#include <iostream>
#include <fstream>
#include <sstream>
#include <optional>
#include "httplib.h"
#include "json.hpp"

using ordered_json = nlohmann::ordered_json; // 关键：保留 JSON 字段顺序

ordered_json schema;
ordered_json config;

// ---------------------------
// 读取文件为字符串
// ---------------------------
std::string read_file(const std::string &path)
{
    std::ifstream ifs(path);
    if (!ifs.is_open())
        return "";
    std::stringstream ss;
    ss << ifs.rdbuf();
    return ss.str();
}

// ---------------------------
// 写文件
// ---------------------------
void write_file(const std::string &path, const std::string &data)
{
    std::ofstream ofs(path);
    ofs << data;
}

// ---------------------------
// 加载 schema.json
// ---------------------------
void load_schema()
{
    std::string txt = read_file("config_schema.json");
    if (txt.empty())
    {
        std::cerr << "ERROR: config_schema.json not found!\n";
        exit(1);
    }
    schema = ordered_json::parse(txt);
}

// ---------------------------
// 加载 config.json，如果不存在则创建
// ---------------------------
void load_or_create_config()
{
    std::string txt = read_file("config.json");
    if (txt.empty())
    {
        std::cout << "config.json not found, creating default.\n";
        // 自动根据 schema 生成一份初始配置
        for (auto &[section, items] : schema.items())
        {
            for (auto &[key, meta] : items.items())
            {
                config[section][key] = meta["default"];
            }
        }
        write_file("config.json", config.dump(4));
        return;
    }

    try
    {
        config = ordered_json::parse(txt);
    }
    catch (...)
    {
        std::cerr << "config.json corrupted, recreating.\n";
        config.clear();
    }

    // 自动修复（补全缺失字段）
    for (auto &[section, items] : schema.items())
    {
        for (auto &[key, meta] : items.items())
        {
            if (!config[section].contains(key))
            {
                config[section][key] = meta["default"];
            }
        }
    }

    write_file("config.json", config.dump(4));
}

// ---------------------------
// 保存配置（含自动类型校验）
// ---------------------------
std::optional<std::string> validate_config(
    const ordered_json &incoming, ordered_json &out)
{
    for (auto &[section, items] : schema.items())
    {

        if (!incoming.contains(section))
            return "缺少配置段：" + section;

        out[section] = ordered_json::object();

        for (auto &[key, meta] : items.items())
        {

            if (!incoming[section].contains(key))
                return "字段 [" + meta.value("title", key) + "] 缺失";

            auto &value = incoming[section][key];

            if (value.is_null())
                return "字段 [" + meta.value("title", key) + "] 不能为空";

            std::string type = meta["type"];
            std::string title = meta.value("title", key);

            try
            {
                if (type == "int")
                {

                    if (value.is_number_integer())
                    {
                        out[section][key] = value.get<int>();
                    }
                    else if (value.is_string())
                    {
                        out[section][key] = std::stoi(value.get<std::string>());
                    }
                    else
                    {
                        return "字段 [" + title + "] 必须为整数";
                    }
                }

                else if (type == "bool")
                {
                    if (value.is_boolean())
                    {
                        out[section][key] = value.get<bool>();
                    }
                    else if (value.is_string())
                    {
                        std::string v = value.get<std::string>();
                        if (v == "1" || v == "true")
                            out[section][key] = true;
                        else if (v == "0" || v == "false")
                            out[section][key] = false;
                        else
                            return "字段 [" + title + "] 必须为布尔值";
                    }
                    else
                    {
                        return "字段 [" + title + "] 必须为布尔值";
                    }
                }

                else
                { // string
                    if (!value.is_string())
                        return "字段 [" + title + "] 必须为字符串";

                    out[section][key] = value.get<std::string>();
                }
            }
            catch (...)
            {
                return "字段 [" + title + "] 格式无效";
            }
        }
    }

    return std::nullopt;
}

int main()
{
    load_schema();
    load_or_create_config();

    httplib::Server svr;

    // 返回页面 HTML
    svr.Get("/config", [](const httplib::Request &, httplib::Response &res)
            { res.set_content(read_file("config.html"), "text/html"); });

    // 返回 schema + config
   svr.Get("/config/data", [](const httplib::Request &, httplib::Response &res)
{
    // ---- 动态加载 schema.json （热更新）----
    ordered_json fresh_schema;
    try {
        fresh_schema = ordered_json::parse(read_file("config_schema.json"));
    } catch(...) {
        // schema 文件损坏或读取失败
        fresh_schema = schema;   // fallback 用旧 schema
    }

    // ---- 自动修复 config，补齐 schema 里新增的字段 ----
    for (auto &[section, items] : fresh_schema.items())
    {
        if (!config.contains(section))
            config[section] = ordered_json::object();

        for (auto &[key, meta] : items.items())
        {
            if (!config[section].contains(key))
                config[section][key] = meta["default"];
        }
    }

    // ---- 覆盖全局 schema ----
    schema = fresh_schema;

    // ---- 返回 schema + config ----
    ordered_json out;
    out["schema"] = schema;
    out["config"] = config;
    res.set_content(out.dump(), "application/json");
});

    // 保存配置
    svr.Post("/config/save", [](const httplib::Request &req, httplib::Response &res)
             {
    ordered_json incoming = ordered_json::parse(req.body);
    ordered_json validated;

    auto err = validate_config(incoming, validated);

    if (err.has_value()) {
        ordered_json r;
        r["status"] = "error";
        r["message"] = err.value();
        res.set_content(r.dump(), "application/json");
        return;
    }

    config = validated;
    write_file("config.json", config.dump(4));

    // ★★★ 写入 mDNS 更新请求 ★★★
    std::string new_devno = config["vehicle"]["device_no"];
    write_file("/run/update_mdns_request", new_devno);

    res.set_content("{\"status\":\"ok\"}", "application/json"); });

    std::cout << "Config server running at http://0.0.0.0:18080/config\n";
    svr.listen("0.0.0.0", 18080);
    return 0;
}