import re
from sqlalchemy.sql import functions as sql_functions

from fpcapture import config


def current_user(db_url=config.FPC_DB_URL):
    """Determines the value to use when setting created_by/updated_by columns
    on a model. SQLite does not support the CURRENT_USER var/function, so
    we need to use a stub value (which is a literal string) when using SQLite.

    Args:
        db_url (str): DB connection URL

    Return:
        str|sqlalchemy.sql.functions.current_user: current DB user
    """

    # DB is assumed to be MySQL if not SQLite
    if re.match('sqlite:\/\/', db_url):
        return 'test@localhost'
    return sql_functions.current_user()