on in one of the directories named in the
``FIXTURE_DIRS`` setting.
"""

from django.contrib.auth.models import Permission
from django.contrib.contenttypes import generic
from django.contrib.contenttypes.models import ContentType
from django.db import models, DEFAULT_DB_ALIAS
from django.conf import settings


class Category(models.Model):
    title = models.CharField(max_length=100)
    description = models.TextField()

    def __unicode__(self):
        return self.title

    class Meta:
        ordering = ('title',)

class Article(models.Model):
    headline = models.CharField(max_length=100, default='Default headline')
    pub_date = models.DateTimeField()

    def __unicode__(self):
        return self.headline

    class Meta:
        ordering = ('-pub_date', 'headline')

class Blog(models.Model):
    name = models.CharField(max_length=100)
    featured = models.ForeignKey(Article, related_name='fixtures_featured_set')
    articles = models.ManyToManyField(Article, blank=True,
                                      related_name='fixtures_articles_set')

    def __unicode__(self):
        return self.name


class Tag(models.Model):
    name = models.CharField(max_length=100)
    tagged_type = models.ForeignKey(ContentType, related_name="fixtures_tag_set")
    tagged_id = models.PositiveIntegerField(default=0)
    tagged = generic.GenericForeignKey(ct_field='tagged_type',
                                       fk_field='tagged_id')

    def __unicode__(self):
        return '<%s: %s> tagged "%s"' % (self.tagged.__class__.__name__,
                                         self.tagged, self.name)

class PersonManager(models.Manager):
    def get_by_natural_key(self, name):
        return self.get(name=name)

class Person(models.Model):
    objects = PersonManager()
    name = models.CharField(max_length=100)
    def __unicode__(self):
        return self.name

    class Meta:
        ordering = ('name',)

    def natural_key(self):
        return (self.name,)

class Visa(models.Model):
    person = models.ForeignKey(Person)
    permissions = models.ManyToManyField(Permission, blank=True)

    def __unicode__(self):
        return '%s %s' % (self.person.name,
                          ', '.join(p.name for p in self.permissions.all()))

class Book(models.Model):
    name = models.CharField(max_length=100)
    authors = models.ManyToManyField(Person)

    def __unicode__(self):
        return '%s by %s' % (self.name,
                          ' and '.join(a.name for a in self.authors.all()))

    class Meta:
        ordering = ('name',)
