State Machine

State-machine rules keep critical transitions valid, auditable, and recoverable.

Visual summary

Domain	Core states	Terminal states
Reservation	draft, confirmed	completed, cancelled
Membership	inactive, active	expired
Coupon redemption	available, redeemed	expired, invalid

Reservation

stateDiagram-v2
  [*] --> draft
  draft --> confirmed: validate slot + payment/approval pass
  confirmed --> completed: service fulfilled
  confirmed --> cancelled: cancel by actor/policy
  draft --> cancelled: abandoned/expired draft
  cancelled --> [*]
  completed --> [*]

Membership

stateDiagram-v2
  [*] --> inactive
  inactive --> active: activation success
  active --> expired: validity period elapsed
  expired --> active: renewal success

Coupon redemption

stateDiagram-v2
  [*] --> available
  available --> redeemed: valid claim
  available --> expired: date/quota elapsed
  available --> invalid: policy revoked
  redeemed --> [*]
  expired --> [*]
  invalid --> [*]

Canonical transition contract

Domain	From	To	Trigger	Reject code
Reservation	draft	confirmed	ReservationConfirmed event	RESERVATION_CONFLICT
Reservation	confirmed	cancelled	actor cancellation + policy check	CANCEL_NOT_ALLOWED
Membership	inactive	active	activation success	MEMBERSHIP_ACTIVATION_FAILED
Coupon	available	redeemed	claim accepted	COUPON_NOT_ELIGIBLE