module Pruning
  module Processing
    class Pruner

      def initialize(tree, indicator_ids)
        @tree = tree
      end

      def prune_tree(nodes, indicator_ids)
        nodes.delete_if do |node|
          unwanted_indicator = indicator_node?(node) && !indicator_ids.include?(node['id'])  
          has_no_wanted_indicators_in_children = prune_tree(children(node), indicator_ids)

          unwanted_indicator && has_no_wanted_indicators_in_children 
        end 
        nodes.empty?
      end

      private
      def children(node)
        node.get('sub-themes', false) ||
        node.get('categories', false) || 
        node.get('indicators', false) ||
        []
      end
      
      def indicator_node?(node)
        children(node).empty?
      end
    end
  end
end