const fs = require("fs");
const path = require("path");
const dotize = require("dotize");

const initializeMailer = () => {
  if (process.env.MAIL_TYPE === "ses") {
    return require("ses-email-sender")({
      AWSAccessKeyID: process.env.AWS_AID,
      AWSSecretKey: process.env.AWS_SECRET,
      ServiceUrl: process.env.AWS_URL,
      port: process.env.AWS_SES_PORT,
    });
  }

  return require("smtp-email-sender")({
    host: process.env.MAIL_HOST,
    port: process.env.MAIL_PORT,
    auth: {
      user: process.env.MAIL_USER,
      pass: process.env.MAIL_PASS,
    },
  });
};

const generateHtml = (template, object) => {
  object = dotize.convert(object);
  const generator = Object.keys(object).map(async key => {
    template = String(template).replace(
      new RegExp(`\\{${key}\\}`, "g"),
      object[key],
    );
  });

  return Promise.all(generator)
    .then(() => template)
    .catch(console.error);
};

module.exports = async (to, subject, template, object) => {
  const mailer = initializeMailer();

  mailer({
    from: ".....",
    to,
    subject,
    html: await generateHtml(
      fs.readFileSync(
        path.resolve(`${__dirname}/../emails`, `${template}.html`),
        "utf8",
      ),
      object,
    ),
  });
};