#!/usr/bin/perl

use strict;
use warnings;

# ---------------------------------------
# ------- ipchange_notify.pl ------------
# ---------------------------------------
# Version: 0.7a
# Check for changes in WAN IP address
# (dynamic). If there is a change since
# the last check, send new IP in email.
# ---------------------------------------
# 2011-02-01
# By: Philip Smith
# ---------------------------------------

use Data::Dumper;
use Email::Send;
use Email::Send::Gmail;
use Email::Simple::Creator;
use HTML::Strip;
use LWP::Simple;
use Path::Class qw( file );
use YAML qw( LoadFile );
use YAML::Dumper;


# load conf yaml
my $config_dir = '.config';
my $default_conf     = file( $config_dir, '', 'ipchange_notify.yaml' );
my $config = LoadFile( -e $default_conf
			? $default_conf
			: die "Cannot load conf! $@\n" );

# check wan ip4 address
my $url = $config->{urls}{check_ip};
my $old_ip = $config->{local_info}{old_ip};
my $new_ip = get_ip($url);
my $diff   = 0;
if ( $new_ip ne $old_ip ) {
	$diff = 1;
	send_email();
	update_conf();
}


sub update_conf {
	my $fh_r;
	my $fh_w;
	my $file = './.config/ipchange_notify.yaml';
	open( $fh_r, '<', $file )
		or die "Cannot open $file to read: $!\n";
	my $line;
	my @lines = <$fh_r>;

	foreach $line ( @lines ) {
		if ( $line =~ m/$old_ip/ ) {
			$line =~ s/$old_ip/$new_ip/;
		}
	}
	close( $fh_r );
	open( $fh_w, '>', $file )
		or die "Cannot open $file to write: $!\n";
	foreach $line ( @lines ) { print $fh_w $line; }
	close( $fh_w );
}

sub send_email {
	# set up email object
	my $email = Email::Simple->create(
		header => [
			From	=> $config->{email_info}{from_email},
			To	=> $config->{email_info}{to_email},
			Suject	=> 'IP Address Change Notification',
		],
		body   => "New IP: $new_ip",
	);

	# send the email notification
	my $sender = Email::Send->new(
		{	mailer		=> 'Gmail',
			mailer_args	=> [
				username => $config->{email_info}{username},
				password => $config->{email_info}{password},
			]
		}
	);
	eval ( $sender->send($email) ) if $diff;
	die "Error sending email: $@\n" if $@;
}

sub get_ip {
	my $url      = shift;
	my $html     = get("$url")
		     or die "Could not fetch index.html: $@\n";
	my $stripper = HTML::Strip->new();
	my $naked    = $stripper->parse( $html );
		       $stripper->eof;
	$new_ip = $1 if $naked =~ /(\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3})/;
	return $new_ip;
}