#!/usr/bin/python

import os
import sys
import argparse
import datetime
import configobj
import socket
import time

# parse command line options
parser = argparse.ArgumentParser(
        description='Hosts checker for py-i2phosts.',
        epilog='Report bugs to https://github.com/i2phosts/py-i2phosts/issues')
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
spec = '''
    log_file = string(default='/var/log/py-i2phosts/master.log')
    log_level = option('debug', 'info', 'warning', 'error', 'critical', default='info')
    lookup_retries = integer(1, 20, default=2)
    '''
spec = spec.split('\n')
config = configobj.ConfigObj(args.config_file, configspec=spec)
if 'include' in config:
    config_included = configobj.ConfigObj(config['include'])
    config.merge(config_included)

# django setup
DJANGO_SETTINGS_MODULE = 'pyi2phosts.settings'
if 'DJANGO_PROJECT_PATH' in config:
    DJANGO_PROJECT_PATH = config['DJANGO_PROJECT_PATH']
else:
    DJANGO_PROJECT_PATH = os.path.dirname(sys.argv[0]) + '/..'
sys.path.insert(1, DJANGO_PROJECT_PATH)
os.environ['DJANGO_SETTINGS_MODULE'] = DJANGO_SETTINGS_MODULE
import django
django.setup()
from pyi2phosts.postkey.models import i2phost
from pyi2phosts.lib.utils import get_logger
from pyi2phosts.lib.utils import validate_config
from pyi2phosts.lib.utils import get_b32

# validate config
validate_config(config)

# configure logger
if args.debug == True:
    log_level = 'debug'
    log_file = None
elif args.verbose == True:
    log_level = 'info'
    log_file = None
else:
    log_level = config['log_level']
    log_file = config['log_file']
log = get_logger(filename=log_file, log_level=log_level)

# determine BOB interface address
if 'bob_addr' in config:
    bob_addr = config['bob_addr']
else:
    log.warning('BOB address isn\'t specified in config, falling back to localhost')
    bob_addr = '127.0.0.1:2827'

# split bob_addr to ip and port
bob_ip, bob_port = bob_addr.split(':')

# connect to BOB
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
try:
    s.connect((bob_ip, int(bob_port)))
    # just receive BOB's greeting
    time.sleep(1)
    data = s.recv(512)
    # make file object
    f = s.makefile('r')
except socket.error, e:
    log.error('failed to connect to BOB: %s', e)
    sys.exit(1)

all_hosts = i2phost.objects.all().order_by('-activated', '-last_seen')
log.info('starting check')
for host in all_hosts:
    log.debug('%s: testing...', host.name)
    # get b32 address from full dest key
    dest = host.b64hash
    b32dest = get_b32(dest)
    # do name lookup query with b32 address
    # it success only if host is alive
    for i in range(config['lookup_retries']):
        s.send('lookup %s\n' % b32dest)
        data = f.readline().rstrip('\n')
        if data == 'ERROR Address Not found.':
            log.debug('%s: unable to resolve, try: %s', host.name, i)
        elif data == 'OK ' + host.b64hash:
            log.info('alive host: %s', host.name)
            # update lastseen timestamp
            host.last_seen = datetime.datetime.utcnow()
            host.save()
            break
        else:
            log.warning('unexpected reply: %s', data)
s.close()
log.info('check finished')