'use strict';

  const TTL_SECS = 30;

  const coreapi = require('komodo-sdk/coreapi');

  const NodeCache = require( "node-cache" );
  
  const cache = new NodeCache({

      stdTTL: TTL_SECS,    

  });

  
  async function lookup(number) {
      if (!number) return;

      if (cache.get(number)) {
          return cache.get(number);
      }

      const [err, lookupResult] = await coreapi({
          path: '/prefixes/lookup',
          method: 'GET',
          qs: {
              number,
          }
      });
  
      if (err || !lookupResult || lookupResult.error) {

          cache.del(number);

          return;
      }

      if (lookupResult.prefix) {
          cache.set(number, lookupResult.prefix);
      } else {
          cache.del(number);
      }

      return lookupResult.prefix;
  }
  
  exports.lookup = lookup;