From c109e68a7ae00916ca431bcaf3425941b07ff474 Mon Sep 17 00:00:00 2001
From: Natercio Moniz <natercio.moniz@gmail.com>
Date: Fri, 7 Nov 2025 13:04:40 +0000
Subject: [PATCH] initial processing of trading212 csv statement

---
 main.go | 71 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 71 insertions(+)

diff --git a/main.go b/main.go
index da29a2c..8352b79 100644
--- a/main.go
+++ b/main.go
@@ -1,4 +1,75 @@
 package main
 
+import (
+	"container/list"
+	"encoding/csv"
+	"errors"
+	"fmt"
+	"io"
+	"log/slog"
+	"os"
+	"strings"
+)
+
 func main() {
+	err := run()
+	if err != nil {
+		slog.Error("fatal error", slog.Any("err", err))
+	}
 }
+
+func run() error {
+	f, err := os.Open("test.csv")
+	if err != nil {
+		return fmt.Errorf("open statement: %w", err)
+	}
+
+	r := csv.NewReader(f)
+
+	assets := make(map[string]*list.List)
+	for {
+		record, err := r.Read()
+		if err != nil {
+			if errors.Is(err, io.EOF) {
+				break
+			}
+			return fmt.Errorf("read statement record: %w", err)
+		}
+
+		switch strings.ToLower(record[0]) {
+		case "market buy":
+			lst, ok := assets[record[2]]
+			if !ok {
+				lst = list.New()
+				assets[record[2]] = lst
+			}
+			lst.PushBack(record[12])
+
+		case "market sell":
+			lst, ok := assets[record[2]]
+			if !ok {
+				return ErrSellWithoutBuy
+			}
+
+			first := lst.Front()
+			if first == nil {
+				return ErrSellWithoutBuy
+			}
+
+			slog.Info("Realised PnL", slog.Any("record", record))
+
+		case "action", "stock split open", "stock split close":
+			// ignored
+
+		default:
+			return fmt.Errorf("unhandled record: %s", record[0])
+		}
+
+	}
+
+	slog.Info("Finish processing statement", slog.Any("assets_count", len(assets)))
+
+	return nil
+}
+
+var ErrSellWithoutBuy = fmt.Errorf("found sell without bought volume")