index.js

const express = require('express');
const lowdDB = require('lowdb');
const FyleSync = require('lowdb/adapters/FileSync');
const joi = require('joi');
const { nanoid } = require('nanoid');
const morgan = require('morgan');

// Server Setup
const PORT = 4000;

// Database Setup
const adapter = new FyleSync('db.json');
const db = lowdDB(adapter);
db.defaults({ users: [], hotels: [] }).write();

// Express Setup
const app = express();

// Global Middlewares
app.use(express.json());
app.use(morgan('dev'));

// Users
// fetch all users
app.get('/api/users', (req, res) => {
  const users = db.get('users').value(); // query
  res.status(200).json({ success: true, data: users });
});

// get an user by id
app.get('/api/users/:id', (req, res) => {
  const { id } = req.params
  const exists = db.get('users').find({ _id: id }).value(); // query
  if (!exists) {
    res.status(404).json({ success: false, message: 'User not found' });
  } else {
    res.status(200).json({ success: true, data: exists });
  }
});

// create new user
app.post('/api/users', (req, res) => {
  const body = req.body;
  // data validation
  const userSchema = joi.object({
    name: joi.string().min(3).max(24).required(),
    lastname: joi.string().min(3).max(24).required(),
    email: joi.string().email().required(),
    username: joi.string().min(3).max(20).alphanum().required(),
    type: joi.string().valid('client', 'owner').required(),
    phone: joi.string().length(10).pattern(/^[0-9]+$/)
  });
  const result = userSchema.validate(body);
  const { value, error } = result;
  const valid = error == null;
  if (!valid) {
    res.status(400).json({ success: false, message: 'Validation error', data: value, error: error });
  } else {
    // query if there is already an user with same email or username
    const exists = db.get('users').find(user => user.email === body.email || user.username === body.username).value();
    if (!exists) {
      // data management for user creation
      const user = {
        _id: nanoid(),
        ...body, 
        createdAt: Date.now(),
      };
      // db management
      db.get('users').push(user).write(); // mutation
      res.status(201).json({ success: true, message: 'User has been created', data: user });
    } else {
      res.status(409).json({ success: false, message: 'Email or Username is already used' });
    }
  }  
});

// update an existing user by id
app.patch('/api/users/:id', (req, res) => {
  const id = req.params.id;
  const body = req.body;
  // validate data
  const userSchema = joi.object({
    name: joi.string().min(3).max(24),
    lastname: joi.string().min(3).max(24),
    email: joi.string().email()
  });
  const result = userSchema.validate(body);
  const { value, error } = result;
  const valid = error == null;
  if (!valid) {
    res.status(400).json({ success: false, message: 'Validation error', data: value, error: error });
  } else {
    const exists = db.get('users').find({ _id: id }).value(); // query
    if (!exists) {
      res.status(404).json({ success: false, message: 'User not found' });
    } else {
      const name = body.name ? body.name : exists.name;
      const lastname = body.lastname ? body.lastname : exists.lastname;
      const email = body.email ? body.email : exists.email;
      const update = { name: name, lastname: lastname, email: email, updatedAt: Date.now() };
      // db management
      const user = db.get('users').find({ _id: id }).assign(update).write();
      res.status(200).json({ success: true,  message: 'User has been updated', data: user });
    }
  }
});

// delete an existing user by id
app.delete('/api/users/:id', (req, res) => {
  const { id } = req.params
  const exists = db.get('users').find({ _id: id }).value(); // query
  if (!exists) {
    res.status(404).json({ success: false, message: 'User not found' });
  } else {
    db.get('users').remove({ _id: id }).write(); // mutation
    res.status(200).json({ success: true, message: 'User has been deleted' });
  }
});

// Hotels
// fetch all hotels
app.get('/api/hotels', (req, res) => {
  const hotels = db.get('hotels').value(); // query
  res.status(200).json({ success: true, data: hotels });
});

// create new hotel
app.post('/api/hotels', (req, res) => {
  const body = req.body;
  // data validation
  const userSchema = joi.object({
    name: joi.string().min(3).max(24).required(),
    phone: joi.string().length(10).pattern(/^[0-9]+$/),
    email: joi.string().email().required(),
    address: joi.string().min(10).max(42).required(),
    ownerId: joi.string().required()
  });
  const result = userSchema.validate(body);
  const { value, error } = result;
  const valid = error == null;
  if (!valid) {
    res.status(400).json({ success: false, message: 'Validation error', data: value, error: error });
  } else {
    // query if there is already an hotel with same name 
    const exists = db.get('hotels').find({ name: body.name }).value();
    // query if customerId is valid
    const validOwnerId = db.get('users').find({ _id: body.ownerId, type: 'owner' }).value();
    if (!exists && validOwnerId) {
      // data management for hotel creation
      const hotel = {
        _id: nanoid(),
        ...body, 
        createdAt: Date.now(),
      };
      // db management
      db.get('hotels').push(hotel).write(); // mutation
      res.status(201).json({ success: true, message: 'Hotel has been created', data: hotel });
    } else {
      res.status(409).json({ success: false, message: 'Hotel name is already taken or owner id is not valid' });
    }
  }  
});

// Custom middleware - express error handler
const errorHandler = require('./middlewares/errorHandler');
app.use(errorHandler);

app.listen(PORT, () => {
  console.log(`App listening on ${PORT}`);
});