from marshmallow import fields, ValidationError
from marshmallow import validate


class EmailOrEmailsListField(fields.List):
    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self._email_validator = validate.Email(
            error="Not a valid email address: {input}"
        )

    def _deserialize(self, value, attr, data, **kwargs):
        if isinstance(value, str):
            if not value:
                ValidationError("Field should not be empty")
            self._email_validator(value)
            return value
        elif isinstance(value, list):
            if not value:
                ValidationError("Field should not be empty")
            for item in value:
                self._email_validator(item)
            return value
        else:
            raise ValidationError("Field should be email or list of emails")