From 372834401b0b08498286c92a206a48654ec86a71 Mon Sep 17 00:00:00 2001
From: Mateus Cruz <mateuscolvr@gmail.com>
Date: Mon, 5 Feb 2024 23:28:09 -0300
Subject: feat: add transaction serializer

---
 lib/handler.ml    |  8 ++++++--
 lib/query.ml      | 14 ++++++++++++++
 lib/serializer.ml | 16 ++++++++++++++++
 3 files changed, 36 insertions(+), 2 deletions(-)
 create mode 100644 lib/serializer.ml

diff --git a/lib/handler.ml b/lib/handler.ml
index fb075ff..121a0c5 100644
--- a/lib/handler.ml
+++ b/lib/handler.ml
@@ -2,7 +2,7 @@ open Piaf
 
 let valid_debit value limit balance =
   let balance_after_op = balance - value in
-  not (balance_after_op <= limit * -1)
+  not (balance_after_op < limit * -1)
 ;;
 
 let create_transaction client_id (db_pool : Query.pool) (request : Request.t) =
@@ -73,7 +73,11 @@ let get_balance client_id (db_pool : Query.pool) (_request : Request.t) =
                let limit = `Int client.mov_limit in
                `Assoc [ "total", total; "data_extrato", date; "limite", limit ]
              in
-             let last_transactions = `List [] in
+             let t =
+               Result.fold ~ok:Fun.id ~error:(fun _ -> [])
+               @@ Query.transactions client_id conn
+             in
+             let last_transactions = `List (List.map Serializer.transaction t) in
              `Assoc [ "saldo", balance; "ultimas_transacoes", last_transactions ]
            in
            Ok (Response.of_string ~body:(Yojson.Safe.to_string json) `OK)
diff --git a/lib/query.ml b/lib/query.ml
index 6e359ce..1fdc2c3 100644
--- a/lib/query.ml
+++ b/lib/query.ml
@@ -45,6 +45,19 @@ module Q = struct
           SELECT @int{value}, @ptime{now()} as time FROM balances WHERE client_id = %int{client_id}
         |sql}]
   ;;
+
+  let transactions =
+    let open Operation in
+    [%rapper
+      get_many
+        {sql|
+          SELECT @int{id}, @int{client_id}, @int{value}, type as @Operation.TransactionType{transaction_type}, @string{description}, @ptime{created_at} FROM transactions
+          WHERE transactions.client_id = %int{client_id}
+          ORDER BY created_at DESC
+          LIMIT 10
+        |sql}
+        record_out]
+  ;;
 end
 
 let ( let* ) = Result.bind
@@ -66,3 +79,4 @@ let execute_transaction ~client_id ~(op : Operation.transaction_op) conn =
 
 let find_client id conn = Q.client ~id conn
 let balance client_id conn = Q.balance ~client_id conn
+let transactions client_id conn = Q.transactions ~client_id conn
diff --git a/lib/serializer.ml b/lib/serializer.ml
new file mode 100644
index 0000000..35464ac
--- /dev/null
+++ b/lib/serializer.ml
@@ -0,0 +1,16 @@
+let transaction (t : Operation.transaction) =
+  let transaction_type =
+    match t.transaction_type with
+    | `Credit -> "c"
+    | `Debit -> "d"
+  in
+  `Assoc
+    [ "valor", `Int t.value
+    ; "tipo", `String transaction_type
+    ; "descricao", `String t.description
+    ; ( "realizada_em"
+      , `String
+          (Format.asprintf "%a" (Ptime.pp_rfc3339 ~tz_offset_s:(-10800) ()) t.created_at)
+      )
+    ]
+;;
-- 
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