class BaseMedia(models.Model):
    title = models.CharField(max_length=100)
    description = models.TextField()
    genre = models.CharField(max_length=50)
    created_at = models.DateTimeField(auto_now_add=True)
    
    class Meta:
        abstract= True
        ordering = ["-created_at", "title"]
        
        
class Book(BaseMedia):
    author = models.CharField(max_length=100, validators=[MinLengthValidator(5, message="Author must be at least 5 characters long")])
    isbn = models.CharField(max_length=20, unique=True, validators=[MinLengthValidator(6, message="ISBN must be at least 6 characters long")])
    
    class Meta(BaseMedia.Meta):
        verbose_name = "Model Book"
        verbose_name_plural = "Models of type - Book"
    
class Movie(BaseMedia):
    director = models.CharField(max_length=100, validators=[MinLengthValidator(8, message="Director must be at least 8 characters long")])
    
    class Meta(BaseMedia.Meta):
        verbose_name = "Model Movie"
        verbose_name_plural = "Models of type - Movie"
    
    
class Music(BaseMedia):
    artist = models.CharField(max_length=100, validators=[MinLengthValidator(9, message="Artist must be at least 9 characters long")])
    
    class Meta(BaseMedia.Meta):
        verbose_name = "Model Music"
        verbose_name_plural = "Models of type - Music "