1 files changed, 22 insertions, 18 deletions
diff --git a/lib/operation.ml b/lib/operation.ml
index 1fb1dd5..3c8df2a 100644
--- a/lib/operation.ml
+++ b/lib/operation.ml
@@ -1,29 +1,34 @@
 module TransactionType = struct
   type t =
-    | Credit
-    | Debit
+    [ `Credit
+    | `Debit
+    ]
 
   let t =
     let encode = function
-      | Credit -> "credit"
-      | Debit -> "debit"
+      | `Credit -> "credit"
+      | `Debit -> "debit"
     in
     let decode = function
-      | "credit" -> Ok Credit
-      | "debit" -> Ok Debit
+      | "credit" -> Ok `Credit
+      | "debit" -> Ok `Debit
       | _ -> Error "Invalid transaction type"
     in
     Caqti_type.(enum ~encode ~decode "transaction_type")
   ;;
 end
 
-type t =
-  | Transaction of
-      { transaction_type : TransactionType.t
-      ; value : int
-      ; description : string
-      }
-  | Balance of { client_id : int }
+type transaction_payload =
+  { value : int
+  ; description : string
+  }
+
+type transaction_op =
+  [ `Credit of transaction_payload
+  | `Debit of transaction_payload
+  ]
+
+type t = Balance of { client_id : int }
 
 type transaction =
   { id : int
@@ -34,15 +39,14 @@ type transaction =
   ; created_at : Ptime.t
   }
 
-let decoder =
+let decoder : transaction_op Utils.Decoder.decoder =
   let open Utils.Decoder in
   let open Syntax in
   let transaction_type_decoder =
-    literal "c" *> return TransactionType.Credit
-    <|> literal "d" *> return TransactionType.Debit
+    literal "c" *> return (fun p -> `Credit p)
+    <|> literal "d" *> return (fun p -> `Debit p)
   in
-  (fun value transaction_type description ->
-    Transaction { value; description; transaction_type })
+  (fun value transaction_type description -> transaction_type { value; description })
   <$> ("valor" <: int)
   <*> ("tipo" <: transaction_type_decoder)
   <*> ("descricao" <: string)