import redis
from redis.lock import Lock

from spotify_charts_notifications.constants import APP_NAME, REDIS_KEY_TTL, REDIS_LOCK_TTL


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'{APP_NAME}/{key}'


def get_redis_lock(redis_client: redis.StrictRedis) -> Lock:
    """Get redis lock"""
    return redis_client.lock(get_key('lock'), timeout=REDIS_LOCK_TTL)


def remove_old_keys(
        redis_client: redis.Redis, current_date: str, market: str) -> None:
    """Remove old keys from redis

    Args:
        redis_client: Redis Client
        current_date: Date with %Y-%m-%d format.
        market: Market short name.
    """
    keys = redis_client.keys(get_key('*'))
    keys_to_remove = []

    for key in keys:
        try:
            key_market, key_date = key.decode().split('/')[1:3]
        except (ValueError, IndexError):
            continue

        if key_market == market and key_date != current_date:
            keys_to_remove.append(key)

    if keys_to_remove:
        redis_client.delete(*keys_to_remove)


def is_new_track(
        date: str, label: str, market: str, user_id: str, track_id: str, redis_client: redis.StrictRedis
) -> bool:
    """Checking is track new or we have already fetched it today

    Args:
        date: Date with %Y-%m-%d format.
        label: One of added, dropped, moves.
        market: Market short name.
        user_id: User ID.
        track_id: Song ID.
        redis_client: Redis client.
    Returns:
        Boolean
    """

    remove_old_keys(redis_client, date, market)
    redis_key = get_key(f'{market}/{date}/{user_id}/{label}')
    if redis_client.sismember(redis_key, track_id):
        return False

    redis_client.sadd(redis_key, track_id)
    redis_client.expire(redis_key, REDIS_KEY_TTL)
    return True