import GLib from 'gi://GLib';
import Gio from 'gi://Gio';
import GObject from 'gi://GObject';
import St from 'gi://St';

import {Extension} from 'resource:///org/gnome/shell/extensions/extension.js';
import * as Main from 'resource:///org/gnome/shell/ui/main.js';
import * as PopupMenu from 'resource:///org/gnome/shell/ui/popupMenu.js';
import * as QuickSettings from 'resource:///org/gnome/shell/ui/quickSettings.js';

const QuickSettingsMenu = Main.panel.statusArea.quickSettings;

// ── constants ────────────────────────────────────────────────────────────────

const SERVICE_NAME       = 'nebula@jallen-nebula.service';
const IFACE_NAME         = 'nebula0';
const POLL_INTERVAL_SECS = 5;
const LOG_PREFIX         = '[nebula-vpn]';

// ── helpers ──────────────────────────────────────────────────────────────────

function log(msg) {
    console.log(`${LOG_PREFIX} ${msg}`);
}

function logErr(msg, err) {
    console.error(`${LOG_PREFIX} ${msg}`, err ?? '');
}

function runCommand(argv) {
    log(`runCommand: ${argv.join(' ')}`);
    try {
        const [ok, stdout, stderr, exitCode] = GLib.spawn_sync(
            null, argv, null, GLib.SpawnFlags.SEARCH_PATH, null,
        );
        const result = {
            success: ok && exitCode === 0,
            stdout:  ok ? new TextDecoder().decode(stdout).trim() : '',
            stderr:  ok ? new TextDecoder().decode(stderr).trim() : '',
        };
        log(`runCommand result: success=${result.success} exitCode=${exitCode} stdout="${result.stdout}" stderr="${result.stderr}"`);
        return result;
    } catch (e) {
        logErr(`runCommand exception for [${argv.join(' ')}]:`, e);
        return {success: false, stdout: '', stderr: ''};
    }
}

function isServiceActive() {
    const r = runCommand(['systemctl', 'is-active', '--quiet', SERVICE_NAME]);
    log(`isServiceActive: ${r.success}`);
    return r.success;
}

function getIfaceInfo() {
    const r = runCommand(['ip', '-brief', 'addr', 'show', IFACE_NAME]);
    if (!r.success || r.stdout === '') {
        log('getIfaceInfo: not found');
        return {found: false, ipv4: null, ipv6: null};
    }
    const parts = r.stdout.split(/\s+/);
    const addrs = parts.slice(2);
    const ipv4  = addrs.find(a => /^\d+\.\d+\.\d+\.\d+\//.test(a)) ?? null;
    const ipv6  = addrs.find(a => a.includes(':') && !a.startsWith('fe80')) ?? null;
    log(`getIfaceInfo: state=${parts[1]} ipv4=${ipv4} ipv6=${ipv6}`);
    return {found: true, ipv4, ipv6};
}

function readSysfs(path) {
    try {
        const [ok, contents] = Gio.File.new_for_path(path).load_contents(null);
        if (!ok) return null;
        const val = parseInt(new TextDecoder().decode(contents).trim(), 10);
        return isNaN(val) ? null : val;
    } catch (_e) {
        return null;
    }
}

function getIfaceStats() {
    const base = `/sys/class/net/${IFACE_NAME}/statistics`;
    const rx   = readSysfs(`${base}/rx_bytes`);
    const tx   = readSysfs(`${base}/tx_bytes`);
    log(`getIfaceStats: rx=${rx} tx=${tx}`);
    return {rx, tx};
}

function formatBytes(bytes) {
    if (bytes === null) return '—';
    if (bytes < 1024) return `${bytes} B`;
    if (bytes < 1024 ** 2) return `${(bytes / 1024).toFixed(1)} KB`;
    if (bytes < 1024 ** 3) return `${(bytes / 1024 ** 2).toFixed(1)} MB`;
    return `${(bytes / 1024 ** 3).toFixed(2)} GB`;
}

function getServiceUptime() {
    const r = runCommand([
        'systemctl', 'show', SERVICE_NAME,
        '--property=ActiveEnterTimestampMonotonic',
    ]);
    if (!r.success) return null;
    const match = r.stdout.match(/=(\d+)/);
    if (!match) return null;
    const elapsedSecs = Math.floor(
        (GLib.get_monotonic_time() - parseInt(match[1], 10)) / 1_000_000
    );
    if (elapsedSecs < 0) return null;
    const h = Math.floor(elapsedSecs / 3600);
    const m = Math.floor((elapsedSecs % 3600) / 60);
    const s = elapsedSecs % 60;
    if (h > 0) return `${h}h ${m}m`;
    if (m > 0) return `${m}m ${s}s`;
    return `${s}s`;
}

function setServiceActive(enable) {
    const action = enable ? 'start' : 'stop';
    log(`setServiceActive: ${action}`);
    runCommand(['systemctl', action, SERVICE_NAME]);
}

// ── Quick Settings toggle tile ────────────────────────────────────────────────

const NebulaToggle = GObject.registerClass(
class NebulaToggle extends QuickSettings.QuickMenuToggle {

    _init() {
        log('NebulaToggle._init');
        super._init({
            title: 'Nebula VPN',
            iconName: 'network-vpn-symbolic',
            toggleMode: true,
        });

        // Header shown at the top of the expanded menu panel
        this.menu.setHeader('network-vpn-symbolic', 'Nebula VPN', 'jallen-nebula');

