#!/usr/bin/perl
# Monitors the door contacts on a Remote Monitoring System (RMS V1)
# see http://www.remotemonitoringsystems.ca/rms/rms.php
# the MIBS are at http://www.remotemonitoringsystems.ca/rms/snmp.php
# the one we want to monitor is the IO port that is wired to a simple NC magnetic door contact
# .1.3.6.1.4.1.21749.1.3.x where x is the io port
#
# GNU license applies
# (C) Alan Madill, amadill --at-- hwy16.com, Jan 2010
#
# requires Net::SNMP

use Net::SNMP;		#Simple network management protocol
use Net::SMTP;		#Simple mail transport protocol
use strict;
require 'ctime.pl';

# we could load these from the command line
my($target) = "10.1.1.1";	# the IP of the RMS board
my($ioport) = "1";		# the IO port the switch is connected to
my($debug) = 0;			# set to 1 for debugging
my($verbose) = 0;		# set to 1 for status messages

# the oid for the io ports on the RMS
my($baseoid) = ".1.3.6.1.4.1.21749.1.3.";
my($community) = "public";		# can't be changed on the RMS

# where we keep the current state of the door contact
my($statefile) = "/root/bin/doorstatus.txt";

# who do we call?
my($maillist) = "/root/bin/alarmcontact.txt";
my($mailhost) = "mail.mydomain.com";

# the counter gets incremented from 0 to max when the door is open and then rolls over to 0 again
# the alarm message is sent out when the counter is 0 and the door is open
# the counter gets reset to 0 when the door makes the transition from open to closed
my($max) = 30;		# every 30 minutes assuming the cron calls it once a minute
my(%state);

my($session) = Net::SNMP->session(-hostname => $target, -community => $community);

if (! defined($session)) {
   print "session creation error: ".$session->error."\n" if ($debug || $verbose);  
   exit;
}

my($oid) = ($baseoid.$ioport);

my($result) = $session->get_request($oid); 

if (! defined($result)) {
   print "no result returned: ".$session->error."\n" if ($verbose);
   $session->close;
   exit;
}

my($status) = $result->{$oid};

print "IO Status: $status\n" if ($verbose);

$session->close;

# open up the status file and read it
open(STATE, "<$statefile");
while (<STATE>) {
   chomp;
   my($a, $b) = split(/\s/, $_, 2);
   $state{$a} = $b;
   print "$a:\t$state{$a}\n" if ($debug);
}
close(STATE);

$status = 0 if ($debug);

exit if ($status && ($state{door} eq 'closed'));		# door is still closed

if (! $status && ($state{door} eq 'closed')) {	# someone just opened the door!
   # send the alarm
   # write the new state
   $state{door} = 'open';
   $state{counter} = 1;
   writestate();
   do_alarm("Door OPEN event at $target");
}

if (! $status && ($state{door} eq 'open')) {  # the door is still open
   $state{counter}++;
   if ($state{counter} == $max) {
      do_alarm("Door STILL OPEN event after $state{counter} minutes at $target");
      $state{counter} = 0;
   }
   writestate();
}

if ($status && ($state{door} eq 'open')) {  # the door just closed
   $state{counter} = 0;
   $state{door} = 'closed';
   do_alarm("Door CLOSED event at $target");
   writestate();
}

sub do_alarm {
   # send the alarm to the list of email addresses
   my($msg) = shift;
   print "Message: $msg\n" if ($verbose);

   my($now) = ctime(time);
   
   open(MAIL, "<$maillist") or die "unable to open $maillist\n";
   while (<MAIL>) {
      chomp;
      my($smtp) = Net::SMTP->new($mailhost) or die "unable to open SMTP\n";
      $smtp->mail('dooralarm@hwy16.com');
      $smtp->to("$_");
      $smtp->data();
      $smtp->datasend("To: $_\n");
      $smtp->datasend("Subject: $msg\n");
      $smtp->datasend("$msg\n");
      $smtp->datasend("door: $state{door}\n");
      $smtp->datasend("time: $now\n");
      $smtp->dataend();
      $smtp->quit;
   }
}

sub writestate {
   # write the current state to file
   my($now) = ctime(time);
 
   open(STATE, ">$statefile") or die "error opening $statefile\n";
   print STATE "door $state{door}\n";
   print STATE "counter $state{counter}\n";
   print STATE "event $now";

   close(STATE);
}