/**
 * Debounce a function. The returned function has a `.cancel()` method
 * so a pending invocation can be cleared in a `useEffect` cleanup to
 * avoid a setState-after-unmount on the trailing call.
 *
 * Intentionally a tiny, no-dependency implementation — `lodash.debounce`
 * pulls 200kB of lodash with it; this is 15 lines, type-safe, and tree-
 * shake-friendly.
 */
export function debounce<T extends (...args: Parameters<T>) => void>(
  func: T,
  wait: number
): ((...args: Parameters<T>) => void) & { cancel: () => void } {
  let timeout: ReturnType<typeof setTimeout> | null = null;

  const debounced = (...args: Parameters<T>) => {
    if (timeout) {
      clearTimeout(timeout);
    }
    timeout = setTimeout(() => {
      func(...args);
    }, wait);
  };

  debounced.cancel = () => {
    if (timeout) {
      clearTimeout(timeout);
      timeout = null;
    }
  };

  return debounced;
}