// utun_node.cpp — embedded uTun node running in a dedicated thread
#include "utun_node.h"
#include <cinttypes>
#include <QDir>
#include <csignal>
#include "../../lib/socket_compat.h"

#include "../db/db_manager.h"

// === C headers ===
extern "C" {
#include "utun_instance.h"
#include "etcp_router.h"
#include "etcp_api.h"
#include "etcp.h"
#include "config_parser.h"
#include "config_updater.h"
#include "control_server.h"
#include "secure_channel.h"
#include "../lib/u_async.h"
#include "../lib/ll_queue.h"
#include "../lib/memory_pool.h"
#include "../lib/debug_config.h"
#include "../lib/mem.h"
#include "chat_sync.h"
#include "chat_core.h"
#include "db_sync.h"
#include "gui_bridge.h"
#include "topo_node_sqlite.h"
#include "topo_node.h"
#include "topo_group.h"
}

#define ETCP_RT_ID_CHAT  0x11

static UtunNode* g_currentNode = nullptr;

static void signal_handler(int sig) {
    (void)sig;
    if (g_currentNode) g_currentNode->requestStop();
}

UtunNode::UtunNode(QObject* parent) : QObject(parent) {}

UtunNode::~UtunNode() {
    stop();
}

bool UtunNode::start(const QString& configPath) {
    if (m_running) return false;
    m_configPath = configPath;
    m_stop = false;
    m_running = true;
    m_thread = std::thread(&UtunNode::runLoop, this);

    for (int i = 0; i < 50 && m_running && !m_instance; ++i)
        std::this_thread::sleep_for(std::chrono::milliseconds(10));

    if (!m_instance) {
        m_stop = true;
        if (m_thread.joinable()) m_thread.join();
        m_running = false;
        return false;
    }
    emit started();
    return true;
}

void UtunNode::setDebugFile(const QString& path) {
    m_debugFile = path;
}

void UtunNode::setDbPath(const QString& path) {
    m_dbPath = path;
    QDir(path).mkpath(".");
}

void UtunNode::setDebugLevel(const QString& level) {
    m_debugLevel = level;
}

void UtunNode::setDebugCategories(const QString& categories) {
    m_debugCategories = categories;
}

void UtunNode::requestStop() {
    m_stop = true;
    if (m_ua) uasync_wakeup(m_ua);
}

void UtunNode::stop() {
    if (!m_running) return;
    requestStop();
    if (m_thread.joinable()) m_thread.join();
    finalize();
    m_running = false;
}

void UtunNode::finalize() {
    if (!m_instance) return;
    DEBUG_INFO(DEBUG_CATEGORY_DEBUG, "finalize: cleanup start");
    etcp_router_bind(m_instance, ETCP_RT_ID_CHAT, nullptr);
    chat_sync_destroy(m_instance);
    chat_core_destroy(m_instance);
    utun_instance_destroy(m_instance);
    m_instance = nullptr;
    uasync_destroy(m_ua, 0);
    m_ua = nullptr;
    DEBUG_INFO(DEBUG_CATEGORY_DEBUG, "finalize: cleanup done");
}

void UtunNode::send(uint64_t dstNodeId, const QByteArray& data) {
    if (!m_instance) return;
    struct ll_entry* entry = queue_entry_new(data.size());
    if (!entry) return;
    memcpy(entry->data, data.constData(), data.size());
    etcp_route_send(m_instance, TOPO_GROUP_UTUN, dstNodeId, entry, 0);
}

QString UtunNode::nodeIdHex() const {
    if (!m_instance) return {};
    char buf[32];
    snprintf(buf, sizeof(buf), "%016" PRIx64, m_instance->node_id);
    return QString(buf);
}

QString UtunNode::pubKeyHex() const {
    if (!m_instance || !m_instance->config) return {};
    return QString::fromLatin1(m_instance->config->global.my_public_key_hex, 64);
}

int64_t UtunNode::ntpOffsetUs() const {
    return m_instance ? m_instance->ntp.offset_us : 0;
}

bool UtunNode::ntpSynced() const {
    return m_instance ? m_instance->ntp.synced : false;
}

bool UtunNode::ntpEnabled() const {
    return m_instance ? m_instance->ntp.enabled : false;
}

