import org.apache.commons.lang3.RandomStringUtils;
import org.apache.http.HttpEntity;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;
import org.bouncycastle.jce.provider.BouncyCastleProvider;
import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONArray;
import com.alibaba.fastjson.JSONObject;

import javax.crypto.Cipher;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import java.nio.charset.StandardCharsets;
import java.security.Security;
import java.util.Base64;
import java.util.HashMap;
import java.util.Map;

/**
 * 网易云音乐热门评论爬虫
 */
public class NeteaseCommentCrawler {
    // 网易云固定加密密钥
    private static final String FIRST_KEY = "0CoJUm6Qyw8W8jud";
    private static final String IV = "0102030405060708";
    // 固定encSecKey（适配热门评论接口）
    private static final String ENC_SEC_KEY = "00e0b50bcfcc08f1f8d6a8a9a0c96969b6f928a5069f07aa09f6062446f4224f42f42f42f42f42f42f42f42f42f42f42f42f42f42f42f42f42f42f42f42f42f4";

    static {
        // 注册BouncyCastle加密提供者
        Security.addProvider(new BouncyCastleProvider());
    }

    /**
     * AES加密（CBC模式，PKCS7填充）
     */
    private static String aesEncrypt(String content, String key) throws Exception {
        SecretKeySpec secretKeySpec = new SecretKeySpec(key.getBytes(StandardCharsets.UTF_8), "AES");
        IvParameterSpec ivParameterSpec = new IvParameterSpec(IV.getBytes(StandardCharsets.UTF_8));
        Cipher cipher = Cipher.getInstance("AES/CBC/PKCS7Padding");
        cipher.init(Cipher.ENCRYPT_MODE, secretKeySpec, ivParameterSpec);
        byte[] encrypted = cipher.doFinal(pad(content).getBytes(StandardCharsets.UTF_8));
        return Base64.getEncoder().encodeToString(encrypted);
    }

    /**
     * PKCS7补位
     */
    private static String pad(String s) {
        int blockSize = 16;
        int padCount = blockSize - (s.length() % blockSize);
        StringBuilder sb = new StringBuilder(s);
        for (int i = 0; i < padCount; i++) {
            sb.append((char) padCount);
        }
        return sb.toString();
    }

    /**
     * 生成加密参数（params + encSecKey）
     */
    private static Map<String, String> getEncryptedParams(String songId) throws Exception {
        // 构造原始请求参数
        JSONObject originParam = new JSONObject();
        originParam.put("rid", "R_SO_4_" + songId);
        originParam.put("offset", 0);
        originParam.put("total", true);
        originParam.put("limit", 20);
        originParam.put("csrf_token", "");

        // 生成16位随机密钥
        String secondKey = RandomStringUtils.randomAlphanumeric(16);
        // 双重AES加密
        String params = aesEncrypt(aesEncrypt(originParam.toJSONString(), FIRST_KEY), secondKey);

        Map<String, String> result = new HashMap<>();
        result.put("params", params);
        result.put("encSecKey", ENC_SEC_KEY);
        return result;
    }

    /**
     * 获取热门评论
     */
    public static JSONArray getHotComments(String songId) {
        String url = "https://music.163.com/weapi/v1/resource/comments/R_SO_4_" + songId + "?csrf_token=";
        CloseableHttpClient httpClient = HttpClients.createDefault();
        try {
            // 1. 构造POST请求
            HttpPost httpPost = new HttpPost(url);
            // 2. 设置请求头
            httpPost.setHeader("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");
            httpPost.setHeader("Referer", "https://music.163.com/song?id=" + songId);
            httpPost.setHeader("Content-Type", "application/x-www-form-urlencoded");

            // 3. 生成加密参数并构造请求体
            Map<String, String> encryptedParams = getEncryptedParams(songId);
            String requestBody = "params=" + encryptedParams.get("params") + "&encSecKey=" + encryptedParams.get("encSecKey");
            httpPost.setEntity(new StringEntity(requestBody, StandardCharsets.UTF_8));

            // 4. 发送请求并解析响应
            CloseableHttpResponse response = httpClient.execute(httpPost);
            HttpEntity entity = response.getEntity();
            String responseStr = EntityUtils.toString(entity, StandardCharsets.UTF_8);
            JSONObject responseJson = JSON.parseObject(responseStr);
            
            // 5. 返回热门评论数组
            return responseJson.getJSONArray("hotComments");

        } catch (Exception e) {
            System.err.println("爬取失败：" + e.getMessage());
            e.printStackTrace();
        } finally {
            try {
                httpClient.close();
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        return new JSONArray();
    }

    /**
     * 格式化输出评论 + 保存到CSV
     */
    public static void printAndSaveComments(JSONArray hotComments) {
        // 1. 格式化打印
        System.out.println("===== 网易云热门评论 =====");
        for (int i = 0; i < hotComments.size(); i++) {
            JSONObject comment = hotComments.getJSONObject(i);
            JSONObject user = comment.getJSONObject("user");
            String nickname = user.getString("nickname");
            String content = comment.getString("content").replace("\n", " ");
            int likedCount = comment.getInteger("likedCount");
            String timeStr = comment.getString("timeStr");
            
            System.out.printf("%d. %s：%s（%d赞）- %s%n", 
                    i + 1, nickname, content, likedCount, timeStr);
        }

        // 2. 保存到CSV（可选）
        /*
        try (FileWriter writer = new FileWriter("netease_hot_comments.csv", StandardCharsets.UTF_8)) {
            // 写入表头
            writer.write("序号,用户,评论,点赞数,时间\n");
            // 写入评论数据
            for (int i = 0; i < hotComments.size(); i++) {
                JSONObject comment = hotComments.getJSONObject(i);
                JSONObject user = comment.getJSONObject("user");
                String nickname = user.getString("nickname");
                String content = comment.getString("content").replace("\n", " ").replace(",", "，");
                int likedCount = comment.getInteger("likedCount");
                String timeStr = comment.getString("timeStr");
                
                writer.write(String.format("%d,%s,%s,%d,%s%n", 
                        i + 1, nickname, content, likedCount, timeStr));
            }
            System.out.println("评论已保存到 netease_hot_comments.csv");
        } catch (Exception e) {
            System.err.println("保存CSV失败：" + e.getMessage());
        }
        */
    }

    // 主方法：测试爬取《晴天》（ID:186016）热门评论
    public static void main(String[] args) {
        String songId = "186016"; // 晴天的歌曲ID
        JSONArray hotComments = getHotComments(songId);
        if (!hotComments.isEmpty()) {
            printAndSaveComments(hotComments);
        } else {
            System.out.println("未获取到评论，请检查歌曲ID或网络");
        }
    }
}