Drupal7 + Ubercart3 Several currencies, enter the exchange rate in the admin panel?

Question

PHP

Faced a small problem. You need to make several currencies in Ubercart, but do it a little tricky.

1. The price of the goods is stored either in EUR or in Rub
   
2. Most likely you need 2 fields for that and that price in the product card
   
3. The price on the site itself is displayed in RUB only
   
4. Do not offer commerce, because 3 thousand. I don’t really want to interrupt the goods, but the migration can’t stand everything, it’s all the same to climb there.
   
5. I figured out the price display on the site itself by adding this code to the product code:
   

   function uc_product_load($nodes) {
   include_once("php.php");
   $a = $euro;
   $vids = array();
   foreach ($nodes as $node) {
   $vids[$node->nid] = $node->vid;
   }
   $result = db_query('SELECT nid, model, list_price, cost, sell_price, weight, weight_units, length, width, height, length_units, pkg_qty, default_qty, ordering, shippable FROM {uc_products} WHERE vid IN (:vids)', array(':vids' => $vids));
   foreach ($result as $node) {
   foreach ($node as $field => $value) {
   $nodes[$node->nid]->$field = $value;
   }
   $nodes[$node->nid]->price = round($nodes[$node->nid]->sell_price*$euro, -1);
   }
   }

   
   

Help is needed to create a rule (if the price is in rub, we output the node sell_price, -1; if in euro, then sell_price*euro), and output 2 fields in the product card, although I think this is not such a big problem, but php is not really I know.