// ilink_client.cpp — 微信 ClawBot iLink 最小示例（C++17，依赖 libcurl）
// 流程: 扫码登录 → 长轮询收消息 → 回声回复
// 编译: g++ -std=c++17 ilink_client.cpp -o ilink -lcurl
//
// 注意: 为控制依赖，JSON 用最朴素的字符串查找提取，仅适合演示。
//       正式项目请引入 nlohmann/json（单头文件），媒体加解密见 docs/03。
#include <curl/curl.h>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <fstream>
#include <iostream>
#include <optional>
#include <random>
#include <string>
#include <thread>
#include <sys/stat.h>

static const std::string BASE_URL = "https://ilinkai.weixin.qq.com";
static const std::string STATE_FILE = "bridge-state.json";

// ---------- 状态: bot_token / 游标（极简 key=value 行存储） ----------
static std::string g_token, g_cursor;

static void load_state() {
    std::ifstream f(STATE_FILE);
    std::string line;
    while (std::getline(f, line)) {
        auto eq = line.find('=');
        if (eq == std::string::npos) continue;
        auto k = line.substr(0, eq), v = line.substr(eq + 1);
        if (k == "bot_token") g_token = v;
        if (k == "cursor") g_cursor = v;
    }
}

static void save_state() {
    std::ofstream f(STATE_FILE, std::ios::trunc);
    f << "bot_token=" << g_token << "\ncursor=" << g_cursor << "\n";
    f.close();
    chmod(STATE_FILE.c_str(), 0600);
}

// ---------- HTTP 封装 ----------
static size_t on_write(char *p, size_t s, size_t n, void *ud) {
    auto *out = static_cast<std::string *>(ud);
    out->append(p, s * n);
    return s * n;
}

static std::string b64(const std::string &in) {   // 极简 base64
    static const char *T = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
    std::string o;
    for (size_t i = 0; i < in.size(); i += 3) {
        unsigned v = (unsigned char)in[i] << 16 |
                     (i+1 < in.size() ? (unsigned char)in[i+1] : 0) << 8 |
                     (i+2 < in.size() ? (unsigned char)in[i+2] : 0);
        o += T[v>>18&63]; o += T[v>>12&63];
        o += i+1 < in.size() ? T[v>>6&63] : '=';
        o += i+2 < in.size() ? T[v&63] : '=';
    }
    return o;
}

// 返回空 optional 表示传输层错误（超时/断网）；业务错误看响应内容
static std::optional<std::string> http(const std::string &method, const std::string &path,
                                       const std::string &body = "", long timeout = 45) {
    CURL *c = curl_easy_init();
    std::string resp;
    static thread_local std::mt19937 rng{std::random_device{}()};

    struct curl_slist *hdrs = nullptr;
    hdrs = curl_slist_append(hdrs, "Content-Type: application/json");
    hdrs = curl_slist_append(hdrs, "AuthorizationType: ilink_bot_token");
    std::string uin = "X-WECHAT-UIN: " + b64(std::to_string(rng()));   // 防重放
    hdrs = curl_slist_append(hdrs, uin.c_str());
    std::string auth;
    if (!g_token.empty()) {
        auth = "Authorization: Bearer " + g_token;
        hdrs = curl_slist_append(hdrs, auth.c_str());
    }

    std::string url = BASE_URL + path;
    curl_easy_setopt(c, CURLOPT_URL, url.c_str());
    curl_easy_setopt(c, CURLOPT_HTTPHEADER, hdrs);
    curl_easy_setopt(c, CURLOPT_WRITEFUNCTION, on_write);
    curl_easy_setopt(c, CURLOPT_WRITEDATA, &resp);
    curl_easy_setopt(c, CURLOPT_TIMEOUT, timeout);
    if (method == "POST") curl_easy_setopt(c, CURLOPT_POSTFIELDS, body.c_str());

    CURLcode rc = curl_easy_perform(c);
    curl_slist_free_all(hdrs);
    curl_easy_cleanup(c);
    if (rc != CURLE_OK) return std::nullopt;
    return resp;
}

