#!/usr/bin/python

import re
import os
import os.path
import sys
import errno
import datetime
import urllib2
import subprocess
import argparse
import configobj
import tempfile
import socket

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

# read config
spec = '''
	proxyurl = string(default='http://localhost:4444/')
	log_file = string(default='/var/log/py-i2phosts/fetcher.log')
	log_level = option('debug', 'info', 'warning', 'error', 'critical', default='info')
	'''
spec = spec.split('\n')
config = configobj.ConfigObj(args.config_file, configspec=spec, file_error=True)
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]) + '/web'
sys.path.insert(1, DJANGO_PROJECT_PATH)
os.environ['DJANGO_SETTINGS_MODULE'] = DJANGO_SETTINGS_MODULE
from pyi2phosts.lib.utils import get_logger
from pyi2phosts.lib.utils import validate_config
from pyi2phosts.extsources.models import ExternalSource

# validate config
validate_config(config)

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

# we want open urls through proxy
proxy_handler = urllib2.ProxyHandler({'http': config['proxyurl']})
opener = urllib2.build_opener(proxy_handler)

all_sources = ExternalSource.objects.filter(active=True)

for source in all_sources:
	log.debug('%s: starting work', source.name)
	if source.last_modified:
		last_modified = source.last_modified.strftime('%a, %d %b %Y %H:%M:%S GMT')
		# prevent redownloading of hosts-file by passing If-Modified-Since http header
		opener.addheaders = [('If-Modified-Since', last_modified)]
		log.debug('%s: appending If-Modified-Since: %s', source.name, last_modified)
	if source.etag:
		opener.addheaders = [('If-None-Match', source.etag)]
		log.debug('%s: appending If-None-Match: %s', source.name, source.etag)
	try:
		log.debug('%s: sending GET...', source.name)
		resp = opener.open(source.url, timeout=60)
	except socket.timeout:
		log.warning('%s: socket timeout', source.name)
		continue
	except urllib2.HTTPError, e:
		if e.code == 304:
			log.info('%s: not modified', source.name)
			source.last_success = datetime.datetime.utcnow()
			source.save()
		else:
			log.warning('%s: can\'t finish the request, error code: %s, reason: %s', source.name, e.code, e.reason)
		continue
	except urllib2.URLError, e:
		log.warning('%s: failed to reach server, reason: %s', source.name, e.reason)
		continue
	# read data from remote and write it to local file
	try:
		log.debug('%s: reading response data', source.name)
		content = resp.read()
	except:
		log.warning('%s: failed to read data', source.name)
		continue
	# save fetched content into temporary file
	fd, tmpfile = tempfile.mkstemp(text=True)
	f = os.fdopen(fd, 'w')
	f.write(content)
	f.close()
	# get last-modified info from header
	lm = resp.headers.get('Last-Modified')
	if lm:
		log.debug('%s: Last-Modified: %s', source.name, lm)
		source.last_modified = datetime.datetime.strptime(lm, '%a, %d %b %Y %H:%M:%S GMT')
	# get ETag
	etag = resp.headers.get('ETag')
	if etag:
		log.debug('%s: ETag: %s', source.name, etag)
		source.etag = etag
	# form command-line for invoke injector
	log.info('%s: adding hosts...', source.name)
	sp_args = ['py-i2phosts-injector', '-s', '-f', tmpfile, '-d',
			'Auto-added from ' + source.name]
	try:
		p = subprocess.Popen(sp_args, shell=False, stdin=None,
				stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
	except OSError, e:
		log.error('failed to exec py-i2phosts-injector: %s', e)
		if e.errno == errno.ENOENT:
			log.error('check your PATH environment variable')
		sys.exit(1)
	out = p.communicate()[0]
	os.remove(tmpfile)
	log.info('%s: injector output: \n%s', source.name, out)
	# update last_success
	source.last_success = datetime.datetime.utcnow()
	log.debug('%s: updating last_success timestamp: %s', source.name, source.last_success)
	source.save()