#!/usr/bin/env python

from string import split, strip, find, upper, lower
from sys import argv, exit
from os import popen, getenv, geteuid
import socket
import subprocess
import struct
import time
from xml.parsers import expat
import time

program = 'mk5watchdog'
author  = 'Helge Rottmann'
version = '0.2'
verdate = '20110510'

def usage():
	exit(1)

class Mk5state:

	def __init__(self):
		self.ok    = False
		self.pid   = 0
		self.id    = ''
		self.mk5   = ''
		self.seq   = 0
		self.vsnA  = 'none'
		self.vsnB  = 'none'
		self.bank  = ' '
		self.state = 'Unknown'
		self.scan  = 0
		self.name  = ''
		self.pos   = 0L
		self.rate  = 0.0
		self.date  = 0.0


	def getmk5(self):
		return self.mk5

class Parser:

	def __init__(self):
		self._parser = expat.ParserCreate()
		self._parser.StartElementHandler = self.start
		self._parser.EndElementHandler = self.end
		self._parser.CharacterDataHandler = self.data
		self.info = Mk5state()
		self.tmp = ''
		self.lastMessageTime = time.time()

	def feed(self, data):
		try:
			self._parser.Parse(data, 0)
		except expat.ExpatError:
			print '\n\n XXX %s XXX' % data 

	def close(self):
		self._parser.Parse("", 1) # end of data
		del self._parser # get rid of circular references

	def start(self, tag, attrs):
		pass

	def end(self, tag):
		if tag == 'mark5Status':
			self.info.ok = True
			self.lastMessageTime = time.time()
		if tag == 'bankAVSN':
			if len(self.tmp) != 8:
				self.info.vsnA = 'none'
			else:
				self.info.vsnA = upper(self.tmp)
		if tag == 'bankBVSN':
			if len(self.tmp) != 8:
				self.info.vsnB = 'none'
			else:
				self.info.vsnB = upper(self.tmp)
		if tag == 'from':
			self.info.mk5 = lower(self.tmp)
		if tag == 'state':
			self.info.state = self.tmp
		if tag == 'playRate':
			self.info.rate = float(self.tmp)
		if tag == 'dataMJD':
			self.info.date = float(self.tmp)
		if tag == 'position':
			self.info.pos = int(self.tmp)
		if tag == 'scanNumber':
			self.info.scan = int(self.tmp)
		if tag == 'scanName':
			self.info.name = self.tmp
		if tag == 'activeBank':
			self.info.bank = self.tmp

	def data(self, data):
		self.tmp = data


def listen(port, group):
	dt = 0.0
	t = 0
	maxtime = 6000

	# Now listen for responses, until either time runs out or we get all we need
	s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
	s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
	s.bind(('', port))
	mreq = struct.pack("4sl", socket.inet_aton(group), socket.INADDR_ANY)
	s.setsockopt(socket.IPPROTO_IP, socket.IP_ADD_MEMBERSHIP, mreq)
	s.settimeout(0.2)
	try:
		while t < maxtime:
			try:
				message = s.recv(1500)
			except socket.timeout:
				t += dt
				continue

			if message[0] != '<':
				continue

			p = Parser()
			p.feed(message)
			restart = False

			if p.info.mk5 == socket.gethostname():

				#message = "%s %s\n" % (time.asctime(), p.info.state)
				#print message
				#logfile.write(message)
				#logfile.flush()

				if p.info.state == "Error": 
					restart = True
			
				if restart:
					try:
					    logfile.write("%s Restarting\n" % (time.asctime()))
					    logfile.flush()

					    retcode = subprocess.call("/etc/init.d/mark5" + " restart", shell=True)

					    if retcode < 0:
						print "Child was terminated by signal", -retcode
					    else:
						print "Child returned", retcode
					except Exception, e:
					    print  "Execution failed:", e

				
			p.close()
	except KeyboardInterrupt:
		return 0
	except:
		return 1
	return 0



if geteuid() != 0:
	print "You must be root to run this script."
	exit(1)

logfile = open('/tmp/mk5watchdog.log', 'w')


port = getenv('DIFX_MESSAGE_PORT')
if port == None:
	print 'DIFX_MESSAGE_PORT needs to be defined'
	exit(0)
else:
	port = int(port)
group = getenv('DIFX_MESSAGE_GROUP')
if group == None:
	print 'DIFX_MESSAGE_GROUP needs to be defined'
	exit(0)

while(listen(port, group)):
	pass

logfile.close()