Files
nroxy/docs/ops/payment-system.md
sirily 9641678fa3 feat: add renewal invoice sweep (#20)
Refs #9

## Summary
- add a worker-side renewal invoice sweep that creates one invoice 72 hours before subscription expiry
- expire elapsed pending invoices automatically and email users when an automatic renewal invoice is created
- stop auto-recreating invoices for the same paid cycle once any invoice already exists for that cycle
- document the current renewal-invoice and pending-invoice expiry behavior

## Testing
- built `infra/docker/web.Dockerfile`
- ran `pnpm --filter @nproxy/db test` inside the built container
- verified `@nproxy/db build` and `@nproxy/web build` during the image build
- built `infra/docker/worker.Dockerfile`

Co-authored-by: sirily <sirily@git.shararam.party>
Reviewed-on: #20
2026-03-11 12:33:03 +03:00

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Markdown

# Payment System
## Purpose
Describe how billing and payment processing currently work in `nproxy`.
This document is about the implemented system, not the desired future state.
## Scope
The current payment system covers:
- default subscription plan bootstrap
- user subscription creation at registration time
- invoice creation through a provider adapter
- automatic renewal-invoice creation `72 hours` before `currentPeriodEnd`
- one renewal-invoice creation attempt per paid cycle unless the user explicitly creates a new one manually
- worker-side polling reconciliation for `pending` invoices
- manual admin activation after an operator verifies that the provider reported a final successful payment status
- automatic expiry of elapsed subscription periods during account and generation access checks
- automatic expiry of elapsed pending invoices
- automatic provider-driven `expired` and `canceled` transitions for pending invoices
- quota-cycle reset on successful activation
The current payment system does not yet cover:
- provider webhooks
- recurring billing
## Main records
### `SubscriptionPlan`
- one default active plan is bootstrapped by `packages/db/src/bootstrap.ts`
- current default seed:
- `code`: `monthly`
- `displayName`: `Monthly`
- `monthlyRequestLimit`: `100`
- `monthlyPriceUsd`: `9.99`
- `billingCurrency`: `USDT`
### `Subscription`
- created for a new user during registration if the default plan exists
- starts in `pending_activation`
- becomes `active` only after successful invoice activation
- stores:
- `activatedAt`
- `currentPeriodStart`
- `currentPeriodEnd`
- `renewsManually`
### `PaymentInvoice`
- stores one provider-facing payment attempt for a subscription
- `pending` means the invoice exists, but the payment is not yet considered final or accepted
- `paid` means the payment is considered final and safe to activate against
- important fields:
- local `id`
- `subscriptionId`
- `provider`
- `providerInvoiceId`
- `status`
- `currency`
- `amountCrypto`
- `amountUsd`
- `paymentAddress`
- `expiresAt`
- `paidAt`
### `UsageLedgerEntry`
- records quota-affecting events
- on successful payment activation the system writes `cycle_reset`
- successful generations later write `generation_success`
### `AdminAuditLog`
- records state-changing admin actions
- the current admin `mark-paid` flow writes:
- `invoice_mark_paid`
- `invoice_mark_paid_replayed`
## Provider boundary
Payment-provider code stays behind `packages/providers/src/payments.ts`.
Current provider contract:
- `createInvoice(input) -> providerInvoiceId, paymentAddress, amountCrypto, amountUsd, currency, expiresAt`
- `getInvoiceStatus(providerInvoiceId) -> pending|paid|expired|canceled + paidAt? + expiresAt?`
Current runtime note:
- the provider adapter is still a placeholder adapter
- worker polling is implemented, but provider-specific HTTP/status mapping is still placeholder logic
- provider callbacks and webhook signature verification are not implemented yet
- the rest of the payment flow is intentionally provider-agnostic
## Registration flow
1. User registers through `POST /api/auth/register`.
2. `packages/db/src/auth-store.ts` creates the user and session.
3. If the default plan exists, the store also creates a `Subscription` in `pending_activation`.
4. At this point the user has an account and a plan assignment, but not an active paid cycle.
## Invoice creation flow
1. Authenticated user calls `POST /api/billing/invoices`.
2. `packages/db/src/billing-store.ts` loads the latest subscription for that user.
3. If there is already a non-expired `pending` invoice for the same subscription, it is reused.
4. Otherwise the app calls the payment-provider adapter `createInvoice`.
5. The returned provider invoice data is persisted as a new local `PaymentInvoice` in `pending`.
6. The API returns invoice details, including provider invoice id, amount, address, and expiry time.
## Automatic renewal invoice flow
1. The worker scans `active` manual-renewal subscriptions.
2. If `currentPeriodEnd` is within the next `72 hours`, the worker checks whether the current paid cycle already has an invoice.
3. If the current cycle has no invoice yet, the worker creates one renewal invoice through the payment-provider adapter.
4. The worker sends the invoice details to the user by email.
5. If any invoice already exists for the current cycle, the worker does not auto-create another one.
Current rule:
- after the first invoice exists for the current paid cycle, automatic re-creation stops for that cycle
- if that invoice later expires or is canceled, the next invoice is created only when the user explicitly goes to billing and creates one
## Payment status semantics
- `pending` does not count as paid.
- `pending` does not activate the subscription.
- `pending` does not reset quota.
- The system must treat an invoice as `paid` only after the payment provider reports a final successful status, meaning the funds are accepted strongly enough for access activation.
- Worker reconciliation now polls provider status for stored `pending` invoices.