// ---------- 极简 JSON 字段提取（仅演示！正式项目用 nlohmann/json） ----------
static std::string pick(const std::string &json, const std::string &key) {
    auto p = json.find("\"" + key + "\":\"");
    if (p == std::string::npos) return "";
    p += key.size() + 4;
    auto e = json.find('"', p);
    return e == std::string::npos ? "" : json.substr(p, e - p);
}

static std::string esc(const std::string &s) {   // 最小 JSON 转义
    std::string o;
    for (char ch : s) {
        if (ch == '"' || ch == '\\') { o += '\\'; o += ch; }
        else if (ch == '\n') o += "\\n";
        else o += ch;
    }
    return o;
}

// ---------- 接口1+2: 扫码登录（get_bot_qrcode / get_qrcode_status） ----------
static void login() {
    auto qr = http("GET", "/ilink/bot/get_bot_qrcode?bot_type=3", "", 15);
    if (!qr) { std::cerr << "获取二维码失败\n"; exit(1); }
    std::string qrcode = pick(*qr, "qrcode");
    std::cout << "请用微信扫码: " << pick(*qr, "qrcode_img_content") << "\n";
    for (int i = 0; i < 480; i++) {   // 最多等 8 分钟
        auto s = http("GET", "/ilink/bot/get_qrcode_status?qrcode=" + qrcode, "", 15);
        if (s && pick(*s, "status") == "confirmed") {   // wait → scaned → confirmed
            g_token = pick(*s, "bot_token");
            save_state();
            std::cout << "登录成功\n";
            return;
        }
        std::this_thread::sleep_for(std::chrono::seconds(1));
    }
    std::cerr << "扫码超时\n"; exit(1);
}

// ---------- 你的 AI 后端: 替换成自己项目的调用 ----------
static std::string ask_your_ai(const std::string &peer, const std::string &text) {
    return "你说的是：" + text;
}

// ---------- 接口4: POST /ilink/bot/sendmessage ----------
static void send_text(const std::string &to, const std::string &text, const std::string &token) {
    for (size_t i = 0; i < std::max(text.size(), size_t(1)); i += 1500) {   // 长文本分片
        std::string body =
            "{\"msg\":{\"to_user_id\":\"" + esc(to) + "\",\"client_id\":\"cpp-" +
            std::to_string(std::time(nullptr)) + "-" + std::to_string(i) + "\","
            "\"message_type\":2,\"message_state\":2,\"context_token\":\"" + esc(token) + "\","
            "\"item_list\":[{\"type\":1,\"text_item\":{\"text\":\"" +
            esc(text.substr(i, 1500)) + "\"}}]}}";
        http("POST", "/ilink/bot/sendmessage", body, 15);
    }
}

// ---------- 接口3: POST /ilink/bot/getupdates 长轮询 ----------
[[noreturn]] static void poll_loop() {
    int failures = 0;
    for (;;) {
        auto resp = http("POST", "/ilink/bot/getupdates",
            "{\"get_updates_buf\":\"" + esc(g_cursor) + "\","
            "\"base_info\":{\"channel_version\":\"1.0.2\"}}", 45);
        if (!resp) {   // 超时/网络错误
            failures++;
            int wait = failures <= 3 ? 2 : 30;   // 退避: 2s ×3 → 30s
            std::cerr << "轮询异常(" << failures << "次)，" << wait << "s 后重试\n";
            std::this_thread::sleep_for(std::chrono::seconds(wait));
            continue;
        }
        if (resp->find("\"errcode\":-14") != std::string::npos) {
            std::cerr << "会话过期(errcode=-14)，请删除 " << STATE_FILE << " 重新扫码\n";
            exit(2);
        }
        std::string buf = pick(*resp, "get_updates_buf");
        if (!buf.empty()) {   // 游标立即落盘
            g_cursor = buf;
            save_state();
        }
        // 演示级提取: 仅第一条文本消息（正式项目按 msgs[] 完整解析）
        std::string peer = pick(*resp, "from_user_id");
        std::string token = pick(*resp, "context_token");
        std::string text = pick(*resp, "text");
        if (!peer.empty() && !token.empty() && !text.empty() &&
            resp->find("\"message_type\":2") == std::string::npos) {
            send_text(peer, ask_your_ai(peer, text), token);
        }
        failures = 0;
    }
}

int main() {
    curl_global_init(CURL_GLOBAL_DEFAULT);
    load_state();
    if (g_token.empty()) login();
    poll_loop();
}