// The runtime that launched this bundle, as one channel of requests (novox/hq ADR 0193, ADR 0198): what a module's code
// asks of its node's tool runner beyond emitting, subscribing and its state, each named by the runtime's method
// (`mesh/seat.publish`, `mesh/provision.get`). The stdio session binds it when the runtime launched the process; a
// bundle never names a transport.

/** What the runtime is asked through: the stdio session provides it. */
export type RuntimeAsk = (method: string, params: unknown) => Promise<unknown>;

let bound: RuntimeAsk | undefined;

/** Bind the channel. The stdio session calls this when the runtime launched the process; a test binds its own. */
export function useRuntime(ask: RuntimeAsk | undefined): void {
  bound = ask;
}

/** Ask the runtime one of its methods; refused with the reason when no runtime launched this bundle. */
export async function askRuntime(method: string, params: unknown): Promise<unknown> {
  if (!bound) {
    throw new Error(`no runtime to ask ${method} of: it is reached through the runtime that launched this bundle (novox/hq ADR 0198)`);
  }
  return bound(method, params);
}

/**
 * Submit an accept, or say an event, on a seat (novox/hq ADR 0259 §3): `subject` whole, as the seat's contract names
 * it (`mesh.seat.<seat>.event.<event>`), de-duplicated by `id` (the same id twice is one message; empty is the
 * runtime's to make). The runtime does it as this module, only as far as its membership lists, and refuses the rest
 * with the reason: the Go side's `stdio.SeatPublish`.
 */
export async function seatPublish(subject: string, body: unknown, id = ""): Promise<void> {
  await askRuntime("mesh/seat.publish", { subject, body, id });
}

/** This module's config value `key`, as mesh-config resolved it for this machine (the Go side's `stdio.Config`). */
export async function config(key: string): Promise<unknown> {
  return askRuntime("mesh/provision.get", { kind: "config", key });
}