export type Announcement<T> = MRpcBaseMsg & { type: "announcement"; args: T };
export type IncompleteArray<T> = ["Missing required items", T];

export type ActionsWithTunnel<
  Actions extends Record<string, (...args: any[]) => any>,
> = {
  [A in keyof Actions]: WithTunnel<Actions[A]>;
};

export type Dependencies<T extends string> = {
  [K in T]: Worker | SharedWorker;
};

/**
 * Comes from the `@mys/m-rpc` library,
 * but it is not exported. Used to identify
 * messages sent via `postMessage`.
 */
export type MRpcBaseMsg = { ns: string; name: string; key: number };

/** */
export type ProxiedActions<
  Actions extends Record<string, (...args: any[]) => any>,
> = {
  [A in keyof Actions]: ProxiedAction<Actions[A]>;
};

export type ProxiedAction<
  Action extends (...args: any[]) => any,
  PromisedReturn =
    (ReturnType<Action> extends Promise<unknown> ? ReturnType<Action>
      : Promise<ReturnType<Action>>),
> = (...args: Parameters<Action>) => PromisedReturn;

/** */
export interface MessengerRealm {
  postMessage: MessagePort["postMessage"];
  addEventListener: MessagePort["addEventListener"];
  removeEventListener: MessagePort["removeEventListener"];
}

/** */
export type Tunnel = {
  disconnect: () => void;
  port: MessagePort;
};

/** */
export type WithTunnel<
  Fn extends (...args: any[]) => any,
  PromisedReturn = (ReturnType<Fn> extends Promise<unknown> ? ReturnType<Fn>
    : Promise<ReturnType<Fn>>),
> = (
  _: { data: Parameters<Fn>[0]; ports: Record<string, MessagePort> },
  ...args: Rest<Parameters<Fn>>
) => PromisedReturn;

// 🛑

type Rest<T> = T extends [any, ...(infer R)[]] ? R : never;