// File IDs are persisted; stable API URLs are used for display only.
const UUID = '[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}';
function fileId(value) {
  if (value && typeof value === 'object') return fileId(value.file_id || value.fileId || (value.file && value.file.id) || value.id || value.path || value.url);
  if (typeof value !== 'string') return '';
  if (new RegExp('^' + UUID + '$', 'i').test(value)) return value;
  var match = value.match(new RegExp('^(?:https?://[^/]+)?/api/files/(' + UUID + ')(?:[?#].*)?$', 'i'));
  return match ? match[1] : '';
}
function uploadReference(value) {
  if (!value || value.error) throw value || new Error('上传失败');
  var id = fileId(value);
  if (!id) throw new Error('上传响应缺少文件 ID，请重试');
  return id;
}
function normalizeUploadResult(value) {
  if (!value || typeof value !== 'object' || value.error) return value;
  var id = fileId(value);
  if (!id) return value;
  return Object.assign({}, value, { file_id: id, path: '/api/files/' + id, url: '/api/files/' + id });
}
function filePayload(action, data) {
  if (!data || typeof data !== 'object') return data;
  var mappings = {
    updateProfile: { avatar: 'avatar_file_id' }, updatePartnerProfile: { avatar: 'avatar_file_id' },
    albumAdd: { cover: 'cover_file_id' }, albumUpdate: { cover: 'cover_file_id' },
    photoAdd: { path: 'file_id' }, diaryAdd: { images: 'image_file_ids' }, diaryUpdate: { images: 'image_file_ids' },
    timelineAdd: { bg_image: 'bg_image_file_id', images: 'image_file_ids' },
    timelineUpdate: { bg_image: 'bg_image_file_id', images: 'image_file_ids' }, checkinDo: { photo: 'photo_file_id' }
  };
  var out = Object.assign({}, data);
  Object.keys(mappings[action] || {}).forEach(function(key) {
    if (!Object.prototype.hasOwnProperty.call(out, key)) return;
    var target = mappings[action][key];
    var value = out[key];
    // Legacy references remain compatible; all new uploads supply UUIDs.
    var convert = function(v) { return fileId(v) || v; };
    if (!Object.prototype.hasOwnProperty.call(out, target)) out[target] = Array.isArray(value) ? value.map(convert) : convert(value);
    delete out[key];
  });
  return out;
}
module.exports = { fileId, uploadReference, normalizeUploadResult, filePayload };