import { useRef } from 'react';

// Which opening of a visit's details is on screen (`<id>#<n>`), derived from visibility so every way back starts a
// new opening that an earlier one cannot write into.
export const useDetailsOpening = (visible: boolean, visitId: string | undefined): string | undefined => {
    const openings = useRef(0);
    const wasVisible = useRef(false);
    if (visible && !wasVisible.current) openings.current += 1;
    wasVisible.current = visible;
    return visible && visitId ? `${visitId}#${openings.current}` : undefined;
};