// services/callTest/locationResolver.js
// Resolve Webex Calling location from a dialed E.164 (store main / AA DID).

import { logger } from '../../utils/logger.js';
import { normalizeE164 } from './config.js';

const LOG_SCOPE = 'calltest:location';
const CACHE_TTL_MS = 60 * 60 * 1000;

let _phoneIndex = null;
let _phoneIndexAt = 0;

async function getWebex() {
  const mod = await import('../../integrations/webex/WebexClient.js');
  return mod.default;
}

function parseLinkNext(linkHeader) {
  if (!linkHeader || typeof linkHeader !== 'string') return null;
  for (const part of linkHeader.split(',')) {
    const m = part.match(/<([^>]+)>\s*;\s*rel\s*=\s*"?next"?/i);
    if (m) return m[1];
  }
  return null;
}

function phoneDigits(value) {
  const d = String(value || '').replace(/\D/g, '');
  if (d.length === 10) return `1${d}`;
  if (d.length === 11 && d.startsWith('1')) return d;
  return d;
}

async function fetchAllNumbers() {
  const webex = await getWebex();
  const all = [];
  let nextUrl = null;
  let data;
  let headers;

  ({ data, headers } = await webex.requestRaw('GET', 'telephony/config/numbers', null, { max: 1000 }));
  const batch = data?.phoneNumbers || [];
  all.push(...batch);
  nextUrl = parseLinkNext(headers?.link || headers?.Link);

  while (nextUrl) {
    ({ data, headers } = await webex.requestRaw('GET', nextUrl));
    all.push(...(data?.phoneNumbers || []));
    nextUrl = parseLinkNext(headers?.link || headers?.Link);
  }

  return all;
}

async function buildPhoneIndex() {
  const now = Date.now();
  if (_phoneIndex && now - _phoneIndexAt < CACHE_TTL_MS) {
    return _phoneIndex;
  }

  logger(LOG_SCOPE, 'Building location phone index from telephony/config/numbers', 'debug');
  const numbers = await fetchAllNumbers();
  const index = new Map();

  for (const n of numbers) {
    const raw = n.phoneNumber || n.number || n.value;
    const loc = n.location;
    if (!raw || !loc?.id) continue;

    const entry = {
      locationId: loc.id,
      locationName: loc.name || null,
      phoneNumber: raw,
    };

    const keys = new Set([phoneDigits(raw), phoneDigits(normalizeE164(raw) || raw)]);
    for (const k of keys) {
      if (k) index.set(k, entry);
    }
  }

  _phoneIndex = index;
  _phoneIndexAt = now;
  logger(LOG_SCOPE, `Phone index built: ${index.size} keys from ${numbers.length} numbers`, 'debug');
  return index;
}

/**
 * Find Webex location for a dialed E.164 (e.g. store main on /calltest dial).
 * @returns {Promise<{locationId: string, locationName: string, phoneNumber: string}|null>}
 */
export async function resolveLocationForDialNumber(dialNumber) {
  const e164 = normalizeE164(dialNumber);
  if (!e164) return null;

  try {
    const index = await buildPhoneIndex();
    const key = phoneDigits(e164);
    const hit = index.get(key);
    if (!hit?.locationName) return null;

    return {
      locationId: hit.locationId,
      locationName: hit.locationName,
      phoneNumber: hit.phoneNumber,
    };
  } catch (err) {
    logger(LOG_SCOPE, `resolveLocationForDialNumber failed: ${err.message}`, 'warn');
    return null;
  }
}

export function _clearLocationCacheForTests() {
  _phoneIndex = null;
  _phoneIndexAt = 0;
}