class User(AbstractUser):
    USERNAME_FIELD = 'email'

    def __str__(self):
        return f'{self.email}, #{self.id}'


class Subscription(models.Model):
    author_type = models.ForeignKey(ContentType, on_delete=models.CASCADE)
    author_id = models.PositiveIntegerField()
    author_object = GenericForeignKey('author_type', 'author_id')

    subscriber = models.ForeignKey(AUTH_USER_MODEL, related_name='subscriptions',
                                   on_delete=models.CASCADE)
    datetime_committed = models.DateTimeField(auto_now_add=True)

    class Meta:
        ordering = ['-datetime_committed']


class Notification(models.Model):
    content_type = models.ForeignKey(ContentType, on_delete=models.CASCADE)
    object_id = models.PositiveIntegerField()
    content_object = GenericForeignKey('content_type', 'object_id')

    creation_date_time = models.DateTimeField(auto_now_add=True)

    def __str__(self):
        return f'Оповещение о новом релизе {self.content_object.name}'

    class Meta:
        ordering = ['-creation_date_time']



class Artist(models.Model):
    name = models.CharField(max_length=256)
    spotify_id = models.CharField(max_length=256, unique=True)

    subscription = GenericRelation(Subscription, related_query_name='artist')

    def __str__(self):
        return f'{self.name}, #{self.pk}'


class Album(models.Model):
    album_types = (
        ('album', 'album'),
        ('single', 'single')
    )
    name = models.CharField(max_length=256)
    spotify_id = models.CharField(max_length=256, unique=True)
    release_date = models.DateField()

    notification = GenericRelation(Notification, related_query_name='album')

    def __str__(self):
        return f'{self.name}, #{self.pk}'

    class Meta:
        ordering = ['-release_date']