const nodemailer = require('nodemailer');

function createTransport(env = process.env) {
  return nodemailer.createTransport({
    host: env.SMTP_HOST,
    port: Number(env.SMTP_PORT || 587),
    secure: Number(env.SMTP_PORT) === 465,
    auth: env.SMTP_USER ? { user: env.SMTP_USER, pass: env.SMTP_PASS } : undefined,
  });
}

function formatPrice(value) {
  return value.toFixed(2).replace('.', ',');
}

async function sendPriceChangeEmail(transport, { from, to, name, url, oldPrice, newPrice }) {
  await transport.sendMail({
    from,
    to,
    subject: `Prijs gewijzigd: ${name}`,
    text: [
      `De prijs van "${name}" is gewijzigd.`,
      `Oude prijs: €${formatPrice(oldPrice)}`,
      `Nieuwe prijs: €${formatPrice(newPrice)}`,
      `Link: ${url}`,
    ].join('\n'),
  });
}

module.exports = { createTransport, sendPriceChangeEmail, formatPrice };