# frozen_string_literal: true

module Namespaces
  module Traversal
    module Recursive
      extend ActiveSupport::Concern

      def root_ancestor
        return self if persisted? && parent_id.nil?

        strong_memoize(:root_ancestor) do
          self_and_ancestors.reorder(nil).find_by(parent_id: nil)
        end
      end

      # Returns all ancestors, self, and descendants of the current namespace.
      def self_and_hierarchy
        object_hierarchy(self.class.where(id: id))
          .all_objects
      end

      # Returns all the ancestors of the current namespaces.
      def ancestors
        return self.class.none unless parent_id

        object_hierarchy(self.class.where(id: parent_id))
          .base_and_ancestors
      end

      # returns all ancestors upto but excluding the given namespace
      # when no namespace is given, all ancestors upto the top are returned
      def ancestors_upto(top = nil, hierarchy_order: nil)
        object_hierarchy(self.class.where(id: id))
          .ancestors(upto: top, hierarchy_order: hierarchy_order)
      end

      def self_and_ancestors(hierarchy_order: nil)
        return self.class.where(id: id) unless parent_id

        object_hierarchy(self.class.where(id: id))
          .base_and_ancestors(hierarchy_order: hierarchy_order)
      end

      # Returns all the descendants of the current namespace.
      def descendants
        object_hierarchy(self.class.where(parent_id: id))
          .base_and_descendants
      end

      def self_and_descendants
        object_hierarchy(self.class.where(id: id))
          .base_and_descendants
      end

      def object_hierarchy(ancestors_base)
        Gitlab::ObjectHierarchy.new(ancestors_base, options: { use_distinct: Feature.enabled?(:use_distinct_in_object_hierarchy, self) })
      end
    end
  end
end