lb.rb

require 'thread'

state = {time: Time.now, status: "Flux Capacitor running"}
messages = Queue.new

class TimeChange
  attr_reader :time
  def initialize(t)
    @time = t
  end
end

class StatusChange
  attr_reader :status
  def initialize(s)
    @status = s
  end
end


Thread.new do
  loop do
    sleep 1
    messages << TimeChange.new(Time.now)
  end
end


Thread.new do
  loop do
    sleep rand(5)
    messages << StatusChange.new(["Central core overheating", "Proton Generator functionality nominal", "Beryllium capacity low"][rand(3)])
  end
end



def update(message, state)
  case message
  when TimeChange then state.merge(time: message.time)
  when StatusChange then state.merge(status: message.status)
  end
end


def render(state)
  "#{state[:time].strftime('%H:%M:%S')}: #{state[:status]}"
end


loop do
  message = messages.pop
  state = update message, state
  puts render(state)
end