<?php
/**
 * @file
 * The implementation of MailSystemInterface which delegates handling of e-mails
 * to the Swift Mailer library.
 */

class SWIFTMailSystem implements MailSystemInterface {

  /**
   * Formats a message composed by drupal_mail().
   *
   * @see http://api.drupal.org/api/drupal/includes--mail.inc/interface/MailSystemInterface/7
   *
   * @param array $message
   *   A message array holding all relevant details for the message.
   *
   * @return string
   *   The message as it should be sent.
   */
  public function format(array $message) {
    if (!empty($message) && is_array($message)) {

      // Get default mail line endings and merge all lines in the e-mail body
      // separated by the mail line endings.
      $line_endings = variable_get('mail_line_endings', MAIL_LINE_ENDINGS);
      $message['body'] = implode($line_endings, $message['body']);

      // Get applicable format.
      $applicable_format = $this->getApplicableFormat($message);

      // Theme message if format is set to be HTML.
      if ($applicable_format == SWIFTMAILER_FORMAT_HTML) {
        if (isset($message['params']['theme'])) {
          $message['body'] = theme($message['params']['theme'], $message);
        }
        else {
          $message['body'] = theme('swiftmailer', $message);
        }

        if (variable_get('swiftmailer_convert_mode', SWIFTMAILER_VARIABLE_CONVERT_MODE_DEFAULT) ||
            !empty($message['params']['convert'])) {

          switch (variable_get('swiftmailer_convert_library')) {
            case SWIFTMAILER_VARIABLE_CONVERT_LIBRARY_MAILSYSTEM:
              $message['plain'] = mailsystem_html_to_text($message['body']);
              break;

            case SWIFTMAILER_VARIABLE_CONVERT_LIBRARY_DEFAULT:
            default:
              $converter = new Html2Text($message['body']);
              $message['plain'] = $converter->getText();
              break;
          }
        }
      }

      // Process any images specified by 'image:' which are to be added later
      // in the process. All we do here is to alter the message so that image
      // paths are replaced with cid's. Each image gets added to the array
      // which keeps track of which images to embed in the e-mail.
      $embeddable_images = array();
      $processed_images = array();
      preg_match_all('/"image:([^"]+)"/', $message['body'], $embeddable_images);
      for ($i = 0; $i < count($embeddable_images[0]); $i++) {
        $image_id = $embeddable_images[0][$i];

        if (isset($processed_images[$image_id])) {
          continue;
        }

        $image_path = trim($embeddable_images[1][$i]);
        $image_name = basename($image_path);

        if (drupal_substr($image_path, 0, 1) == '/') {
          $image_path = drupal_substr($image_path, 1);
        }

        $image = new stdClass();
        $image->uri = $image_path;
        $image->filename = $image_name;
        $image->filemime = file_get_mimetype($image_path);
        $image->cid = rand(0, 9999999999);
        $message['params']['images'][] = $image;
        $message['body'] = preg_replace($image_id, 'cid:' . $image->cid, $message['body']);
        $processed_images[$image_id] = 1;

      }

      return $message;
    }
  }

  /**
   * Sends a message composed by drupal_mail().
   *
   * @see http://api.drupal.org/api/drupal/includes--mail.inc/interface/MailSystemInterface/7
   *
   * @param array $message
   *   A message array holding all relevant details for the message.
   *
   * @return boolean
   *   TRUE if the message was successfully sent, and otherwise FALSE.
   */
  public function mail(array $message) {

    // Include required files.
    require_once(dirname(dirname(__FILE__)) . '/helpers/conversion.inc');
    require_once(dirname(dirname(__FILE__)) . '/helpers/utilities.inc');

    // Validate whether the Swift Mailer module has been configured.
    $library_path = variable_get('swiftmailer_path', SWIFTMAILER_VARIABLE_PATH_DEFAULT);
    if (empty($library_path)) {
      watchdog('swiftmailer', 'An attempt to send an e-mail failed. The Swift Mailer library could not be found by the Swift Mailer module.', array(), WATCHDOG_ERROR);
      drupal_set_message(t('An attempt to send the e-mail failed. The e-mail has not been sent.'), 'error');
      return;
    }

    // Include the Swift Mailer library.
    require_once(DRUPAL_ROOT . '/' . $library_path . '/lib/swift_required.php');

    try {

      // Create a new message.
      $m = Swift_Message::newInstance();

      // Not all Drupal headers should be added to the e-mail message.
      // Some headers must be suppressed in order for Swift Mailer to
      // do its work properly.
      $suppressable_headers = swiftmailer_get_supressable_headers();

      // Keep track of whether we need to respect the provided e-mail
      // format or not
      $respect_format = variable_get('swiftmailer_respect_format', SWIFTMAILER_VARIABLE_RESPECT_FORMAT_DEFAULT);

