DealDocumentScreening/docs/adr/0001-charge-saved-method-port.md

Charge-saved-method port, own subscription brain

Two payment providers must support recurring subscription renewals (YooKassa RUB, bePaid BYN), each with incompatible native recurring models (YooKassa save_payment_method + charge by payment id; bePaid card tokens). Rather than delegating subscription lifecycle to provider-native subscription engines (e.g. Stripe Billing style), we keep the existing worker-billing scheduler as the single subscription brain and extend the PaymentProvider port with one primitive: charge_saved_method(token, amount, currency, …). Each adapter maps it to its provider's saved-card mechanism. This keeps renewal scheduling, dunning (day 1/3/7 retries), period anchoring and refund policy provider-agnostic, and lets a future provider (e.g. Stripe) slot in behind the same port without migrating subscription state.

Consequences

• Saved Payment Methods are provider- and currency-bound; they can never be reused across providers or currencies (see ADR-0002).
• ЕРИП payments (bePaid bank rails) cannot save a method: ЕРИП-origin subscriptions are forced auto_renew = FALSE and renew manually via bot/email instructions.