"""Redis缓存客户端"""
import json
import redis.asyncio as aioredis
from app.core.config import settings
from app.core.logger import logger

_redis_client = None


async def get_redis() -> aioredis.Redis:
    global _redis_client
    if _redis_client is None:
        _redis_client = aioredis.from_url(
            f"redis://{settings.REDIS_HOST}:{settings.REDIS_PORT}",
            encoding="utf-8",
            decode_responses=True,
        )
    return _redis_client


# Session键前缀
SESSION_PREFIX = "session:"
LOCK_PREFIX = "lock:"
RATE_PREFIX = "rate:"


async def set_session(user_id: int, session_data: dict, expire: int = 86400):
    """存储用户会话"""
    r = await get_redis()
    key = f"{SESSION_PREFIX}{user_id}"
    await r.setex(key, expire, json.dumps(session_data, ensure_ascii=False))


async def get_session(user_id: int) -> dict | None:
    """获取用户会话"""
    r = await get_redis()
    key = f"{SESSION_PREFIX}{user_id}"
    data = await r.get(key)
    if data:
        return json.loads(data)
    return None


async def delete_session(user_id: int):
    """删除用户会话"""
    r = await get_redis()
    key = f"{SESSION_PREFIX}{user_id}"
    await r.delete(key)


async def acquire_lock(name: str, expire: int = 60) -> bool:
    """获取分布式锁"""
    r = await get_redis()
    key = f"{LOCK_PREFIX}{name}"
    result = await r.set(key, "1", nx=True, ex=expire)
    return result is True


async def release_lock(name: str):
    """释放分布式锁"""
    r = await get_redis()
    key = f"{LOCK_PREFIX}{name}"
    await r.delete(key)


async def incr_rate(key: str, expire: int = 86400) -> int:
    """限流计数"""
    r = await get_redis()
    rate_key = f"{RATE_PREFIX}{key}"
    count = await r.incr(rate_key)
    if count == 1:
        await r.expire(rate_key, expire)
    return count


async def get_counter(key: str) -> int:
    """获取计数"""
    r = await get_redis()
    rate_key = f"{RATE_PREFIX}{key}"
    val = await r.get(rate_key)
    return int(val) if val else 0