FIX consider customer prices by qty in ajax fetch

Consider the experimental function PRODUIT_CUSTOMER_PRICES_BY_QTY_MULTIPRICES (customer prices by qty) in ajax product fetch

htdocs/product/ajax/products.php

@@ -2,6 +2,7 @@
 /* Copyright (C) 2006      Andre Cianfarani     <acianfa@free.fr>
  * Copyright (C) 2005-2013 Regis Houssin        <regis.houssin@inodbox.com>
  * Copyright (C) 2007-2011 Laurent Destailleur  <eldy@users.sourceforge.net>
+ * Copyright (C) 2020      Josep Lluís Amador   <joseplluis@lliuretic.cat>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -79,14 +80,14 @@ if (!empty($action) && $action == 'fetch' && !empty($id))
 		$found = false;
 
 		$price_level = 1;
-		if ($socid > 0 && !empty($conf->global->PRODUIT_MULTIPRICES)) {
+		if ($socid > 0 && (!empty($conf->global->PRODUIT_MULTIPRICES) || !empty($conf->global->PRODUIT_CUSTOMER_PRICES_BY_QTY_MULTIPRICES))) {
 			$thirdpartytemp = new Societe($db);
 			$thirdpartytemp->fetch($socid);
 			$price_level = $thirdpartytemp->price_level;
 		}
 
 		// Price by qty
-		if (!empty($price_by_qty_rowid) && $price_by_qty_rowid >= 1 && (!empty($conf->global->PRODUIT_CUSTOMER_PRICES_BY_QTY))) 		// If we need a particular price related to qty
+		if (!empty($price_by_qty_rowid) && $price_by_qty_rowid >= 1 && (!empty($conf->global->PRODUIT_CUSTOMER_PRICES_BY_QTY) || !empty($conf->global->PRODUIT_CUSTOMER_PRICES_BY_QTY_MULTIPRICES))) // If we need a particular price related to qty
 		{
 			$sql = "SELECT price, unitprice, quantity, remise_percent";
 			$sql .= " FROM ".MAIN_DB_PREFIX."product_price_by_qty ";
@@ -108,7 +109,7 @@ if (!empty($action) && $action == 'fetch' && !empty($id))
 		}
 
 		// Multiprice
-		if (!$found && isset($price_level) && $price_level >= 1 && (!empty($conf->global->PRODUIT_MULTIPRICES))) // If we need a particular price level (from 1 to 6)
+		if (!$found && isset($price_level) && $price_level >= 1 && (!empty($conf->global->PRODUIT_MULTIPRICES) || !empty($conf->global->PRODUIT_CUSTOMER_PRICES_BY_QTY_MULTIPRICES))) // If we need a particular price level (from 1 to 6)
 		{
 			$sql = "SELECT price, price_ttc, price_base_type, tva_tx";
 			$sql .= " FROM ".MAIN_DB_PREFIX."product_price ";