/**
 * AV (Atlas) device-discovery service.
 *
 * Thin shim over integrations/atlas: pulls the Atlas devices belonging to a
 * store and shapes each into a renderer-friendly object the storeDetail AV
 * report consumes. Mirrors the contract of services/webexPhone.js — on any
 * unrecoverable failure (missing ATLAS_AUTH_KEY, transport error) it returns
 * `{ devices: [], unavailable: true, reason }` rather than throwing, so the
 * bot can render a banner alongside whatever other AV data (MDM Apple TVs
 * etc.) is still available.
 *
 * Atlas field names vary subtly across device types; `shapeAtlasDevice`
 * picks defensively from the locations the collabFinder reference touched
 * (`state.IpAddress`, `state.MacAddress`, `connection_status`, `status`,
 * etc.). The renderer treats `online === null` as "unknown" so an unfamiliar
 * payload degrades gracefully.
 */

const { getAtlasDevicesForStore } = require('../integrations/atlas/atlasDevices');
const logger = require('../utils/logger');

const ONLINE_KEYWORDS = new Set(['online', 'connected', 'active', 'up']);
const OFFLINE_KEYWORDS = new Set(['offline', 'disconnected', 'inactive', 'down']);

function deriveOnline(dev) {
  // Try the most specific fields first; fall back to top-level `status`.
  const candidates = [
    dev?.connection_status,
    dev?.state?.connection_status,
    dev?.state?.status,
    dev?.status,
  ];

  for (const c of candidates) {
    if (typeof c === 'boolean') return c;
    if (typeof c !== 'string') continue;
    const lower = c.trim().toLowerCase();
    if (!lower) continue;
    if (ONLINE_KEYWORDS.has(lower)) return true;
    if (OFFLINE_KEYWORDS.has(lower)) return false;
  }
  return null;
}

function pickFirst(...values) {
  for (const v of values) {
    if (v !== undefined && v !== null && v !== '') return v;
  }
  return null;
}

function shapeAtlasDevice(dev) {
  const state = dev?.state || {};
  const model = pickFirst(
    typeof dev?.model === 'string' ? dev.model : null,
    dev?.model?.name,
    dev?.model_name,
    dev?.product
  );
  const firmware = pickFirst(dev?.firmware?.version, dev?.firmware_version, state?.firmware);

  return {
    id: dev?.id || null,
    name: dev?.name || dev?.displayName || 'Unknown AV Device',
    model,
    firmware,
    mac: pickFirst(dev?.mac, state?.MacAddress, state?.macAddress, dev?.mac_address),
    ip: pickFirst(state?.IpAddress, state?.ipAddress, dev?.ip, dev?.ip_address),
    online: deriveOnline(dev),
    lastSeen: pickFirst(
      dev?.last_connection,
      dev?.last_seen,
      state?.lastSeen,
      state?.last_seen,
      dev?.updated_at
    ),
  };
}

/**
 * Collect AV devices for the given store. Always resolves with the
 * unavailable banner contract — never throws — so the storeDetail layer can
 * compose this alongside MDM and Meraki output without try/catch noise.
 */
async function collectAvStatus(storeNumber) {
  logger.debug('collectAvStatus start', { storeNumber });

  let result;
  try {
    result = await getAtlasDevicesForStore(storeNumber);
  } catch (err) {
    logger.error('Atlas lookup threw unexpectedly', { storeNumber, error: err.message });
    return { devices: [], unavailable: true, reason: err.message };
  }

  if (result.unavailable) {
    return { devices: [], unavailable: true, reason: result.reason };
  }

  const devices = (result.devices || []).map(shapeAtlasDevice);
  logger.info('collectAvStatus done', { storeNumber, count: devices.length });
  return { devices };
}

module.exports = {
  collectAvStatus,
  // Exposed for tests
  shapeAtlasDevice,
  deriveOnline,
};