from django.core.exceptions import ValidationError
from django.utils.translation import gettext as _


class LettersAndDigitsValidator:

    def validate(self, password, user=None):
        vals = {
            'Password must contain an uppercase letter.': lambda s: any(x.isupper() for x in s),
            'Password must contain a lowercase letter.': lambda s: any(x.islower() for x in s),
            'Password must contain a digit.': lambda s: any(x.isdigit() for x in s),
            'Password cannot contain white spaces.': lambda s: not any(x.isspace() for x in s)
        }
        valid = None
        for n, val in vals.items():
            if not val(password):
                valid = False
                raise ValidationError(n)
        return valid

    def get_help_text(self):
        return _(
            "Your password must contain an uppercase letter, a lowercase letter, and a digit"
        )