'use strict';

const nodemailer = require('nodemailer'),
  Email = require('email-templates'),
  hbs = require('handlebars'),
  assert = require('assert'),
  fs = require('fs-extra'),
  cloneDeep = require('clone-deep'),
  path = require('path'),
  utils = require('./utils'),
  env = require('./env'),
  { Errors, DEFAULT_LANG } = require('./constants');
const { AppInputError } = require('./app_error');

const TemplateType = Object.freeze({
  PUG: 'pug', // default
  HANDLEBARS: 'hbs',
});

const Templates = Object.freeze({
  RESET_PASSWORD: 'reset-password',
  PASSWORD_RESET: 'password-reset',
  UPDATE_PAYMENT: 'update-payment',
  UPDATE_BILL_ADDRESS: 'update-address',
  CURRENT_SUBSCRIPTIONS: 'current-subscriptions',
  SUB_RENEWAL_REMIND: 'sub-renewal-remind',
  SUB_TRIAL_END_REMIND: 'sub-trial-end-remind',
});

const transporter = nodemailer.createTransport({
  host: env.SMTP_HOST,
  port: env.SMTP_PORT,
  secure: env.SMTP_SECURE,
  auth: {
    user: env.SMTP_USR,
    pass: env.SMTP_PWD
  },
  // debug: true,
  // logger: true
});

function registerHbsPartials(partialsPath) {
  // Ref handlebars with vars in templates: https://github.com/forwardemail/email-templates/issues/283
  // hbs is your own instance of handlebars, with partials

  // Register all available partials under the emails' partials folder
  const partialDir = path.join(process.cwd() + partialsPath);
  // const partialFiles = 
  fs.readdir(partialDir, (err, partialFiles) => {
    if (!err && !utils.isEmptyArray(partialFiles)) {
      for (let i = 0; i < partialFiles.length; i++) {
        const pfile = partialFiles[i];
        hbs.registerPartial(path.basename(pfile, '.hbs'), require(path.join(partialDir, pfile)));
      }
      // Override consolidate's handlebars instance
      // email.config.views.options.engineSource.requires.handlebars = hbs;
    }
  });
}
registerHbsPartials('/emails/partials/');
hbs.registerHelper('$t', function (key, options) {
  // Translation helper to translate message by key or with hash
  return options.data.root.t({ phrase: key, locale: options.data.root.locale }, options.hash);
});

require('handlebars-helpers')(['comparison']);

const agmMailSig = ['Best,', 'AgMision Team'];

const debugging = false;

const defaultMailOps = {
  transport: transporter,
  preview: debugging,
  send: true,
  i18n: {
    locales: ['en', 'es', 'pt']
  }
};

function init(ops) {
  if (ops) {
    Object.assign({}, defaultMailOps, ops);
  }
}

function _toLocale(locals) {
  if (!utils.isEmptyObj(locals) && !utils.hasProperty(locals, 'locale')) {
    const _locals = cloneDeep(locals);
    _locals.locale = _locals.lang || DEFAULT_LANG;
    delete _locals.lang;
    return _locals;
  }
  return locals;
}

/**
 * Send an email with given template and additional info
 * @param {*} template the template name
 * @param {*} locals additional metadata
 * @returns 
 */
async function sendMail(template, locals, to, from) {
  const email = await createEmail({ from: from, to: to });

  return email.send({
    template: template,
    // message: {
    //   to: to,
    // },
    locals: _toLocale(locals)
  });
}

/**
 * Send a text email from to with the mail options
 * @param {*} contentOps { subject: <the mail subject>, text: <the text body content> } 
 */
async function sendTextMail(contentOps, to, cc) {
  if (utils.isEmptyObj(contentOps))
    return;

  const _mailOps = Object.assign(contentOps,
    {
      from: 'AgMission <noreply@agnav.com>',
      to: to || 'agm_admin@agnav.com'
    });
  if (cc) _mailOps.cc = cc;

  return transporter.sendMail(_mailOps);
}

/**
 * Create an Email instance
 * @param {*} emailOps  { from, to }
 */
async function createEmail(emailOps, templateType = TemplateType.PUG) {

  let _ops = Object.assign(
    {
      message: {
        from: emailOps && emailOps.from || 'AgMission <noreply@agnav.com>'
      }
    },
    defaultMailOps);
  if (templateType === 'hbs') {
    _ops = {
      ..._ops, views: {
        options: {
          extension: 'hbs'
        },
        engineSource: { requires: { handlebars: hbs } }
      },
      /* For relative assets or ones located within the same server */
      // juice: true,
      // juiceResources: {
      //   webResources: {
      //     images: true,
      //     // relativeTo: path.join(process.cwd(), '/emails/assets'),
      //   }
      // }
    }
  }

  if (emailOps && emailOps.to) {
    _ops.message.to = emailOps.to;
  }

  const email = new Email(_ops);
  return email;
}

async function sendHandlebarsEmail(template, locals, to, from = null) {

  assert(template, AppInputError.create(Errors.TEMPLATE_NOT_FOUND));
  assert(to, AppInputError.create(Errors.TO_NOT_FOUND));

  const email = await createEmail({ locale: 'pt', to: to }, TemplateType.HANDLEBARS);

  await email.send({
    template: template,
    locals: {
      ..._toLocale(locals)
    }
  });
}

