from django.db import models
from django.core.cache import cache
from django.forms.models import model_to_dict


class SingletonModel(models.Model):
    class Meta:
        abstract = True

    def save(self, *args, **kwargs):
        cache_key = f'{self._meta.model_name}_singleton_key'
        self.pk = 1
        super(SingletonModel, self).save(*args, **kwargs)

        # Reset cache
        data = model_to_dict(self)
        cache.set(cache_key, data, 60 * 60 * 24)

    def delete(self, *args, **kwargs):
        pass

    @classmethod
    def load(cls):
        cache_key = f'{cls._meta.model_name}_singleton_key'
        data = cache.get(cache_key)
        if not data:
            instance, created = cls.objects.get_or_create(pk=1)
            data = model_to_dict(instance)
            cache.set(cache_key, data, 60 * 60 * 24)
        return cls(**data)