The last money-intake slice: reverse a paid order best-effort, exactly once. All
refunds are admin-triggered (E7) — no rail pushes an unsolicited refund (Robokassa
via its refund API / cabinet, VK via support, Telegram via refundStarPayment), so
this ships the engine they all converge on, not a webhook.
The Refund method matches the paid order, appends a refund ledger row (idempotent on
(provider, provider_refund_id) — distinct from the fund's payment id, so both
coexist), and revokes the funded chips floored at 0 (never negative — D27,
balances_chips_chk). When the chips were already spent, the unrecoverable remainder
is recorded as a per-account loss + abuse flag in the new additive
payments.account_risk table (read by the E7 report). The refund ledger row's chip
delta is what was actually reclaimed (the ledger stays reconcilable); the full
reversal rides in the snapshot; the order stays paid.
Additive migration (a new table only) -> rollback-safe, no contour wipe. Robokassa
refund-status polling is deferred (a worker not worth it at low chargeback volume);
failed events are not wired (no rail signals a hard post-charge server decline).
Tests: integration (full revoke; revoke-after-spend = floor-0 + loss + abuse;
duplicate idempotent; unpaid-order guard). Docs: PAYMENTS(+ru) §9, PLAN (E5 -> DONE).
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.
Wire the VK Mini Apps ("голоса") rail end to end, reusing the intake engine. The
wallet.order endpoint branches by rail: a VK context opens a pending order
(provider vk) and returns its id, which the client passes to VKWebAppShowOrderBox.
VK's two-phase payment callback is verified at the gateway with the app protected
key (GATEWAY_VK_APP_SECRET) and proxied to a backend intake handler: get_item
returns the ordered pack's title and vote price; a chargeable order_status_change
credits the vk segment exactly once (the same Fund, idempotent on VK's own order
id) and records a succeeded event, so the dispatcher push refreshes the wallet.
Integration test for the VK order->credit path.
Deliver payment_events to connected clients as an in-app wallet-refresh push: a
background dispatcher drains undispatched events and publishes a KindNotification
"payment" signal, marking each delivered; the client bumps a wallet-refresh
counter the open Wallet screen watches, re-fetching in place. A return-focus
refetch is the fallback. The Robokassa Success/Fail return now serves a
self-closing page (the payment opens in a separate window) so the customer drops
back into the live app instead of a cold start. Integration test for the event
drain/mark queue.
Cover the order→callback→credit path over Postgres: a funded order credits its
segment exactly once; a replayed callback for the same order credits nothing
(the ledger idempotency index holds); a mismatched paid amount is refused with
no write; an expired pending order is still honoured by a late valid callback.
Ilia Denisov