/**
  * Product's commission rate in percentage form
  *
  * Eg: 50 for 50%
  *
  * @param int $product_id
  *
  * @return float
  */
 public static function get_commission_rate($product_id)
 {
     $commission = 0;
     $parent = get_post_ancestors($product_id);
     if ($parent) {
         $product_id = $parent[0];
     }
     $vendor_id = WCV_Vendors::get_vendor_from_product($product_id);
     $product_commission = get_post_meta($product_id, 'pv_commission_rate', true);
     $vendor_commission = WCV_Vendors::get_default_commission($vendor_id);
     $default_commission = WC_Vendors::$pv_options->get_option('default_commission');
     if ($product_commission != '' && $product_commission !== false) {
         $commission = $product_commission;
     } else {
         if ($vendor_commission != '' && $vendor_commission !== false) {
             $commission = $vendor_commission;
         } else {
             if ($default_commission != '' && $default_commission !== false) {
                 $commission = $default_commission;
             }
         }
     }
     return apply_filters('wcv_commission_rate_percent', $commission, $product_id);
 }