Updated NavigableMap field parsing

config/navigablemap.go

@@ -181,6 +181,24 @@ func (nM *NavigableMap) getNextMap(mp map[string]interface{}, spath string) (map
 		}
 	} else {
 		switch mv := mi.(type) {
+		case []interface{}:
+			// in case we create the map using json and we marshall the value into a map[string]interface{}
+			// we can have slice of interfaces that is masking a slice of map[string]interface{}
+			// this is for CostDetails BalanceSummaries
+			if *idx < len(mv) {
+				mm := mv[*idx]
+				switch mmv := mm.(type) {
+				case map[string]interface{}:
+					return mmv, nil
+				case *map[string]interface{}:
+					return *mmv, nil
+				case NavigableMap:
+					return mmv.data, nil
+				case *NavigableMap:
+					return mmv.data, nil
+				default:
+				}
+			}
 		case []map[string]interface{}:
 			if *idx < len(mv) {
 				return mv[*idx], nil

engine/cdr_test.go

@@ -244,6 +244,20 @@ func TestFieldAsStringForCostDetails(t *testing.T) {
 		AccountSummary: &AccountSummary{
 			Tenant: "cgrates.org",
 			ID:     "AccountFromAccountSummary",
+			BalanceSummaries: []*BalanceSummary{
+				&BalanceSummary{
+					UUID:  "f9be602747f4",
+					ID:    "monetary",
+					Type:  utils.MONETARY,
+					Value: 0.5,
+				},
+				&BalanceSummary{
+					UUID:  "2e02510ab90a",
+					ID:    "voice",
+					Type:  utils.VOICE,
+					Value: 10,
+				},
+			},
 		},
 	}
 
@@ -284,6 +298,14 @@ func TestFieldAsStringForCostDetails(t *testing.T) {
 	} else if fldVal != eFldVal {
 		t.Errorf("field: <%v>, expected: <%v>, received: <%v>", prsr, eFldVal, fldVal)
 	}
+
+	prsr = config.NewRSRParserMustCompile("~CostDetails.AccountSummary.BalanceSummaries[1].ID", true)
+	eFldVal = "voice"
+	if fldVal, err := cdr.FieldAsString(prsr); err != nil {
+		t.Error(err)
+	} else if fldVal != eFldVal {
+		t.Errorf("field: <%v>, expected: <%v>, received: <%v>", prsr, eFldVal, fldVal)
+	}
 }
 
 func TestFormatCost(t *testing.T) {