active_admin_monkey_patch.rb

module ExtendedActionItems
  private

  def add_default_action_items
    super
    add_default_toggle_filter_action_item
  end

  def add_default_toggle_filter_action_item
    add_action_item :filter, only: :index do
      link_to I18n.t('active_admin.filter_button'), '#', class: 'filter_button'
    end
  end
end

module ActiveAdmin
  module ViewHelpers
    include ApplicationHelper
  end

  class ResourceController < BaseController
    before_action :patch_params, only: :index
    after_action :store_location, only: :index
    QUERY_DATE_FIELDS = %i(created_at updated_at last_visit_at)

    def patch_params
      return unless params[:q].present?
      QUERY_DATE_FIELDS.each do |field|
        field_lteq = "#{field}_lteq"
        next unless params[:q][field_lteq.to_sym].present?
        params[:q][field_lteq.to_sym] = send(field_lteq)
      end
    end

    QUERY_DATE_FIELDS.each do |field|
      field_lteq = "#{field}_lteq"
      define_method(field_lteq) do
        params[:q][field_lteq.to_sym].to_date.end_of_day
      end
    end

    def store_location
      session[:return_to] = request.get? ? request.original_url : request.referer
    end

    def redirect_back(*options)
      tag_options = {}
      options.first.each { |k, v| tag_options[k] = v } unless options.empty?
      path = session.delete(:return_to) || :back
      redirect_to path, tag_options
    end
  end

  class Resource
    prepend ExtendedActionItems
  end
end