// Transactional email via Resend (resend.com).
import { Resend } from "resend";
import { magicCodeHtml } from "./email-templates";

const FROM_DEFAULT = "noreply@proteinea.com";

function getResend(): Resend {
  const key = process.env.RESEND_API_KEY;
  if (!key) {
    throw new Error(
      "RESEND_API_KEY is not set. Cannot send emails in production.",
    );
  }
  return new Resend(key);
}

/**
 * Send a magic-link verification code to the given email address.
 * Throws on any send failure — caller should catch and return a 500.
 */
export async function sendMagicCode(
  email: string,
  code: string,
): Promise<void> {
  const resend = getResend();
  const from = process.env.RESEND_FROM ?? FROM_DEFAULT;

  const { error } = await resend.emails.send({
    from,
    to: email,
    subject: "Your Antibody Studio verification code",
    html: magicCodeHtml(code),
  });

  if (error) {
    throw new Error(`Resend API error: ${error.message}`);
  }
}