        // ── menu body ──────────────────────────────────────────────

        this._statusItem = new PopupMenu.PopupMenuItem('', {reactive: false});
        this._statusItem.label.set_style('font-weight: bold;');
        this.menu.addMenuItem(this._statusItem);

        this._ipv4Item = new PopupMenu.PopupMenuItem('', {reactive: false});
        this.menu.addMenuItem(this._ipv4Item);

        this._ipv6Item = new PopupMenu.PopupMenuItem('', {reactive: false});
        this.menu.addMenuItem(this._ipv6Item);

        this.menu.addMenuItem(new PopupMenu.PopupSeparatorMenuItem());

        // "Network" expandable submenu
        this._networkSubmenu = new PopupMenu.PopupSubMenuMenuItem('Network');
        this._uptimeItem = new PopupMenu.PopupMenuItem('', {reactive: false});
        this._rxItem     = new PopupMenu.PopupMenuItem('', {reactive: false});
        this._txItem     = new PopupMenu.PopupMenuItem('', {reactive: false});
        this._networkSubmenu.menu.addMenuItem(this._uptimeItem);
        this._networkSubmenu.menu.addMenuItem(this._rxItem);
        this._networkSubmenu.menu.addMenuItem(this._txItem);
        this.menu.addMenuItem(this._networkSubmenu);

        this.menu.addMenuItem(new PopupMenu.PopupSeparatorMenuItem());

        const refreshItem = new PopupMenu.PopupMenuItem('Refresh');
        refreshItem.connect('activate', () => this._refresh());
        this.menu.addMenuItem(refreshItem);

        // ── wire up the toggle click ───────────────────────────────
        this.connect('clicked', () => this._onToggle());

        // ── initial state + polling ────────────────────────────────
        this._active = false;
        this._refresh();
        this._timerId = GLib.timeout_add_seconds(
            GLib.PRIORITY_DEFAULT,
            POLL_INTERVAL_SECS,
            () => { this._refresh(); return GLib.SOURCE_CONTINUE; },
        );
        log(`NebulaToggle._init: poll timer id=${this._timerId}`);
    }

    _refresh() {
        log('_refresh: polling');
        this._active = isServiceActive();
        const iface  = getIfaceInfo();
        const stats  = getIfaceStats();
        const uptime = this._active ? getServiceUptime() : null;
        log(`_refresh: active=${this._active} iface=${JSON.stringify(iface)} stats=${JSON.stringify(stats)} uptime=${uptime}`);
        this._updateUI(iface, stats, uptime);
    }

    _updateUI(iface, stats, uptime) {
        log(`_updateUI: active=${this._active}`);

        // Sync the toggle checked state without re-triggering the click handler
        this.set({checked: this._active});

        if (this._active) {
            this.subtitle = iface.ipv4 ?? 'connected';
            this._statusItem.label.text  = 'Status: Connected';
            this._ipv4Item.label.text    = iface.ipv4 ? `IPv4: ${iface.ipv4}` : 'IPv4: —';
            this._ipv6Item.label.text    = iface.ipv6 ? `IPv6: ${iface.ipv6}` : 'IPv6: —';
            this._ipv4Item.visible       = true;
            this._ipv6Item.visible       = true;
            this._networkSubmenu.visible = true;
            this._uptimeItem.label.text  = `Uptime: ${uptime ?? '—'}`;
            this._rxItem.label.text      = `RX: ${formatBytes(stats.rx)}`;
            this._txItem.label.text      = `TX: ${formatBytes(stats.tx)}`;
        } else {
            this.subtitle = null;
            this._statusItem.label.text  = 'Status: Disconnected';
            this._ipv4Item.visible       = false;
            this._ipv6Item.visible       = false;
            this._networkSubmenu.visible = false;
        }
    }

    _onToggle() {
        const target = !this._active;
        log(`_onToggle: → ${target ? 'start' : 'stop'}`);
        setServiceActive(target);
        // Optimistic update
        this._active = target;
        this._updateUI(getIfaceInfo(), getIfaceStats(), null);
        // Confirm after systemd settles
        GLib.timeout_add_seconds(GLib.PRIORITY_DEFAULT, 2, () => {
            log('_onToggle: confirmation poll');
            this._refresh();
            return GLib.SOURCE_REMOVE;
        });
    }

    destroy() {
        log('NebulaToggle.destroy');
        if (this._timerId) {
            GLib.source_remove(this._timerId);
            this._timerId = null;
        }
        super.destroy();
    }
});

// ── System indicator (lives in the Quick Settings panel) ─────────────────────

const NebulaIndicator = GObject.registerClass(
class NebulaIndicator extends QuickSettings.SystemIndicator {

    _init() {
        log('NebulaIndicator._init');
        super._init();

        // Small icon shown in the top bar when the VPN is active
        this._indicator = this._addIndicator();
        this._indicator.icon_name = 'network-vpn-symbolic';
        this._indicator.visible   = false;

        const toggle = new NebulaToggle();

        // Keep the top-bar indicator icon in sync with toggle state
        toggle.connect('notify::checked', () => {
            this._indicator.visible = toggle.checked;
        });

        this.quickSettingsItems.push(toggle);

        // Insert into the Quick Settings menu — same call GSConnect uses
        QuickSettingsMenu.addExternalIndicator(this);
        log('NebulaIndicator._init: added to QuickSettings');
    }

    destroy() {
        log('NebulaIndicator.destroy');
        this.quickSettingsItems.forEach(item => item.destroy());
        super.destroy();
    }
});

// ── Extension lifecycle ───────────────────────────────────────────────────────

let nebulaIndicator = null;

export default class NebulaVpnExtension extends Extension {
    enable() {
        log('enable');
        nebulaIndicator = new NebulaIndicator();
    }

    disable() {
        log('disable');
        nebulaIndicator?.destroy();
        nebulaIndicator = null;
    }
}