handle stock split

2026-05-16 15:34:24 +01:00
parent 5cdccfcdb1
commit 7cc5d1cf75
6 changed files with 258 additions and 35 deletions
--- a/internal/trading212/record.go
+++ b/internal/trading212/record.go
@@ -18,7 +18,7 @@ import (
 type Record struct {
 	symbol    string
 	timestamp time.Time
-	side      internal.Kind
+	kind      internal.Kind
 	quantity  decimal.Decimal
 	price     decimal.Decimal
 	fees      decimal.Decimal
@@ -45,7 +45,7 @@ func (r Record) AssetCountry() int64 {
 }

 func (r Record) Kind() internal.Kind {
-	return r.side
+	return r.kind
 }

 func (r Record) Quantity() decimal.Decimal {
@@ -81,34 +81,26 @@ func NewRecordReader(r io.Reader, f *internal.OpenFIGI) *RecordReader {
 }

 const (
-	MarketBuy       = "market buy"
-	MarketSell      = "market sell"
-	LimitBuy        = "limit buy"
-	LimitSell       = "limit sell"
-	StockSplitOpen  = "Stock split open"
-	StockSplitClose = "Stock split close"
+	MarketBuy        = "market buy"
+	MarketSell       = "market sell"
+	LimitBuy         = "limit buy"
+	LimitSell        = "limit sell"
+	StockSplitOpen   = "stock split open"
+	StockSplitClose  = "stock split close"
+	StokDistribution = "stock distribution"
 )

 func (rr RecordReader) ReadRecord(ctx context.Context) (internal.Record, error) {
+	var splitRec *splitRecord
+
 	for {
 		raw, err := rr.reader.Read()
 		if err != nil {
 			return Record{}, fmt.Errorf("read record: %w", err)
 		}

-		var side internal.Kind
-		switch strings.ToLower(raw[0]) {
-		case MarketBuy, LimitBuy:
-			side = internal.KindBuy
-		case MarketSell, LimitSell:
-			side = internal.KindSell
-		case StockSplitOpen, StockSplitClose:
-			// TODO: emit a special event that triggers a readjustment of unsold stock
+		if strings.ToLower(raw[0]) == "action" {
 			continue
-		case "action": // TODO: this is the header, there's probably a better way to handle this
-			continue
-		default:
-			return Record{}, fmt.Errorf("parse record type: %s", raw[0])
 		}

 		qant, err := parseDecimal(raw[6])
@@ -141,9 +133,50 @@ func (rr RecordReader) ReadRecord(ctx context.Context) (internal.Record, error)
 			return Record{}, fmt.Errorf("parse record french transaction tax: %w", err)
 		}

+		var kind internal.Kind
+		switch strings.ToLower(raw[0]) {
+		case MarketBuy, LimitBuy:
+			kind = internal.KindBuy
+		case MarketSell, LimitSell:
+			kind = internal.KindSell
+		case StockSplitOpen:
+			if splitRec != nil {
+				return nil, fmt.Errorf("split already open")
+			}
+
+			splitRec = &splitRecord{
+				Record: Record{
+					symbol:       raw[2],
+					kind:         internal.KindSplit,
+					quantity:     qant,
+					price:        price,
+					fees:         conversionFee,
+					taxes:        stampDutyTax.Add(frenchTxTax),
+					timestamp:    ts,
+					natureGetter: figiNatureGetter(ctx, rr.figi, raw[2]),
+				},
+			}
+
+			continue
+
+		case StockSplitClose:
+			if splitRec == nil {
+				return nil, fmt.Errorf("missing split open")
+			}
+			splitRec.ratio = splitRec.Record.Quantity().Div(qant)
+			return splitRec, nil
+
+		case StokDistribution:
+			slog.Warn("Found stock distribution but can't handle it")
+			continue
+
+		default:
+			return Record{}, fmt.Errorf("parse record type: %s", raw[0])
+		}
+
 		return Record{
 			symbol:       raw[2],
-			side:         side,
+			kind:         kind,
 			quantity:     qant,
 			price:        price,
 			fees:         conversionFee,
@@ -190,3 +223,13 @@ func parseOptionalDecimal(s string) (decimal.Decimal, error) {

