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
@@ -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})
+}