import redis

from smelog.factory import BoundLogger


def init_redis(host: str, port: int, logger: BoundLogger) -> redis.Redis or None:
    """Init redis client connection.
    Args:
        host (str): Redis server host.
        port (int): Redis server port.
        logger (logging.Logger): Logging object.
    Returns:
        redis.Redis or None: Redis client instance or None if smth goes wrong.
    """
    try:
        redis_client = redis.StrictRedis(host, port)
    except Exception as e:
        redis_client = None
        logger.warning("Redis is not initialized!")
        logger.warning(f"Redis: {e}")

    return redis_client


def get_version_key(os: str, prefix: str) -> str:
    """Compose a Redis key.
    Args:
        os (str): os key.
        prefix (str): Config object.
    Returns:
        str: Complete key constructed by concatenated prefix + key.
    """
    return f"{prefix}/{os}"