import org.jsoup.Jsoup;
import org.jsoup.nodes.Document;
import org.jsoup.nodes.Element;
import org.jsoup.select.Elements;
import java.io.*;
import java.util.*;

public class SimpleCrawler {
    private static final String BASE_URL = "https://www.people.com.cn";
    private static final String 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";
    
    public static void main(String[] args) throws Exception {
        List<NewsItem> allNews = new ArrayList<>();
        
        System.out.println("正在爬取人民网新闻...");
        try {
            allNews.addAll(crawlNews(BASE_URL));
        } catch (Exception e) {
            System.out.println("爬取失败: " + e.getMessage());
        }
        
        Set<String> seen = new HashSet<>();
        List<NewsItem> uniqueNews = new ArrayList<>();
        for (NewsItem item : allNews) {
            String key = item.title + "|" + item.url;
            if (!seen.contains(key)) {
                seen.add(key);
                uniqueNews.add(item);
            }
        }
        
        Collections.sort(uniqueNews, (a, b) -> Integer.compare(b.hotRank, a.hotRank));
        
        int limit = Math.min(500, uniqueNews.size());
        List<NewsItem> topNews = uniqueNews.subList(0, limit);
        
        System.out.println("正在导出 " + topNews.size() + " 条新闻到CSV...");
        exportToCSV(topNews, "people_news_500.csv");
        
        System.out.println("完成！CSV文件已生成: people_news_500.csv");
    }
    
    private static List<NewsItem> crawlNews(String url) throws Exception {
        List<NewsItem> news = new ArrayList<>();
        int rank = 1;
        
        Document doc = Jsoup.connect(url)
                .userAgent(USER_AGENT)
                .timeout(30000)
                .get();
        
        Elements items = doc.select("a");
        for (Element item : items) {
            String title = item.text().trim();
            String itemUrl = item.attr("abs:href");
            
            if (isValidNews(title, itemUrl)) {
                String category = classifyNews(itemUrl);
                news.add(new NewsItem(title, itemUrl, category, rank++));
            }
        }
        return news;
    }
    
    private static boolean isValidNews(String title, String url) {
        if (title == null || title.isEmpty() || title.length() < 8) return false;
        if (url == null || url.isEmpty() || !url.startsWith("http")) return false;
        if (!url.contains("people.com.cn")) return false;
        
        String[] invalidKeywords = {"图片", "视频", "广告", "关于我们", "联系我们", "隐私政策", 
            "免责声明", "网站地图", "京ICP证", "许可证", "下载客户端", "人民日报社概况",
            "地方频道", "信息网络传播", "广播电视节目", "增值电信业务", "互联网新闻信息",
            "网络文化经营", "服务条款", "意见反馈", "设为首页", "加入收藏", "站内搜索"};
        
        for (String keyword : invalidKeywords) {
            if (title.contains(keyword)) return false;
        }
        
        String[] invalidPaths = {"/img/", "/GB/50142/", "/GB/1018/", "/GB/422044/", "/GB/408835/"};
        for (String path : invalidPaths) {
            if (url.contains(path)) return false;
        }
        
        return true;
    }
    
    private static String classifyNews(String url) {
        if (url.contains("/politics.") || url.contains("/cpc.")) {
            return "时政新闻";
        } else if (url.contains("/finance.") || url.contains("/economy.")) {
            return "财经新闻";
        } else if (url.contains("/health.")) {
            return "健康资讯";
        } else if (url.contains("/ent.") || url.contains("/sports.")) {
            return "文体娱乐";
        } else {
            return "热点资讯";
        }
    }
    
    private static void exportToCSV(List<NewsItem> news, String filename) throws Exception {
        try (BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(filename), "UTF-8"))) {
            writer.write("标题,链接,分类,热度排名");
            writer.newLine();
            for (NewsItem item : news) {
                writer.write(String.format("\"%s\",\"%s\",\"%s\",%d", 
                    item.title.replace("\"", "\"\""), 
                    item.url.replace("\"", "\"\""), 
                    item.category, 
                    item.hotRank));
                writer.newLine();
            }
        }
    }
    
    static class NewsItem {
        String title, url, category;
        int hotRank;
        NewsItem(String t, String u, String c, int r) { title = t; url = u; category = c; hotRank = r; }
    }
}