package utils;

import org.apache.hc.client5.http.classic.methods.HttpGet;
import org.apache.hc.client5.http.impl.classic.CloseableHttpClient;
import org.apache.hc.client5.http.impl.classic.CloseableHttpResponse;
import org.apache.hc.client5.http.impl.classic.HttpClients;
import org.apache.hc.core5.http.protocol.BasicHttpContext;

import org.apache.hc.core5.http.io.entity.EntityUtils;

import org.jsoup.Jsoup;
import org.jsoup.nodes.Document;
import java.net.URLEncoder;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;


public class Utils {
    // 随机User-Agent列表
    private static final List<String> USER_AGENTS = new ArrayList<>();
    static {
        USER_AGENTS.add("Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/123.0.0.0 Safari/537.36");
        USER_AGENTS.add("Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/122.0.0.0 Safari/537.36");
        USER_AGENTS.add("Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Firefox/124.0");
        USER_AGENTS.add("Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Edge/123.0.0.0");
        USER_AGENTS.add("Mozilla/5.0 (Macintosh; Intel Mac OS X 14_4) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/17.4 Safari/605.1.15");
        USER_AGENTS.add("Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/121.0.0.0 Safari/537.36");
        USER_AGENTS.add("Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Firefox/123.0");
        USER_AGENTS.add("Mozilla/5.0 (Macintosh; Intel Mac OS X 14_3) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/17.3 Safari/605.1.15");
        USER_AGENTS.add("Mozilla/5.0 (Linux; Android 10; SM-G973F) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/123.0.0.0 Mobile Safari/537.36");
        USER_AGENTS.add("Mozilla/5.0 (iPhone; CPU iPhone OS 17_4 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/17.4 Mobile/15E148 Safari/604.1");
    }
    
    // 随机Referer列表
    private static final List<String> REFERERS = new ArrayList<>();
    static {
        REFERERS.add("https://www.google.com/");
        REFERERS.add("https://www.bing.com/");
        REFERERS.add("https://www.baidu.com/");
        REFERERS.add("https://scholar.google.com/");
        REFERERS.add("https://www.sciencedirect.com/");
        REFERERS.add("https://link.springer.com/");
        REFERERS.add("https://ieeexplore.ieee.org/");
        REFERERS.add("https://dl.acm.org/");
        REFERERS.add("https://kns.cnki.net/");
        REFERERS.add("https://www.google.com/search");
    }
    
    private static final Random RANDOM = new Random();
    
    // 发送 HTTP GET 请求
    public static String sendGetRequest(String urlString) throws Exception {
        System.out.println("正在发送HTTP请求: " + urlString);
        
        // 尝试多次普通HTTP请求，使用不同的User-Agent和Referer
        for (int i = 0; i < 2; i++) { // 减少重试次数，避免卡住
            String html = sendHttpGetRequest(urlString);
            if (!html.isEmpty()) {
                return html;
            }
            // 每次失败后添加更长的延迟
            int delay = 2000 + i * 1000;
            System.out.println("第 " + (i + 1) + " 次请求失败，添加延迟: " + delay + "ms");
            Thread.sleep(delay);
        }
        
        // 暂时禁用Selenium，因为初始化可能会卡住
        System.out.println("所有HTTP请求都失败，暂时跳过Selenium...");
        return "";
    }
    
    // 使用普通HTTP请求
    private static String sendHttpGetRequest(String urlString) throws Exception {
        long startTime = System.currentTimeMillis();
        
        // 设置请求超时时间
        final int TIMEOUT = 15000; // 15秒
        
        try {
            // 使用默认的HttpClient
            CloseableHttpClient httpClient = HttpClients.createDefault();
            
            HttpGet httpGet = new HttpGet(urlString);
            
            // 随机选择User-Agent
            String userAgent = USER_AGENTS.get(RANDOM.nextInt(USER_AGENTS.size()));
            // 随机选择Referer
            String referer = REFERERS.get(RANDOM.nextInt(REFERERS.size()));
            
            // 添加更完整的HTTP头信息，模拟真实浏览器
            httpGet.setHeader("User-Agent", userAgent);
            httpGet.setHeader("Accept", "text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,*/*;q=0.8");
            httpGet.setHeader("Accept-Language", "zh-CN,zh;q=0.8,en-US;q=0.5,en;q=0.3");
            httpGet.setHeader("Accept-Encoding", "gzip, deflate, br");
            httpGet.setHeader("Connection", "keep-alive");
            httpGet.setHeader("Referer", referer);
            httpGet.setHeader("Upgrade-Insecure-Requests", "1");
            httpGet.setHeader("Sec-Fetch-Dest", "document");
            httpGet.setHeader("Sec-Fetch-Mode", "navigate");
            httpGet.setHeader("Sec-Fetch-Site", "cross-site");
            httpGet.setHeader("Sec-Fetch-User", "?1");
            httpGet.setHeader("Cache-Control", "max-age=0");
            httpGet.setHeader("DNT", "1");
            httpGet.setHeader("TE", "trailers");
            
