feat(payments): Telegram Stars payment rail

Accept real money via Telegram Stars (XTR) — the third intake rail alongside Robokassa (direct) and VK Votes. Only the bot reaches Telegram, so the rail funnels through the reverse mTLS bot-link: - the gateway mints the invoice on a CreateInvoice command (the bot calls createInvoiceLink, XTR; the link goes to WebApp.openInvoice); - the bot gates each pre_checkout_query via a ValidatePreCheckout unary (the order must exist, be still creditable and not already paid — the reusable-invoice double-pay guard; the decline reason is localised to the order account's language); - a completed successful_payment is queued in a durable pure-Go SQLite outbox and forwarded via a ForwardPayment unary, credited once (idempotent on telegram_payment_charge_id, honours an expired order), re-driven on restart and every 30s. The rail is wired by TELEGRAM_STARS_OUTBOX_DIR (default /data) but stays inert until a chip pack carries an XTR price, so seeding a Stars price in the admin is the go-live. Tests: backend integration (order->forward->credit once, duplicate, pre_checkout gate) + bot outbox unit (idempotent, restart re-drive) + executor createInvoice. Docs: PAYMENTS(+ru) §9, ARCHITECTURE, the platform/telegram README, PLAN.
2026-07-09 21:35:29 +02:00
parent 5612bb624d
commit 6e03ce0131
32 changed files with 1830 additions and 94 deletions
@@ -129,6 +129,101 @@ func TestPaymentsVKOrderFundCredits(t *testing.T) {
 	}
 }

+// TestPaymentsTelegramStarsRail exercises the Telegram Stars rail over Postgres: an order prices the
+// pack in whole stars (XTR); a pre_checkout on the pending order is approved; the forwarded payment
+// credits the telegram segment exactly once (idempotent on the Telegram charge id); and a
+// pre_checkout after the order is paid is declined (a reusable invoice link paid twice).
+func TestPaymentsTelegramStarsRail(t *testing.T) {
+	ctx := context.Background()
+	svc := newPaymentsService()
+	acc := uuid.New()
+	prod := seedPackProduct(t, 50, methodPrice{method: "telegram", currency: "XTR", amount: 40}) // 40 stars fund 50 chips
+
+	res, err := svc.CreateOrder(ctx, acc, payments.NewContext("telegram", "android"), []payments.Source{payments.SourceTelegram}, prod, "telegram")
+	if err != nil {
+		t.Fatalf("create telegram order: %v", err)
+	}
+	if res.Amount.Currency() != payments.CurrencyStar || res.Amount.Minor() != 40 {
+		t.Fatalf("telegram order amount = %s, want 40 XTR", res.Amount)
+	}
+
+	// pre_checkout on the pending order: approved, and it reports the account for reason localisation.
+	starAmt, _ := payments.MoneyFromMinor(40, payments.CurrencyStar)
+	pc, err := svc.ValidatePreCheckout(ctx, res.OrderID, starAmt)
+	if err != nil {
+		t.Fatalf("pre_checkout: %v", err)
+	}
+	if !pc.OK || pc.AccountID != acc {
+		t.Fatalf("pre_checkout = %+v, want approved for account %s", pc, acc)
+	}
+
+	// The forwarded successful_payment credits once, idempotent on the Telegram charge id.
+	out, err := svc.Fund(ctx, res.OrderID, "telegram", "tg-charge-1", starAmt)
+	if err != nil {
+		t.Fatalf("telegram fund: %v", err)
+	}
+	if out.AlreadyCredited || out.Chips != 50 || out.Source != payments.SourceTelegram {
+		t.Fatalf("telegram fund outcome = %+v, want 50 chips credited to telegram", out)
+	}
+	if got := readBalance(t, acc, "telegram"); got != 50 {
+		t.Errorf("telegram balance after fund = %d, want 50", got)
+	}
+
+	// A retried forward (same charge id, e.g. a lost ack) credits nothing more.
+	out2, err := svc.Fund(ctx, res.OrderID, "telegram", "tg-charge-1", starAmt)
+	if err != nil {
+		t.Fatalf("duplicate telegram fund: %v", err)
+	}
+	if !out2.AlreadyCredited {
+		t.Error("retried forward not flagged AlreadyCredited")
+	}
+	if got := readBalance(t, acc, "telegram"); got != 50 {
+		t.Errorf("telegram balance after retry = %d, want 50 (credited once)", got)
+	}
+
+	// pre_checkout after the order is paid: declined (the reusable-link double-pay guard).
