import redis

from apistar import Component, Settings


class RedisBackend:
    def __init__(self, settings: Settings) -> None:
        """
        Configure a new redis backend

        Args:
            settings: The application settings dictionary

        """

        redis_config = settings['REDIS']
        self.host = redis_config.get('HOST')
        self.port = redis_config.get('PORT')
        self.password = redis_config.get('PASSWORD')

        # TODO add connection pooling


class Client:
    def __init__(self, backend: RedisBackend):
        self.backend = backend


def get_redis_client(backend: RedisBackend):
    """
    Create a new redis session

    """
    client = redis.Redis(host=backend.host,
                         port=backend.port,
                         password=backend.password)
    return client


components = [
    Component(RedisBackend),
    Component(Client, init=get_redis_client)
]