export type TransportState =
  | { readonly kind: "dormant"; readonly reason: string }
  | { readonly kind: "send-only"; readonly binding: unknown }
  | {
      readonly kind: "receiving";
      readonly binding: unknown;
      readonly receiverGeneration: string;
    };

export type TransportResult<T> =
  | { readonly ok: true; readonly value: T }
  | { readonly ok: false; readonly error: TransportError };

export type TransportError =
  | {
      readonly code: "unavailable" | "invalid-request" | "context-mismatch";
      readonly committed: false;
      readonly cause?: unknown;
    }
  | { readonly code: "cancelled"; readonly committed: false; readonly cause?: unknown }
  | { readonly code: "commit-indeterminate"; readonly committed: "unknown"; readonly cause: unknown };

/** Internal cross-domain stub; concrete command/result types arrive with their owning phases. */
export interface TransportPort {
  state(): TransportState;
  send(command: unknown, signal: AbortSignal): Promise<TransportResult<unknown>>;
  reply(command: unknown, signal: AbortSignal): Promise<TransportResult<unknown>>;
  waitForReceipt(query: unknown, signal: AbortSignal): Promise<TransportResult<unknown>>;
}