import redis
from redis.lock import Lock

from config import Config

config = Config()


def get_redis_client(host: str or None, port: str) -> None or redis.client:
    if not host:
        return
    return redis.StrictRedis(config.REDIS_HOST, config.REDIS_PORT)


redis_client = get_redis_client(config.REDIS_HOST, config.REDIS_PORT)


def get_key(key: str) -> str:
    """Compose a Redis key.
    Args:
        key (str): Key.
    Returns:
        str: Complete key constructed by concatenated prefix + key.
    """
    return f"{config.APP_NAME}/{key}"


def get_redis_lock() -> Lock or None:
    """Get redis lock
    Returns:
        Lock or None: Redis lock.
    """

    if not redis_client:
        return
    return redis_client.lock(get_key("lock"), timeout=config.REDIS_LOCK_TTL)