 	return parseDecimal(s)
 }
+
+type splitRecord struct {
+	Record
+
+	ratio decimal.Decimal
+}
+
+func (sr splitRecord) Quantity() decimal.Decimal {
+	return sr.ratio
+}
--- a/internal/trading212/record_test.go
+++ b/internal/trading212/record_test.go
@@ -30,7 +30,7 @@ func TestRecordReader_ReadRecord(t *testing.T) {
 			r:    bytes.NewBufferString(`Market buy,2025-07-03 10:44:29,XX1234567890,ABXY,"Aspargus Broccoli",EOF987654321,2.4387014200,7.3690000000,USD,1.17995999,,"EUR",15.25,"EUR",0.25,"EUR",0.02,"EUR",,`),
 			want: Record{
 				symbol:       "XX1234567890",
-				side:         internal.KindBuy,
+				kind:         internal.KindBuy,
 				quantity:     ShouldParseDecimal(t, "2.4387014200"),
 				price:        ShouldParseDecimal(t, "7.3690000000"),
 				timestamp:    time.Date(2025, 7, 3, 10, 44, 29, 0, time.UTC),
@@ -44,7 +44,7 @@ func TestRecordReader_ReadRecord(t *testing.T) {
 			r:    bytes.NewBufferString(`Market sell,2025-08-04 11:45:30,XX1234567890,ABXY,"Aspargus Broccoli",EOF987654321,2.4387014200,7.9999999999,USD,1.17995999,,"EUR",15.25,"EUR",,,0.02,"EUR",0.1,"EUR"`),
 			want: Record{
 				symbol:       "XX1234567890",
-				side:         internal.KindSell,
+				kind:         internal.KindSell,
 				quantity:     ShouldParseDecimal(t, "2.4387014200"),
 				price:        ShouldParseDecimal(t, "7.9999999999"),
 				timestamp:    time.Date(2025, 8, 4, 11, 45, 30, 0, time.UTC),
@@ -123,8 +123,8 @@ func TestRecordReader_ReadRecord(t *testing.T) {
 				t.Fatalf("want symbol %v but got %v", tt.want.symbol, got.Symbol())
 			}

-			if got.Kind() != tt.want.side {
-				t.Fatalf("want side %v but got %v", tt.want.side, got.Kind())
+			if got.Kind() != tt.want.kind {
+				t.Fatalf("want side %v but got %v", tt.want.kind, got.Kind())
 			}

 			if got.Price().Cmp(tt.want.price) != 0 {
@@ -154,6 +154,70 @@ func TestRecordReader_ReadRecord(t *testing.T) {
 	}
 }

+func TestRecordReader_ReadRecord_Split(t *testing.T) {
+	// open row has the NEW (post-split) position: more shares at lower price
+	// close row has the OLD (pre-split) position: fewer shares at higher price
+	// ratio = openQty / closeQty = 0.5 / 0.1 = 5 (a 5:1 split)
+	splitOpen  := `Stock split open,2025-06-03 05:34:16,XX1234567890,ABXY,"Aspargus Broccoli",EOF111111111,0.5000000000,20.0000000000,EUR,1.00000000,,,10.00,"EUR",,,,,,`
+	splitClose := `Stock split close,2025-06-03 05:34:16,XX1234567890,ABXY,"Aspargus Broccoli",EOF222222222,0.1000000000,100.0000000000,EUR,1.00000000,0.00,"EUR",10.00,"EUR",,,,,,`
+
+	t.Run("well-formed split pair returns split record with correct ratio", func(t *testing.T) {
+		rr := NewRecordReader(
+			bytes.NewBufferString(splitOpen+"\n"+splitClose),
+			NewFigiClientSecurityTypeStub(t, "Common Stock"),
+		)
+
+		got, err := rr.ReadRecord(t.Context())
+		if err != nil {
+			t.Fatalf("ReadRecord() failed: %v", err)
+		}
+
+		if got.Kind() != internal.KindSplit {
+			t.Errorf("want kind %v but got %v", internal.KindSplit, got.Kind())
+		}
+		if got.Symbol() != "NO0013536151" {
+			t.Errorf("want symbol NO0013536151 but got %v", got.Symbol())
+		}
+
+		wantTimestamp := time.Date(2025, 6, 3, 5, 34, 16, 0, time.UTC)
+		if !got.Timestamp().Equal(wantTimestamp) {
+			t.Errorf("want timestamp %v but got %v", wantTimestamp, got.Timestamp())
+		}
+
+		// ratio = openQty / closeQty = 0.1245045 / 0.0249009 ≈ 5
+		openQty := ShouldParseDecimal(t, "0.1245045000")
+		closeQty := ShouldParseDecimal(t, "0.0249009000")
+		wantRatio := openQty.Div(closeQty)
+		if !got.Quantity().Equal(wantRatio) {
+			t.Errorf("want ratio %v but got %v", wantRatio, got.Quantity())
+		}
+	})
+
+	t.Run("close without prior open errors", func(t *testing.T) {
+		rr := NewRecordReader(
+			bytes.NewBufferString(splitClose),
+			NewFigiClientSecurityTypeStub(t, "Common Stock"),
+		)
+
+		_, err := rr.ReadRecord(t.Context())
+		if err == nil {
+			t.Fatal("expected error but got none")
+		}
+	})
+
+	t.Run("two opens without close errors", func(t *testing.T) {
+		rr := NewRecordReader(
+			bytes.NewBufferString(splitOpen+"\n"+splitOpen),
+			NewFigiClientSecurityTypeStub(t, "Common Stock"),
+		)
+
+		_, err := rr.ReadRecord(t.Context())
+		if err == nil {
+			t.Fatal("expected error but got none")
+		}
+	})
+}
+
 func Test_figiNatureGetter(t *testing.T) {
 	tests := []struct {
 		name string // description of this test case