<?php
// inspired by https://www.mailgun.com/blog/email/double-opt-in-with-php-mailgun/

// import PHPMailer classes into the global namespace
use PHPMailer\PHPMailer\PHPMailer;
use PHPMailer\PHPMailer\SMTP;
use PHPMailer\PHPMailer\Exception;

$dname = dirname(__FILE__); 
require $dname . '/Exception.php';
require $dname . '/PHPMailer.php';
require $dname . '/SMTP.php';

function MakeConfirmationHash($confEmail, $confCode) {
  return md5($confEmail . $confCode);
}

function SendConfirmationEmail($recipientAddress) {
  global $general, $smtp, $mail;

  $hashedUnique = MakeConfirmationHash($recipientAddress, $general["uniqueKey"]);
  $confirmQuery = http_build_query(["c" => $hashedUnique, "e" => $recipientAddress]);
  $confirmURL = $general["siteURL"] . $general["confirmScript"] . "?" . $confirmQuery;

  // create PHPMailer instance
  $mailer = new PHPMailer(true);

  try {
    //Server settings
//    $mailer->SMTPDebug = SMTP::DEBUG_SERVER;                      //Enable verbose debug output
    $mailer->isSMTP();
    $mailer->Host       = $smtp["host"];
    $mailer->SMTPAuth   = $smtp["auth"];
    $mailer->Username   = $smtp["username"];
    $mailer->Password   = $smtp["password"];
    //$mailer->SMTPSecure = PHPMailer::ENCRYPTION_SMTPS;            //Enable implicit TLS encryption
    $mailer->Port       = $smtp["port"];   //TCP port to connect to; use 587 if you have set `SMTPSecure = PHPMailer::ENCRYPTION_STARTTLS`

    //Recipients
    $mailer->setFrom($smtp["fromAddress"], $smtp["fromName"]);
    $mailer->addAddress($recipientAddress);     //Add a recipient

    //Content
    $mailer->CharSet = "UTF-8";
    $mailer->isHTML(true);
    $mailer->Subject = $mail["subject"];
    $mailer->Body    = str_replace("%confirmURL%", $confirmURL, $mail["bodyHTML"]);
    $mailer->AltBody = str_replace("%confirmURL%", $confirmURL, $mail["bodyText"]);

    $mailer->send();
    return TRUE;
  } catch (Exception $e) {
    error_log("Message error: " . $e);
    return FALSE;
  }
}


require($dname . "/settings.php");

if (isset($_POST['email'])) { 
  $email = SanitizeEmail(trim($_POST['email']));
//  error_log("Received subscription request for address " . $email . " ..."); //DEBUG
  $result = SendConfirmationEmail($email);
  if ( $result == TRUE ) {
    header('Location: /newsletter/subscribed.html');
    error_log("Message to " . $email . " has been sent.");
  } else {
    header('Location: /newsletter/subscribe-error.html');
    error_log("Message to " . $email . " could not be sent.");
  }
}
?>