# frozen_string_literal: true

module Eac
  module DataTableHelper
    class Column
      EMPTY_VALUE = '-'

      attr_reader :label

      def initialize(label, path, block)
        @label = label
        @path = path.to_s.split('.')
        @block = block
      end

      def record_value(record)
        v = Node.new(record, @path).value
        if v.present?
          @block ? @block.call(v) : v
        else
          EMPTY_VALUE
        end
      end

      private

      def node_value(node, subpath)
        return node if subpath.empty?
      end

      class Node
        def initialize(node, path)
          @node = node
          @path = path
        end

        def value
          return @node if @node.nil? || @path.empty?

          subpath = @path.dup
          n = subpath.shift
          return Node.new(@node.send(n), subpath).value if @node.respond_to?(n)

          raise "Instance of #{@node.class} does not respond to #{n}"
        end
      end
    end
  end
end