from django.conf import settings
from django.db import models

from .validators import LanguageValidator

class LanguageField(models.CharField):
    default_validators = [LanguageValidator()]

    def __init__(self, *args, **kwargs):
        kwargs.setdefault("max_length", 16)
        super().__init__(*args, **kwargs)

    def pre_save(self, model_instance, add):
        value = getattr(model_instance, self.attname, None)
        if value:
            value = value.lower()
            if "_" in value:
                lang, country = value.split("_")
                value = "_".join([lang, country.upper()])
            setattr(model_instance, self.attname, value)
            return value
        else:
            return super().pre_save(model_instance, add)