/**
 * Time is injected so tests can run whole rounds quickly and deterministically.
 * Production uses the real clock; the engine itself never reads time.
 */
export interface Clock {
  now(): number;
  setTimeout(fn: () => void, ms: number): TimerHandle;
  clearTimeout(handle: TimerHandle): void;
  setInterval(fn: () => void, ms: number): TimerHandle;
  clearInterval(handle: TimerHandle): void;
}

export type TimerHandle = { readonly __timer: unique symbol } | ReturnType<typeof setTimeout>;

export const realClock: Clock = {
  now: () => Date.now(),
  setTimeout: (fn, ms) => {
    const t = setTimeout(fn, Math.max(0, ms));
    t.unref?.();
    return t;
  },
  clearTimeout: (h) => clearTimeout(h as ReturnType<typeof setTimeout>),
  setInterval: (fn, ms) => {
    const t = setInterval(fn, ms);
    t.unref?.();
    return t;
  },
  clearInterval: (h) => clearInterval(h as ReturnType<typeof setInterval>),
};