// IlinkBridge.java — 微信 ClawBot iLink 最小示例（Java 11+，零第三方依赖）
// 流程: 扫码登录 → 长轮询收消息 → 回声回复
// 运行: javac IlinkBridge.java && java IlinkBridge
//
// 注意: 为保持零依赖，JSON 解析用最朴素的正则提取，仅适合演示。
//       正式项目请换 Jackson / Gson，并按 docs/04 的模块划分组织代码。
import java.net.URI;
import java.net.URLEncoder;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;
import java.nio.charset.StandardCharsets;
import java.nio.file.*;
import java.security.SecureRandom;
import java.time.Duration;
import java.util.*;
import java.util.regex.*;

public class IlinkBridge {
    static final String BASE_URL = "https://ilinkai.weixin.qq.com";
    // 扫码轮询的 base；收到 scaned_but_redirect 时切换，其余 API 仍走固定 BASE_URL。
    static String apiBaseUrl = BASE_URL;
    static final Path STATE_FILE = Path.of("bridge-state.json");

    // ---------- 状态: bot_token / 游标 / context_token（极简 key=value 存储） ----------
    static Properties state = new Properties();

    static void loadState() throws Exception {
        if (Files.exists(STATE_FILE))
            try (var in = Files.newInputStream(STATE_FILE)) { state.load(in); }
    }

    static void saveState() throws Exception {
        try (var out = Files.newOutputStream(STATE_FILE)) { state.store(out, "ilink bridge state"); }
        STATE_FILE.toFile().setReadable(false, false);
        STATE_FILE.toFile().setReadable(true, true);   // 近似 600
    }

    // ---------- 通用请求头: 鉴权 + 防重放 X-WECHAT-UIN + iLink-App 标识 ----------
    // 注: get_bot_qrcode / get_qrcode_status（预绑定阶段）无 token 时不带 Authorization，
    //     但 iLink-App-Id / iLink-App-ClientVersion / AuthorizationType / X-WECHAT-UIN 恒带。
    static HttpRequest.Builder req(String url) {
        var b = HttpRequest.newBuilder(URI.create(url))
                .timeout(Duration.ofSeconds(50))
                .header("Content-Type", "application/json")
                .header("AuthorizationType", "ilink_bot_token")
                .header("X-WECHAT-UIN", Base64.getEncoder().encodeToString(
                        Integer.toString(new SecureRandom().nextInt() >>> 1).getBytes()))
                .header("iLink-App-Id", "bot")
                // 2.4.8 -> (2&0xff)<<16 | (4&0xff)<<8 | (8&0xff) = 132104（数字字符串，非 "1"）
                .header("iLink-App-ClientVersion", "132104");
        String token = state.getProperty("bot_token");
        if (token != null) b.header("Authorization", "Bearer " + token);
        return b;
    }

    static final HttpClient client = HttpClient.newHttpClient();

    static String post(String path, String json) throws Exception {
        var r = client.send(req(BASE_URL + path)
                .POST(HttpRequest.BodyPublishers.ofString(json)).build(),
                HttpResponse.BodyHandlers.ofString());
        return r.body();
    }

    // ---------- 极简 JSON 字段提取（仅演示！正式项目用 Jackson/Gson） ----------
    static String pick(String json, String key) {
        var m = Pattern.compile("\"" + key + "\"\\s*:\\s*\"((?:[^\"\\\\]|\\\\.)*)\"").matcher(json);
        return m.find() ? m.group(1).replace("\\\"", "\"") : null;
    }

    static List<String> pickAll(String json, String key) {
        var out = new ArrayList<String>();
        var m = Pattern.compile("\"" + key + "\"\\s*:\\s*\"((?:[^\"\\\\]|\\\\.)*)\"").matcher(json);
        while (m.find()) out.add(m.group(1));
        return out;
    }

