manyfold/app/controllers/concerns/permittable.rb

module Permittable
  extend ActiveSupport::Concern

  included do
    before_action :find_caber_subjects, only: [:create, :update] # rubocop:todo Rails/LexicallyScopedActionFilter
  end

  def find_caber_subjects
    params.values.each do |param|
      if param.is_a?(ActionController::Parameters) && param.has_key?("caber_relations_attributes")
        param["caber_relations_attributes"].transform_values! do |value|
          if value["subject"].present?
            subject = case value["subject"]
            when "role::member"
              Role.find_by!(name: :member)
            when "role::public"
              nil
            when Group::TYPED_ID_PATTERN
              Group.find_by_typed_id(value["subject"], scope: policy_scope(Group))
            else
              User.match!(identifier: value["subject"], scope: policy_scope(User))
            end
            value["subject_id"] = subject&.id
            value["subject_type"] = subject&.class&.name
          end
          value
        rescue ActiveRecord::RecordNotFound
          nil
        end
        param["caber_relations_attributes"].compact!
      end
    end
  end
end