const redis = require('redis');
const debug = require('debug')('talk:redis');
const url = process.env.TALK_REDIS_URL || 'redis://localhost';

module.exports = {
  createClient() {
    let client = redis.createClient(url, {
      retry_strategy: function(options) {
        if (options.error && options.error.code === 'ECONNREFUSED') {

          // End reconnecting on a specific error and flush all commands with a individual error
          return new Error('The server refused the connection');
        }
        if (options.total_retry_time > 1000 * 60 * 60) {

          // End reconnecting after a specific timeout and flush all commands with a individual error
          return new Error('Retry time exhausted');
        }

        if (options.times_connected > 10) {

          // End reconnecting with built in error
          return undefined;
        }

        // reconnect after
        return Math.max(options.attempt * 100, 3000);
      }
    });

    client.ping((err) => {
      if (err) {
        console.error('Can\'t ping the redis server!');

        throw err;
      }

      debug('connection established');
    });

    return client;
  }
};