// 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.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";
    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 ----------
    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()));
        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+2: 扫码登录（get_bot_qrcode / get_qrcode_status） ----------
    static void login() throws Exception {
        var qr = client.send(req(BASE_URL + "/ilink/bot/get_bot_qrcode?bot_type=3")
                .GET().build(), HttpResponse.BodyHandlers.ofString()).body();
        String qrcode = pick(qr, "qrcode");
        System.out.println("请用微信扫码: " + pick(qr, "qrcode_img_content"));
        long deadline = System.currentTimeMillis() + 8 * 60_000;
        while (System.currentTimeMillis() < deadline) {
            var s = client.send(req(BASE_URL + "/ilink/bot/get_qrcode_status?qrcode=" + qrcode)
                    .header("iLink-App-ClientVersion", "1").GET().build(),
                    HttpResponse.BodyHandlers.ofString()).body();
            if ("confirmed".equals(pick(s, "status"))) {     // wait → scaned → confirmed
                state.setProperty("bot_token", pick(s, "bot_token"));
                state.setProperty("bot_id", pick(s, "ilink_bot_id"));
                saveState();
                System.out.println("登录成功, bot: " + state.getProperty("bot_id"));
                return;
            }
            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();
    }
}