################################
# DNS Module                   #
################################

# Copyright 2010 Lenny Herold <lenny@gatorglory.com>

# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.

# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.

# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

package BotModules::DNS;
use vars qw(@ISA);
use Net::DNS;
@ISA = qw(BotModules);
1;

# RegisterConfig - Called when initialised, should call registerVariables
sub RegisterConfig {
    my $self = shift;
    $self->SUPER::RegisterConfig(@_);
    $self->registerVariables(
      # [ name, save?, settable? ]
    );
}

sub Help {
	my $self = shift;
	my ($event) = @_;
	return {
		'' => "This module performs hostname and reverse DNS lookups.",
		'host, !host' => 'Perform a lookup for the specified hostname or IP.',
		'mx, !mx' => 'Perform an MX record lookup for the specified hostname or IP.',
	};
}

sub Told {
	my $self = shift;
	my ($event, $message) = @_;

	if ($message =~ /^(\s*!?host\s+)(.+)$/osi) {
		my $lookup = $2;
		my @result = host_lookup($lookup);
		foreach (@result) { $self->say($event, "$lookup $_") }
	} elsif ($message =~/^(\s*!?mx\s+)(.+)$/osi) {
		my $lookup = $2;
		my @result = mx_lookup($lookup);
		unless ($result[0] =~ /failed/) {
			foreach my $record (@result) { 
				$self->say($event, "$lookup mail is handled by " . $record->preference . " " . $record->exchange . "\n") }
		} else {
			$self->say($event, $result[0])
		}
	} else {
		return $self->SUPER::Told(@_);
	}
	return 0;
}

sub Heard {
	my $self = shift;
	my($event, $message) = @_;

	if ($message =~ /^(\s*!?host\s+)(.+)$/) {
		my $lookup = $2;
		my @result = host_lookup($lookup);
		foreach (@result) { $self->say($event, "$lookup $_") }
	} elsif ($message =~/^(\s*!?mx\s+)(.+)$/osi) {
		my $lookup = $2;
		my @result = mx_lookup($lookup);
		unless ($result[0] =~ /failed/) {
			foreach my $record (@result) { 
				$self->say($event, "$lookup mail is handled by " . $record->preference . " " . $record->exchange . "\n") }
		} else {
			$self->say($event, $result[0])
		}
	} else {
		return $self->SUPER::Heard(@_);
	}
	return 0;

}

sub host_lookup {
	my $host = shift;
	my @answer;

	my $res   = Net::DNS::Resolver->new;
	my $query = $res->search("$host");
  
	if ($query) {
		foreach my $rr ($query->answer) {
			if ($rr->type eq "A" ) { push (@answer, ("has address " . $rr->address . "\n")) }
			if ($rr->type eq "CNAME" ) { push (@answer, ("is an alias for " . $rr->cname . "\n")) }
	}
	} else {
		push (@answer, "Lookup failed: " . $res->errorstring . "\n");
	}
	return @answer;
}

sub mx_lookup {
	my $host = shift;

	my $res = Net::DNS::Resolver->new;
	my @answer  = mx($res, $host);
  
	unless (@answer) { push (@answer, "Lookup failed: " . $res->errorstring . "\n") }
	return @answer;
}