cursed_report.rb

module ShellScriptUtils
  class CursedReport
    def initialize(message = nil)
      @clear_commands = []
      @message = message
      update @message
    end

    def update(message)
      clear @message     # clear the current message
      @message = message # udpate with the new message
      puts @message      # output new message
    end

    private

    def clear(string)
      return unless string

      build_clear_command(string)
      print @clear_commands.join.chomp
      reset_clear_commands
    end

    def build_clear_command(string)
      newlines = string.scan(/\n/).size + 1
      add_command move_beg_line
      add_command clear_line
      newlines.times do
        add_command move_up_line
        add_command clear_line
      end
    end

    def add_command(command)
      @clear_commands << command
    end

    def reset_clear_commands
      @clear_commands = []
    end

    def move_beg_line
      "\r"
    end

    def move_up_line
      "\e[A"
    end

    def clear_line
      "\e[K"
    end
  end
end