#!/usr/bin/perl -w

use strict;
use File::stat;

$^I = "";

@ARGV = ();
push @ARGV, glob "*.{net,org,fr,com,in-addr.arpa,local}";
push @ARGV, ("private", "public");

my @file = @ARGV;

foreach (@file)
{
    my $name = $_;
    my $sb = stat($name);
    my ($sec,$min,$hour,$mday,$mon,$year,$wday,$yday,$isdst) = localtime($sb->mtime);
    $year += 1900;
    $mon += 1;
    my $serial = sprintf("%d%02d%02d%02d", $year, $mon, $mday, 1);
    @ARGV = ();
    push @ARGV, $name;
    if ($sb->ctime == $sb->mtime)
    {
	while (<>) 
	{
	    if ($_ =~ m/;.*serial/i)
	    {
		my $last = $_;
		$last =~ s/^([[:space:]]+)([[:digit:]]+)([[:space:]]*;.*serial.*)/$2/ix;
		chomp $last;
		($serial = $last + 1) if (substr($last,0,8) eq substr($serial,0,8));
		s/$last/$serial/;
	    }
	    print;
	}
	close STDIN;
	utime $sb->atime, $sb->mtime-1, $name;
	printf ";; SOA of $name\n";
	printf "; serial: %s.\n", $serial;
    }
    else
    {
	printf ";; serial/modification time of $_ differ, skipping...\n";
    }
}