const Queue = require('rethinkdb-job-queue')
const qOptions = {
  name: 'Mathematics' // The queue and table name
}
const cxnOptions = {
  db: 'JobQueue', // The name of the database in RethinkDB
}

const q = new Queue(cxnOptions, qOptions)

const job = q.createJob({
  numerator: 123,
  denominator: 456
})

q.process((job, next) => {
    try {
      let result = job.numerator / job.denominator
      // Do something with your result
      return next(null, result)
    } catch (err) {
      console.error(err)
      return next(err)
    }
})

return q.addJob(job).catch((err) => {
  console.error(err)
})

// The following is not related to rethinkdb-job-queue.
// This is the nodemailer configuration
const nodemailer = require('nodemailer')
const transporter = nodemailer.createTransport({
  service: 'Mailgun',
  auth: {
    user: '[email protected]',
    pass: 'your-api-key-here'
  }
})

// Setup e-mail data with unicode symbols
var mailOptions = {
  from: '"Registration" <[email protected]>', // Sender address
  subject: 'Registration', // Subject line
  text: 'Click here to complete your registration', // Plaintext body
  html: '<b>Click here to complete your registration</b>' // HTML body
}

// rethinkdb-job-queue configuration
const Queue = require('rethinkdb-job-queue')

// Queue options have defaults and are not required
const qOptions = {
  name: 'RegistrationEmail', // The queue and table name
  masterInterval: 310000, // Database review period in milliseconds
  changeFeed: true, // Enables events from the database table
  concurrency: 100,
  removeFinishedJobs: 2592000000, // true, false, or number of milliseconds
}

// Connection options have defaults and are not required
// You can replace these options with a rethinkdbdash driver object
const cxnOptions = {
  host: 'localhost',
  port: 28015,
  db: 'JobQueue', // The name of the database in RethinkDB
}

// This is the main queue instantiation call
const q = new Queue(cxnOptions, qOptions)

// Customizing the default job options for new jobs
q.jobOptions = {
  priority: 'normal',
  timeout: 300000,
  retryMax: 3, // Four attempts, first then three retries
  retryDelay: 600000 // Time in milliseconds to delay retries
}

const job = q.createJob()
// The createJob method will only create the job locally.
// It will need to be added to the queue.
// You can decorate the job with any data to be saved for processing
job.recipient = '[email protected]'

q.process((job, next) => {
  // Send email using job.recipient as the destination address
  mailOptions.to = job.recipient
  return transporter.sendMail(mailOptions).then((info) => {
    console.dir(info)
    return next(null, info)
  }).catch((err) => {
    // This catch is for nodemailer sendMail errors.
    return next(err)
  })
})

return q.addJob(job).then((savedJobs) => {
  // savedJobs is an array of the jobs added with updated properties
}).catch((err) => {
  console.error(err)
})