Email form sender with AWS Lambda, Brevo & reCAPTCHA

/* global fetch */

export const handler = async (event, context) => {
  console.log("Starting contact form function");

  // Validate parameters
  const { firstName, lastName, email, message, token } = JSON.parse(event.body)
    
  if (!firstName || !lastName || !email || !message || !token) {
    return { statusCode: 400, body: JSON.stringify({ statusMessage: "Missing required fields" })}
  }
  
  // Validate captcha
  const verifyResponse = await fetch("https://www.google.com/recaptcha/api/siteverify", {
    method: "POST",
    headers: {
      "content-type": "application/x-www-form-urlencoded",
    },
    body: `secret=${process.env.RECAPTCHA_SECRET}&response=${token}`,
  })
  const verifyResponseBody = await verifyResponse.json()
  if (!verifyResponse.ok) {
    return "Unable to validate captcha at this time."
  }

  if (verifyResponseBody.success !== true) {
    return "Invalid captcha response."
  }
  
  // Send email
  const emailSendResponse = await fetch("https://api.brevo.com/v3/smtp/email", {
    method: "POST",
    headers: {
      accept: "application/json",
      "api-key": process.env.BREVO_KEY,
      "content-type": "application/json",
    },
    body: JSON.stringify({
      to: [{ email: process.env.EMAIL_TO_ADDRESS, name: process.env.EMAIL_TO_NAME }],
      sender: {
        email: email,
        name: `${firstName} ${lastName}`,
      },
      subject: process.env.EMAIL_SUBJECT,
      textContent: message,
    }),
  })

  if (!emailSendResponse.ok) {
    return "Message could not be sent at this time."
  }

  return "Message sent!"
}