server.js

const express = require('express');
const favicon = require('serve-favicon')
const bodyParser = require('body-parser');
const path = require('path');
const { randomBytes } = require('crypto');
const { passport } = require('./auth.js');
const requireHttps = require('./require-https.js');
const {
  validate, GreetingSchema,
} = require('./validation.js');
let dbClient = null;
let collections = null;
let dynamodbClient = null;
if ('development' === process.env.NODE_ENV) dbClient = require('./db').dbClient;
if ('development' === process.env.NODE_ENV) collections = require('./db').collections;
if ('development' !== process.env.NODE_ENV) dynamodbClient = require('./db').dynamodbClient;
const { errorHandler, asyncMiddleware } = require('./error-handler.js');
const logger = require('./logger.js');

const apiBaseUrl = '/api/v1';
const app = express();

if ('true' === process.env.HTTPS) app.use(requireHttps);;
app.use(bodyParser.json());
app.use(express.static(path.join(__dirname, '../client/build')));
app.use(favicon(path.join(__dirname, '../client/build', 'favicon.ico')))

// Remove empty strings (DynamoDB doesn't accept)
const scrubObject = (obj) => {
  const scrubbed = obj;
  Object.keys(scrubbed).forEach((key) => {
    if (typeof scrubbed[key] === 'object' && scrubbed[key] !== null) {
      scrubbed[key] = scrubObject(scrubbed[key]); // Nested object
    } else if (scrubbed[key] === '') {
      scrubbed[key] = null; // Null instead of empty for DynamoDB
    }
  });
  return scrubbed;
};

const generateUniqueHexId = async (collection) => {
  const randomHexId = randomBytes(4).toString('hex').toUpperCase();
  if (await collection.countDocuments({ id: randomHexId }, { limit: 1 }) > 0) {
    return generateUniqueHexId(collection); // Ensure ID is unique
  }
  return randomHexId;
};

// Choose and save greeting
app.post(`${apiBaseUrl}/greeting`,
  asyncMiddleware(async (req, res) => {
    if ('development' === process.env.NODE_ENV) {
      const scrubbed = scrubObject(req.body);
      await validate(GreetingSchema, scrubbed); // Validate submitted form against schema
      const greetingsCollection = dbClient.db.collection(collections.GREETINGS);
      const id = await generateUniqueHexId(greetingsCollection);
      const currentIsoDate = new Date().toISOString();
      const greetingItem = {
        ...scrubbed,
        id,		
        createdAt: currentIsoDate,
        updatedAt: currentIsoDate,
      };
  
      logger.info('Saving to db: ' + JSON.stringify(greetingItem));
  
      const greeting = req.body["greeting"];
      await greetingsCollection.insertOne({
        ...greetingItem,
      });		
  
      return res.json({ id, greeting});
    } else {
      logger.info('Saving to db: ' + JSON.stringify(req.body));
  
      const greeting = req.body["greeting"];
      const result = await dynamodbClient.addGreeting(greeting);
      const id = result.id;
      
      return res.json({ id, greeting});
    }
  }));


// Get existing greeting
app.get(`${apiBaseUrl}/greeting/:latest`,
  asyncMiddleware(async (req, res) => {
    if ('development' === process.env.NODE_ENV) {
      const greetingsCollection = dbClient.db.collection(collections.GREETINGS);
      const greetingItems = await greetingsCollection.find({}, {sort:{$natural:-1}, limit: 10}).toArray();
      logger.info('Reading from db: ' + JSON.stringify(greetingItems));
      return res.json({greetingItems});
    } else {
      const greetingItems = await dynamodbClient.getGreetings();
      logger.info('Reading from db: ' + JSON.stringify(greetingItems));
      return res.json({greetingItems});
    }
  }));

// Client app
if (process.env.NODE_ENV === 'production') {
  app.get('/*', (req, res) => res.sendFile(path.join(__dirname, '../client/build/index.html')));
}

app.use(errorHandler);

module.exports = app;