$key = "{{@randomkey}}";
if(!empty($_GET['altcha'])) {
  $salt = base64_encode(random_bytes(15));
  $rnd_nb = random_int(0, 100);
  $challenge = hash("sha256", $salt.$rnd_nb, false);
  $signature = hash_hmac("sha256", $challenge, $key, false);

  echo json_encode([
    "algorithm" => "SHA-256",
    "challenge" => $challenge,
    "signature" => $signature,
    "salt" => $salt
  ]);
}
if(!empty($_POST)) {
  $forms = [
  {~ foreach(@forms as @form): ~}
  '{{@form.id}}' => [
      'content' => "{{@form.content}}",
      'subject' => "{{@form.tags->subject}}",
      'destination' => "{{@form.tags->destination}}"
  ],
  {~ endforeach ~}
  ];

  $id = intval($_POST['form_id']);
  $mail = $forms[$id];
  foreach($_POST as $field => $value) {
    $mail['content'] = str_replace("[[$field]]", $value, $mail['content']);
    $mail['subject'] = str_replace("[[$field]]", $value, $mail['subject']);
  }
  {~ if(@form_config.smtp): ~}
  require_once("./email.php");
  $smtp = new Snipworks\Smtp\Email("{{@form_config.server}})", {{@form_config.port}});
  $smtp->setProtocol(Snipworks\Smtp\Email::SSL);
  $smtp->setLogin("{{@form_config.user}}", "{{@form_config.password}}");
  $smtp->setFrom("{{@form_config.from}}");
  $smtp->setSubject($mail['subject']);
  $smtp->setTextMessage($mail['content']);
  $smtp->setHtmlMessage($mail['content']);
  $smtp->addTo($mail['destination']);
  {~ else: ~}
  mail($mail['destination'], $mail['subject'], $mail['content']);
  {~ endif ~}

  header('Location: ' . $_SERVER['HTTP_REFERER']);
}