#!/usr/bin/env ruby
# vim:expandtab shiftwidth=2 softtabstop=2

require 'rubygems'
require 'getoptions'
require 'net/dns/resolver'

PROGNAME = File.basename($0)

def usage
  warn "#{PROGNAME} zone slave [...]"
  exit 64
end

options = GetOptions.new(%w(srcaddr=s timeout=i verbose+))
verbosity = options[:verbose] || 0

zone, *slaves = ARGV
usage if slaves.empty?

packet = Net::DNS::Packet.new(zone, 'SOA')
packet.header = Net::DNS::Header.new(:opCode => Net::DNS::Header::NOTIFY, :aa => 1, :rd => 0)
p packet if verbosity > 1

res = Net::DNS::Resolver.new
res.udp_timeout = options[:timeout] if options[:timeout]
res.source_address = options[:srcaddr] if options[:srcaddr]
res.log_level = Net::DNS::WARN

slaves.each do |slave|
  res.nameservers = slave
  print "#{zone}: notify #{slave}: " if verbosity > 0
  begin
    reply = res.send(packet)
  rescue NoResponseError => exc
    print "#{zone}: notify #{slave}: " if verbosity < 1
    puts "error: #{exc.message}"
  end

  if reply
    error, cause = reply.header.rCode_str
    case error
    when 'NoError'
      puts "#{error} (#{cause})" if verbosity > 0
    else
      print "#{zone}: notify #{slave}: " if verbosity < 1
      puts "#{error} (#{cause})"
    end
    p reply if verbosity > 1
  end
end

exit 0