export const SWIPE_THRESHOLD_PX = 60;

export function detectSwipeNavigationAction({
  startX,
  startY,
  endX,
  endY,
  threshold = SWIPE_THRESHOLD_PX
}) {
  if (
    !Number.isFinite(startX) ||
    !Number.isFinite(startY) ||
    !Number.isFinite(endX) ||
    !Number.isFinite(endY)
  ) {
    return null;
  }

  const deltaX = endX - startX;
  const deltaY = endY - startY;
  const absX = Math.abs(deltaX);
  const absY = Math.abs(deltaY);

  if (absX < threshold || absX <= absY) {
    return null;
  }

  return deltaX > 0 ? 'previous' : 'next';
}

if (typeof window !== 'undefined') {
  window.detectSwipeNavigationAction = detectSwipeNavigationAction;
  window.SWIPE_THRESHOLD_PX = SWIPE_THRESHOLD_PX;
}