making pay, & refactoring

YavscLib/IcommandLine.cs

@@ -1,11 +1,18 @@
 namespace YavscLib.Billing
 {
-    public interface ICommandLine
+    public interface IBillItem {
+        string Description { get; set; }
+        int Count { get; set; }
+        decimal UnitaryCost { get; set; }
+        string Currency { get; set; }
+
+    }
+    public interface ICommandLine : IBillItem
     {
+        // FIXME too hard: no such generic name in any interface
          long Id { get; set; }
-         string Description { get; set; }
-         int Count { get; set; }
-         decimal UnitaryCost { get; set; }
+
+        // FIXME too far: perhaps no existing estimate
          long EstimateId { get; set; }
 
     }

YavscLib/Workflow/IQuery.cs

@@ -1,10 +1,16 @@
 namespace YavscLib.Models.Workflow
 {
+    using System.Collections.Generic;
     using YavscLib;
+    using YavscLib.Billing;
 
-    public interface IQuery: IBaseTrackedEntity
+    public interface IQuery: IBaseTrackedEntity, IBillable
     {
         QueryStatus Status { get; set; }
     }
+    public interface IBillable {
+        string Description { get; set; }
+        List<IBillItem> GetBillItems();
 
+    }
 }