import redis.asyncio as redis
from ..config_loader import global_config as config
from ..utils.logger import logger
from ..utils.singleton import Singleton

class RedisManager(Singleton):
    """
    Redis 连接管理器（异步单例）
    """
    _redis = None

    def __init__(self):
        """
        初始化 Redis 管理器
        """
        # 调用父类 __init__ 确保单例初始化
        super().__init__()

    async def initialize(self):
        """
        异步初始化 Redis 连接并进行健康检查
        """
        if self._redis is None:
            try:
                redis_config = config.redis
                host = redis_config.host
                port = redis_config.port
                db = redis_config.db
                password = redis_config.password
                
                logger.info(f"正在尝试连接 Redis: {host}:{port}, DB: {db}")

                self._redis = redis.Redis(
                    host=host,
                    port=port,
                    db=db,
                    password=password,
                    decode_responses=True,
                    ssl=False
                )
                if await self._redis.ping():
                    logger.success("Redis 连接成功！")
                else:
                    logger.error("Redis 连接失败: PING 命令无响应")
            except Exception as e:
                logger.exception(f"Redis 初始化时发生未知错误: {e}")
                self._redis = None

    @property
    def redis(self):
        """
        获取 Redis 连接实例
        """
        if self._redis is None:
            raise ConnectionError("Redis 未初始化或连接失败，请先调用 initialize()")
        return self._redis

    async def get(self, name):
        """
        获取指定键的值
        """
        return await self.redis.get(name)

    async def set(self, name, value, ex=None):
        """
        设置指定键的值
        """
        return await self.redis.set(name, value, ex=ex)

    async def execute_lua_script(self, script: str, keys: list, args: list):
        """
        以原子方式执行 Lua 脚本

        Args:
            script (str): 要执行的 Lua 脚本字符串
            keys (list): 脚本中使用的 Redis 键 (KEYS[1], KEYS[2], ...)
            args (list): 传递给脚本的参数 (ARGV[1], ARGV[2], ...)

        Returns:
            Any: 脚本的返回值
        """
        try:
            # redis-py 内部会自动处理脚本的缓存 (EVAL/EVALSHA)
            lua_script = self.redis.register_script(script)
            return await lua_script(keys=keys, args=args)
        except Exception as e:
            logger.error(f"执行 Lua 脚本失败: {e}")
            logger.debug(f"脚本内容: {script}")
            raise


# 全局 Redis 管理器实例
redis_manager = RedisManager()