/**
 * Module dependencies.
 */
import Debug from 'debug';
import http from 'http';
import { Application } from './app';

const debug = Debug('server:startup');

const { app, metricsInterval } = Application;

/**
 * Get port from environment
 */

const port = normalizePort(process.env.PORT || process.env.NODE_PORT || '3000');
// app.set('port', port);

/**
 * Create HTTP server.
 */

const server = http.createServer(app.callback());

/**
 * Listen on provided port, on all network interfaces.
 */

server.listen(port);
server.on('error', onError);
server.on('listening', onListening);
server.on('close', () => {
  clearInterval(metricsInterval);
});

/**
 * Normalize a port into a number, string, or false.
 */
/* istanbul ignore next */
function normalizePort(val: string) {
  let port = parseInt(val, 10);

  if (isNaN(port)) {
    // named pipe
    return val;
  }

  if (port >= 0) {
    // port number
    return port;
  }

  return false;
}

/**
 * Event listener for HTTP server "error" event.
 */
/* istanbul ignore next */
function onError(error: any) {
  if (error.syscall !== 'listen') {
    throw error;
  }

  let bind = typeof port === 'string'
    ? 'Pipe ' + port
    : 'Port ' + port;

  // handle specific listen errors with friendly messages
  switch (error.code) {
    case 'EACCES':
      console.error(bind + ' requires elevated privileges');
      process.exit(1);
      break;
    case 'EADDRINUSE':
      console.error(bind + ' is already in use');
      process.exit(1);
      break;
    default:
      throw error;
  }
}

/**
 * Event listener for HTTP server "listening" event.
 */

function onListening() {
  let addr = server.address();
  let bind = typeof addr === 'string'
    ? 'pipe ' + addr
    : 'port ' + addr!.port;
  debug('Listening on ' + bind);
}

export default server;