WC_Order::get_user PHP Method

    public function get_user()
    {
        return $this->get_user_id() ? get_user_by('id', $this->get_user_id()) : false;
    }

 public static function order_status_changed($id, $status = '', $new_status = '')
 {
     $rules = get_option('woorule_rules', array());
     foreach ($rules as $k => $rule) {
         $enabled = get_option($rule['enabled']['id']) === 'yes' ? true : false;
         if ($enabled) {
             $which_event = get_option($rule['occurs']['id']);
             $is_opt_in_rule = false;
             $want_in = true;
             if (isset($rule['show_opt_in'])) {
                 $is_opt_in_rule = get_option($rule['show_opt_in']['id']) === 'yes' ? true : false;
             }
             if ($is_opt_in_rule) {
                 $want_in = get_post_meta($id, 'woorule_opt_in_' . $k, false);
                 if (!empty($want_in)) {
                     $want_in = $want_in[0] === 'yes' ? true : false;
                 }
             }
             if ($want_in && $new_status === $which_event) {
                 $integration = new WC_Integration_RuleMailer();
                 $order = new WC_Order($id);
                 $user = $order->get_user();
                 $currency = $order->get_order_currency();
                 $order_subtotal = $order->order_total - ($order->order_shipping_tax + $order->order_shipping) - $order->cart_discount;
                 $items = $order->get_items();
                 $brands = array();
                 $categories = array();
                 $tags = array();
                 foreach ($items as $item) {
                     $p = new WC_Product_Simple($item['product_id']);
                     $brands[] = $p->get_attribute('brand');
                     // this is bullshit
                     $cat = strip_tags($p->get_categories(''));
                     $tag = strip_tags($p->get_tags(''));
                     if (!empty($cat)) {
                         $categories[] = $cat;
                     }
                     if (!empty($tag)) {
                         $tags[] = $tag;
                     }
                 }
                 $subscription = array('apikey' => $integration->api_key, 'update_on_duplicate' => get_option($rule['update_on_duplicate']['id']) === 'yes' ? true : false, 'auto_create_tags' => get_option($rule['auto_create_tags']['id']) === 'yes' ? true : false, 'auto_create_fields' => get_option($rule['auto_create_fields']['id']) === 'yes' ? true : false, 'tags' => explode(',', get_option($rule['tags']['id'])), 'subscribers' => array('email' => $order->billing_email, 'phone_number' => $order->billing_phone, 'fields' => array(array('key' => 'Order.Number', 'value' => $order->get_order_number()), array('key' => 'Order.Date', 'value' => $order->order_date), array('key' => 'Order.FirstName', 'value' => $order->billing_first_name), array('key' => 'Order.LastName', 'value' => $order->billing_last_name), array('key' => 'Order.Street1', 'value' => $order->billing_address_1), array('key' => 'Order.Street2', 'value' => $order->billing_address_2), array('key' => 'Order.City', 'value' => $order->billing_city), array('key' => 'Order.Country', 'value' => $order->billing_country), array('key' => 'Order.State', 'value' => $order->billing_state), array('key' => 'Order.Subtotal', 'value' => $order_subtotal), array('key' => 'Order.Discount', 'value' => $order->cart_discount), array('key' => 'Order.Shipping', 'value' => $order->order_shipping + $order->order_shipping_tax), array('key' => 'Order.Total', 'value' => $order->order_total), array('key' => 'Order.Vat', 'value' => $order->order_tax))));
                 if (!empty($categories)) {
                     $subscription['subscribers']['fields'][] = array('key' => 'Order.Categories', 'value' => $categories, 'type' => 'multiple');
                 }
                 if (!empty($tags)) {
                     $subscription['subscribers']['fields'][] = array('key' => 'Order.Tags', 'value' => array($tags), 'type' => 'multiple');
                 }
                 if (!empty($brands)) {
                     $subscription['subscribers']['fields'][] = array('key' => 'Order.Brands', 'value' => $brands, 'type' => 'multiple');
                 }
                 $api = WP_RuleMailer_API::get_instance();
                 $api::subscribe($integration->api_url, $subscription);
             }
         }
     }
 }