from django.db import models
from django.utils.crypto import get_random_string

try:
    from django_scopes import scopes_disabled
except ImportError:
    scopes_disabled = False
    

class RandomSlugMixin(models.Model):
    """
    some alternatives for slug_chars:
    abcdeghjkpqrsxyz23456789  # 24 chars, max clarity while being all lowercase
    ABCDGHKLMNQRTabcdeghjr23456789  # 30 chars, max clarity mixed case
    abcdefghijkmnpqrstuwxyz123467890  # 32 chars, all lowercase
    """
    slug_chars = 'abcdefghijkmnpqrstuwxyz123467890'

    class Meta:
        abstract = True

    slug = models.CharField(max_length=6, unique=True)

    def save(self, **kwargs):
        self.generate_slug()
        super().save(**kwargs)

    def generate_slug(self):
        if not self.slug:
            self.slug = self.generate_new_slug()

    def generate_new_slug(self):
        slug = get_random_string(self.slug_length, self.slug_chars)
        if self.__class__.objects.filter(slug=slug).exists():
            return self.generate_new_slug()
        return slug

    @property
    def slugs_available(self):
        return self.slug_count_total - self.__class__.objects.count()

    @property
    def slug_count_total(self):
        return len(self.slug_chars) ** self.slug_length

    @property
    def slug_length(self):
        return self.__class__._meta.get_field('slug').max_length

    if scopes_disabled:
        generate_new_slug = scopes_disabled(generate_new_slug)
        slugs_available = scopes_disabled(slugs_available)


class RandomSlugPKMixin(RandomSlugMixin):
    slug = models.CharField(max_length=6, unique=True, primary_key=True)

    class Meta:
        abstract = True