module FHIR
  module STU3
    # Extend ElementDefinition for profile validation code
    class ElementDefinition < FHIR::STU3::Model
      # children is used to hierarchically arrange elements
      # so profile validation is easier to compute
      attr_accessor :children
      attr_accessor :local_name
      attr_accessor :marked_for_keeping

      def add_descendent(element)
        @children = [] if @children.nil?
        element.local_name = element.path.gsub("#{path}.", '')
        if @children.last && element.path.start_with?(@children.last.path)
          if element.path == @children.last.path
            # slicing
            @children << element
          else
            @children.last.add_descendent(element)
          end
        else
          @children << element
        end
      end

      def keep_children(whitelist = [])
        @marked_for_keeping = true if whitelist.include?(path)
        return unless @children

        @children.each do |child|
          child.keep_children(whitelist)
        end
      end

      def sweep_children
        return unless @children

        @children.each(&:sweep_children)
        @children.keep_if(&:marked_for_keeping)
        @marked_for_keeping = !@children.empty? || @marked_for_keeping
      end

      def print_children(spaces = 0)
        puts "#{' ' * spaces}+#{local_name || path}"
        return nil unless @children

        @children.each do |child|
          child.print_children(spaces + 2)
        end
        nil
      end
    end
  end
end