+	pc2, err := svc.ValidatePreCheckout(ctx, res.OrderID, starAmt)
+	if err != nil {
+		t.Fatalf("pre_checkout after paid: %v", err)
+	}
+	if pc2.OK || pc2.Reason != payments.PreCheckoutAlreadyPaid {
+		t.Errorf("pre_checkout after paid = %+v, want a decline with already_paid", pc2)
+	}
+}
+
+// TestPaymentsTelegramPreCheckoutDeclines covers the pre_checkout decline reasons: an unknown order
+// and an amount that no longer matches.
+func TestPaymentsTelegramPreCheckoutDeclines(t *testing.T) {
+	ctx := context.Background()
+	svc := newPaymentsService()
+	starAmt, _ := payments.MoneyFromMinor(40, payments.CurrencyStar)
+
+	// An unknown order id declines as gone, with no account to localise against.
+	pc, err := svc.ValidatePreCheckout(ctx, uuid.New(), starAmt)
+	if err != nil {
+		t.Fatalf("pre_checkout unknown: %v", err)
+	}
+	if pc.OK || pc.Reason != payments.PreCheckoutGone || pc.AccountID != (uuid.UUID{}) {
+		t.Errorf("pre_checkout unknown = %+v, want a gone decline with no account", pc)
+	}
+
+	// A pending order validated at the wrong amount declines as price-changed.
+	acc := uuid.New()
+	prod := seedPackProduct(t, 100, methodPrice{method: "telegram", currency: "XTR", amount: 80})
+	res, err := svc.CreateOrder(ctx, acc, payments.NewContext("telegram", "android"), []payments.Source{payments.SourceTelegram}, prod, "telegram")
+	if err != nil {
+		t.Fatalf("create telegram order: %v", err)
+	}
+	wrong, _ := payments.MoneyFromMinor(40, payments.CurrencyStar)
+	pc2, err := svc.ValidatePreCheckout(ctx, res.OrderID, wrong)
+	if err != nil {
+		t.Fatalf("pre_checkout mismatch: %v", err)
+	}
+	if pc2.OK || pc2.Reason != payments.PreCheckoutPriceChanged {
+		t.Errorf("pre_checkout mismatch = %+v, want a price_changed decline", pc2)
+	}
+}
+
 // TestPaymentsFundAmountMismatch verifies a callback whose paid amount does not match the order is
 // refused and credits nothing (§9: verify the amount after matching by order id).
 func TestPaymentsFundAmountMismatch(t *testing.T) {
@@ -2,6 +2,7 @@ package payments

 import (
 	"context"
+	"errors"
 	"fmt"

 	"github.com/google/uuid"
@@ -80,6 +81,49 @@ func (s *Service) Fund(ctx context.Context, orderID uuid.UUID, provider, provide
 	return s.store.fund(ctx, orderID, provider, providerPaymentID, paid, s.clock())
 }

+// Pre-checkout decline reason codes. They are language-neutral: the transport layer localises them
+// to the order account's preferred language before showing the payer (the reason is displayed in the
+// Telegram payment sheet).
+const (
+	// PreCheckoutGone means no order matches — an unknown or stale invoice payload.
+	PreCheckoutGone = "order_gone"
+	// PreCheckoutAlreadyPaid means the order is already paid (a reusable invoice link paid twice).
+	PreCheckoutAlreadyPaid = "already_paid"
+	// PreCheckoutPriceChanged means the amount or currency no longer matches the order.
+	PreCheckoutPriceChanged = "price_changed"
+)
+
+// PreCheckoutOutcome is the pre-charge validation of a Telegram Stars order. OK approves the charge;
+// otherwise Reason is a decline reason code the transport localises. AccountID is the order's account
+// (for localising the reason to its preferred language); it is the zero UUID when the order is unknown.
+type PreCheckoutOutcome struct {
+	OK        bool
+	Reason    string
+	AccountID uuid.UUID
+}
+
+// ValidatePreCheckout answers whether a Stars pre_checkout_query for orderID paying amount may be
+// approved, before any star is charged. It approves an order that exists, is not already paid (a
+// reusable invoice link paid a second time is refused here) and whose expected amount and currency
+// match the invoice. A pending or honoured-expired order is approved — a late credit is honoured
+// (§9/D23). A missing order or a mismatch is a clean decline with a reason code, not an error.
