class DEBUGGER__::Session

def show_help arg = nil
  instructions = (DEBUGGER__.commands.keys + DEBUGGER__.commands.values).uniq
  print_instructions = proc do |desc|
    desc.split("\n").each do |line|
      next if line.start_with?(" ") # workaround for step back
      formatted_line = line.gsub(/[\[\]\*]/, "").strip
      instructions.each do |inst|
        if formatted_line.start_with?("`#{inst}")
          desc.sub!(line, colorize(line, [:CYAN, :BOLD]))
        end
      end
    end
    @ui.puts desc
  end
  print_category = proc do |cat|
    @ui.puts "\n"
    @ui.puts colorize("### #{cat}", [:GREEN, :BOLD])
    @ui.puts "\n"
  end
  DEBUGGER__.helps.each { |cat, cs|
    # categories
    if arg.nil?
      print_category.call(cat)
    else
      cs.each { |ws, _|
        if ws.include?(arg)
          print_category.call(cat)
          break
        end
      }
    end
    # instructions
    cs.each { |ws, desc|
      if arg.nil? || ws.include?(arg)
        print_instructions.call(desc.dup)
        return if arg
      end
    }
  }
  @ui.puts "not found: #{arg}" if arg
end