const axios = require('axios');
const config = require('../config');
const { parseStoreNumber } = require('../utils/validate');
const { withRetry } = require('../utils/retry');
const logger = require('../utils/logger');

const merakiAxios = axios.create({
  baseURL: config.meraki.baseUrl,
  headers: {
    'X-Cisco-Meraki-API-Key': config.meraki.apiKey,
    'Content-Type': 'application/json',
  },
  timeout: 20000,
});

// In-memory cache
let cachedNetworks = [];
let lastCacheTime = 0;
let inFlightRefresh = null;
const CACHE_TTL_MS = 4 * 60 * 60 * 1000; // 4 hours

const RETRY_OPTS = { retries: 2, initialDelayMs: 500 };

async function refreshMerakiNetworksCache() {
  // Coalesce concurrent callers onto a single in-flight refresh.
  if (inFlightRefresh) return inFlightRefresh;

  const start = Date.now();
  logger.info('Refreshing Meraki networks cache');

  inFlightRefresh = (async () => {
    try {
      const url = `/organizations/${config.meraki.orgId}/networks?perPage=5000`;
      const res = await withRetry(() => merakiAxios.get(url), RETRY_OPTS);
      cachedNetworks = res.data || [];
      lastCacheTime = Date.now();
      logger.info('Meraki networks cache refreshed', {
        count: cachedNetworks.length,
        durationMs: Date.now() - start,
      });
    } catch (err) {
      logger.error('Failed to refresh Meraki networks cache', { error: err.message });
      // Keep the (possibly stale) cache and let callers decide what to do.
    } finally {
      inFlightRefresh = null;
    }
  })();

  return inFlightRefresh;
}

async function getMerakiNetworks(forceRefresh = false) {
  const now = Date.now();
  if (forceRefresh || cachedNetworks.length === 0 || now - lastCacheTime > CACHE_TTL_MS) {
    await refreshMerakiNetworksCache();
  }
  return cachedNetworks;
}

async function findMerakiNetwork(storeNum) {
  const normalized = parseStoreNumber(storeNum);
  if (!normalized) return null;

  // Many store networks in Meraki are named with a 5-digit padded store number.
  const searchTerm = normalized.padStart(5, '0').slice(-5);

  const networks = await getMerakiNetworks();
  logger.debug('Searching Meraki networks', { storeNum: normalized, searchTerm });

  let bestMatch = null;
  let bestScore = -1;

  for (const net of networks) {
    const name = (net.name || '').toLowerCase();
    const term = searchTerm.toLowerCase();

    if (!name.includes(term)) continue;

    const score =
      name.includes(` ${term}`) || name.includes(`-${term}`) || name.includes(`${term} `)
        ? 100
        : 50;

    if (score > bestScore) {
      bestScore = score;
      bestMatch = net;
    }
  }

  if (bestMatch) {
    logger.info('Best Meraki network match', { name: bestMatch.name, id: bestMatch.id });
  } else {
    logger.info('No Meraki network match', { storeNum });
  }
  return bestMatch;
}

async function getMerakiDeviceAvailabilities(networkId) {
  if (!networkId || !config.meraki.orgId) return [];

  try {
    const res = await withRetry(
      () =>
        merakiAxios.get(`/organizations/${config.meraki.orgId}/devices/availabilities`, {
          params: { networkIds: [networkId] },
        }),
      RETRY_OPTS
    );
    return res.data || [];
  } catch (err) {
    logger.error('Device availabilities failed', { error: err.message });
    return [];
  }
}

async function getMerakiClients(networkId) {
  if (!networkId) return [];

  try {
    // 7-day window catches registers and printers that only check in occasionally.
    const timespanSeconds = 7 * 24 * 60 * 60;
    const res = await withRetry(
      () =>
        merakiAxios.get(`/networks/${networkId}/clients`, {
          params: { perPage: 1000, timespan: timespanSeconds },
        }),
      RETRY_OPTS
    );

    const clients = res.data || [];
    logger.info('Fetched Meraki clients', { count: clients.length, networkId });
    return clients;
  } catch (err) {
    logger.error('Failed to fetch Meraki clients', { error: err.message, networkId });
    return [];
  }
}

module.exports = {
  findMerakiNetwork,
  getMerakiClients,
  getMerakiDeviceAvailabilities,
  refreshMerakiNetworksCache,
};