module ActiveAdmin::BreadcrumbHelper

def build_breadcrumb_links(path = request.path, html_options = {})
  config = active_admin_config.breadcrumb
  if config.is_a?(Proc)
    instance_exec(controller, &config)
  elsif config.present?
    default_breadcrumb_links(path, html_options)
  end
end

def default_breadcrumb_links(path, html_options = {})
  # remove leading "/" and split up the URL
  # and remove last since it's used as the page title
  parts = path.split("/").select(&:present?)[0..-2]
  parts.each_with_index.map do |part, index|
    # 1. try using `display_name` if we can locate a DB object
    # 2. try using the model name translation
    # 3. default to calling `titlecase` on the URL fragment
    if ID_FORMAT_REGEXP.match?(part) && parts[index - 1]
      parent = active_admin_config.belongs_to_config.try :target
      config = parent && parent.resource_name.route_key == parts[index - 1] ? parent : active_admin_config
      name = display_name config.find_resource part
    end
    name ||= I18n.t "activerecord.models.#{part.singularize}", count: 2.1, default: part.titlecase
    # Don't create a link if the resource's show action is disabled
    if !config || config.defined_actions.include?(:show)
      link_to name, "/" + parts[0..index].join("/"), html_options
    else
      name
    end
  end
end