"""
Redis sliding window rate limiter.
"""
import time
from redis.asyncio import Redis


async def is_rate_limited(
    redis: Redis,
    key: str,
    limit: int,
    window_seconds: int = 60,
) -> tuple[bool, int]:
    """
    Returns (is_limited, requests_remaining).
    Uses a sorted set with timestamps as scores for sliding window.
    """
    now = time.time()
    window_start = now - window_seconds
    pipe = redis.pipeline()
    pipe.zremrangebyscore(key, 0, window_start)
    pipe.zadd(key, {str(now): now})
    pipe.zcard(key)
    pipe.expire(key, window_seconds + 1)
    results = await pipe.execute()
    count = results[2]
    remaining = max(0, limit - count)
    return count > limit, remaining