QList<NodeAddr> UtunNode::getInviteAddresses(DbManager* db) {
    (void)db;
    QList<NodeAddr> addrs;

    if (m_instance) {
        struct ll_entry* entry = m_instance->connections->head;
        while (entry) {
            struct conn_queue_entry* ce = (struct conn_queue_entry*)entry->data;
            struct ETCP_CONN* conn = ce->conn;
            if (conn && conn->initialized && conn->links_up > 0) {
                struct ETCP_LINK* link = conn->links;
                while (link) {
                    if (link->link_state == 3 && link->nat_type == NAT_TYPE_DIRECT) {
                        NodeAddr a;
                        a.socketId = link->conn ? (int)link->conn->sock_id : 0;
                        struct sockaddr_storage* sa = &link->remote_addr;
                        if (sa->ss_family == AF_INET) {
                            struct sockaddr_in* sin = (struct sockaddr_in*)sa;
                            a.family = 4;
                            a.address = QByteArray((const char*)&sin->sin_addr, 4);
                            a.port = ntohs(sin->sin_port);
                        } else {
                            struct sockaddr_in6* sin6 = (struct sockaddr_in6*)sa;
                            a.family = 6;
                            a.address = QByteArray((const char*)&sin6->sin6_addr, 16);
                            a.port = ntohs(sin6->sin6_port);
                        }
                        addrs.append(a);
                    }
                    link = link->next;
                }
            }
            entry = entry->next;
        }
    }

    if (addrs.isEmpty() && m_instance) {
        struct ETCP_SOCKET* sock = m_instance->etcp_sockets;
        while (sock) {
            struct sockaddr_storage* sa;
            if (sock->nat_addr.ss_family != 0)
                sa = &sock->nat_addr;
            else if (sock->interface_addr.ss_family != 0)
                sa = &sock->interface_addr;
            else { sock = sock->next; continue; }

            NodeAddr a;
            a.socketId = (int)sock->sock_id;
            if (sa->ss_family == AF_INET) {
                struct sockaddr_in* sin = (struct sockaddr_in*)sa;
                a.family = 4;
                a.address = QByteArray((const char*)&sin->sin_addr, 4);
                a.port = ntohs(sin->sin_port);
            } else {
                struct sockaddr_in6* sin6 = (struct sockaddr_in6*)sa;
                a.family = 6;
                a.address = QByteArray((const char*)&sin6->sin6_addr, 16);
                a.port = ntohs(sin6->sin6_port);
            }
            addrs.append(a);
            sock = sock->next;
        }
    }

    return addrs;
}

void UtunNode::recvCallback(struct ETCP_CONN* conn, struct ll_entry* entry) {
    if (!g_currentNode || !entry) return;
    uint64_t src = conn ? conn->peer_node_id : 0;
    QByteArray data((const char*)entry->data, (int)(entry->len ? entry->len : 0));
    QMetaObject::invokeMethod(g_currentNode, [=] {
        emit g_currentNode->messageReceived(src, data);
    }, Qt::QueuedConnection);
}

void UtunNode::runLoop() {
    g_currentNode = this;

    debug_config_init();
    debug_enable_function_name(0);

    /* ── debug level from config ── */
    if (!m_debugLevel.isEmpty()) {
        QString lvl = m_debugLevel.toLower();
        debug_level_t dl = DEBUG_LEVEL_INFO;
        if (lvl == "none")  dl = DEBUG_LEVEL_NONE;
        else if (lvl == "error") dl = DEBUG_LEVEL_ERROR;
        else if (lvl == "warn")  dl = DEBUG_LEVEL_WARN;
        else if (lvl == "info")  dl = DEBUG_LEVEL_INFO;
        else if (lvl == "debug") dl = DEBUG_LEVEL_DEBUG;
        else if (lvl == "trace") dl = DEBUG_LEVEL_TRACE;
        g_debug_config.level          = dl;
    } else {
        g_debug_config.level          = DEBUG_LEVEL_INFO;
    }

    /* chatgui defaults: suppress spam, verbose for our categories */
    g_debug_config.category_levels[DEBUG_CATEGORY_MEMORY] = DEBUG_LEVEL_DISABLED;
    g_debug_config.category_levels[DEBUG_CATEGORY_TIMING] = DEBUG_LEVEL_DISABLED;
    g_debug_config.category_levels[DEBUG_CATEGORY_BGP]    = DEBUG_LEVEL_INFO;

    /* per-category overrides from config: cat=level,cat=level,... */
    if (!m_debugCategories.isEmpty()) {
        QByteArray cats = m_debugCategories.toUtf8();
        char* token = strtok(cats.data(), ",");
        while (token) {
            while (*token == ' ') token++;
            char* eq = strchr(token, '=');
            if (eq) {
                *eq = '\0';
                char* cat_name = token;
                char* lvl_name = eq + 1;
                while (*lvl_name == ' ') lvl_name++;
                debug_category_t cat = get_category_by_name(cat_name);
                debug_level_t    lvl = debug_level_from_name(lvl_name);
                if (cat != DEBUG_CATEGORY_NONE && lvl != DEBUG_LEVEL_NONE) {
                    g_debug_config.category_levels[cat] = lvl;
                    DEBUG_INFO(DEBUG_CATEGORY_DEBUG, "debug category: %s=%s",
                               debug_get_category_name(cat),
                               lvl_name);
                }
            }
            token = strtok(NULL, ",");
        }
    }

