/**
 * Планировщик пинга сервисов из списка настроек.
 * Периодически вызывает refreshPingServicesCache и обновляет кеш для GET /api/ping-services.
 */

const { readS3TextObject } = require('./s3Service');
const { refreshPingServicesCache } = require('../routes/miscRoutes');

const UI_SETTINGS_KEY = 'bgp_data/rt_ui_settings.json';

const DEFAULT_INTERVAL_MINUTES = 2;

let schedulerTimer = null;
let lastScheduledRunAt = null;

function getSettingsFromUiSettings(uiSettings) {
  return {
    enabled: uiSettings.pingServicesSchedulerEnabled !== false,
    intervalMinutes: Math.max(1, Math.min(1440, parseInt(uiSettings.pingServicesSchedulerIntervalMinutes, 10) || DEFAULT_INTERVAL_MINUTES)),
  };
}

/**
 * Время следующего запуска по расписанию (timestamp или null если выключено).
 */
function getNextRunAt(settings) {
  if (!settings || !settings.enabled) return null;
  const intervalMs = (settings.intervalMinutes || DEFAULT_INTERVAL_MINUTES) * 60 * 1000;
  const from = lastScheduledRunAt || Date.now();
  return from + intervalMs;
}

/**
 * Запустить планировщик пинг-сервисов.
 * @param {object} logger - pino logger
 */
function initPingServicesScheduler(logger) {
  const log = logger || console;

  async function tick() {
    lastScheduledRunAt = Date.now();
    let uiSettings;
    try {
      const raw = await readS3TextObject(UI_SETTINGS_KEY).catch(() => ({ body: '{}' }));
      uiSettings = JSON.parse(raw?.body || '{}') || {};
    } catch (_) {
      return;
    }
    const settings = getSettingsFromUiSettings(uiSettings);
    if (!settings.enabled) return;

    log.info({ component: 'ping-services-scheduler' }, 'Running ping services refresh');
    refreshPingServicesCache().catch((err) => {
      log.error({ component: 'ping-services-scheduler', err: err?.message }, 'Ping services refresh failed');
    });
  }

  async function schedule() {
    let uiSettings;
    try {
      const raw = await readS3TextObject(UI_SETTINGS_KEY).catch(() => ({ body: '{}' }));
      uiSettings = JSON.parse(raw?.body || '{}') || {};
    } catch (_) {
      return;
    }
    const settings = getSettingsFromUiSettings(uiSettings);
    if (!settings.enabled) {
      log.info({ component: 'ping-services-scheduler' }, 'Ping services scheduler disabled in settings');
      return;
    }
    const intervalMs = settings.intervalMinutes * 60 * 1000;
    log.info(
      { component: 'ping-services-scheduler', intervalMinutes: settings.intervalMinutes },
      'Ping services scheduler started (first run in 15 s, then every %d min)',
      settings.intervalMinutes
    );
    schedulerTimer = setInterval(tick, intervalMs);
    setTimeout(() => tick(), 15 * 1000);
  }

  schedule();
}

function stopPingServicesScheduler() {
  if (schedulerTimer) {
    clearInterval(schedulerTimer);
    schedulerTimer = null;
  }
}

module.exports = {
  initPingServicesScheduler,
  stopPingServicesScheduler,
  getSettingsFromUiSettings,
  getNextRunAt,
};