#!/usr/bin/env ruby --disable=gems --disable=rubyopt
GC.disable

module System
  extend self
  def cpu_count
    return Java::Java.lang.Runtime.getRuntime.availableProcessors if defined? Java::Java
    return File.read('/proc/cpuinfo').scan(/^processor\s*:/).size if File.exist? '/proc/cpuinfo'
    require 'win32ole'
    WIN32OLE.connect("winmgmts://").ExecQuery("select * from Win32_ComputerSystem").NumberOfProcessors
  rescue LoadError
    Integer `sysctl -n hw.ncpu 2>/dev/null` rescue 1
  end
end

if ENV['DYNO']
  # we're on Heroku
  case `uname -u`.to_i
  when 256   then concurrency = 2  # 1x dyno
  when 512   then concurrency = 4  # 2x dyno
  when 32768 then concurrency = 16 # px dyno
  else $stderr.puts "Unkown dyno type, selecting concurrency of 4, because"
  end
end

case ENV['RACK_ENV'] || 'development'
when 'production'  then concurrency ||= System.cpu_count
when 'development' then concurrency ||= 2 # use at least two so we can be sure things work concurrencly
else                    concurrency ||= 1
end

concurrency = System.cpu_count if ARGV[0] == '--nginx' and System.cpu_count < concurrency
print concurrency