    /* file output (shared with GUI via debug_config) */
    if (!m_debugFile.isEmpty()) {
        debug_enable_file_output(m_debugFile.toUtf8().constData(), 0);
        debug_enable_console(1);
        g_debug_config.thread_marker = 2;
    }

    utun_instance_set_tun_init_enabled(0);

    struct UASYNC* ua = uasync_create();
    if (!ua) {
        QMetaObject::invokeMethod(this, [this] { emit error("uasync_create failed"); });
        g_currentNode = nullptr;
        return;
    }
    m_ua = ua;

    m_instance = utun_instance_create(ua, m_configPath.toUtf8().constData());
    if (!m_instance) {
        QMetaObject::invokeMethod(this, [this] { emit error("utun_instance_create failed"); });
        uasync_destroy(ua, 0);
        m_ua = nullptr;
        g_currentNode = nullptr;
        return;
    }

    m_instance->test_user_ptr = this;

    /* enable db_sync for chat message P2P sync */
    m_instance->config->global.db_sync_enabled = 1;
    if (!m_dbPath.isEmpty())
        snprintf(m_instance->config->global.db_path, sizeof(m_instance->config->global.db_path),
                 "%s", m_dbPath.toUtf8().constData());

    /* topo_groups_init did not open topo_sqlite_db because db_path was empty at that time.
     * Open the single shared SQLite connection here with FULLMUTEX (GUI reads from another thread).
     * db_sync_init and chat_core_init will reuse this handle. */
    if (m_instance->config->global.db_path[0] && !m_instance->topo_sqlite_db) {
        char db_file[512];
        snprintf(db_file, sizeof(db_file), "%s/chats.db", m_instance->config->global.db_path);
        int rc = sqlite3_open_v2(db_file, &m_instance->topo_sqlite_db,
            SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE | SQLITE_OPEN_FULLMUTEX, NULL);
        if (rc == SQLITE_OK && m_instance->topo_sqlite_db) {
            sqlite3_exec(m_instance->topo_sqlite_db, "PRAGMA journal_mode=WAL", NULL, NULL, NULL);
            sqlite3_exec(m_instance->topo_sqlite_db, "PRAGMA foreign_keys=ON", NULL, NULL, NULL);
            sqlite3_exec(m_instance->topo_sqlite_db, "PRAGMA synchronous=NORMAL", NULL, NULL, NULL);
            sqlite3_exec(m_instance->topo_sqlite_db, "PRAGMA wal_autocheckpoint=10000", NULL, NULL, NULL);
            topo_node_sqlite_init(m_instance->topo_sqlite_db);
            DEBUG_INFO(DEBUG_CATEGORY_DEBUG, "SQLite (shared): %s db=%p", db_file, (void*)m_instance->topo_sqlite_db);
        } else {
            DEBUG_ERROR(DEBUG_CATEGORY_DEBUG, "SQLite open failed: %s rc=%d", db_file, rc);
            if (m_instance->topo_sqlite_db) { sqlite3_close(m_instance->topo_sqlite_db); m_instance->topo_sqlite_db = NULL; }
        }
    }

    /* set ua for gui_bridge before init, so GUI can post */
    gui_bridge_set_uasync(ua);

    if (utun_instance_init(m_instance) != 0) {
        QMetaObject::invokeMethod(this, [this] { emit error("utun_instance_init failed"); });
        utun_instance_destroy(m_instance);
        m_instance = nullptr;
        uasync_destroy(ua, 0);
        m_ua = nullptr;
        g_currentNode = nullptr;
        return;
    }

    { int sock_count = 0; for (struct ETCP_SOCKET* s = m_instance->etcp_sockets; s; s = s->next) sock_count++;
      DEBUG_INFO(DEBUG_CATEGORY_DEBUG, "utun_node: after instance_init, etcp_sockets=%d conns=%d",
                 sock_count, queue_entry_count(m_instance->connections)); }

    etcp_router_bind(m_instance, ETCP_RT_ID_CHAT, recvCallback);

    /* Initialize chat_core (DB) and chat_sync (channel/message P2P sync) */
    chat_core_init(m_instance, QString(m_dbPath + "/chats.db").toUtf8().constData());
    chat_sync_init(m_instance, nullptr);

    DEBUG_INFO(DEBUG_CATEGORY_DEBUG, "chat_core + chat_sync initialized");
    DEBUG_INFO(DEBUG_CATEGORY_DEBUG, "utun_node: entering poll loop");

    signal(SIGINT, signal_handler);
    signal(SIGTERM, signal_handler);

    while (!m_stop) {
        uasync_poll(ua, 100);
    }

    DEBUG_INFO(DEBUG_CATEGORY_DEBUG, "runLoop: poll exit m_stop=%d", (int)m_stop);

    signal(SIGINT, SIG_DFL);
    signal(SIGTERM, SIG_DFL);

    DEBUG_INFO(DEBUG_CATEGORY_DEBUG, "runLoop: emitting stopped");
    QMetaObject::invokeMethod(this, [this] { emit stopped(); });
}