import type { MapOverlayPosition } from './map.types';

/**
 * Absolute-position classes for each of the nine overlay anchors.
 *
 * Every surveyed application recreated this positioning by hand and settled its
 * `z-index` by guesswork. Centralizing it keeps the legend, the notice, the
 * scale bar and the attribution on one predictable stacking layer.
 */
const POSITION_CLASSES: Record<MapOverlayPosition, string> = {
  'top-left': 'top-3 left-3',
  'top-center': 'top-3 left-1/2 -translate-x-1/2',
  'top-right': 'top-3 right-3',
  'middle-left': 'top-1/2 left-3 -translate-y-1/2',
  'middle-center': 'top-1/2 left-1/2 -translate-x-1/2 -translate-y-1/2',
  'middle-right': 'top-1/2 right-3 -translate-y-1/2',
  'bottom-left': 'bottom-3 left-3',
  'bottom-center': 'bottom-3 left-1/2 -translate-x-1/2',
  'bottom-right': 'bottom-3 right-3',
};

/**
 * Returns the Tailwind classes that pin an overlay to one of the nine anchors.
 *
 * The result is positioned against the nearest positioned ancestor, so the
 * overlay must sit inside an element with `relative` — `<Map>`'s own container
 * already is one.
 */
export function mapOverlayPositionClasses(position: MapOverlayPosition): string {
  return `absolute z-10 ${POSITION_CLASSES[position]}`;
}

export const MAP_OVERLAY_POSITIONS = Object.keys(POSITION_CLASSES) as MapOverlayPosition[];