Added WIP definition of ISummaryService

Author: topnax

Services/Services/SummaryService.cs

@@ -0,0 +1,20 @@
+using Model;
+
+namespace Services
+{
+    public interface ISummaryService
+    {
+        public record Summary(decimal AbsoluteProfit, decimal RelativeProfit, decimal MarketValue);
+
+        public Summary GetMarketOrderSummary(MarketOrder order, decimal assetPrice);
+        
+        public Summary GetPortfolioEntrySummary(PortfolioEntry entry, decimal assetPrice);
+        
+        public Summary GetPortfolioSummary(Portfolio entry, decimal assetPrice);
+    }
+    
+    public class SummaryServiceImpl
+    {
+        
+    }
+}