            // 执行请求
            System.out.println("开始执行HTTP请求...");
            System.out.println("请求超时设置: " + TIMEOUT + "ms");
            
            CloseableHttpResponse response = null;
            try {
                // 使用Future来处理超时
                java.util.concurrent.Future<CloseableHttpResponse> future = java.util.concurrent.Executors.newSingleThreadExecutor().submit(new java.util.concurrent.Callable<CloseableHttpResponse>() {
                    @Override
                    public CloseableHttpResponse call() throws Exception {
                        try {
                            return (CloseableHttpResponse) httpClient.executeOpen(null, httpGet, new BasicHttpContext());
                        } catch (Exception e) {
                            throw new RuntimeException(e);
                        }
                    }
                });
                
                try {
                    response = future.get(TIMEOUT, java.util.concurrent.TimeUnit.MILLISECONDS);
                } catch (java.util.concurrent.TimeoutException e) {
                    System.out.println("HTTP请求超时: " + e.getMessage());
                    future.cancel(true);
                    return "";
                }
                
                // 获取响应状态码
                int statusCode = response.getCode();
                System.out.println("HTTP响应状态码: " + statusCode);
                System.out.println("使用的User-Agent: " + userAgent);
                System.out.println("使用的Referer: " + referer);
                
                if (statusCode != 200) {
                    System.out.println("HTTP请求失败，状态码: " + statusCode);
                    return "";
                }
                
                // 读取响应内容
                System.out.println("正在读取响应内容...");
                // 限制读取的内容长度，避免程序卡住
                String html = EntityUtils.toString(response.getEntity(), "UTF-8");
                // 如果内容长度超过100000字符，只保留前100000字符
                if (html.length() > 100000) {
                    html = html.substring(0, 100000);
                    System.out.println("响应内容过长，已截断为100000字符");
                }
                
                long endTime = System.currentTimeMillis();
                System.out.println("HTTP请求完成，耗时: " + (endTime - startTime) + "ms");
                System.out.println("响应内容长度: " + html.length() + " 字符");
                
                // 检查响应内容是否为空或包含反爬信息
                if (html == null || html.isEmpty()) {
                    System.out.println("响应内容为空");
                    return "";
                }
                
                // 检查是否是反爬页面
                boolean isAntiCrawl = false;
                String[] antiCrawlKeywords = {"captcha", "verify", "robot", "Robot", "reCAPTCHA", "blocked", "Blocked"};
                for (String keyword : antiCrawlKeywords) {
                    if (html.contains(keyword)) {
                        isAntiCrawl = true;
                        break;
                    }
                }
                
                // 特殊处理arXiv，因为它的页面可能包含一些被误判为反爬的关键词
                if (urlString.contains("arxiv.org")) {
                    isAntiCrawl = false; // 对于arXiv，我们信任它返回的内容
                }
                
                if (isAntiCrawl) {
                    System.out.println("检测到反爬页面");
                    return "";
                }
                
                // 智能延迟，模拟真实用户行为，使用更随机的延迟时间
                int delay = RANDOM.nextInt(1500) + 800; // 800-2300ms
                System.out.println("添加随机延迟: " + delay + "ms");
                Thread.sleep(delay);
                
                return html;
            } finally {
                // 确保响应和客户端被关闭
                if (response != null) {
                    try {
                        response.close();
                    } catch (Exception e) {
                        System.out.println("关闭响应时出错: " + e.getMessage());
                    }
                }
                try {
                    httpClient.close();
                } catch (Exception e) {
                    System.out.println("关闭HTTP客户端时出错: " + e.getMessage());
                }
            }
        } catch (java.net.SocketTimeoutException e) {
            System.out.println("HTTP请求超时: " + e.getMessage());
            return "";
        } catch (java.io.IOException e) {
            System.out.println("HTTP请求IO错误: " + e.getMessage());
            return "";
        } catch (Exception e) {
            System.out.println("发送HTTP请求时出错: " + e.getMessage());
            e.printStackTrace();
            return "";
        }
    }
    
    // 解析 HTML
    public static Document parseHtml(String html) {
        return Jsoup.parse(html);
    }
    
    // URL 编码
    public static String urlEncode(String value) throws Exception {
        return URLEncoder.encode(value, "UTF-8");
    }
    
    // 生成唯一文件名
    public static String generateFileName(String keyword) {
        return keyword + "_" + System.currentTimeMillis() + ".json";
    }
    
    // 清理文件名中的非法字符
    public static String cleanFileName(String fileName) {
        return fileName.replaceAll("[\\/:*?\"<>|]", "_");
    }
    
    // 清理论文标题用于文件名
    public static String cleanTitleForFileName(String title) {
        if (title == null || title.isEmpty()) {
            return "untitled";
        }
        String cleaned = title.trim()
            .replaceAll("[\\\\/:*?\"<>|]", "_")
            .replaceAll("\\s+", "_")
            .replaceAll("_+", "_");
        if (cleaned.length() > 100) {
            cleaned = cleaned.substring(0, 100);
        }
        return cleaned;
    }
}