/**
 * 层与图的 bucket 归属。见 spec §3.3。
 * bucket 决定资源落进 framework/ui/atlas-{common,login,hall,room} 哪个目录。
 */

/** 登录相关：按层名点名，因其 LayerID 散落在 1..29 段内。 */
const LOGIN_LAYERS = new Set(['Logo_Layer', 'Login_Layer', 'Auth_layer', 'Bind_Layer', 'phoneInfo']);

/** 命名笼统、语义不明的层：标 unassigned 交人工归位，不猜。 */
const UNASSIGNED_LAYERS = new Set([
  'Layer6', 'Layer13', 'Layer403', 'Layer411', 'Layer601', 'Layer603', 'Layer618',
]);

const ROOM_ID_MIN = 50;
const COMMON_ID_MIN = 600;

export function layerBucket(layerId, layerName) {
  if (UNASSIGNED_LAYERS.has(layerName)) return 'unassigned';
  if (LOGIN_LAYERS.has(layerName)) return 'login';
  if (layerId >= COMMON_ID_MIN) return 'common';
  if (layerId >= ROOM_ID_MIN) return 'room';
  return 'hall';
}

/**
 * 每张图按引用它的对象所在层决定 bucket。
 * 跨多个 bucket → common；无对象引用 → unassigned。
 */
export function imageBuckets(source) {
  const layerBucketById = new Map(
    source.layers.map((l) => [l.layerId, layerBucket(l.layerId, l.name)]),
  );

  const bucketsPerImage = new Map();
  for (const obj of source.objects.values()) {
    if (!obj.ImageFileID) continue;
    const b = layerBucketById.get(obj.BelongLayerID);
    if (!b) continue;
    if (!bucketsPerImage.has(obj.ImageFileID)) bucketsPerImage.set(obj.ImageFileID, new Set());
    bucketsPerImage.get(obj.ImageFileID).add(b);
  }

  const out = new Map();
  for (const id of source.images.keys()) {
    const set = bucketsPerImage.get(id);
    if (!set || set.size === 0) { out.set(id, 'unassigned'); continue; }
    const real = [...set].filter((b) => b !== 'unassigned');
    if (real.length === 0) out.set(id, 'unassigned');
    else if (real.length === 1) out.set(id, real[0]);
    else out.set(id, 'common');
  }
  return out;
}