feat: add CreateInvoiceLink and RefundStarPayment

CreateInvoiceLink (payments.exportInvoice, sharing the invoice-media builder
with SendInvoice) and RefundStarPayment (payments.refundStarsCharge).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: ernado

payments_extra.go

@@ -0,0 +1,36 @@
+package botapi
+
+import (
+	"context"
+
+	"github.com/gotd/td/tg"
+)
+
+// CreateInvoiceLink creates a link for an invoice and returns it. The created
+// invoice can be paid by any user who follows the link.
+func (b *Bot) CreateInvoiceLink(ctx context.Context, params InvoiceParams) (string, error) {
+	res, err := b.raw.PaymentsExportInvoice(ctx, invoiceMedia(params))
+	if err != nil {
+		return "", asAPIError(err)
+	}
+
+	return res.URL, nil
+}
+
+// RefundStarPayment refunds a successful payment in Telegram Stars to the given
+// user. chargeID is the telegram_payment_charge_id from the successful payment.
+func (b *Bot) RefundStarPayment(ctx context.Context, userID int64, chargeID string) error {
+	user, err := b.resolveInputUser(ctx, userID)
+	if err != nil {
+		return err
+	}
+
+	if _, err := b.raw.PaymentsRefundStarsCharge(ctx, &tg.PaymentsRefundStarsChargeRequest{
+		UserID:   user,
+		ChargeID: chargeID,
+	}); err != nil {
+		return asAPIError(err)
+	}
+
+	return nil
+}

payments_extra_test.go

@@ -0,0 +1,60 @@
+package botapi
+
+import (
+	"context"
+	"testing"
+
+	"github.com/gotd/td/tg"
+)
+
+func TestCreateInvoiceLink(t *testing.T) {
+	inv := newMockInvoker()
+	inv.reply(tg.PaymentsExportInvoiceRequestTypeID, &tg.PaymentsExportedInvoice{URL: "https://t.me/invoice/abc"})
+
+	params := InvoiceParams{
+		Title:       "Item",
+		Description: "An item",
+		Payload:     "payload",
+		Currency:    "XTR",
+		Prices:      []LabeledPrice{{Label: "Item", Amount: 100}},
+	}
+
+	link, err := newMockBot(inv).CreateInvoiceLink(context.Background(), params)
+	if err != nil {
+		t.Fatalf("CreateInvoiceLink: %v", err)
+	}
+
+	if link != "https://t.me/invoice/abc" {
+		t.Fatalf("link = %q", link)
+	}
+
+	var req tg.PaymentsExportInvoiceRequest
+
+	inv.decode(t, tg.PaymentsExportInvoiceRequestTypeID, &req)
+
+	media, ok := req.InvoiceMedia.(*tg.InputMediaInvoice)
+	if !ok || media.Title != "Item" {
+		t.Fatalf("media = %#v", req.InvoiceMedia)
+	}
+}
+
+func TestRefundStarPayment(t *testing.T) {
+	inv := newMockInvoker()
+	inv.reply(tg.PaymentsRefundStarsChargeRequestTypeID, okUpdates())
+
+	if err := newMockBot(inv).RefundStarPayment(context.Background(), 99, "charge_123"); err != nil {
+		t.Fatalf("RefundStarPayment: %v", err)
+	}
+
+	var req tg.PaymentsRefundStarsChargeRequest
+
+	inv.decode(t, tg.PaymentsRefundStarsChargeRequestTypeID, &req)
+
+	if req.ChargeID != "charge_123" {
+		t.Fatalf("charge id = %q", req.ChargeID)
+	}
+
+	if _, ok := req.UserID.(*tg.InputUser); !ok {
+		t.Fatalf("user = %#v", req.UserID)
+	}
+}

send_invoice.go

@@ -36,19 +36,9 @@ type InvoiceParams struct {
 	IsFlexible                bool `json:"is_flexible,omitempty"`
 }
 
-// SendInvoice sends an invoice.
-func (b *Bot) SendInvoice(ctx context.Context, chat ChatID, params InvoiceParams, opts ...SendOption) (*Message, error) {
-	var cfg sendConfig
-
-	for _, o := range opts {
-		o(&cfg)
-	}
-
-	peer, err := b.resolveInputPeer(ctx, chat)
-	if err != nil {
-		return nil, err
-	}
-
+// invoiceMedia builds the MTProto invoice media shared by SendInvoice and
+// CreateInvoiceLink.
+func invoiceMedia(params InvoiceParams) *tg.InputMediaInvoice {
 	suggested := make([]int64, len(params.SuggestedTipAmounts))
 	for i, a := range params.SuggestedTipAmounts {
 		suggested[i] = int64(a)
@@ -91,6 +81,24 @@ func (b *Bot) SendInvoice(ctx context.Context, chat ChatID, params InvoiceParams
 		})
 	}
 
+	return media
+}
+
+// SendInvoice sends an invoice.
+func (b *Bot) SendInvoice(ctx context.Context, chat ChatID, params InvoiceParams, opts ...SendOption) (*Message, error) {
+	var cfg sendConfig
+
+	for _, o := range opts {
+		o(&cfg)
+	}
+
+	peer, err := b.resolveInputPeer(ctx, chat)
+	if err != nil {
+		return nil, err
+	}
+
+	media := invoiceMedia(params)
+
 	builder := &b.sender.To(peer).Builder
 
 	builder, err = b.applySendConfig(builder, cfg)