// src/wg/relayreg.cpp — DragonRelay HTTP registration client for Artemis.
//
// Depends on: libcurl, nlohmann/json (header-only, shipped with Sunshine)
//
// Build: add relayreg.cpp to the CMake target and link curl.

#include "relayreg.h"

#include <curl/curl.h>
#include <nlohmann/json.hpp>

#include <stdexcept>
#include <string>

namespace wg {

using json = nlohmann::json;

// ── libcurl write callback ────────────────────────────────────────────────────

static size_t curlWrite(void *data, size_t size, size_t nmemb, void *userp) {
    size_t total = size * nmemb;
    static_cast<std::string *>(userp)->append(static_cast<char *>(data), total);
    return total;
}

// ── RelayReg ──────────────────────────────────────────────────────────────────

RelayReg::RelayReg() {
    curl_global_init(CURL_GLOBAL_DEFAULT);
}

RelayReg::~RelayReg() {
    curl_global_cleanup();
}

// ── HTTP helper ───────────────────────────────────────────────────────────────

int RelayReg::request(const std::string &method,
                      const std::string &path,
                      const std::string &body,
                      std::string &responseOut) {
    responseOut.clear();

    CURL *curl = curl_easy_init();
    if (!curl) return -1;

    std::string url = m_base + path;
    curl_easy_setopt(curl, CURLOPT_URL, url.c_str());
    curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, curlWrite);
    curl_easy_setopt(curl, CURLOPT_WRITEDATA, &responseOut);
    curl_easy_setopt(curl, CURLOPT_TIMEOUT, 15L);
    curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, 1L);

    // Headers
    struct curl_slist *hdrs = nullptr;
    hdrs = curl_slist_append(hdrs, "Content-Type: application/json");
    if (!m_jwt.empty()) {
        std::string auth = "Authorization: Bearer " + m_jwt;
        hdrs = curl_slist_append(hdrs, auth.c_str());
    }
    curl_easy_setopt(curl, CURLOPT_HTTPHEADER, hdrs);

    // Method + body
    if (method == "POST" || method == "PUT") {
        curl_easy_setopt(curl, CURLOPT_CUSTOMREQUEST, method.c_str());
        curl_easy_setopt(curl, CURLOPT_POSTFIELDS, body.c_str());
        curl_easy_setopt(curl, CURLOPT_POSTFIELDSIZE, (long)body.size());
    } else if (method == "DELETE") {
        curl_easy_setopt(curl, CURLOPT_CUSTOMREQUEST, "DELETE");
    }
    // GET is default

    CURLcode res = curl_easy_perform(curl);
    long httpCode = 0;
    if (res == CURLE_OK)
        curl_easy_getinfo(curl, CURLINFO_RESPONSE_CODE, &httpCode);

    curl_slist_free_all(hdrs);
    curl_easy_cleanup(curl);

    if (res != CURLE_OK) {
        if (m_log) m_log(std::string("curl error: ") + curl_easy_strerror(res));
        return -1;
    }
    return (int)httpCode;
}

// ── login ─────────────────────────────────────────────────────────────────────

bool RelayReg::login(const std::string &username, const std::string &password,
                     std::string &errOut) {
    json body = { {"username", username}, {"password", password} };
    std::string resp;
    int code = request("POST", "/api/auth/login", body.dump(), resp);
    if (code != 200) {
        errOut = "login failed (HTTP " + std::to_string(code) + "): " + resp;
        return false;
    }
    try {
        auto j = json::parse(resp);
        m_jwt = j.at("token").get<std::string>();
        if (m_log) m_log("Logged in to DragonRelay");
        return true;
    } catch (const std::exception &e) {
        errOut = std::string("login JSON parse: ") + e.what();
        return false;
    }
}

void RelayReg::logout() {
    m_jwt.clear();
}

// ── provisionVPN ──────────────────────────────────────────────────────────────

bool RelayReg::provisionVPN(const std::string &deviceName,
                             VPNConf &out, std::string &errOut) {
    json body = { {"device_name", deviceName} };
    std::string resp;
    int code = request("POST", "/api/vpn/peer", body.dump(), resp);
    if (code != 200 && code != 201) {
        errOut = "provisionVPN failed (HTTP " + std::to_string(code) + "): " + resp;
        return false;
    }
    try {
        auto j = json::parse(resp);
        out.id        = j.at("id").get<std::string>();
        out.name      = j.at("name").get<std::string>();
        out.publicKey = j.at("public_key").get<std::string>();
        out.allowedIP = j.at("allowed_ip").get<std::string>();
        out.conf      = j.at("conf").get<std::string>();
        if (m_log) m_log("VPN peer provisioned: " + out.name + " @ " + out.allowedIP);
        return true;
    } catch (const std::exception &e) {
        errOut = std::string("provisionVPN JSON: ") + e.what();
        return false;
    }
}

bool RelayReg::deleteVPNPeer(const std::string &peerId, std::string &errOut) {
    std::string resp;
    int code = request("DELETE", "/api/vpn/peer/" + peerId, "", resp);
    if (code != 200 && code != 204) {
        errOut = "deleteVPNPeer failed (HTTP " + std::to_string(code) + ")";
        return false;
    }
    return true;
}

// ── registerHost ──────────────────────────────────────────────────────────────

bool RelayReg::registerHost(const std::string &name, const std::string &wgIP,
                             int port, std::string &errOut) {
    json body = { {"name", name}, {"wg_ip", wgIP}, {"port", port} };
    std::string resp;
    int code = request("POST", "/api/host/register", body.dump(), resp);
    if (code != 200 && code != 201) {
        errOut = "registerHost failed (HTTP " + std::to_string(code) + "): " + resp;
        return false;
    }
    if (m_log) m_log("Registered host '" + name + "' at " + wgIP + ":" + std::to_string(port));
    return true;
}

bool RelayReg::heartbeat(std::string &errOut) {
    std::string resp;
    int code = request("PUT", "/api/host/heartbeat", "{}", resp);
    if (code != 200 && code != 204) {
        errOut = "heartbeat failed (HTTP " + std::to_string(code) + ")";
        return false;
    }
    return true;
}

bool RelayReg::unregisterHost(std::string &errOut) {
    std::string resp;
    int code = request("DELETE", "/api/host/unregister", "", resp);
    if (code != 200 && code != 204) {
        errOut = "unregisterHost failed (HTTP " + std::to_string(code) + ")";
        return false;
    }
    if (m_log) m_log("Unregistered from DragonRelay");
    return true;
}

} // namespace wg