Created function to retrieve total discounted amount of a commonobject

Also added an ODT tag to let people add it to their invoices, etc..

ChangeLog

@@ -54,6 +54,8 @@ For users:
 - New: [ task #210 ] Can choose cash account during POS login
 - New: [ task #104 ] Can create an invoice from several orders
 - New: Update libs/tools/logo for DoliWamp (now use PHP 5.3).
+- New: Added ODT Template tag {object_total_discount}
+
 New experimental modules:
 - New: Add margin management module.
 - New: Add commissions management module.
@@ -81,6 +83,7 @@ For developers:
   expedition, order supplier and order invoice (lines included), intervention card, project, tasks.
 - New: Add ChromePHP output into syslog module.
 - New: Add PRODUCT_PRICE_MODIFY trigger.
+- New: Created function to retrieve total amount of discount of an invoice/proposal...
 
 For translators:
 - New: Update language files (de, tr, pt, ca, es, en, fr).

htdocs/core/class/commonobject.class.php

@@ -4,6 +4,7 @@
  * Copyright (C) 2010-2011 Juanjo Menent        <jmenent@2byte.es>
  * Copyright (C) 2012      Christophe Battarel  <christophe.battarel@altairis.fr>
  * Copyright (C) 2011-2012 Philippe Grand	    <philippe.grand@atoo-net.com>
+ * Copyright (C) 2012      Marcos García        <marcosgdf@gmail.com>
  *
  * 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
@@ -2214,6 +2215,27 @@ abstract class CommonObject
         return $nb;
     }
 
+    /**
+     * Function that returns the total amount of discounts applied.
+     * 
+     * @return false|float False is returned if the discount couldn't be retrieved
+     */
+    function getTotalDiscount()
+    {
+        $sql = 'SELECT (SUM(`subprice`) - SUM(`total_ht`)) as `discount` FROM '.MAIN_DB_PREFIX.$this->table_element.'det WHERE `'.$this->fk_element.'` = '.$this->id;
+
+        $query = $this->db->query($sql);
+        
+        if ($query)
+        {
+            $result = $this->db->fetch_object($query);
+
+            return price2num($result->discount);
+        }
+
+        return false;
+    }
+
     /**
      *	Set extra parameters
      *

htdocs/core/modules/facture/doc/doc_generic_invoice_odt.modules.php

@@ -124,6 +124,7 @@ class doc_generic_invoice_odt extends ModelePDFFactures
         	'object_total_ht'=>price($object->total_ht,0,$outputlangs),
             'object_total_vat'=>price($object->total_tva,0,$outputlangs),
             'object_total_ttc'=>price($object->total_ttc,0,$outputlangs),
+            'object_total_discount' => price($object->getTotalDiscount(), 0, $outputlangs),
             'object_vatrate'=>(isset($object->tva)?vatrate($object->tva):''),
             'object_note_private'=>$object->note,
             'object_note'=>$object->note_public,