var express = require('express'),
    app = express(),
    cors = require('cors'),
    helmet = require('helmet'),
    mysql = require('mysql'),
    bodyParser = require('body-parser'),
    crypto = require('crypto'),
    algorithm = 'aes-256-ctr',
    password = 'zyxcba',
    port = 3000;

app.use(cors());
app.use(helmet());
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({
    extended: false
}));

var database = mysql.createPool({
  connectionLimit : 100,
  host: 'localhost',
  user: '*****',
  password: '*****',
  database: 'devesh',
  port: 3306
});

/**
 * Encrypt function
 */
function encrypt(text){
  var cipher = crypto.createCipher(algorithm,password)
  var crypted = cipher.update(text,'utf8','hex')
  crypted += cipher.final('hex');
  return crypted;
}

/**
 * Decrypt function
 */
function decrypt(text){
  var decipher = crypto.createDecipher(algorithm,password)
  var dec = decipher.update(text,'hex','utf8')
  dec += decipher.final('utf8');
  return dec;
}

app.post('/encrypt',function(req,res){

  const appData = {};
  const first_name = req.body.first_name;
  const last_name = req.body.last_name;
  const age = req.body.age;

  const userData = {
    first_name: encrypt(first_name),
    last_name : encrypt(last_name),
    age: age
  }

  database.getConnection(function(err,connection){
    if(err){
      appData['error'] = 1;
      appData['data'] = 'Internal server error'
      res.status(500).json(appData);
    }else{
      connection.query('INSERT INTO employee SET?',userData,function(err,rows,fields){
        if(err){
          appData['error'] = 1;
          appData['data'] = 'Error adding data'
          res.status(500).json(appData);
        }else{
          appData['error'] = 0;
          appData['data'] = 'Data saved in encrypted form succesfully!'
          res.status(200).json(appData);
        }
      });
      connection.release();
    }
  });
});

app.listen(port, function(){
  console.log('Server listening to port',port);
})