$:.unshift File.dirname(__FILE__)

# Pong version 0.1 by Alex Chaffee
require "fileutils"

module Pong
  class Series < Array
    MAX = 32767

    def num(n)
      n = MAX if n.nil?
      [n, size].min
    end

    def last(n = MAX)
      num = num(n)
      self.slice(-num, num)
    end

    def sum(n = MAX)
      last(n).inject(0){|memo, value|
        value.nil? ? memo : (memo + value)
      }
    end

    def mean(n = MAX)
      size == 0 ? 0 : sum(n) / num(n)
    end

    def nils(n = MAX)
      last(n).select{|value| value.nil? }.size
    end

    def nil_percent(n = MAX)
      (nils(n).to_f / num(n).to_f) * 100.0
    end
  end

  class Host
    attr_reader :pings, :hostname, :address

    def initialize(hostname)
      @hostname = @address = hostname
      @output = "/tmp/#{hostname}.out"
      FileUtils.rm_rf(@output) if File.exist?(@output)
      FileUtils.touch(@output)
    end

    def start
      @pings = Series.new
      process = IO.popen("ping #{hostname}")
      Thread.new do
        while (line = process.gets)
          parse(line) unless line.nil?
        end
      end
    end

    def parse(line)
      m = /^PING (\S*) \(([0-9.]*)\)/.match(line)
      unless m.nil?
        @address = m[2]
      end

      m = /icmp_seq=([0-9]*).*time=([0-9.]*)/.match(line)
      unless m.nil?
        seq = m[1].to_i
        time = m[2].to_f
        pings[seq] = time
      end
    end

    def missing(n=nil)
      pings.nils(n)
    end

    def missing_percent(n=nil)
      pings.nil_percent(n)
    end

    def mean(n=nil)
      pings.mean(n)
    end

    def stats(n=nil)
      [
        "%8.3f msec" % (mean(n)),
        "%4d (%.2f%%)" % [missing(n), missing_percent(n)],
        "#{hostname} (#{address})",
      ].join("\t")
    end

    def header
      [
        "Mean     ",
        "Missing  ",
        "Host"
      ].join("\t")
    end

  end

  class Hosts < Array
    def self.from_args(args)
      hosts = Hosts.new
      args = ['localhost'] if args.empty?
      args.each do |arg|
        host = Host.new(arg)
        hosts << host
      end
      hosts
    end

    def stats(n = nil)
      puts n.nil? ? "Entire run (#{first.pings.size} sec):" : "Last #{n} seconds:"
      puts first.header
      self.each do |host|
        puts host.stats(n)
      end
    end

    def run
      each {|host| host.start }
      while true
        system("clear")
        stats(10)
        puts
        stats(60)
        puts
        stats
        sleep(5)
      end
    end
  end
end