class Eco::Data::Locations::NodeDiff
  # Adjusts ArrayDiff for Nodes diffs in a location structure
  class NodesDiff < Eco::Data::Hashes::ArrayDiff
    extend Eco::Data::Locations::NodeDiff::Selectors

    SELECTORS = %i[id name id_name insert unarchive update move archive]
    selector *SELECTORS

    class_resolver :diff_result_class, Eco::Data::Locations::NodeDiff
    attr_reader :original_tree

    def initialize(*args, original_tree:, **kargs, &block)
      super(*args, **kargs, &block)
      @original_tree = original_tree
    end

    def diffs
      @diffs ||= super.select do |res|
        res.unarchive? || res.id_name? || res.insert? || res.move? || res.archive?
      end
    end

    def diffs_details
      section = '#' * 10
      msg  = ''
      if insert?
        msg << " #{section}  I N S E R T S  #{section}\n"
        msg << insert.map {|d| d.diff_hash.pretty_inspect}.join('')
      end

      if update?
        msg << "\n #{section}  U P D A T E S  #{section}\n"
        update.each do |d|
          flags  = ''
          #flags << 'i' if d.id?
          flags << 'n' if d.diff_name?
          flags << 'm' if d.move?
          flags << 'u' if d.unarchive?
          msg << "<< #{flags} >> "
          msg << d.diff_hash.pretty_inspect
        end
      end

      if archive?
        msg << "\n #{section}  A R C H I V E S  #{section}\n"
        msg << archive.map {|d| d.diff_hash.pretty_inspect}.join('')
      end

      msg
    end

    def diffs_summary
      return "There were no differences identified" if diffs.empty?
      msg  = "Identified #{diffs.count} differences:\n"
      msg << when_present(insert, '') do |count|
        "  • #{count} nodes to insert\n"
      end
      msg << when_present(update, '') do |count|
        "  • #{count} nodes to update\n"
      end
      # msg << when_present(id, '') do |count|
      #   "    • #{count} nodes to change id\n"
      # end
      msg << when_present(name, '') do |count|
        "    • #{count} nodes to change name\n"
      end
      msg << when_present(move, '') do |count|
        "    • #{count} nodes to move\n"
      end
      msg << when_present(unarchive, '') do |count|
        "    • #{count} nodes to unarchive\n"
      end
      msg << when_present(archive, '') do |count|
        "  • #{count} nodes to archive\n"
      end
      msg
    end

    private

    def when_present(list, default = nil)
      count = list.count
      if count > 0
        yield(count)
      else
        default
      end
    end
  end
end