from enum import Enum, auto
from typing import Dict, Any, Callable, List
import threading


class EventType(Enum):
    """事件类型枚举"""
    SYSTEM_STARTUP = auto()
    SYSTEM_SHUTDOWN = auto()
    PLUGIN_LOADED = auto()
    PLUGIN_UNLOADED = auto()
    MESSAGE_RECEIVED = auto()
    MESSAGE_PROCESSED = auto()
    CUSTOM_EVENT = auto()


class EventSystem:
    """事件系统，用于插件间通信"""
    _instance = None
    _lock = threading.Lock()
    
    def __new__(cls):
        with cls._lock:
            if cls._instance is None:
                cls._instance = super(EventSystem, cls).__new__(cls)
                cls._instance._subscribers = {}
                cls._instance._initialized = False
            return cls._instance
    
    def __init__(self):
        if not self._initialized:
            self._subscribers = {}
            self._initialized = True
    
    def subscribe(self, event_type: EventType, callback: Callable[[Dict[str, Any]], None]) -> None:
        """
        订阅事件
        
        Args:
            event_type: 事件类型
            callback: 回调函数，接收事件数据
        """
        if event_type not in self._subscribers:
            self._subscribers[event_type] = []
        
        if callback not in self._subscribers[event_type]:
            self._subscribers[event_type].append(callback)
    
    def unsubscribe(self, event_type: EventType, callback: Callable[[Dict[str, Any]], None]) -> None:
        """
        取消订阅事件
        
        Args:
            event_type: 事件类型
            callback: 回调函数
        """
        if event_type in self._subscribers and callback in self._subscribers[event_type]:
            self._subscribers[event_type].remove(callback)
    
    def publish(self, event_type: EventType, data: Dict[str, Any]) -> None:
        """
        发布事件
        
        Args:
            event_type: 事件类型
            data: 事件数据
        """
        if event_type in self._subscribers:
            for callback in self._subscribers[event_type]:
                try:
                    callback(data)
                except Exception as e:
                    print(f"事件处理错误: {e}")
    
    def get_subscribers(self, event_type: EventType) -> List[Callable]:
        """
        获取事件订阅者
        
        Args:
            event_type: 事件类型
            
        Returns:
            订阅者列表
        """
        return self._subscribers.get(event_type, [])