#!/usr/bin/env python3
# -*- coding: utf-8 -*-

"""
爬虫基类
"""

import logging
from abc import ABC, abstractmethod
from typing import List, Optional
import aiohttp
import asyncio

from ..models import HotTopic, HotTopicSource

logger = logging.getLogger(__name__)


class BaseCrawler(ABC):
    """爬虫基类"""
    
    source: HotTopicSource = HotTopicSource.CUSTOM
    name: str = "基础爬虫"
    
    def __init__(self):
        self.logger = logging.getLogger(f"{__name__}.{self.__class__.__name__}")
        self._session: Optional[aiohttp.ClientSession] = None
    
    @abstractmethod
    async def fetch(self) -> List[HotTopic]:
        """
        获取热点列表
        
        Returns:
            热点话题列表
        """
        pass
    
    async def fetch_with_retry(self, max_retries: int = 3) -> List[HotTopic]:
        """带重试的获取"""
        for attempt in range(max_retries):
            try:
                return await self.fetch()
            except Exception as e:
                self.logger.warning(f"获取失败 (尝试 {attempt + 1}/{max_retries}): {e}")
                if attempt < max_retries - 1:
                    await asyncio.sleep(2 ** attempt)  # 指数退避
        
        self.logger.error(f"{self.name} 获取失败，已达最大重试次数")
        return []
    
    async def _get_session(self) -> aiohttp.ClientSession:
        """获取 HTTP 会话"""
        if self._session is None or self._session.closed:
            self._session = aiohttp.ClientSession(
                headers=self._get_default_headers(),
                timeout=aiohttp.ClientTimeout(total=30)
            )
        return self._session
    
    async def close(self):
        """关闭会话"""
        if self._session and not self._session.closed:
            await self._session.close()
    
    def _get_default_headers(self) -> dict:
        """获取默认请求头"""
        return {
            'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36',
            'Accept': 'text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8',
            'Accept-Language': 'zh-CN,zh;q=0.9,en;q=0.8',
        }
    
    async def __aenter__(self):
        return self
    
    async def __aexit__(self, exc_type, exc_val, exc_tb):
        await self.close()