<?php
// 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';

// read ini file
$ini_file = '../../config.ini';
$ini = parse_ini_file($ini_file, TRUE);

// general constants
$general = [
  // string concatenated with email address to create a non-recreatable md5 hash 
  'uniqueKey' => $ini['hash']['uniqueKey'], // works like password salt  
  // file name of confirm script
  'confirmScript' => '/newsletter/confirm.php',
  // status code to be used when redirection to success or error page 
  'statusCode' => 'HTTP/1.1 303 See Other',
  // array of SQL statements used
  'sql' => [
    'create_table' => 'CREATE TABLE IF NOT EXISTS subscribers (id INTEGER PRIMARY KEY, email TEXT NOT NULL UNIQUE, name TEXT);',
    'create_record' => 'INSERT INTO subscribers(email, name) VALUES(:e, :n);',
    'read_record' => 'SELECT 1 FROM subscribers WHERE email = :e;',
    'update_record' => '',
    'delete_record' => 'DELETE FROM subscribers WHERE email = :e;'
  ],
  'notificationAddress' => 'webseite@tobias-radloff.de'
]; 
// complete site URL
$general['siteURL'] = $ini['general']['protocol'] . '://' . $ini['general']['domain']; 

$smtp = $ini['smtp'];
$db = $ini['db'];

function GetConfirmationHash($confEmail) {
  global $general;
  return md5($confEmail . $general['uniqueKey']);
}

// connects to database and returns PDO object
function getPDO($dbType = 'sqlite') {
  global $db;
  return new \PDO($db[$dbType]['dsn']);
}

// Sends an email to single recipient with subject, body and sender info specified in an array
function SendEmail($toAddress, $mailContents) {
  global $general, $smtp;
  $mail = new PHPMailer(true);

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

  // recipient
  $mail->addAddress($toAddress); 

  // content
  $mail->CharSet = 'UTF-8';
  if ( isset($mailContents['bodyHTML']) and $mailContents['bodyHTML'] != '' ) {
    $mail->isHTML(true);
    $mail->Body    = $mailContents['bodyHTML'];
    $mail->AltBody = $mailContents['bodyText'];
  } else {
    $mail->isHTML(false);
    $mail->Body    = $mailContents['bodyText'];
  }
  $mail->Subject = $mailContents['subject'];
  $mail->setFrom($mailContents['fromAddress'], $mailContents['fromName']);

  // send
  $mail->send();
}


function MakeSureTableExists($pdo) {
  global $general;
  $query = $pdo->prepare($general['sql']['create_table']);
  if ( ! $query->execute() ) {
    return 'Unbekannter Datenbankfehler';
  }
  return TRUE;
}

// returns true if record does not yet exist in database; error string otherwise
function NotYetSubscribed($email, $pdo = NULL) {
  if (!isset($pdo)) {
    $pdo = getPDO();
  }

  $result = MakeSureTableExists($pdo);
  if ( gettype($result) == 'string' ) {
    return $result; 
  }

  global $general;
  $query = $pdo->prepare($general['sql']['read_record']);
  if ( ! $query->execute([':e' => $email]) ) {
    return 'Fehler beim Zugriff auf Datenbank';
  }

  if ( $query->fetch() ) {
    return "Emailadresse {$email} ist bereits eingetragen";
  }

  // success
  return TRUE;
}


// redirects to specified URL via GET request and conveys an optional message; then exits  
function GracefulExit($location, $message = NULL) {
  global $general;
  header($general['statusCode']);
  if (isset($message)) {
    $location .= '?' . http_build_query(['msg' => $message]);
    error_log("Redirecting to {$location} now …");
  }
  header("Location: {$location}");
  exit;
}
?>