"""通用 HTTP 爬虫基类 - 为基于 HTTP 请求的插件提供封装"""
import random
import asyncio
import httpx
from typing import List
from app.core.plugin_system import BaseCrawlerPlugin


class BaseHTTPPlugin(BaseCrawlerPlugin):
    """基于 HTTP 的爬虫插件基类"""

    def __init__(self):
        super().__init__()
        self.user_agents = [
            "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36",
            "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/119.0.0.0 Safari/537.36",
            "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/118.0.0.0 Safari/537.36",
            "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:109.0) Gecko/20100101 Firefox/121.0",
        ]
        self.urls: List[str] = []
        self.current_url: str = ""

    def get_headers(self) -> dict:
        return {
            "User-Agent": random.choice(self.user_agents),
            "Accept": "text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8",
            "Accept-Language": "zh-CN,zh;q=0.8,zh-TW;q=0.7,zh-HK;q=0.5,en-US;q=0.3,en;q=0.2",
            "Connection": "keep-alive",
        }

    async def fetch(self, url: str, timeout: float = 15.0, retries: int = 2) -> str:
        """异步抓取指定 URL 的 HTML 内容"""
        from app.core.log import logger
        headers = self.get_headers()
        transport = httpx.AsyncHTTPTransport(retries=0)
        for attempt in range(retries):
            async with httpx.AsyncClient(headers=headers, transport=transport, follow_redirects=True) as client:
                try:
                    response = await client.get(url, timeout=timeout)
                    if response.status_code == 200:
                        content = response.content
                        encoding = response.encoding
                        if encoding == "utf-8" or not encoding:
                            try:
                                return content.decode("utf-8")
                            except UnicodeDecodeError:
                                return content.decode("gbk", errors="ignore")
                        return content.decode(encoding, errors="ignore")
                    else:
                        logger.warning(f"Fetch {url} returned status {response.status_code}")
                except Exception as e:
                    logger.warning(f"Fetch {url} failed (attempt {attempt + 1}/{retries}): {e}")
                if attempt < retries - 1:
                    await asyncio.sleep(random.uniform(1, 3))
        return ""

    async def fetch_all(self, urls: List[str], timeout: float = 15.0) -> List[str]:
        """并发抓取多个 URL，限制单个插件内部并发为 3"""
        semaphore = asyncio.Semaphore(3)

        async def _fetch_limited(url: str):
            async with semaphore:
                return await self.fetch(url, timeout=timeout)

        tasks = [_fetch_limited(url) for url in urls]
        return await asyncio.gather(*tasks)