const fs = require('fs');
const bodyParser = require('body-parser');
const jsonServer = require('json-server');
const jwt = require('jsonwebtoken');

const server = jsonServer.create();

const router = jsonServer.router('./db.json');

const userdb = JSON.parse(fs.readFileSync('./users.json', 'UTF-8'));

server.use(bodyParser.urlencoded({extended: true}))
server.use(bodyParser.json())
//server.use(jsonServer.defaults());

const SECRET_KEY = '123456789';
const expiresIn = '1h';

// Create a token from a payload
function createToken(payload){
    return jwt.sign(payload, SECRET_KEY, {expiresIn});
  }

// Verify the token
function verifyToken(token){
    return  jwt.verify(token, SECRET_KEY, (err, decode) => decode !== undefined ?  decode : err);
  }

  // Check if the user exists in database
function isAuthenticated({phone, password}){
    return userdb.users.findIndex(user => user.phone === phone && user.password === password) !== -1;
  }

  server.post('/auth/login', (req, res) => {
    const {phone, password} = req.body;
    if (isAuthenticated({phone, password}) === false) {
      const status = 401;
      const message = 'Incorrect phone or password';
      res.status(status).json({status, message});
      return;
    }
    const access_token = createToken({phone, password});
    res.status(200).json({access_token});
  });

  server.use(/^(?!\/auth).*$/,  (req, res, next) => {
    if (req.headers.authorization === undefined || req.headers.authorization.split(' ')[0] !== 'Bearer') {
      const status = 401;
      const message = 'Bad authorization header';
      res.status(status).json({status, message});
      return;
    }
    try {
       verifyToken(req.headers.authorization.split(' ')[1]);
       next();
    } catch (err) {
      const status = 401;
      const message = 'Error: access_token is not valid';
      res.status(status).json({status, message});
    }
  });

  server.use(router);

  server.listen(3000, () => {
    console.log('Run Auth API Server');
  })