# On Linux, parse /proc/uptime
module Sys
   class Uptime
      class Error < StandardError; end

      VERSION = '0.5.1'

      @@file = '/proc/uptime'

      # Returns the uptime in seconds
      #
      def self.seconds
         begin
            IO.readlines(@@file).to_s.split.first.to_i
         rescue Exception => err
            raise Error, err
         end
      end

      # Returns the uptime in minutes
      #
      def self.minutes
         self.seconds / 60
      end

      # Returns the uptime in hours
      #
      def self.hours
         self.minutes / 60
      end

      # Returns the uptime in days
      #
      def self.days
         self.hours / 24
      end

      # Returns the uptime as a colon separated string, including days,
      # hours, minutes and seconds
      #
      def self.uptime
         seconds = self.seconds
         days    = seconds / 86400
         seconds -= days * 86400
         hours   = seconds / 3600
         seconds -= hours * 3600
         minutes = seconds / 60
         seconds -= minutes * 60

         "#{days}:#{hours}:#{minutes}:#{seconds}"
      end

      # Returns the uptime as a four element array, including days, hours,
      # minutes and seconds
      #
      def self.dhms
         self.uptime.split(":")
      end

      # Returns the time the system was booted as a Time object
      def self.boot_time
         Time.now - self.seconds
      end
   end
end