module ActiveAdmin
  module Helpers
    module Collection
      # Works around this issue: https://github.com/rails/rails/issues/7121
      #
      # GROUP BY + COUNT drops SELECT statement. This leads to SQL error when
      # the ORDER statement mentions a column defined in the SELECT statement.
      #
      # We remove the ORDER statement to work around this issue.
      def collection_size(collection=collection)
        if collection.group_values.present?
          collection.reorder("").count # is a Hash
        else
          collection
        end.count
      end

      def collection_is_empty?(collection=collection)
        collection_size(collection) == 0
      end
    end
  end
end