diff --git a/webapp/services/BattleDataService.php b/webapp/services/BattleDataService.php
index 108fb14c..57907067 100644
--- a/webapp/services/BattleDataService.php
+++ b/webapp/services/BattleDataService.php
@@ -511,7 +511,22 @@ class BattleDataService extends BaseService {
 
     private function randWeight($items)
     {
-        $spaces = array();
+        $weights = array();
+        {
+            $weight = 0;
+            foreach ($items as $item) {
+                $weight += (int)($item * 10000);
+                array_push($weights, $weight);
+            }
+        }
+        if (count($weights) > 0) {
+            $rnd = rand(0, $weights[count($weights) - 1]);
+            for ($i = 0; $i < count($weights); ++$i) {
+                if ($rnd <= $weights[$i]) {
+                    return $i;
+                }
+            }
+        }
         return -1;
     }