New rolling duration method moved to manager singleton.

src/engine/gameManager/NPCManager.java

@@ -29,6 +29,7 @@ import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ThreadLocalRandom;
+import java.util.concurrent.TimeUnit;
 
 import static engine.math.FastMath.acos;
 
@@ -530,4 +531,25 @@ public enum NPCManager {
 
         return itemList;
     }
+
+    public static long calcRollingDuration(NPC vendor, int templateID) {
+
+        ItemTemplate template = ItemTemplate.templates.get(templateID);
+        float rollingDuration;
+
+        if (template == null)
+            return 0;
+
+        if (template.item_bane_rank > 0)
+            return (long) (template.item_bane_rank * 60 * 60 * 3 * 1000 * Float.parseFloat(ConfigManager.MB_PRODUCTION_RATE.getValue()));
+
+        if (vendor.building == null)
+            return 600;
+
+        rollingDuration = vendor.getBuilding().getRank() * -5L + 40;
+        rollingDuration = TimeUnit.MINUTES.toMillis((long) rollingDuration);
+        rollingDuration *= Float.parseFloat(ConfigManager.MB_PRODUCTION_RATE.getValue());
+
+        return (long) rollingDuration;
+    }
 }