import type { Asset } from './Asset';
import { isPlaceableType } from './AssetTypes';
import { containerReaches } from './container';
import type { ObjectHolder, Project } from './Project';

/**
 * Why `asset` cannot be placed into `holder`, or '' when it can. A drag needs the answer while
 * it hovers, `PlaceAssetCommand` needs it at the drop; both ask here so the preview cannot
 * promise a placement the command then refuses.
 */
export function placementRejection(project: Project, holder: ObjectHolder, asset: Asset): string {
  if (!isPlaceableType(asset.type)) return 'A scene cannot be placed into a scene';
  if (asset.type === 'container' && containerReaches(project, asset, holder.id))
    return `${asset.name} cannot contain ${holder.name}: that nests forever`;
  return '';
}