// newsletter.js
// Copyright (C) 2021 Digital Telepresence, LLC
// License: Apache-2.0

'use strict';

const DTP_COMPONENT_NAME = 'newsletter';

const path = require('path');
require('dotenv').config({ path: path.resolve(__dirname, '..', '..', '.env') });

const mongoose = require('mongoose');

const { SitePlatform, SiteLog } = require(path.join(__dirname, '..', '..', 'lib', 'site-lib'));

module.pkg = require(path.resolve(__dirname, '..', '..', 'package.json'));
module.config = {
  componentName: DTP_COMPONENT_NAME,
  root: path.resolve(__dirname, '..', '..'),
};

module.log = new SiteLog(module, module.config.componentName);

module.sendNewsletter = async (job) => {

  module.log.info('newsletter email job received', { data: job.data });

  const NewsletterRecipient = mongoose.model('NewsletterRecipient');

  try {
    /*
     * Create one Bull Queue job per email to be delivered.
     */
    await NewsletterRecipient
      .find({ 'flags.isVerified': true, 'flags.isOptIn': true, 'flags.isRejected': false })
      .lean()
      .cursor()
      .eachAsync(async (recipient) => {
        try {
          const jobData = {
            newsletterId: job.data.newsletterId,
            recipient: recipient.address,
          };
          const jobOptions = {
            attempts: 3,
          };
          await module.jobQueue.add('email-send', jobData, jobOptions);
        } catch (error) {
          module.log.error('failed to create newsletter email job');
          // but continue
        }
      }, { parallel: 4 });
  } catch (error) {
    module.log('failed to send newsletter', { newsletterId: job.data.newsletterId, error });
    throw error; // throw error to Bull so it can report in job reports
  }
};

module.sendNewsletterEmail = async (job) => {
  const { newsletter: newsletterService, email: emailService } = module.services;
  const { newsletterId, recipient } = job.data;
  try {

    let newsletter = module.newsletters[newsletterId];

    if (!newsletter) {
      newsletter = await newsletterService.getById(newsletterId);
      module.newsletters[newsletterId] = newsletter; //TODO: clean up memory leak of newsletter (remove when all emails are sent)
    }

    if (!newsletter) {
      throw new Error('newsletter not found');
    }

    const response = await emailService.send({
      from: 'demo@wherever.com',
      to: recipient,
      subject: newsletter.title,
      html: newsletter.content.html,
      text: newsletter.content.text,
    });

    job.log(`newsletter email sent: ${response}`);
  } catch (error) {
    module.error('failed to send newsletter email', { newsletterId, recipient, error });
    throw error; // throw error to Bull so it can report in job reports
  }
};

(async ( ) => {
  try {
    /*
     * Platform startup
     */
    await SitePlatform.startPlatform(module);

    const { jobQueue: jobQueueService } = module.services;
    
    module.jobQueue = await jobQueueService.getJobQueue('newsletter', {
      attempts: 3,
    });
    module.jobQueue.process('email', module.sendNewsletter);
    module.jobQueue.process('email-send', module.sendNewsletterEmail);

    /*
     * Worker startup
     */
    module.log.info(`${module.pkg.name} v${module.pkg.version} Newsletter worker started`);
  } catch (error) {
    module.log.error('failed to start Newsletter worker', { error });
    process.exit(-1);
  }
})();