#!/usr/bin/perl

use strict;
use warnings;
use Martnet::DDNS;
use File::Temp qw/tempfile/;

my $ddns = Martnet::DDNS->new();

my @vh = $ddns->get();

my @all = parse_slavefile("/etc/bind/martnet.slave.zones.9");

# For each virtual host, see if we've got it already
my $changecount = 0;
foreach my $i (@vh) {
    unless (contains_zone($i, @all)) {
	# If we find any differences, we rewrite the file
	do_rewrite(@vh);
	last;
    }
}

exit 0;

sub parse_slavefile {
    my ($f) = @_;

    my @ret;
    
    open(my $fh, $f) || die "Can't open $f: $!";
    while (<$fh>) {
	if (/^zone\s+\"([^\"]+)\"\s+\{/) {
	    push ( @ret, { zone => $1 } );
	}
    }
    return @ret;
}

sub do_rewrite {
    my (@vh) = @_;
    my ($fh, $path) = tempfile();
    foreach my $i (sort {$a->{zone} cmp $b->{zone}} @vh) {
	print $fh "zone \"$i->{zone}\" { type slave; file \"/var/cache/bind/db.$i->{zone}\"; masters { $i->{master}; }; };\n";
    }
    close $fh;
    print "Installing new slave host list\n";
    system("install -o bind -g bind $path /etc/bind/martnet.slave.zones.9");
    print "Reloading DNS files\n";
    system("rndc reload");
}

sub contains_zone {
    my ($zone, @zl) = @_;

    foreach my $i (@zl) {
	return 1
	    if ($i->{zone} eq $zone);
    }
    return 0;
}