/**
  * Sync all inventory from Square (expensive)
  * @todo if searching for square id fails, check for SKU
  */
 public function sync_all_inventory()
 {
     // refresh cache first to get the latest inventory
     $this->connect->refresh_inventory_cache();
     $square_inventory = $this->connect->get_square_inventory();
     // hopefully there has been a manual sync prior so that square item id
     // has already been saved in the product/variation metas to prevent
     // unnecessary round trip requests to Square to find the SKU
     foreach ($square_inventory as $variation_id => $stock) {
         $wc_product = WC_Square_Utils::get_wc_product_for_square_item_variation_id($variation_id);
         if (is_object($wc_product)) {
             $wc_product->set_stock((int) $stock);
         }
     }
     return true;
 }