#!/usr/bin/env ruby

# Copyright (c) 2006 Konstantin Saurbier 
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
# 1. Redistributions of source code must retain the above copyright
#    notice, this list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above copyright
#    notice, this list of conditions and the following disclaimer in the
#    documentation and/or other materials provided with the distribution.
# 3. The name of the author may not be used to endorse or promote products
#    derived from this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
# IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
# OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
# IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
# BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
# LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
# AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
# OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
# SUCH DAMAGE.


## Load modules
#
# Load date class (needed for recognizing and creating the serial)
require 'date'


## Get zone-file
file = ARGV[0] 


## Initialize variables
#
# contains current date 
date = Date.today()
#
# match contains the regular expression for the comparison of the
# current date and the serial
match = Regexp.new(date.to_s.gsub(/-/,""))
#
# output buffers the results
output = Array.new()
#
# serial contains the serialnumber
serial = 0


# Read and process every line of the zone-file
f = File.new(file, "r")
f.each_line do |line|
        if(line =~ /SOA/)
                # Get current serial from zone
                serial = line.scan(/\d{10}/)[0].to_i

                # Is the current serial of today?
                if(serial.to_s =~ match)
                        # Increment serial and replace it
                        serial += 1
                        line.gsub!(/\d{10}/, serial.to_s)
                else
                        # Create serial consisting of current
                        # date and 01 at the end.
                        serial = date.to_s.gsub(/-/, "") + "01"
                        # Replace serial
                        line.gsub!(/\d{10}/, serial)
                end
        end

        # Buffer lines 
        output 
        	
         line
end

# Close zone-file
f.close

# Open zone-file for writing.
f = File.new(file, "w")
f.puts(output)
f.close

#EOF