- If the provider reports final `paid`, the worker activates access from provider `paidAt` when that timestamp is available.
- If the provider reports final `paid` after a local fallback expiry, provider `paid` still wins and access is activated.
- If the provider reports final `expired` or `canceled`, the worker finalizes the local invoice to the same terminal status.
## Worker reconciliation flow
1. The worker loads a batch of `pending` invoices that have `providerInvoiceId`.
2. For each invoice, it calls `paymentProviderAdapter.getInvoiceStatus(providerInvoiceId)`.
3. If the provider still reports `pending`, the worker leaves the invoice unchanged.
4. If the provider reports `paid`, the worker calls the same idempotent activation path as admin `mark-paid`.
5. If the provider reports `expired` or `canceled`, the worker atomically moves the local invoice from `pending` to that terminal state.
6. After provider polling, the worker also expires any still-pending invoices whose local `expiresAt` has elapsed.
7. If a manual admin action or another worker already finalized the invoice, reconciliation degrades to replay/no-op behavior instead of duplicating side effects.
Implementation note:
- invoice creation paths take a per-subscription database lock so manual invoice creation and worker renewal creation do not create duplicate invoices for the same subscription at the same time.
## Invoice listing flow
- `GET /api/billing/invoices` returns the user's invoices ordered by newest first.
- This is a read-only view over persisted `PaymentInvoice` rows.
- The worker also marks `pending` invoices `expired` when `expiresAt` has passed.
## Current activation flow
The implemented activation paths are:
- automatic worker reconciliation after provider final status
- manual admin override after an operator verifies provider final status outside the app
Shared activation behavior:
- `markInvoicePaid` runs inside one database transaction.
- If the invoice is `pending`, the store:
- updates the invoice to `paid`
- sets `paidAt`
- updates the related subscription to `active`
- sets `activatedAt` if it was not already set
- sets `currentPeriodStart = paidAt`
- sets `currentPeriodEnd = paidAt + 30 days`
- clears `canceledAt`
- writes a `UsageLedgerEntry` with `entryType = cycle_reset`
- writes an `AdminAuditLog` entry `invoice_mark_paid` when actor metadata is present
Manual admin path:
1. An authenticated admin calls `POST /api/admin/invoices/:id/mark-paid`.
2. The web app resolves the admin session and passes actor metadata into the billing store.
3. This endpoint is intended to be used only after the operator has already verified that the provider reached a final successful payment state.
4. The API returns the updated invoice.
Important constraint:
- `mark-paid` is not evidence by itself that a `pending` invoice became payable.
- It is only the current manual mechanism for recording that the provider has already given final confirmation outside the app.
## Idempotency and transition rules
`markInvoicePaid` is replay-safe.
### Allowed cases
- `pending -> paid`
- `paid -> paid` as a no-op replay
### Replay behavior
If the invoice is already `paid`:
- the subscription is not mutated again
- no extra `cycle_reset` entry is created
- an audit event `invoice_mark_paid_replayed` is written
### Rejected cases
If the invoice is already terminal:
- `expired`
- `canceled`
the store rejects the request with `invoice_transition_not_allowed`.
If the invoice does not exist, the store returns `invoice_not_found`.
## How quota ties to payment
- A user can create generation requests only with an active subscription.
- Approximate quota shown to the user is derived from `generation_success` entries since the current billing cycle start.
- A successful payment activation starts a new cycle by writing `cycle_reset` and moving the subscription window forward.
- Failed generations do not consume quota.
- When a subscription period has elapsed, user-facing quota is no longer shown as an active-cycle quota.
## Subscription period enforcement
- `currentPeriodEnd` is the hard end of paid access.
- At or after `currentPeriodEnd`, the runtime no longer treats the subscription as active.
- During generation access checks, an elapsed `active` subscription is transitioned to `expired` before access is denied.
- During account and billing reads, an elapsed `active` or `past_due` subscription is normalized to `expired` so the stored lifecycle is reflected consistently.
- There is no grace period after `currentPeriodEnd`.
## HTTP surface
- `POST /api/billing/invoices`
- create or reuse the current pending invoice for the authenticated user
- `GET /api/billing/invoices`
- list the authenticated user's invoices
- `POST /api/admin/invoices/:id/mark-paid`
- admin-only manual payment activation path
## Error behavior
Current payment-specific errors surfaced by the web app:
- `invoice_not_found` -> `404`
- `invoice_transition_not_allowed` -> `409`
## Current limitations
- The provider adapter still uses placeholder status lookups; real provider HTTP integration is not implemented yet.
- No provider callback or webhook signature verification path exists yet.
- Manual admin `mark-paid` still exists as an override, so operator judgment is still part of the system for exceptional cases.
- The worker polls invoice status in batches; there is no provider push path yet.
## Required future direction
- Replace placeholder provider status lookups with real provider integration.
- Add provider callbacks or webhook ingestion on top of polling where the chosen provider supports it.
- Reduce or remove the need for operator judgment in the normal payment-success path.
## Code references
- `packages/db/src/bootstrap.ts`
- `packages/db/src/auth-store.ts`
- `packages/db/src/billing-store.ts`
- `packages/db/src/account-store.ts`
- `packages/providers/src/payments.ts`
- `apps/web/src/main.ts`