#!/usr/bin/python

import os
import sys
import pwd
import argparse
import datetime
import time
import hashlib
import base64
import configobj
import daemon
import daemon.pidlockfile

from i2p import samclasses
from i2p import socket

def check():
	all_hosts = i2phost.objects.all()

	# determine SAM interface address
	if 'sam_addr' in config:
		sam_addr = config['sam_addr']
	else:
		log.warning('SAM address isn\'t specified in config, falling back to localhost')
		sam_addr = '127.0.0.1:7656'
	S = samclasses.BaseSession(sam_addr)

	log.info('starting check')
	for host in all_hosts:
		log.debug('testing %s', host.name)
		# get b32 address from full dest key
		dest = host.b64hash
		raw_key = base64.b64decode(dest.encode('utf-8'), '-~')
		hash = hashlib.sha256(raw_key)
		b32dest = base64.b32encode(hash.digest()).lower().replace('=', '')+'.b32.i2p'
		# do name lookup query with b32 address
		# it success only if host is alive
		try:
			a = S._namelookup(b32dest)
		except socket.NetworkError, e:
			log.debug('%s: %s', host.name, e.args[0][0])
			continue
		log.info('alive host: %s', host.name)
		# update lastseen timestamp
		host.last_seen = datetime.datetime.now()
		host.save()
	S.close()
	log.info('check finished')

def main():
	while True:
		check()
		if args.debug or args.verbose:
			sys.exit(0)
		else:
			time.sleep(float(config['check_interval']))

# parse command line options
parser = argparse.ArgumentParser(
		description='Hosts checker for py-i2phosts.',
		epilog='Report bugs to http://zzz.i2p/topics/733')
parser.add_argument('-d', '--debug', action='store_true',
		help='set loglevel to debug and write messages to stdout'),
parser.add_argument('-v', '--verbose', action='store_true',
		help='set loglevel to info and write messages to stdout'),
parser.add_argument('-c', '--config', default='/etc/py-i2phosts/checker.conf', dest='config_file',
		help='config file to use')
args = parser.parse_args()

# read config
config = configobj.ConfigObj(args.config_file)
if 'include' in config:
	config_included = configobj.ConfigObj(config['include'])
	config.merge(config_included)

# django setup
DJANGO_SETTINGS_MODULE = 'settings'
if 'DJANGO_PROJECT_PATH' in config:
	DJANGO_PROJECT_PATH = config['DJANGO_PROJECT_PATH']
else:
	DJANGO_PROJECT_PATH = os.path.dirname(sys.argv[0]) + '/web'
sys.path.insert(1, DJANGO_PROJECT_PATH)
os.environ['DJANGO_SETTINGS_MODULE'] = DJANGO_SETTINGS_MODULE
from web.postkey.models import i2phost
from web.lib.utils import get_logger

# configure logger
if args.debug == True:
	log_level = 'debug'
	log_file = None
elif args.verbose == True:
	log_level = 'info'
	log_file = None
else:
	if 'log_level' in config:
		log_level = config['log_level']
	else:
		sys.stderr.write('"log_level" missing in config\n')
		sys.exit(1)
	if 'log_file' in config:
		log_file = config['log_file']
	else:
		sys.stderr.write('"log_file missing in config\n')
		sys.exit(1)

if not args.debug and not args.verbose:
	# get pid object for daemon
	if 'pid_file' in config:
		pid = daemon.pidlockfile.TimeoutPIDLockFile(config['pid_file'], 10)
	else:
		sys.stderr.write('"pid_file" missing in config\n')
		sys.exit(1)
	# create daemon context
	d = daemon.DaemonContext(pidfile=pid, umask=077)
	# write stderr to logfile # FIXME: and how we will deal with log rotation?
	logfile = open(config['log_file'], 'a')
	d.stderr = logfile
	d.stdout = logfile
	# drop privileges when started as root
	if os.getuid() == 0:
		runas = '_pyi2phosts'
		pw_entry = pwd.getpwnam(runas)
		d.uid = pw_entry[2]
		d.gid = pw_entry[3]
	d.open() # become daemon
log = get_logger(filename=log_file, log_level=log_level)
main()