class ReeDao::Agg

def call(dao, ids_or_scope, **opts, &block)
  scope = if ids_or_scope.is_a?(Array) && ids_or_scope.any? { _1.is_a?(Integer) }
    return [] if ids_or_scope.empty?
    dao.where(id: ids_or_scope)
  elsif ids_or_scope.is_a?(Integer)
    dao.where(id: ids_or_scope)
  else
    ids_or_scope
  end
  list = scope.is_a?(Sequel::Dataset) ? scope.all : scope
  if opts[:to_dto]
    list = list.map do |item|
      list = opts[:to_dto].call(item)
    end
  end
  load_associations(dao.unfiltered, list, **opts, &block) if block_given?
  if ids_or_scope.is_a?(Array)
    list.sort_by { ids_or_scope.index(_1.id) }
  else
    list
  end
end

def load_associations(dao, list, **opts, &block)
  return if list.empty?
  local_vars = block.binding.eval(<<-CODE, __FILE__, __LINE__ + 1)
    vars = self.instance_variables
    vars.reduce({}) { |hsh, var| hsh[var] = self.instance_variable_get(var); hsh }
  CODE
  agg_caller = block.binding.eval("self")
  associations = Associations.new(agg_caller, list, local_vars, dao, **opts).instance_exec(list, &block)
  if dao.db.in_transaction? || ReeDao.load_sync_associations_enabled?
    associations
  else
    associations[:association_threads].map do |association, assoc_type, assoc_name, opts, block|
      association.load(assoc_type, assoc_name, **opts, &block)
    end
    associations[:field_threads].map do |association, field_proc|
      association.handle_field(field_proc)
    end
  end
end