      // Process headers provided by Drupal. We want to add all headers which
      // are provided by Drupal to be added to the message. For each header we
      // first have to find out what type of header it is, and then add it to
      // the message as the particular header type.
      if (!empty($message['headers']) && is_array($message['headers'])) {
        foreach ($message['headers'] as $header_key => $header_value) {

          // Check wether the current header key is empty or represents
          // a header that should be suppressed. If yes, then skip header.
          if (empty($header_key) || in_array($header_key, $suppressable_headers)) {
            continue;
          }

          // Skip 'Content-Type' header if the message to be sent will be a
          // multipart message or the provided format is not to be respected.
          if ($header_key == 'Content-Type' && (!$respect_format || swiftmailer_is_multipart($message))) {
            continue;
          }

          // Get header type.
          $header_type = swiftmailer_get_headertype($header_key, $header_value);

          // Add the current header to the e-mail message.
          switch ($header_type) {
            case SWIFTMAILER_HEADER_ID:
              swiftmailer_add_id_header($m, $header_key, $header_value);
              break;

            case SWIFTMAILER_HEADER_PATH:
              swiftmailer_add_path_header($m, $header_key, $header_value);
              break;

            case SWIFTMAILER_HEADER_MAILBOX:
              swiftmailer_add_mailbox_header($m, $header_key, $header_value);
              break;

            case SWIFTMAILER_HEADER_DATE:
              swiftmailer_add_date_header($m, $header_key, $header_value);
              break;

            case SWIFTMAILER_HEADER_PARAMETERIZED:
              swiftmailer_add_parameterized_header($m, $header_key, $header_value);
              break;

            default:
              swiftmailer_add_text_header($m, $header_key, $header_value);
              break;

          }
        }
      }

      // Set basic message details.
      swiftmailer_remove_header($m, 'From');
      swiftmailer_remove_header($m, 'To');
      swiftmailer_remove_header($m, 'Subject');

      if ($message['from'] == variable_get('site_mail', '')) {
        $sender_name = variable_get('swiftmailer_sender_name', '');
        if (empty($sender_name)) {
          $sender_name = variable_get('site_name', 'Drupal');
        }
        $sender_email = variable_get('swiftmailer_sender_email', '');
        if (empty($sender_email)) {
          $sender_email = variable_get('site_mail', '');
        }
        $message['from'] = '"' . $sender_name . '" <' . $sender_email . '>';
      }

      // Parse 'from' and 'to' mailboxes.
      $from = swiftmailer_parse_mailboxes($message['from']);
      $to = swiftmailer_parse_mailboxes($message['to']);

      // Set 'from', 'to' and 'subject' headers.
      $m->setFrom($from);
      $m->setTo($to);
      $m->setSubject($message['subject']);

      // Get applicable format.
      $applicable_format = $this->getApplicableFormat($message);

      // Get applicable character set.
      $applicable_charset = $this->getApplicableCharset($message);

      // Set body.
      $m->setBody($message['body'], $applicable_format, $applicable_charset);

      // Add alternative plain text version if format is HTML and plain text
      // version is available.
      if ($applicable_format == SWIFTMAILER_FORMAT_HTML && !empty($message['plain'])) {
        $m->addPart($message['plain'], SWIFTMAILER_FORMAT_PLAIN, $applicable_charset);
      }

      // Validate that $message['params']['files'] is an array.
      if (empty($message['params']['files']) || !is_array($message['params']['files'])) {
        $message['params']['files'] = array();
      }
      
      // Let other modules get the chance to add attachable files.
      $files = module_invoke_all('swiftmailer_attach', $message['key']);
      if (!empty($files) && is_array($files)) {
        $message['params']['files'] = array_merge(array_values($message['params']['files']), array_values($files));
      }

      // Attach files.
      if (!empty($message['params']['files']) && is_array($message['params']['files'])) {
        $this->attach($m, $message['params']['files']);
      }
      
      // Attach files (provide compatibility with mimemail)
      if (!empty($message['params']['attachments']) && is_array($message['params']['attachments'])) {
        $this->attachAsMimeMail($m, $message['params']['attachments']);
      }

      // Embed images.
      if (!empty($message['params']['images']) && is_array($message['params']['images'])) {
        $this->embed($m, $message['params']['images']);
      }

      static $mailer;

      // If required, create a mailer which will be used to send the message.
      if (empty($mailer)) {

        // Get the configured transport type.
        $transport_type = variable_get('swiftmailer_transport', SWIFTMAILER_VARIABLE_TRANSPORT_DEFAULT);