/**
 * Send update payment email notification so the customer can decide to update with a new payment method to continue using services
 * @param {*} locals  { locale: 'en', name, pmType: 'American Visa', pmEnding: '4321', hostname: 'localhost' }
 * @param {*} to the destination email address.
 * @param {*} from (Optional) the sender email address.
 */
async function sendUpdatePaymentEmail(locals, to, from) {
  assert(locals && locals.name && locals.hostname, AppInputError.create());

  locals.updatePmUrl = `https://${locals.hostname}/update-pm`;
  await sendHandlebarsEmail(Templates.UPDATE_PAYMENT, locals, to, from);
}

/**
 * Send update Billing Address email notification so the customer can decide to update with a valid address (for tax purpose).
 * @param {*} locals  { locale: 'en', userId, name, address: {line1, line2, city, state, postalCode, Country (country name)}, hostname: 'localhost' }
 * @param {*} to the destination email address.
 * @param {*} from (Optional) the sender email address.
 */
async function sendUpdateBillingAddressEmail(locals, to, from) {
  assert(locals && locals.userId && locals.name && locals.hostname && !utils.isEmptyObj(locals.address), AppInputError.create());

  locals.updateAddrUrl = `https://${locals.hostname}/update-bill-address/${locals.userId}`;
  await sendHandlebarsEmail(Templates.UPDATE_BILL_ADDRESS, locals, to, from);
}

/**
 * Send confirmation email with current subscriptions to the customer email address (normally after any subscription updates)
 * @param {*} locals  { locale: 'en', userId, name, package: [{ name, billCyle, startDate }], addon: [name, quantity, billCyle, startDate] }
 * @param {*} to the destination email address.
 * @param {*} from (Optional) the sender email address.
 */
async function sendCurSubcriptionsEmail(locals, to, from) {
  assert(locals && locals.name, AppInputError.create());

  await sendHandlebarsEmail(Templates.CURRENT_SUBSCRIPTIONS, locals, to, from);
}

/**
 * Send upcoming renewal reminder of a subscription to the customer (auto-renewal enabled)
 * @param {*} locals { subName, upPmDate, cardType, cardEnding, chargeAmount, hostname: 'localhost' }
 * @param {*} to the destination email address.
 * @param {*} from (Optional) the sender email address.
 *  */
async function sendSubRenewalRemindEmail(locals, to, from) {
  assert(locals && locals.name && locals.hostname, AppInputError.create());

  await sendHandlebarsEmail(Templates.SUB_RENEWAL_REMIND, locals, to, from);
}

/** 
 * Send trial ending reminder of a subscription to the customer (auto-renewal enabled)
 * @param {*} locals { subName, upPmDate, cardType, cardEnding, chargeAmount, hostname: 'localhost' }
 * @param {*} to the destination email address.
 * @param {*} from (Optional) the sender email address.
 *  */
async function sendSubTrialEndingRemindEmail(locals, to, from) {
  assert(locals && locals.name && locals.hostname, AppInputError.create());

  locals.manageSubUrl = `https://${locals.hostname}/manage-subscription/${locals.userId}`;
  await sendHandlebarsEmail(Templates.SUB_TRIAL_END_REMIND, locals, to, from);
}

// NOTE: For Testing only
async function sendTestMail(req, res) {

  let sent = true;
  try {
    // const custId = '5a1d6c05ffb94e7875c68dd9';
    // const updateUrl = `https://${req.hostname}/update-pm/${custId}`;

    // await sendHandlebarsEmail(
    //   Templates.UPDATE_PAYMENT,
    //   { locale: 'en', name: 'Trung Hoang', pmType: 'American Visa', pmEnding: '4321', updatePmUrl: updateUrl },
    //   'trungh@agnav.com',
    // );

    await sendHandlebarsEmail(
      Templates.CURRENT_SUBSCRIPTIONS,
      {
        name: "Trung Hoang",
        // package: [{ name: "ess_2", billCycle: "year", startDate: utils.timestampToDate(1692720405) }],
        // addon: [{ name: "addon_1", billCycle: "month", quantity: 1, startDate: utils.timestampToDate(1692720405) }]
      },
      'trungh@agnav.com, trungduyhoang@gmail.com',
    );
  } catch (err) {
    console.log(err);
    sent = false;
  }

  res.send({ msg: `Message sent ${sent}` }).end();
}


module.exports = {
  agmMailSig, sendMail, sendTextMail, sendUpdatePaymentEmail, sendUpdateBillingAddressEmail, sendCurSubcriptionsEmail, sendSubTrialEndingRemindEmail, sendSubRenewalRemindEmail,
  sendTestMail
}