ResourcefulHumans/transactional-emails

'use strict'

let Promise = require('bluebird')
Promise.promisifyAll(require('fs'))
let path = require('path')
let glob = require('glob')
let globAsync = Promise.promisify(glob)
let fs = require('fs')
let _defaults = require('lodash/defaults')
let juice = require('juice')
let juiceResourcesAsync = Promise.promisify(juice.juiceResources)
let handlebars = require('handlebars')

const loadIncludes = () =>
  globAsync(path.join(__dirname, '/emails/includes/*.{txt,html}')).then(
    includes => {
      const includeData = {
        txt: [],
        html: []
      }
      return Promise.map(includes, include => {
        return fs.readFileAsync(include, 'utf8').then(data => {
          const id = include
            .replace(path.join(__dirname, '/emails/includes/'), '')
            .replace(/\.[^.]+$/, '')
          if (/\.txt$/.test(include)) {
            includeData.txt.push({ id, data })
          } else {
            includeData.html.push({ id, data })
          }
        })
      }).then(() => includeData)
    }
  )

module.exports = {
  /**
   * @returns {Promise}
   */
  load: () => {
    return Promise.join(
      fs.readFileAsync(
        path.join(__dirname, '/emails/templates/layout.html'),
        'utf8'
      ),
      fs.readFileAsync(
        path.join(__dirname, '/emails/templates/layout.txt'),
        'utf8'
      ),
      globAsync(path.join(__dirname, '/emails/*.json')),
      loadIncludes()
    ).spread((htmlLayout, textLayout, emails, includes) => {
      return Promise.map(emails, email => {
        let identifier = path.basename(email, '.json')
        let emailConfig = require(email)
        let template = emailConfig.template ? emailConfig.template : identifier
        let product = emailConfig.product ? emailConfig.product : 'netwoRHk'
        return Promise.join(
          fs
            .readFileAsync(
              path.join(__dirname, '/emails/templates/' + template + '.html'),
              'utf8'
            )
            .then(htmlTemplate => {
              return Promise.map(includes.html, include => {
                htmlTemplate = htmlTemplate.replace(
                  '{{includes.' + include.id + '}}',
                  include.data
                )
              }).then(() =>
                juiceResourcesAsync(
                  handlebars.compile(htmlLayout)({
                    content: htmlTemplate,
                    product,
                    area: emailConfig.area,
                    title: emailConfig.title,
                    title2: emailConfig.title2
                  }),
                  {
                    webResources: {
                      images: false,
                      relativeTo: path.join(__dirname, '/emails/')
                    }
                  }
                )
              )
            }),
          fs.readFileAsync(
            path.join(__dirname, '/emails/templates/' + template + '.txt'),
            'utf8'
          )
        ).spread((htmlTemplate, textTemplate) => {
          return Promise.map(includes.txt, include => {
            textTemplate = textTemplate.replace(
              '{{includes.' + include.id + '}}',
              include.data
            )
          }).then(() => {
            return {
              identifier,
              subject: emailConfig.subject,
              defaults: _defaults({}, emailConfig.defaults),
              html: htmlTemplate,
              text: handlebars.compile(textLayout)({
                content: textTemplate,
                product,
                title: emailConfig.title,
                title2: emailConfig.title2
              })
            }
          })
        })
      })
    })
  }
}