        // Configure the mailer based on the configured transport type.
        switch ($transport_type) {
          case SWIFTMAILER_TRANSPORT_SMTP:
            // Get transport configuration.
            $host = variable_get('swiftmailer_smtp_host', SWIFTMAILER_VARIABLE_SMTP_HOST_DEFAULT);
            $port = variable_get('swiftmailer_smtp_port', SWIFTMAILER_VARIABLE_SMTP_PORT_DEFAULT);
            $encryption = variable_get('swiftmailer_smtp_encryption', SWIFTMAILER_VARIABLE_SMTP_ENCRYPTION_DEFAULT);
            $username = variable_get('swiftmailer_smtp_username', SWIFTMAILER_VARIABLE_SMTP_USERNAME_DEFAULT);
            $password = variable_get('swiftmailer_smtp_password', SWIFTMAILER_VARIABLE_SMTP_PASSWORD_DEFAULT);

            // Instantiate transport.
            $transport = Swift_SmtpTransport::newInstance($host, $port);
            $transport->setLocalDomain('[127.0.0.1]');

            // Set encryption (if any).
            if (!empty($encryption)) {
              $transport->setEncryption($encryption);
            }

            // Set username (if any).
            if (!empty($username)) {
              $transport->setUsername($username);
            }

            // Set password (if any).
            if (!empty($password)) {
              $transport->setPassword($password);
            }

            $mailer = Swift_Mailer::newInstance($transport);
            break;

          case SWIFTMAILER_TRANSPORT_SENDMAIL:
            // Get transport configuration.
            $path = variable_get('swiftmailer_sendmail_path', SWIFTMAILER_VARIABLE_SENDMAIL_PATH_DEFAULT);
            $mode = variable_get('swiftmailer_sendmail_mode', SWIFTMAILER_VARIABLE_SENDMAIL_MODE_DEFAULT);

            // Instantiate transport.
            $transport = Swift_SendmailTransport::newInstance($path . ' -' . $mode);
            $mailer = Swift_Mailer::newInstance($transport);
            break;

          case SWIFTMAILER_TRANSPORT_NATIVE:
            // Instantiate transport.
            $transport = Swift_MailTransport::newInstance();
            $mailer = Swift_Mailer::newInstance($transport);
            break;

          case SWIFTMAILER_TRANSPORT_SPOOL:
            // Instantiate transport.
            $spooldir = variable_get('swiftmailer_spool_directory', SWIFTMAILER_VARIABLE_SPOOL_DIRECTORY_DEFAULT);
            $spool = new Swift_FileSpool($spooldir);
            $transport = Swift_SpoolTransport::newInstance($spool);
            $mailer = Swift_Mailer::newInstance($transport);
            break;
        }
      }
      drupal_alter('swiftmailer', $mailer, $m);
      swiftmailer_filter_message($m);
      // Send the message.
      return $mailer->send($m);


    }
    catch (Exception $e) {

      $headers = !empty($m) ? $m->getHeaders() : '';
      $headers = !empty($headers) ? nl2br($headers->toString()) : 'No headers were found.';
      watchdog('swiftmailer',
        'An attempt to send an e-mail message failed, and the following error
        message was returned : @exception_message<br /><br />The e-mail carried
        the following headers:<br /><br />!headers',
        array('@exception_message' => $e->getMessage(), '!headers' => $headers),
        WATCHDOG_ERROR);
      drupal_set_message(t('An attempt to send an e-mail message failed.'), 'error');
    }
  }

  /**
   * Process attachments.
   *
   * @param Swift_Message $m
   *   The message which attachments are to be added to.
   * @param array $files
   *   The files which are to be added as attachments to the provided message.
   */
  private function attach(Swift_Message $m, array $files) {

    // Iterate through each array element.
    foreach ($files as $file) {

      if ($file instanceof stdClass) {

        // Validate required fields.
        if (empty($file->uri) || empty($file->filename) || empty($file->filemime)) {
          continue;
        }

        // Get file data.
        if (valid_url($file->uri, TRUE)) {
          $content = file_get_contents($file->uri);
        }
        else {
          $content = file_get_contents(drupal_realpath($file->uri));
        }

        $filename = $file->filename;
        $filemime = $file->filemime;

        // Attach file.
        $m->attach(Swift_Attachment::newInstance($content, $filename, $filemime));
      }
    }

  }

  /**
   * Process MimeMail attachments.
   *
   * @param Swift_Message $m
   *   The message which attachments are to be added to.
   * @param array $attachments.
   *   The attachments which are to be added message.
   */
  private function attachAsMimeMail(Swift_Message $m, array $attachments) {

    // Iterate through each array element.
    foreach ($attachments as $a) {

      if (is_array($a)) {
        
        // Validate that we've got either 'filepath' or 'filecontent.
        if (empty($a['filepath']) && empty($a['filecontent'])) {
          continue;
        }
        
