package com.crawler.crawler.impl;

import com.crawler.crawler.BaseCrawler;
import com.crawler.model.CrawlerData;

import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class HunanUniversityNewsCrawler extends BaseCrawler {
    private static final String BASE_URL = "https://news.hnu.edu.cn";

    @Override
    public String getCrawlerName() {
        return "HunanUniversityNewsCrawler";
    }

    @Override
    protected List<CrawlerData> parseHtml(String html) {
        List<CrawlerData> results = new ArrayList<>();
        Set<String> seenUrls = new HashSet<>();
        
        if (html == null || html.isEmpty()) {
            return results;
        }
        
        Pattern linkPattern = Pattern.compile(
            "<a\\s+[^>]*href\\s*=\\s*[\"']([^\"']+)[\"'][^>]*>([^<]+)</a>",
            Pattern.CASE_INSENSITIVE
        );
        
        Matcher matcher = linkPattern.matcher(html);
        
        while (matcher.find() && results.size() < 30) {
            String url = matcher.group(1);
            String title = matcher.group(2).trim();
            
            if (isValidUrl(url) && isValidTitle(title) && !seenUrls.contains(url)) {
                url = normalizeUrl(url);
                
                CrawlerData data = new CrawlerData();
                data.setTitle(cleanText(title));
                data.setUrl(url);
                data.setSource(getCrawlerName());
                results.add(data);
                seenUrls.add(url);
            }
        }
        
        return results;
    }
    
    private String normalizeUrl(String url) {
        if (url == null) return null;
        url = url.trim();
        if (url.startsWith("//")) {
            return "https:" + url;
        }
        if (url.startsWith("/")) {
            return BASE_URL + url;
        }
        if (!url.startsWith("http")) {
            return BASE_URL + "/" + url;
        }
        return url;
    }
    
    private boolean isValidUrl(String url) {
        if (url == null || url.isEmpty()) {
            return false;
        }
        if (url.contains("mailto:") || url.contains("javascript:")) {
            return false;
        }
        if (url.contains("webscan.360.cn")) {
            return false;
        }
        return true;
    }
    
    private boolean isValidTitle(String title) {
        if (title == null || title.isEmpty()) {
            return false;
        }
        String cleaned = cleanText(title);
        if (cleaned == null || cleaned.length() < 2) {
            return false;
        }
        if (cleaned.length() > 100) {
            return false;
        }
        String lower = cleaned.toLowerCase();
        if (lower.contains("更多") || lower.contains("查看")) {
            return false;
        }
        return true;
    }
    
    private String cleanText(String text) {
        if (text == null) return null;
        return text.replaceAll("<[^>]+>", "")
                   .replaceAll("&nbsp;", " ")
                   .replaceAll("&#[0-9]+;", "")
                   .replaceAll("&[a-zA-Z]+;", " ")
                   .replaceAll("\\s+", " ")
                   .replaceAll("[<>]", "")
                   .trim();
    }
}