ama-team / cookbook-linux-user-management

        class Persister

          attr_reader :node

          # @param [Chef::Node] node

          def initialize(node)

            @node = node

          end

          def retrieve(context_name)

            data = fetch(context_name) || {}

            Entity::Mapper.map(data, AMA::Chef::User::Model::State)

          end

          def persist(context_name, state)

            save([context_name], Entity::Mapper.normalize(state))

          end

          private

          def save(path, data)

            data = data.normalize if data.respond_to? :normalize

            write_handle(*path[0..-2])[path[-1]] = data

          end

          def fetch(*path)

            read_handle(*path)

          end

          def delete(*path)

            return if path.empty?

            path = [path] if path.is_a?(String)

            return if read_handle(path).nil?

            write_handle(path[0..-2]).delete(path[-1])

          end

          def expand_path(*path)

            %w[ama user state].push(*path)

          end

          def read_handle(*path)

            expand_path(*path).reduce(node) do |cursor, segment|

              cursor && cursor.key?(segment) ? cursor[segment] : nil

            end

          end

          def write_handle(*path)

            expand_path(*path).reduce(node.normal) do |cursor, segment|

              cursor[segment] = {} unless cursor.key?(segment)

              cursor[segment]

            end

          end

        end