Shortcode for Visual Form Builder Survey

add_shortcode('survey_results','vfb_survey_results');
function vfb_survey_results($atts) {
   /*
   * This shortcode will tally the results of a Visual Form Builder form.
   *
    * Usage: [mam_survey_results form_id=n]
    *     where n is the id number of the form to tally.
    *
    * Only fields of type 'checkbox', 'radio', or 'select' are totalled.
    *
    * It is a good idea to have an option like '-- Please Select --' as
    * the default item in a 'select' field.  Otherwise, the first item
    * is shown as selected if the user does not choose another one.
    *
   */
   global $wpdb;
   extract( shortcode_atts( array(
         'form_id' => '0',
         ),
      $atts
      )
   );
   if (!$form_id) {
      return "<p>Missing form_id:  [survey_results form_id='form id']</p>";
   }

   // Get the fields in the form in order of appearance
   $sql = "
   SELECT * FROM {$wpdb->prefix}vfb_pro_fields
   WHERE form_id = $form_id
   AND field_type IN ('checkbox', 'radio', 'select')
   ORDER BY field_sequence
   ";
   $field_defs = $wpdb->get_results($sql);

   // Add (Not Selected) for radio and checkboxes because they will show
   // an empty value if none are selected.
   $not_selected = '(Not Selected)';
   foreach ($field_defs as $field_def) {
      $option_names = unserialize($field_def->field_options);
      if ($field_def->field_type == 'checkbox' || $field_def->field_type == 'radio') {
         $option_names[] = $not_selected;
      }
      $field_def->option_names = $option_names;
   }

   // Get the responses
   $sql = "
   SELECT * FROM {$wpdb->prefix}vfb_pro_entries
   WHERE form_id = $form_id
   AND entry_approved = 1
   ";
   $survey_rows = $wpdb->get_results($sql);

   // Tabulate the results
   $total_responses = 0;
   foreach ($survey_rows as $survey_row) {
      ++$total_responses;
      $options = unserialize($survey_row->data);
      foreach ($options as $option) {
         $type = $option['type'];
         if ($type == 'select' || $type == 'radio' || $type == 'checkbox') {
            $id = $option['id'];
            $name = $option['name'];
            $value = $option['value'];
            if ($type == 'checkbox' || $type == 'radio') {
               if (empty($value)) {
                  $value = $not_selected;
               }
            }
            if ($type == 'checkbox') {
               $values = explode(',', $value);
            } else {
               $values = array( $value );
            }
            $totals[$id]['name'] = $name;
            foreach ($values as $onevalue) {
               ++$totals[$id]['counts'][trim($onevalue)];
            }
         }
      }
   }

   // Format the results
   ob_start(); ?>
   <div class='vfb-survey-results vfbsr-form-<?php echo $form_id; ?>'>
      <div class='vfbsr-total-responses-line'>
         <span class='vfbsf-total-responses-label'>Total Responses:</span>
         <span class='vfbsr-total-responses'><?php echo $total_responses; ?></span>
      </div>

      <?php foreach ($field_defs as $field_def) {
         $total = $totals[$field_def->field_id];
         $counts = $total['counts'];
         $name = $total['name'];
      ?>
      <div class='vfbsr-field'>
         <span class='vfbsr-field-name'><?php echo $name; ?></span>
         <ul class='vfbsr-option-counts'>
         <?php
         // Use field def option names so that we show only current options.
         // Some may have been added, deleted, or rearranged after the survey
         // was first deployed.
         $option_names = $field_def->option_names;
         foreach ($option_names as $option_name) {
            $name = trim($option_name);
            $count = $counts[$name];
            if ($count) { ?>
               <li>
                  <span class='vfbsr-count'><?php echo $count; ?></span>
                  &nbsp;<span class='vfbsr-option-name'><?php echo $option_name; ?></span>
               </li>
            <?php }
         } ?>
         </ul>
      </div><!-- vfbsr-field -->
      <?php } ?>
   </div><!-- vfbsr-survey-results -->

   <?php $results = ob_get_clean();
   return $results;
}