/*
 * Copyright (C) 2019 StApps
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */
import {Logger} from '@openstapps/logger';
import * as http from 'http';
import {app} from './app';

/**
 * Get port from environment and store in Express.
 */
// tslint:disable-next-line: strict-boolean-expressions
const port = normalizePort(process.env.PORT || '3000');
// TODO: Can we remove that? It doesn't look like it is read at all.
app.set('port', port);

/**
 * Create HTTP server.
 */
const server = http.createServer(app);

/**
 * Listen on provided port, on all network interfaces.
 */
server.listen(port);
server.on('error', onError);
server.on('listening', onListening);

/**
 * Normalize a port into a number, string, or false.
 */
function normalizePort(value: string) {
  const portNumber = parseInt(value, 10);

  if (isNaN(portNumber)) {
    // named pipe
    return value;
  }

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

  return false;
}

/**
 * Event listener for HTTP server "error" event.
 */
// tslint:disable-next-line: completed-docs
async function onError(error: { code: string; syscall: string; }) {
  if (error.syscall !== 'listen') {
    throw error;
  }

  const bind = typeof port === 'string'
    ? `Pipe ${port}`
    : `Port ${port}`;

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

/**
 * Event listener for HTTP server "listening" event.
 */
function onListening() {
  const addr = server.address();
  const bind = typeof addr === 'string'
    ? `pipe  ${addr}`
    : `port ${addr.port}`;
  Logger.ok(`Listening on ${bind}`);
}