const express = require('express');
const expressStatus = require('express-status-monitor');
const crypto = require('crypto');
const fs = require('fs');
const path = require('path');

const app = express();

app.use(expressStatus());

app.get('/', (req, res) => {
  res.send('Hello world');
});

app.get('/regex', (req, res) => {
  const userAgent = `aaaa${req.headers['user-agent']}`;
  res.send(`greedy regex (a+)+ ${(/(a+)+/).test(userAgent)}`);
});

app.get('/crypto', (req, res) => {
  const buf = crypto.randomBytes(256);
  res.send(`crypto.randomBytes(256): ${buf}`);
});

app.get('/file', (req, res) => {
  const hash = crypto.createHash('sha512');
  const filename = path.resolve(__dirname, 'package-lock.json');
  const stream = fs.ReadStream(filename);

  const randomString = Math.random().toString(36).substring(2, 15) + Math.random().toString(36).substring(2, 15);
  hash.update(randomString);

  stream.on('data', (data) => {
    hash.update(data);
  });

  // making digest
  stream.on('end', () => {
    res.send(`file hash: ${hash.digest('hex')}`);
  });
});

app.listen(3000, () => {
  console.log('Test server on port 3000!');
});