writers in writing package

internal/writing/csv/writer.go

@@ -0,0 +1,59 @@
+// Package csv renders an internal.AggregatorWriter as the CSV schema
+// expected by Modelo 3 do Anexo J.
+package csv
+
+import (
+	"encoding/csv"
+	"fmt"
+	"io"
+
+	"github.com/nmoniz/any2anexoj/internal"
+)
+
+type CSVWriter struct {
+	w *csv.Writer
+}
+
+func NewCSVWriter(w io.Writer) *CSVWriter {
+	return &CSVWriter{w: csv.NewWriter(w)}
+}
+
+func (cw *CSVWriter) Render(aw *internal.AggregatorWriter) error {
+	err := cw.w.Write([]string{
+		"source_country", "code",
+		"realization_year", "realization_month", "realization_day", "realization_value",
+		"acquisition_year", "acquisition_month", "acquisition_day", "acquisition_value",
+		"expenses", "foreign_tax_paid", "counter_country",
+	})
+	if err != nil {
+		return fmt.Errorf("write csv header: %w", err)
+	}
+
+	for ri := range aw.Iter() {
+		err := cw.w.Write(reportItemToRow(ri))
+		if err != nil {
+			return fmt.Errorf("write csv row: %w", err)
+		}
+	}
+
+	cw.w.Flush()
+	return cw.w.Error()
+}
+
+func reportItemToRow(ri internal.ReportItem) []string {
+	return []string{
+		fmt.Sprintf("%d", ri.AssetCountry),
+		string(ri.Nature),
+		fmt.Sprintf("%d", ri.SellTimestamp.Year()),
+		fmt.Sprintf("%d", int(ri.SellTimestamp.Month())),
+		fmt.Sprintf("%d", ri.SellTimestamp.Day()),
+		ri.SellValue.StringFixed(2),
+		fmt.Sprintf("%d", ri.BuyTimestamp.Year()),
+		fmt.Sprintf("%d", int(ri.BuyTimestamp.Month())),
+		fmt.Sprintf("%d", ri.BuyTimestamp.Day()),
+		ri.BuyValue.StringFixed(2),
+		ri.Fees.StringFixed(2),
+		ri.Taxes.StringFixed(2),
+		fmt.Sprintf("%d", ri.BrokerCountry),
+	}
+}

internal/writing/csv/writer_test.go

@@ -0,0 +1,78 @@
+package csv_test
+
+import (
+	"bytes"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/nmoniz/any2anexoj/internal"
+	"github.com/nmoniz/any2anexoj/internal/writing/csv"
+	"github.com/shopspring/decimal"
+)
+
+func TestCSVWriter_Render(t *testing.T) {
+	aw := internal.NewAggregatorWriter()
+	ctx := t.Context()
+
+	items := []internal.ReportItem{
+		{
+			Symbol:        "AAPL",
+			Nature:        internal.NatureG01,
+			BrokerCountry: 826, // United Kingdom
+			AssetCountry:  840, // United States
+			BuyValue:      decimal.NewFromFloat(100.50),
+			BuyTimestamp:  time.Date(2023, 1, 15, 0, 0, 0, 0, time.UTC),
+			SellValue:     decimal.NewFromFloat(150.75),
+			SellTimestamp: time.Date(2023, 6, 20, 0, 0, 0, 0, time.UTC),
+			Fees:          decimal.NewFromFloat(2.50),
+			Taxes:         decimal.NewFromFloat(5.00),
+		},
+		{
+			Symbol:        "VWRL",
+			Nature:        internal.NatureG20,
+			BrokerCountry: 196, // Portugal equivalent demo
+			AssetCountry:  372, // Ireland
+			BuyValue:      decimal.NewFromFloat(200.00),
+			BuyTimestamp:  time.Date(2024, 2, 1, 0, 0, 0, 0, time.UTC),
+			SellValue:     decimal.NewFromFloat(250.25),
+			SellTimestamp: time.Date(2024, 7, 10, 0, 0, 0, 0, time.UTC),
+			Fees:          decimal.NewFromFloat(1.00),
+			Taxes:         decimal.NewFromFloat(0.00),
+		},
+	}
+
+	for _, ri := range items {
+		if err := aw.Write(ctx, ri); err != nil {
+			t.Fatalf("write report item: %v", err)
+		}
+	}
+
+	var buf bytes.Buffer
+	if err := csv.NewCSVWriter(&buf).Render(aw); err != nil {
+		t.Fatalf("render: %v", err)
+	}
+
+	out := buf.String()
+
+	wantHeader := "source_country,code,realization_year,realization_month,realization_day,realization_value,acquisition_year,acquisition_month,acquisition_day,acquisition_value,expenses,foreign_tax_paid,counter_country"
+	if !strings.HasPrefix(out, wantHeader+"\n") {
+		t.Errorf("expected header row %q, got output:\n%s", wantHeader, out)
+	}
+
+	wantRow1 := "840,G01,2023,6,20,150.75,2023,1,15,100.50,2.50,5.00,826"
+	if !strings.Contains(out, wantRow1+"\n") {
+		t.Errorf("expected row 1 %q in output:\n%s", wantRow1, out)
+	}
+
+	wantRow2 := "372,G20,2024,7,10,250.25,2024,2,1,200.00,1.00,0.00,196"
+	if !strings.Contains(out, wantRow2+"\n") {
+		t.Errorf("expected row 2 %q in output:\n%s", wantRow2, out)
+	}
+
+	// Make sure the header only appears once and we have exactly 1 header + 2 data rows.
+	lines := strings.Split(strings.TrimRight(out, "\n"), "\n")
+	if got, want := len(lines), 3; got != want {
+		t.Errorf("expected %d lines (1 header + 2 rows), got %d:\n%s", want, got, out)
+	}
+}