hacktouch_occupancy_powersave

#!/usr/bin/ruby

# HackTouch Occupancy Power Saver
#  Turns off the HackTouch monitors when nobody is around.
# Input: statistics.occupancy
# Output: SSH 'tvcontrol' commands to HackTouches

require 'rubygems'
require 'amqp'
require 'inifile'
require 'json'

cfg = IniFile.load(File.expand_path("~/.labamqprc"))
amqp_host = cfg['broker']['BrokerHost']
amqp_user = cfg['hacktouch_occupancy_powersave']['BrokerUsername']
amqp_pass = cfg['hacktouch_occupancy_powersave']['BrokerPassword']

AMQP.logging = true
AMQP.start(:host => amqp_host, :user => amqp_user, :pass => amqp_pass) do
  amq = AMQP::Channel.new
  exchange = amq.fanout('statistics.occupancy', :durable => false, :auto_delete => false);
  queue = amq.queue('statistics.occupancy.hacktouch', :durable => false, :auto_delete => true);
  queue.bind(exchange);
  queue.subscribe do |header, raw_msg|
    msg = JSON.parse(raw_msg)
    next if !msg['change']
    hacktouch = cfg['hacktouch_occupancy_powersave'][msg['area']]
    next if !hacktouch  # no hacktouches in this area
    if(msg['occupied']) then
      # turn on the HackTouch monitor
      puts "Area is now occupied, turning on #{hacktouch}."
      system("ssh pi@#{hacktouch} tvservice -p");
      # i have no idea why, but this sequence is required to make it work again
      system("ssh pi@#{hacktouch} fbset -xres 1920 -yres 1080 -depth 24");
      system("ssh pi@#{hacktouch} fbset -xres 1920 -yres 1080 -depth 16");
      system("ssh pi@#{hacktouch} xrefresh -d :0.0");
    else
      # turn off the HackTouch monitor
      puts "Area is now vacant, turning off #{hacktouch}."
      system("ssh pi@#{hacktouch} tvservice -o");
    end
  end
end