from functools import lru_cache

from redis import Redis
from redis.asyncio import Redis as AsyncRedis
from redis.asyncio.sentinel import Sentinel as AsyncSentinel
from redis.sentinel import Sentinel

from alien_gateway.config import settings


def _sentinel_kwargs() -> dict:
    return settings.REDIS_SENTINEL_KWARGS


def _redis_connection_kwargs() -> dict:
    return {
        "password": settings.REDIS_PASSWORD or None,
        "db": settings.REDIS_DB,
        "socket_timeout": settings.REDIS_SOCKET_TIMEOUT,
        "socket_connect_timeout": settings.REDIS_CONNECT_TIMEOUT,
        "retry_on_timeout": True,
        "decode_responses": True,
    }


def _ensure_sentinel_nodes() -> None:
    if not settings.REDIS_SENTINEL_NODES:
        raise RuntimeError("REDIS_SENTINELS 未配置，无法通过 Sentinel 连接 Redis。")


@lru_cache(maxsize=1)
def get_sentinel_client() -> Sentinel:
    _ensure_sentinel_nodes()
    return Sentinel(
        settings.REDIS_SENTINEL_NODES,
        socket_timeout=settings.REDIS_SOCKET_TIMEOUT,
        socket_connect_timeout=settings.REDIS_CONNECT_TIMEOUT,
        sentinel_kwargs=_sentinel_kwargs(),
    )


@lru_cache(maxsize=1)
def get_async_sentinel_client() -> AsyncSentinel:
    _ensure_sentinel_nodes()
    return AsyncSentinel(
        settings.REDIS_SENTINEL_NODES,
        socket_timeout=settings.REDIS_SOCKET_TIMEOUT,
        socket_connect_timeout=settings.REDIS_CONNECT_TIMEOUT,
        sentinel_kwargs=_sentinel_kwargs(),
    )


def get_redis_master() -> Redis:
    return get_sentinel_client().master_for(
        service_name=settings.REDIS_MASTER_NAME,
        **_redis_connection_kwargs(),
    )


def get_redis_slave() -> Redis:
    return get_sentinel_client().slave_for(
        service_name=settings.REDIS_MASTER_NAME,
        **_redis_connection_kwargs(),
    )


def get_async_redis_master() -> AsyncRedis:
    return get_async_sentinel_client().master_for(
        service_name=settings.REDIS_MASTER_NAME,
        **_redis_connection_kwargs(),
    )


def get_async_redis_slave() -> AsyncRedis:
    return get_async_sentinel_client().slave_for(
        service_name=settings.REDIS_MASTER_NAME,
        **_redis_connection_kwargs(),
    )


def get_redis() -> Redis:
    # 默认返回主节点客户端，统一写入入口
    return get_redis_master()


def get_async_redis() -> AsyncRedis:
    # 默认返回主节点客户端，统一写入入口
    return get_async_redis_master()


def check_redis_connection() -> dict:
    """
    通过 Sentinel 获取当前主节点并执行 ping，返回连接状态与主节点地址。
    """
    sentinel = get_sentinel_client()
    redis_client = get_redis_master()
    pong = redis_client.ping()
    host, port = sentinel.discover_master(settings.REDIS_MASTER_NAME)
    return {
        "ok": bool(pong),
        "master_name": settings.REDIS_MASTER_NAME,
        "master_host": host,
        "master_port": port,
        "db": settings.REDIS_DB,
    }