slotcars.rb

require 'rubygems'
require 'pp'

DURATION = 60
INTERVAL = 3
SPEEDS = {
  :off => 0,
  :slow => 0.3334,
  :medium => 0.75,
  :fast => 1
}

$count = 0
$current_speed = :off

while true
  now = Time.now
  messages = (0..rand(100)).map { |i| now + rand(DURATION) }.sort

  histogram = Array.new(DURATION/INTERVAL, 0)
  messages.each do |time|
    delta = time - now
    segment = (delta/INTERVAL).floor
    histogram[segment] += 1
  end
  
  p histogram
  while histogram.any?
    msgs = histogram.shift
    $count += msgs
    
    distance = (SPEEDS[$current_speed] * INTERVAL).floor
    $count -= distance
    $count = 0 if $count < 0 # huh?
    
    $current_speed = case $count
      when 0 then :off
      when 1..2 then :slow
      when 3..5 then :medium
      when 5..100 then :fast
      else :apeshit
    end
    puts "#{$count}:\t+#{msgs}\t-#{distance}\t#{$current_speed}"
    sleep INTERVAL
  end                      
end