    // ---------- 接口1: POST /ilink/bot/get_bot_qrcode 获取登录二维码（官方姿势） ----------
    static String fetchQrcode() throws Exception {
        // 官方为 POST + body {"local_token_list":[...]}，非裸 GET。首次绑定传空数组；
        // 若已持久化其它 bot_token 可收集传入（最多 10 个），官方据此识别触发 binded_redirect。
        return post("/ilink/bot/get_bot_qrcode?bot_type=3", "{\"local_token_list\":[]}");
    }

    // ---------- 接口2: GET /ilink/bot/get_qrcode_status 轮询扫码状态（完整状态机） ----------
    static void login() throws Exception {
        // 状态机: wait / scaned / scaned_but_redirect / need_verifycode /
        //         verify_code_blocked / binded_redirect / confirmed / expired
        // 两大坑（务必读 docs/02 §4.5）：
        //   ① 码服务端 TTL≈60s，生成后须在窗口内扫（超窗服务端自返回 expired，此处换新码）。
        //   ② 「换码竞态」：一旦收到 scaned（或 scaned_but_redirect / need_verifycode），
        //      绝不能再换码——换码会砍掉"扫码→确认"会话，微信端显示成功但后端永远收不到 confirmed。
        var qr = fetchQrcode();
        String qrcode = pick(qr, "qrcode");
        if (qrcode == null) throw new RuntimeException("获取二维码失败");
        System.out.println("请用微信扫码: " + pick(qr, "qrcode_img_content"));
        System.out.println("(二维码内容即上面的 liteapp URL，请用二维码库编码展示；勿把 qrcode 字段当二维码)");
        long deadline = System.currentTimeMillis() + 8 * 60_000;
        String verifyCode = null;
        var sc = new Scanner(System.in);
        while (System.currentTimeMillis() < deadline) {
            String path = "/ilink/bot/get_qrcode_status?qrcode="
                    + URLEncoder.encode(qrcode, StandardCharsets.UTF_8);
            if (verifyCode != null)
                path += "&verify_code=" + URLEncoder.encode(verifyCode, StandardCharsets.UTF_8);
            String s = client.send(req(apiBaseUrl + path).GET().build(),
                    HttpResponse.BodyHandlers.ofString()).body();
            String status = pick(s, "status");
            switch (status == null ? "" : status) {
                case "wait":
                    System.out.println("等待扫码...");
                    break;
                case "scaned":
                    verifyCode = null;
                    System.out.println("已扫码，请在手机上确认...（此后绝不换码，避免砍掉确认会话）");
                    break;
                case "scaned_but_redirect":
                    verifyCode = null;
                    String host = pick(s, "redirect_host");
                    if (host != null && !host.isEmpty()) {
                        apiBaseUrl = "https://" + host;
                        System.out.println("IDC 重定向，切换轮询至 " + apiBaseUrl);
                    }
                    break;
                case "need_verifycode":
                    System.out.print("请在手机微信上输入显示的数字后回车: ");
                    System.out.flush();
                    verifyCode = sc.nextLine().trim();
                    continue;
                case "verify_code_blocked":
                    verifyCode = null;
                    System.out.println("配对码多次输入错误，重新获取二维码");
                    qr = fetchQrcode();
                    qrcode = pick(qr, "qrcode");
                    System.out.println("新二维码: " + pick(qr, "qrcode_img_content"));
                    continue;
                case "binded_redirect":
                    System.out.println("该 bot 已绑定过本实例，视为连接成功");
                    return;
                case "confirmed":
                    state.setProperty("bot_token", pick(s, "bot_token"));
                    state.setProperty("bot_id", pick(s, "ilink_bot_id"));
                    if (pick(s, "baseurl") != null) state.setProperty("baseurl", pick(s, "baseurl"));
                    saveState();
                    System.out.println("登录成功, bot: " + state.getProperty("bot_id"));
                    return;
                case "expired":
                    // 码过期（服务端作废）→ 换新码；仅在 expired 时换，scaned 后绝不换
                    verifyCode = null;
                    System.out.println("二维码已过期，重新获取");
                    qr = fetchQrcode();
                    qrcode = pick(qr, "qrcode");
                    System.out.println("新二维码: " + pick(qr, "qrcode_img_content"));
                    continue;
                default:
                    System.out.println("未知状态: " + status);
            }
            Thread.sleep(1000);
        }
        throw new RuntimeException("扫码超时");
    }