+func (s *Service) ValidatePreCheckout(ctx context.Context, orderID uuid.UUID, amount Money) (PreCheckoutOutcome, error) {
+	ord, err := s.store.orderByID(ctx, orderID)
+	if errors.Is(err, ErrOrderNotFound) {
+		return PreCheckoutOutcome{OK: false, Reason: PreCheckoutGone}, nil
+	}
+	if err != nil {
+		return PreCheckoutOutcome{}, err
+	}
+	if ord.status == "paid" {
+		return PreCheckoutOutcome{OK: false, Reason: PreCheckoutAlreadyPaid, AccountID: ord.accountID}, nil
+	}
+	if amount.Currency() != Currency(ord.currency) || amount.Minor() != ord.expectedAmount {
+		return PreCheckoutOutcome{OK: false, Reason: PreCheckoutPriceChanged, AccountID: ord.accountID}, nil
+	}
+	return PreCheckoutOutcome{OK: true, AccountID: ord.accountID}, nil
+}
+
 // ExpireOrders marks pending orders older than the configured lifetime as expired, returning how
 // many were swept. It backs the periodic pending reaper; expiry is cosmetic (a late valid callback
 // still credits — see Fund).
@@ -80,6 +80,10 @@ func (s *Server) registerRoutes() {
 		// the Robokassa Result callback when a merchant is configured.
 		u.POST("/wallet/order", s.handleWalletOrder)
 		s.internal.POST("/payments/vk/callback", s.handleVKCallback)
+		// The Telegram Stars rail: the bot forwards a pre_checkout validation and a completed
+		// payment over the reverse bot-link; the gateway proxies both onto these gateway-only routes.
+		s.internal.POST("/payments/telegram/precheckout", s.handleTelegramPreCheckout)
+		s.internal.POST("/payments/telegram/payment", s.handleTelegramPayment)
 		if s.robokassa.MerchantLogin != "" {
 			s.internal.POST("/payments/robokassa/result", s.handleRobokassaResult)
 		}
@@ -18,6 +18,7 @@ import (
 const (
 	providerRobokassa = "robokassa" // the direct (RUB) rail
 	providerVK        = "vk"        // the VK Votes rail
+	providerTelegram  = "telegram"  // the Telegram Stars (XTR) rail
 )

 // walletOrderRequest is the POST body of a chip-pack purchase: the pack to fund.
@@ -25,16 +26,25 @@ type walletOrderRequest struct {
 	ProductID string `json:"product_id"`
 }

-// walletOrderResponse returns the created order id and the provider launch URL the client opens.
+// walletOrderResponse returns the created order id and the rail's launch details. RedirectURL is
+// the provider's hosted-payment URL for the direct rail (empty for VK/Telegram, which settle
+// in-app). Rail names the settling rail so the gateway knows how to launch it; for the Telegram
+// Stars rail the gateway mints the invoice link from InvoiceTitle and InvoiceAmount (whole stars)
+// via the bot and returns it in RedirectURL.
 type walletOrderResponse struct {
-	OrderID     string `json:"order_id"`
-	RedirectURL string `json:"redirect_url"`
+	OrderID       string `json:"order_id"`
+	RedirectURL   string `json:"redirect_url"`
+	Rail          string `json:"rail"`
+	InvoiceTitle  string `json:"invoice_title,omitempty"`
+	InvoiceAmount int64  `json:"invoice_amount,omitempty"`
 }

-// handleWalletOrder opens a pending order to fund a chip pack and returns the Robokassa
-// hosted-payment URL for the client to open. It is direct-rail only for now (VK/TG land later);
-// it enforces the wallet gate and D36 (a direct purchase requires a confirmed email anchor). No
-// chips are credited here — only later, by the verified Result callback.
+// handleWalletOrder opens a pending order to fund a chip pack and returns the rail's launch
+// details for the client: the Robokassa hosted-payment URL (direct), the order id for
+// VKWebAppShowOrderBox (VK), or the pack title and star amount the gateway mints into a Stars
+// invoice link (Telegram). It enforces the wallet gate and, on the direct rail, D36 (a purchase
+// requires a confirmed email anchor). No chips are credited here — only later, by the verified
+// provider callback.
 func (s *Server) handleWalletOrder(c *gin.Context) {
 	uid, ok := userID(c)
 	if !ok {
@@ -80,6 +90,7 @@ func (s *Server) handleWalletOrder(c *gin.Context) {
 		c.JSON(http.StatusOK, walletOrderResponse{
 			OrderID:     res.OrderID.String(),
 			RedirectURL: s.robokassa.PaymentURL(res.OrderID, res.Amount.Major(), res.Title),
+			Rail:        providerRobokassa,
 		})
 	case payments.SourceVK:
 		res, err := s.payments.CreateOrder(ctx, uid, cxt, present, productID, providerVK)
@@ -88,7 +99,23 @@ func (s *Server) handleWalletOrder(c *gin.Context) {
 			return
 		}
 		// The client passes the order id to VKWebAppShowOrderBox as the item; there is no redirect.