        // Validate required fields.
        if (empty($a['filename']) || empty($a['filemime'])) {
          continue;
        }

        // Attach file (either using a static file or provided content).
        if (!empty($a['filepath'])) {
          $file = new stdClass();
          $file->uri = $a['filepath'];
          $file->filename = $a['filename'];
          $file->filemime = $a['filemime'];
          $this->attach($m, array($file));
        }
        else {
          $m->attach(Swift_Attachment::newInstance($a['filecontent'], $a['filename'], $a['filemime']));  
        }
        
      }
    }

  }
  
  /**
   * Process inline images..
   *
   * @param Swift_Message $m
   *   The message which inline images are to be added to.
   * @param array $images
   *   The images which are to be added as inline images to the provided
   *   message.
   */
  private function embed(Swift_Message $m, array $images) {

    // Iterate through each array element.
    foreach ($images as $image) {

      if ($image instanceof stdClass) {

        // Validate required fields.
        if (empty($image->uri) || empty($image->filename) || empty($image->filemime) || empty($image->cid)) {
          continue;
        }

        // Keep track of the 'cid' assigned to the embedded image.
        $cid = NULL;

        // Get image data.
        if (valid_url($image->uri, TRUE)) {
          $content = file_get_contents($image->uri);
        }
        else {
          $content = file_get_contents(drupal_realpath($image->uri));
        }

        $filename = $image->filename;
        $filemime = $image->filemime;

        // Embed image.
        $cid = $m->embed(Swift_Image::newInstance($content, $filename, $filemime));

        // The provided 'cid' needs to be replaced with the 'cid' returned
        // by the Swift Mailer library.
        $body = $m->getBody();
        $body = preg_replace('/cid:' . $image->cid . '/', $cid, $body);
        $m->setBody($body);
      }
    }
  }

  /**
   * Returns the applicable format.
   *
   * @param array $message
   *   The message for which the applicable format is to be determined.
   *
   * @return string
   *   A string being the applicable format.
   *
   */
  private function getApplicableFormat($message) {

    // Get the configured default format.
    $default_format = variable_get('swiftmailer_format', SWIFTMAILER_VARIABLE_FORMAT_DEFAULT);

    // Get whether the provided format is to be respected.
    $respect_format = variable_get('swiftmailer_respect_format', SWIFTMAILER_VARIABLE_RESPECT_FORMAT_DEFAULT);

    // Check if a format has been provided particularly for this message. If
    // that is the case, then apply that format instead of the default format.
    $applicable_format = !empty($message['params']['format']) ? $message['params']['format'] : $default_format;

    // Check if the provided format is to be respected, and if a format has been
    // set through the header "Content-Type". If that is the case, the apply the
    // format provided. This will override any format which may have been set
    // through $message['params']['format'].
    if ($respect_format && !empty($message['headers']['Content-Type'])) {
      $format = $message['headers']['Content-Type'];
      $format = preg_match('/.*\;/U', $format, $matches);

      if ($format > 0) {
        $applicable_format = trim(substr($matches[0], 0, -1));
      } else {
        $applicable_format = $default_format;
      }

    }

    return $applicable_format;

  }

  /**
   * Returns the applicable charset.
   *
   * @param array $message
   *   The message for which the applicable charset is to be determined.
   *
   * @return string
   *   A string being the applicable charset.
   *
   */
  private function getApplicableCharset($message) {

    // Get the configured default format.
    $default_charset = variable_get('swiftmailer_character_set', SWIFTMAILER_VARIABLE_CHARACTER_SET_DEFAULT);

    // Get whether the provided format is to be respected.
    $respect_charset = variable_get('swiftmailer_respect_format', SWIFTMAILER_VARIABLE_RESPECT_FORMAT_DEFAULT);

    // Check if a format has been provided particularly for this message. If
    // that is the case, then apply that format instead of the default format.
    $applicable_charset = !empty($message['params']['charset']) ? $message['params']['charset'] : $default_charset;

    // Check if the provided format is to be respected, and if a format has been
    // set through the header "Content-Type". If that is the case, the apply the
    // format provided. This will override any format which may have been set
    // through $message['params']['format'].
    if ($respect_charset && !empty($message['headers']['Content-Type'])) {
      $format = $message['headers']['Content-Type'];
      $format = preg_match('/charset.*=.*\;/U', $format, $matches);

      if ($format > 0) {
        $applicable_charset = trim(substr($matches[0], 0, -1));
        $applicable_charset = preg_replace('/charset=/', '', $applicable_charset);
      } else {
        $applicable_charset = $default_charset;
      }

    }

    return $applicable_charset;

  }

}