otp.js

require('dotenv').config();
const { createClient } = require('redis');
const crypto = require('crypto');
const Messente = require('messente_api');
const { ERROR_MESSAGES } = require('./constants.js');

const OTP_EXPIRY = 60 * 5; // 5 minutes

const redis = createClient();
redis.on('error', err => console.log('Redis Client Error', err));
redis.connect();

const client = Messente.ApiClient.instance;
const basicAuth = client.authentications['basicAuth'];
basicAuth.username = process.env.MESSENTE_API_USERNAME;
basicAuth.password = process.env.MESSENTE_API_PASSWORD;
const api = new Messente.OmnimessageApi();

const getOTP = () => crypto.randomInt(0,1000000).toString().padStart(6,'0')

const cacheOTP = async (phoneNumber, otp) => {
    await redis.set(`OTP:${phoneNumber}`, otp, 'EX',OTP_EXPIRY)
}

const checkOTP = async (phoneNumber, otp) => {
    const cachedOTP = await redis.get(`OTP:${phoneNumber}`)

    if (!cachedOTP) throw new Error(ERROR_MESSAGES.OTP_NOT_FOUND)
    if (cachedOTP !== otp) throw new Error(ERROR_MESSAGES.OTP_DOES_NOT_MATCH)

    // If we got here it was successful. Clear and return true
    await redis.del(`OTP:${phoneNumber}`)
    return true
}

const sendOTP = async (phoneNumber, otp) => {
    const text = `${otp} is your verification code`;
    const sender = 'Holonym';

    // const viber = Messente.Viber.constructFromObject({text, sender});
    // const whatsappText = Messente.WhatsAppText.constructFromObject({text});
    // const whatsapp = Messente.WhatsApp.constructFromObject({text:whatsappText});
    const sms = Messente.SMS.constructFromObject({text, sender});

    const omnimessage = Messente.Omnimessage.constructFromObject({
        messages: [sms/*,viber*/],
        to: phoneNumber
    });

    api.sendOmnimessage(omnimessage, (error, data, response) => {
        console.error('error?', error);
        console.log('data', data);
        // console.log('response', response)
    })
}

async function begin(phoneNumber, countryCode) {
    const otp = getOTP();
    await cacheOTP(phoneNumber, otp);
    await sendOTP(phoneNumber, otp);
}

async function verify(phoneNumber, otp) {
    return await checkOTP(phoneNumber, otp);
}


module.exports = {
    begin,
    verify
}
// todo: fallbacks: viber -> whatsapp -> sms? or sms -> viber -> whatsapp? or sms -> whatsapp -> viber? SMS is most expensive but also what our users expect. Perhaps do viber or whatsapp if SMS doesn't deliver??
// todo: delivery webhook