import type { VirtualizerHandle } from "virtua/svelte";

export const getVirtualizerPageSize = (
	virtualizer: VirtualizerHandle | undefined,
	focusedIndex: number,
	headerHeight: number,
): number => {
	if (!virtualizer || !headerHeight) return 10;
	const rowHeight = virtualizer.getItemSize(focusedIndex) || headerHeight;
	return Math.max(
		1,
		Math.floor((virtualizer.getViewportSize() - headerHeight) / rowHeight),
	);
};