-		c.JSON(http.StatusOK, walletOrderResponse{OrderID: res.OrderID.String()})
+		c.JSON(http.StatusOK, walletOrderResponse{OrderID: res.OrderID.String(), Rail: providerVK})
+	case payments.SourceTelegram:
+		res, err := s.payments.CreateOrder(ctx, uid, cxt, present, productID, providerTelegram)
+		if err != nil {
+			s.abortErr(c, err)
+			return
+		}
+		// The gateway mints the Stars invoice link from the title and amount via the bot (only
+		// the bot reaches Telegram) and returns it to the client as RedirectURL; the amount is in
+		// whole stars (the XTR minor unit is the star). No chips are credited until the verified
+		// successful_payment is forwarded back through the bot.
+		c.JSON(http.StatusOK, walletOrderResponse{
+			OrderID:       res.OrderID.String(),
+			Rail:          providerTelegram,
+			InvoiceTitle:  res.Title,
+			InvoiceAmount: res.Amount.Minor(),
+		})
 	default:
 		c.AbortWithStatusJSON(http.StatusNotImplemented, errorResponse{Error: errorBody{Code: "rail_unavailable", Message: "this payment method is not available yet"}})
 	}
@@ -225,3 +252,148 @@ func (s *Server) handleVKCallback(c *gin.Context) {
 		c.JSON(http.StatusOK, vkErrorResponse(100, "unknown notification", false))
 	}
 }
+
+// telegramPreCheckoutRequest is the bot's pre_checkout validation, forwarded through the gateway:
+// the order in the invoice payload and the amount and currency Telegram is about to charge.
+type telegramPreCheckoutRequest struct {
+	OrderID  string `json:"order_id"`
+	Amount   int64  `json:"amount"`
+	Currency string `json:"currency"`
+}
+
+// telegramPreCheckoutResponse tells the bot whether to approve the pre_checkout_query; Reason is a
+// short message the bot surfaces to the payer on a decline.
+type telegramPreCheckoutResponse struct {
+	OK     bool   `json:"ok"`
+	Reason string `json:"reason,omitempty"`
+}
+
+// handleTelegramPreCheckout validates a Telegram Stars pre_checkout_query before the charge,
+// reached only through the gateway (the bot's ValidatePreCheckout, forwarded on the internal
+// route). It approves an order that exists, is not already paid (a reusable invoice link paid twice
+// is refused here, before any star moves) and whose amount and currency match. A malformed
+// reference is a decline, not an error.
+func (s *Server) handleTelegramPreCheckout(c *gin.Context) {
+	var req telegramPreCheckoutRequest
+	if err := c.ShouldBindJSON(&req); err != nil {
+		abortBadRequest(c, "invalid request body")
+		return
+	}
+	ctx := c.Request.Context()
+	orderID, err := uuid.Parse(req.OrderID)
+	if err != nil {
+		c.JSON(http.StatusOK, telegramPreCheckoutResponse{OK: false, Reason: telegramDeclineText(payments.PreCheckoutGone, "")})
+		return
+	}
+	amount, err := payments.MoneyFromMinor(req.Amount, payments.Currency(req.Currency))
+	if err != nil {
+		c.JSON(http.StatusOK, telegramPreCheckoutResponse{OK: false, Reason: telegramDeclineText(payments.PreCheckoutGone, "")})
+		return
+	}
+	out, err := s.payments.ValidatePreCheckout(ctx, orderID, amount)
+	if err != nil {
+		s.log.Error("telegram pre_checkout validate failed", zap.String("order", orderID.String()), zap.Error(err))
+		c.AbortWithStatusJSON(http.StatusInternalServerError, errorResponse{Error: errorBody{Code: "internal", Message: "internal error"}})
+		return
+	}
+	reason := ""
+	if !out.OK {
+		// Localise the decline to the order account's preferred language (the reason shows in the
+		// Telegram payment sheet). An unknown order has no account, so it falls back to English.
+		lang := ""
+		if s.accounts != nil && out.AccountID != (uuid.UUID{}) {
+			if acc, aerr := s.accounts.GetByID(ctx, out.AccountID); aerr == nil {
+				lang = acc.PreferredLanguage
+			}
+		}
+		reason = telegramDeclineText(out.Reason, lang)
+	}
+	c.JSON(http.StatusOK, telegramPreCheckoutResponse{OK: out.OK, Reason: reason})
+}
+
+// telegramDeclineText renders a pre-checkout decline reason code in the payer's language (ru or
+// anything else falls back to English), for display in the Telegram payment sheet.
