import asyncio
import logging
from typing import Callable, Dict, List, Any, Awaitable

logger = logging.getLogger("cs_agent")

class AsyncEventBus:
    """
    异步事件总线：解耦业务触发与平台发送。
    支持一个事件被多个订阅者监听。
    """
    def __init__(self):
        self._listeners: Dict[str, List[Callable[..., Awaitable[None]]]] = {}

    def subscribe(self, event_type: str, callback: Callable[..., Awaitable[None]]):
        """订阅事件"""
        if event_type not in self._listeners:
            self._listeners[event_type] = []
        self._listeners[event_type].append(callback)
        logger.info(f"[EventBus] 新订阅者已注册到事件: {event_type}")

    async def emit(self, event_type: str, **kwargs):
        """发布事件：异步广播给所有订阅者"""
        if event_type not in self._listeners:
            return

        tasks = []
        for callback in self._listeners[event_type]:
            tasks.append(asyncio.create_task(callback(**kwargs)))
        
        if tasks:
            results = await asyncio.gather(*tasks, return_exceptions=True)
            for i, r in enumerate(results):
                if isinstance(r, Exception):
                    logger.error(f"[EventBus] 事件 {event_type} 订阅者 {i} 异常: {r}")
            logger.info(f"[EventBus] 事件 {event_type} 已广播给 {len(tasks)} 个订阅者")

# 全局单例，所有模块共用这一个广播台
bus = AsyncEventBus()