import type {BuildingSceneLayerTileset, BuildingSceneSublayer} from '../../types';

const OBJECT_3D_LAYER_TYPE = '3DObject';

/**
 * Parses Builiding Scene Layer and creates tileset
 * @param data
 * @param options
 * @param context
 */
export async function parseBuildingSceneLayer(
  data: ArrayBuffer,
  url: string
): Promise<BuildingSceneLayerTileset> {
  const layer0 = JSON.parse(new TextDecoder().decode(data));
  const {sublayers} = layer0;

  return {
    header: layer0,
    sublayers: parseSublayersTree(sublayers, url)
  };
}

/**
 * Recursively parses Building Scene Layer sublayers.
 * @param sublayers
 * @param url
 */
function parseSublayersTree(
  sublayers: BuildingSceneSublayer[],
  url: string
): BuildingSceneSublayer[] {
  let layers: BuildingSceneSublayer[] = [];

  for (let index = 0; index < sublayers.length; index++) {
    const subLayer = sublayers[index];
    const {id, layerType, visibility = true, ...rest} = subLayer;

    // Add support only for 3DObject layer type for I3S purposes.
    if (layerType === OBJECT_3D_LAYER_TYPE) {
      const sublayerUrl = `${url}/sublayers/${id}`;

      layers.push({
        url: sublayerUrl,
        id,
        layerType,
        visibility,
        ...rest
      });
    }

    if (subLayer?.sublayers?.length) {
      layers = [...layers, ...parseSublayersTree(subLayer.sublayers, url)];
    }
  }

  return layers;
}