#!/usr/bin/env python

import sys, time, serial
from daemon import Daemon
from subprocess import Popen, PIPE

def checksum(msg):
  c = 0
  for ca in msg:
    c ^= ord(ca)

  return chr(c)

def bcd(val):
  iu = int(val / 10)
  il = int(val % 10)
  return chr(iu * 16 + il)

def disk_usage():
  pr = Popen("df -h | grep \"/mnt/data\"", shell=True, stdout=PIPE)
  r = pr.wait()
  if r != 0:
    return "Unknown"
  d = pr.stdout.read()
  if len(d) == 0:
    return "Unknown"

  d = d.split()

  if len(d) < 3:
    return "Unknown"

  if len(d[-3]) > 5:
    return "Unknown"

  if len(d[-2]) > 4:
    return "Unknown"

  return "D: %4s (%5s Free)" % (d[-2], d[-3])

def mem_info():
  f = file("/proc/meminfo", "r")
  d = f.read()
  f.close()

  d = d.splitlines()
  for l in d:
    if l.find("MemTotal:") > -1:
      mt = int(l.split()[1])
    elif l.find("MemFree:") > -1:
      mf = int(l.split()[1])

  return "RAM %4sGB: %4sGB Fr" % ("%1.2f" % (mt / (1024.0 * 1024.0)), "%1.2f" % (mf / (1024.0 * 1024.0)))

def raid_status():
  f = file("/proc/mdstat", "r")
  d = f.read()
  f.close()

  if d.find("recovery = ") > -1:
    d = d[d.find("recovery = ") + len("recovery = "):]
    d = d.split()[0]
    return "RAID: Rcvrng (%6s)" % d

  else:
    return "RAID: Unknown"

def temp_status():
  pr = Popen("sensors -A", shell=True, stdout=PIPE)
  pr.wait()

  d = pr.stdout.read()
  d = d.splitlines()

  t = []
  for i in range(1, len(d), 3):
    t.append(float(d[i].split("+")[1].split("\xc2")[0]))

  t = sum(t) / len(t)

  return "Temp: %5s C" % ("%3.1f" % t)

class MyDaemon(Daemon):
  def run(self):
    s = serial.Serial("/dev/ttyS0")
    
    # send the startup / CLS message
    msg = "\x0F" + "\x55" * 21
    s.write("\xAA" + msg + checksum(msg))
    time.sleep(0.2)

    while True:
      msg = "\x00" + time.strftime("Updated: %H:%M %d/%m")
      while len(msg) < 22:
        msg += " "
      s.write("\xAA" + msg + checksum(msg))
      s.read()

      msg = "\x02" + mem_info()
      while len(msg) < 22:
        msg += " "
      s.write("\xAA" + msg + checksum(msg))
      s.read()

      msg = "\x03" + disk_usage()
      while len(msg) < 22:
        msg += " "
      s.write("\xAA" + msg + checksum(msg))
      s.read()

      msg = "\x04" + raid_status()
      while len(msg) < 22:
        msg += " "
      s.write("\xAA" + msg + checksum(msg))
      s.read()

      msg = "\x05" + temp_status()
      while len(msg) < 22:
        msg += " "
      s.write("\xAA" + msg + checksum(msg))
      s.read()

      # update the RTC on the display
      msg = "\x08"
      t = time.localtime()
      msg += bcd(t.tm_sec)
      msg += bcd(t.tm_min)
      msg += bcd(t.tm_hour)
      while len(msg) < 22:
        msg += " "
      s.write("\xAA" + msg + checksum(msg))

      if self.test:
        break
      time.sleep(60)

if __name__ == "__main__":
  daemon = MyDaemon('/tmp/monitor_daemon.pid')
  daemon.test = False
  if len(sys.argv) == 2:
    if 'start' == sys.argv[1]:
      daemon.start()
    elif 'stop' == sys.argv[1]:
      daemon.stop()
    elif 'restart' == sys.argv[1]:
      daemon.restart()
    elif 'test' == sys.argv[1]:
      daemon.test = True
      daemon.run()
    else:
      print "Unknown command"
      sys.exit(2)
    sys.exit(0)
  else:
    print "usage: %s start|stop|restart" % sys.argv[0]
    sys.exit(2)