application_policy.rb with permitted_params or permitted_attributes used in active_admin

application_policy.rb

class ApplicationPolicy
  attr_reader :user, :record

  def initialize(user, record)
    @user = user
    @record = record
  end

  def index?
    true
  end

  def show?
    scope.where(:id => record.id).exists?
  end

  def create?
    true
  end

  def new?
    create?
  end

  def update?
    true
  end

  def edit?
    update?
  end

  def destroy?
    false
  end

  def scope
    Pundit.policy_scope!(user, record.class)
  end

  def permitted_params
    @permitted_params = PermittedParams.new(self, &@@permit_params)
  end

  def self.permit_params(&block)
    @@permit_params = block
  end

  protected

  class PermittedParams < Array
    attr_reader :user, :record

    def initialize(policy, &block)
      @policy = policy
      @block = block

      @user = policy.user
      @record = policy.record

      process
    end

    def new?
      record.is_a?(Class) || record.new_record?
    end

    def [](v)
      @hash ||= self.class.to_hash(self)

      !!@hash[v]
    end

    private

    def process
      instance_eval(&@block)
    end

    def self.to_hash(array)
      Hash[*array.flat_map do |v|
        if v.is_a?(Hash)
          hk, kv = v.first

          [hk, (kv.is_a?(Array) ? to_hash(kv) : true)]
        else
          [v, true]
        end
      end]
    end
  end
end

example.rb

class PropertyPolicy < ApplicationPolicy
  permit_params do
    concat([{translations_attributes: [:id, :name, :description, :locale]}])

    if (user.admin? || user.super_admin?) || new?
      concat([
        :price,
        {type_ids: []}
      ])
    end
  end
end

ActiveAdmin.register Property do
  decorate_with PropertyDecorator

  permit_params do
    policy(resource).permitted_params
  end
end