const cacheManager = require('cache-manager');
const mangodbStore = require('cache-manager-mongodb');

const GLOBAL_KEY_PREFIX = 'torrentio-addon';
const STREAM_KEY_PREFIX = `${GLOBAL_KEY_PREFIX}|stream`;

const STREAM_TTL = process.env.STREAM_TTL || 24 * 60 * 60; // 24 hours
const STREAM_EMPTY_TTL = process.env.STREAM_EMPTY_TTL || 30 * 60; // 30 minutes
// When the streams are empty we want to cache it for less time in case of timeouts or failures

const MONGO_URI = process.env.MONGODB_URI;
const NO_CACHE = process.env.NO_CACHE || false;

const cache = initiateCache();

function initiateCache() {
  if (NO_CACHE) {
    return null;
  } else if (MONGO_URI) {
    return cacheManager.caching({
      store: mangodbStore,
      uri: MONGO_URI,
      options: {
        collection: 'torrentio-addon',
        ttl: STREAM_TTL
      },
      ttl: STREAM_TTL,
      ignoreCacheErrors: true
    });
  } else {
    return cacheManager.caching({
      store: 'memory',
      ttl: STREAM_TTL
    });
  }
}

function cacheWrap(key, method, options) {
  if (NO_CACHE || !cache) {
    return method();
  }
  return cache.wrap(key, method, options);
}

function cacheWrapStream(id, method) {
  return cacheWrap(`${STREAM_KEY_PREFIX}:${id}`, method, {
    ttl: (streams) => streams.length ? STREAM_TTL : STREAM_EMPTY_TTL
  });
}

module.exports = { cacheWrapStream };