#!/usr/bin/env python3
"""
网络搜索模块

有两种模式：
1. Bing Web Search API（优先）：需设置环境变量 BING_API_KEY
2. 网页搜索回退：从 cn.bing.com 抓取，但服务器环境常反爬拦截

当搜索不可用时，返回空列表。采集器已处理此情况——LLM 直接生成选题。
"""
import logging, os, re
from typing import List, Dict, Optional
from urllib.parse import quote_plus
import requests

logger = logging.getLogger(__name__)

UA = "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/126.0.0.0 Safari/537.36"

BING_API_KEY = os.getenv("BING_API_KEY", "")


def search_api(query: str, max_results: int = 5) -> List[Dict]:
    """Bing Web Search API（需要 BING_API_KEY 环境变量）"""
    if not BING_API_KEY:
        return []
    try:
        resp = requests.get(
            "https://api.bing.microsoft.com/v7.0/search",
            params={"q": query, "count": max_results, "mkt": "zh-CN"},
            headers={"Ocp-Apim-Subscription-Key": BING_API_KEY},
            timeout=10
        )
        if resp.status_code != 200:
            logger.warning(f"Bing API 返回 {resp.status_code}")
            return []
        data = resp.json()
        results = []
        for item in data.get("webPages", {}).get("value", [])[:max_results]:
            results.append({
                "title": item.get("name", "")[:120],
                "url": item.get("url", ""),
                "content": item.get("snippet", "")[:300],
                "source": "bing_api"
            })
        logger.info(f"Bing API '{query[:20]}': {len(results)} 条")
        return results
    except Exception as e:
        logger.warning(f"Bing API 失败: {e}")
        return []


def search_scrape(query: str, max_results: int = 5) -> List[Dict]:
    """从 cn.bing.com 抓取搜索结果（服务器环境常遭受反爬，返回空为正常）"""
    try:
        resp = requests.get(
            "https://cn.bing.com/search",
            params={"q": query, "setlang": "zh-cn", "cc": "cn", "count": "15"},
            headers={"User-Agent": UA, "Accept-Language": "zh-CN,zh;q=0.9"},
            timeout=15
        )
        if resp.status_code != 200:
            return []

        html = resp.text
        results = []
        seen = set()

        for m in re.finditer(
            r'<li[^>]*class="[^"]*b_algo[^"]*"[^>]*>.*?<a[^>]*href="([^"]*)"[^>]*>(.*?)</a>',
            html, re.DOTALL
        ):
            href, title_raw = m.group(1), m.group(2)
            title = re.sub(r'<[^>]+>', '', title_raw).strip()
            if not title or len(title) < 8 or href in seen:
                continue
            if re.search(r'(bing\.com|microsoft\.com|beian\.miit|beian\.mps)', href, re.I):
                continue
            if re.search(r'(zdic|hanyu|hancibao|chengyu|dict\.|iciba|bishun)', href, re.I):
                continue
            if len(title) <= 5:
                continue
            seen.add(href)
            results.append({"title": title[:120], "url": href, "content": "", "source": "bing"})
            if len(results) >= max_results:
                break

        return results
    except Exception as e:
        logger.warning(f"Bing 抓取失败: {e}")
        return []


def search(query: str, max_results: int = 5) -> List[Dict]:
    """统一搜索接口：API 优先 → 网页抓取回退"""
    if BING_API_KEY:
        results = search_api(query, max_results)
        if results:
            return results

    results = search_scrape(query, max_results)
    if results:
        return results

    logger.info(f"搜索 '{query[:20]}' 无结果（服务器环境限制，不影响采集器正常运行）")
    return []