import debug from 'debug';
import http from 'http';
import mongoose from 'mongoose';
import app from './app';

/**
 * Get MONGO_URL from environment or config and connect mongodb throw mongoose.
 */
mongoose.Promise = global.Promise;
mongoose.connect(process.env.MONGO_URL, {
  useNewUrlParser: true,
  useUnifiedTopology: true,
  useCreateIndex: true,
});

mongoose.connection.on('error', () => {
  console.error(
    'Could not connect to MongoDB. Did you forget to run `mongod`?',
  );
});

mongoose.connection.on('connected', () => {
  console.info(`APP MONGODB@${mongoose.version}:`, process.env.MONGO_URL);
});

mongoose.connection.on('disconnected', () => {
  console.info(`Mongoose disconnected to: ${process.env.MONGO_URL}`);
});

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

/**
 * Normalize a port into a number, string, or false.
 */
function normalizePort(val) {
  const port = parseInt(val, 10);
  if (Number.isNaN(port)) {
    // named pipe
    return val;
  }
  if (port >= 0) {
    // port number
    return port;
  }
  return false;
}

/**
 * Get PORT from environment and store in Express.
 */
const port = normalizePort(process.env.PORT || 3000);
app.set('port', port);

/**
 * Event listener for HTTP server "error" event.
 */
function onError(error) {
  if (error.syscall !== 'listen') {
    throw error;
  }
  const bind = typeof port === 'string' ? `Pipe ${port}` : `Port ${port}`;
  // handle specific listen errors with friendly messages
  switch (error.code) {
    case 'EACCES':
      console.error(`${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() {
  const addr = server.address();
  const bind = typeof addr === 'string' ? `pipe ${addr}` : `port ${addr.port}`;
  debug('MERNjs:app')(`Listening on ${bind} in ${app.get('env')} env`);
}

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