from abc import ABC, abstractmethod
from typing import Dict, Any, Optional
from datetime import datetime, timedelta

class BaseService(ABC):
    """基础服务类，为扩展提供统一接口"""
    
    def __init__(self):
        self.cache = {}
        self.cache_timeout = timedelta(seconds=30)
    
    @abstractmethod
    def get_data(self, **kwargs) -> Optional[Dict[str, Any]]:
        """获取数据的抽象方法"""
        pass
    
    def get_cached_data(self, cache_key: str, **kwargs) -> Optional[Dict[str, Any]]:
        """带缓存的数据获取"""
        # 检查缓存
        if cache_key in self.cache:
            cached_item = self.cache[cache_key]
            if datetime.now() - cached_item['timestamp'] < self.cache_timeout:
                return cached_item['data']
        
        # 获取新数据
        data = self.get_data(**kwargs)
        if data:
            # 更新缓存
            self.cache[cache_key] = {
                'data': data,
                'timestamp': datetime.now()
            }
        
        return data
    
    def clear_cache(self):
        """清理缓存"""
        self.cache.clear()