feat: backend service

backend/internal/lobby/errors.go

@@ -0,0 +1,54 @@
+package lobby
+
+import "errors"
+
+// Sentinel errors surface common rejection reasons across the lobby
+// package. Handlers map them to HTTP envelopes through `respondLobbyError`
+// in `internal/server/handlers_user_lobby_helpers.go`.
+//
+// Adding a new sentinel here is a deliberate API change: it appears in the
+// handler error map and may surface as a new wire `code` value. Reuse the
+// existing set when the behaviour overlaps.
+var (
+	// ErrInvalidInput reports request-level validation failures (empty
+	// fields, malformed cron expressions, unknown enum values, race-name
+	// policy rejections). Maps to 400 invalid_request.
+	ErrInvalidInput = errors.New("lobby: invalid input")
+
+	// ErrNotFound reports that the requested record (game, application,
+	// invite, membership, race name) does not exist or is not visible to
+	// the caller. Maps to 404 not_found.
+	ErrNotFound = errors.New("lobby: not found")
+
+	// ErrForbidden reports that the caller is authenticated but not
+	// authorised for the requested action — most commonly "not the owner
+	// of this private game". Maps to 403 forbidden.
+	ErrForbidden = errors.New("lobby: forbidden")
+
+	// ErrConflict reports that the requested action conflicts with the
+	// current persisted state (illegal status transition, duplicate
+	// application, race-name canonical taken, invite already redeemed).
+	// Maps to 409 conflict.
+	ErrConflict = errors.New("lobby: conflict")
+
+	// ErrInvalidStatus reports a state-machine transition rejected by the
+	// game/application/invite/membership status. Treated as ErrConflict
+	// at the wire boundary; carried as a separate sentinel so transition
+	// callers can branch on it without parsing the wrapped message.
+	ErrInvalidStatus = errors.New("lobby: invalid status transition")
+
+	// ErrRaceNameTaken reports that a race-name canonical key is already
+	// claimed by a different user (registered, reserved, or
+	// pending_registration). Treated as ErrConflict at the wire boundary.
+	ErrRaceNameTaken = errors.New("lobby: race name is taken")
+
+	// ErrEntitlementExceeded reports that the caller already holds the
+	// maximum number of registered race names allowed by their tier.
+	// Treated as ErrConflict at the wire boundary.
+	ErrEntitlementExceeded = errors.New("lobby: entitlement quota exceeded")
+
+	// ErrPendingExpired reports that the pending_registration window
+	// passed before the user attempted to promote it to registered.
+	// Treated as ErrConflict at the wire boundary.
+	ErrPendingExpired = errors.New("lobby: pending registration expired")
+)