+func telegramDeclineText(code, lang string) string {
+	ru := lang == "ru"
+	switch code {
+	case payments.PreCheckoutAlreadyPaid:
+		if ru {
+			return "Этот заказ уже оплачен."
+		}
+		return "This order has already been paid."
+	case payments.PreCheckoutPriceChanged:
+		if ru {
+			return "Цена изменилась — начните покупку заново."
+		}
+		return "The price has changed; please start the purchase again."
+	default:
+		if ru {
+			return "Этот заказ больше недоступен."
+		}
+		return "This order is no longer available."
+	}
+}
+
+// telegramPaymentRequest is a completed Stars payment forwarded from the bot's outbox through the
+// gateway: the order, the Telegram charge id (the idempotency key), the stars paid, and the payer.
+type telegramPaymentRequest struct {
+	OrderID                 string `json:"order_id"`
+	TelegramPaymentChargeID string `json:"telegram_payment_charge_id"`
+	Amount                  int64  `json:"amount"`
+	TelegramUserID          int64  `json:"telegram_user_id"`
+}
+
+// telegramPaymentResponse reports the durable outcome to the bot: Credited is true once the order
+// is credited (or already was). A false with a 200 means the payment was recorded but not creditable
+// (the bot drops it); a 5xx means a transient failure the bot retries.
+type telegramPaymentResponse struct {
+	Credited bool `json:"credited"`
+}
+
+// handleTelegramPayment credits a completed Telegram Stars payment, reached only through the gateway
+// (the bot's ForwardPayment, forwarded on the internal route). It credits the matched order exactly
+// once (idempotent on the Telegram charge id, honoured even if the order expired) and records a
+// succeeded event. A permanent rejection (unknown order, amount mismatch) is answered 200 with
+// Credited=false so the bot stops retrying a payment it cannot place; a transient failure is a 5xx
+// the bot retries.
+func (s *Server) handleTelegramPayment(c *gin.Context) {
+	var req telegramPaymentRequest
+	if err := c.ShouldBindJSON(&req); err != nil {
+		abortBadRequest(c, "invalid request body")
+		return
+	}
+	orderID, err := uuid.Parse(req.OrderID)
+	if err != nil {
+		s.log.Warn("telegram payment: bad order id", zap.String("charge", req.TelegramPaymentChargeID))
+		c.JSON(http.StatusOK, telegramPaymentResponse{Credited: false})
+		return
+	}
+	paid, err := payments.MoneyFromMinor(req.Amount, payments.CurrencyStar)
+	if err != nil {
+		c.JSON(http.StatusOK, telegramPaymentResponse{Credited: false})
+		return
+	}
+	ctx := c.Request.Context()
+	outcome, err := s.payments.Fund(ctx, orderID, providerTelegram, req.TelegramPaymentChargeID, paid)
+	if err != nil {
+		if errors.Is(err, payments.ErrOrderNotFound) || errors.Is(err, payments.ErrAmountMismatch) ||
+			errors.Is(err, payments.ErrNotAPack) || errors.Is(err, payments.ErrProductNotFound) {
+			// The star charge already happened but the order cannot be placed; record it loudly for
+			// an operator and tell the bot to stop retrying (an operator refunds or credits by hand).
+			s.log.Error("telegram payment rejected (charge taken, not credited)",
+				zap.String("order", orderID.String()), zap.String("charge", req.TelegramPaymentChargeID), zap.Error(err))
+			c.JSON(http.StatusOK, telegramPaymentResponse{Credited: false})
+			return
+		}
+		s.log.Error("telegram fund failed", zap.String("order", orderID.String()), zap.Error(err))
+		c.AbortWithStatusJSON(http.StatusInternalServerError, errorResponse{Error: errorBody{Code: "internal", Message: "internal error"}})
+		return
+	}
+	if !outcome.AlreadyCredited {
+		payload, _ := json.Marshal(map[string]any{"chips": outcome.Chips, "source": string(outcome.Source)})
+		if err := s.payments.RecordPaymentEvent(ctx, outcome.AccountID, &orderID, "succeeded", payload); err != nil {
+			s.log.Error("record telegram payment event failed", zap.String("order", orderID.String()), zap.Error(err))
+		}
+	}
+	c.JSON(http.StatusOK, telegramPaymentResponse{Credited: true})
+}