require 'socket'
require 'open-uri'
require 'date'

require 'timeout'

module Rudy
  
  # A motley collection of methods that Rudy loves to call!
  module Utils
    extend self
    include Socket::Constants
    
    # Return the external IP address (the one seen by the internet)
    def external_ip_address
      ip = nil
      %w{solutious.com/ip myip.dk/ whatismyip.com }.each do |sponge| # w/ backup
        break unless ip.nil?
        ip = (open("http://#{sponge}") { |f| /([0-9]{1,3}\.){3}[0-9]{1,3}/.match(f.read) }).to_s rescue nil
      end
      ip += "/32" if ip
      ip
    end
    
    # Return the local IP address which receives external traffic
    # from: http://coderrr.wordpress.com/2008/05/28/get-your-local-ip-address/
    # NOTE: This <em>does not</em> open a connection to the IP address. 
    def internal_ip_address
      # turn off reverse DNS resolution temporarily 
      orig, Socket.do_not_reverse_lookup = Socket.do_not_reverse_lookup, true   
      ip = UDPSocket.open {|s| s.connect('75.101.137.7', 1); s.addr.last } # Solutious IP
      ip += "/24" if ip
      ip
    ensure  
      Socket.do_not_reverse_lookup = orig
    end
    
    # Generates a canonical tag name in the form:
    #     rudy-2009-12-31-r1
    # where r1 refers to the revision number that day
    def generate_tag(revision=1)
      n = DateTime.now
      y = n.year.to_s.rjust(4, "20")
      m = n.month.to_s.rjust(2, "0")
      d = n.mday.to_s.rjust(2, "0")
      "rudy-%4s-%2s-%2s-r%s" % [y, m, d, revision.to_s.rjust(2, "0")] 
    end
    
    
    def service_available?(host, port, wait=3)
      begin
        status = Timeout::timeout(wait) do
          socket = Socket.new( AF_INET, SOCK_STREAM, 0 )
          sockaddr = Socket.pack_sockaddr_in( port, host )
          socket.connect( sockaddr )
        end
        true
      rescue Errno::EAFNOSUPPORT, Errno::ECONNREFUSED, SocketError, Timeout::Error => ex
        false
      end
    end
  end
end