    // ---------- 你的 AI 后端: 替换成自己项目的调用 ----------
    static String askYourAI(String peerId, String text) {
        // 例: 用 client 调本地 HTTP 后端 POST http://127.0.0.1:8000/chat
        return "你说的是：" + text;
    }

    static String esc(String s) {   // 最小 JSON 转义
        return s.replace("\\", "\\\\").replace("\"", "\\\"").replace("\n", "\\n");
    }

    // ---------- 接口4: POST /ilink/bot/sendmessage ----------
    static void sendText(String toUserId, String text, String contextToken) throws Exception {
        for (int i = 0; i < Math.max(text.length(), 1); i += 1500) {   // 长文本分片
            post("/ilink/bot/sendmessage", """
                {"msg":{
                  "to_user_id":"%s",
                  "client_id":"%s",
                  "message_type":2,
                  "message_state":2,
                  "context_token":"%s",
                  "item_list":[{"type":1,"text_item":{"text":"%s"}}]
                }}""".formatted(esc(toUserId), UUID.randomUUID(),
                                esc(contextToken), esc(text.substring(i, Math.min(i + 1500, text.length())))));
        }
    }

    // ---------- 接口3: POST /ilink/bot/getupdates 长轮询 ----------
    static void pollLoop() throws Exception {
        int failures = 0;
        while (true) {
            try {
                String resp = post("/ilink/bot/getupdates",
                        "{\"get_updates_buf\":\"" + esc(state.getProperty("cursor", "")) + "\"," +
                        "\"base_info\":{\"channel_version\":\"1.0.2\"}}");

                if ("-14".equals(pick(resp, "errcode"))) {   // 会话过期
                    System.err.println("会话过期(errcode=-14)，请删除 bridge-state.json 重新扫码");
                    System.exit(2);
                }

                String buf = pick(resp, "get_updates_buf");
                if (buf != null && !buf.isEmpty()) {         // 游标立即落盘
                    state.setProperty("cursor", buf);
                    saveState();
                }

                // 演示级提取: 逐条消息的 from_user_id / context_token / text
                // （正则无法严谨配对嵌套结构，正式项目务必用 JSON 库按 msgs[] 解析）
                var peers = pickAll(resp, "from_user_id");
                var tokens = pickAll(resp, "context_token");
                var texts = pickAll(resp, "text");
                for (int i = 0; i < peers.size() && i < tokens.size(); i++) {
                    String text = i < texts.size() ? texts.get(i) : "";
                    if (text.isBlank()) continue;
                    state.setProperty("ctx." + peers.get(i), tokens.get(i));
                    saveState();
                    try {
                        sendText(peers.get(i), askYourAI(peers.get(i), text), tokens.get(i));
                    } catch (Exception e) {
                        System.err.println("处理消息失败: " + e);
                    }
                }
                failures = 0;
            } catch (java.net.http.HttpTimeoutException e) {
                continue;                                     // 长轮询正常超时
            } catch (Exception e) {
                failures++;
                long wait = failures <= 3 ? 2000 : 30_000;    // 退避: 2s ×3 → 30s
                System.err.println("轮询异常(" + failures + "次)，" + wait / 1000 + "s 后重试: " + e);
                Thread.sleep(wait);
            }
        }
    }

    public static void main(String[] args) throws Exception {
        loadState();
        if (state.getProperty("bot_token") == null) login();
        pollLoop();
    }
}