#!/usr/bin/python
# -*- coding: utf-8 -*-

import re
import math
import socket
import struct
import pkgutil
import urlparse
import json
import logging
import urllib2
from argparse import ArgumentParser

gfwlist_url = 'https://raw.githubusercontent.com/gfwlist/gfwlist/master/gfwlist.txt'


def parse_args():
    parser = ArgumentParser()
    parser.add_argument('-i', '--input', dest='input',
                        help='path to gfwlist', metavar='GFWLIST')
    parser.add_argument('-f', '--file', dest='output', required=True,
                        help='path to output pac', metavar='PAC')
    parser.add_argument('-p', '--proxy', dest='proxy', required=True,
                        help='the proxy parameter in the pac file, '
                             'for example, "SOCKS5 127.0.0.1:1080;"',
                        metavar='PROXY')
    parser.add_argument('--user-rule', dest='user_rule',
                        help='user rule file, which will be appended to'
                             ' gfwlist')
    parser.add_argument('--direct-rule', dest='direct_rule',
                        help='user rule file, contains domains not bypass proxy')
    parser.add_argument('--localtld-rule', dest='localtld_rule',
                        help='local TLD rule file, contains TLDs with a leading dot not bypass proxy')
    parser.add_argument('--ip-file', dest='ip_file',
                        help='delegated-apnic-latest from apnic.net')
    return parser.parse_args()

#from https://github.com/Leask/Flora_Pac
def ip2long(ip):
    packedIP = socket.inet_aton(ip)
    return struct.unpack("!L", packedIP)[0]

#from https://github.com/Leask/Flora_Pac
def fetch_ip_data():
    args = parse_args()
    if (args.ip_file):
        with open(args.ip_file, 'rb') as f:
            data = f.read()
    else:
        #fetch data from apnic
        print "Fetching data from apnic.net, it might take a few minutes, please wait..."
        url=r'http://ftp.apnic.net/apnic/stats/apnic/delegated-apnic-latest'
      # url=r'http://flora/delegated-apnic-latest' #debug
        data=urllib2.urlopen(url).read()

    cnregex=re.compile(r'apnic\|cn\|ipv4\|[0-9\.]+\|[0-9]+\|[0-9]+\|a.*',re.IGNORECASE)
    cndata=cnregex.findall(data)

    results=[]
    prev_net=''

    for item in cndata:
        unit_items=item.split('|')
        starting_ip=unit_items[3]
        num_ip=int(unit_items[4])

        imask=0xffffffff^(num_ip-1)
        #convert to string
        imask=hex(imask)[2:]
        mask=[0]*4
        mask[0]=imask[0:2]
        mask[1]=imask[2:4]
        mask[2]='0' #imask[4:6]
        mask[3]='0' #imask[6:8]

        #convert str to int
        mask=[ int(i,16 ) for i in mask]
        mask="%d.%d.%d.%d"%tuple(mask)

        #mask in *nix format
        mask2=32-int(math.log(num_ip,2))

        ip=starting_ip.split('.')
        ip[2] = '0'
        ip[3] = '0'
        starting_ip = '.'.join(ip)
        if starting_ip != prev_net:
            results.append((ip2long(starting_ip), ip2long(mask), mask2))
            prev_net = starting_ip

    results.insert(0, (ip2long('127.0.0.1'),   ip2long('255.0.0.0'),   0))
    results.insert(1, (ip2long('10.0.0.0'),    ip2long('255.0.0.0'),   0))
    results.insert(2, (ip2long('172.16.0.0'),  ip2long('255.240.0.0'), 0))
    results.insert(3, (ip2long('192.168.0.0'), ip2long('255.255.0.0'), 0))
    def ip(item):
        return item[0]

    results = sorted(results, key = ip)
    return results

def decode_gfwlist(content):
    # decode base64 if have to
    try:
        if '.' in content:
            raise Exception()
        return content.decode('base64')
    except:
        return content


def get_hostname(something):
    try:
        # quite enough for GFW
        if not something.startswith('http:'):
            something = 'http://' + something
        r = urlparse.urlparse(something)
        return r.hostname
    except Exception as e:
        logging.error(e)
        return None


def add_domain_to_set(s, something):
    hostname = get_hostname(something)
    if hostname is not None:
        s.add(hostname)


def combine_lists(content, user_rule=None):
    gfwlist = content.splitlines(False)
    if user_rule:
        gfwlist.extend(user_rule.splitlines(False))
    return gfwlist


def parse_gfwlist(gfwlist):
    domains = set()
    for line in gfwlist:
        if line.find('.*') >= 0:
            continue
        elif line.find('*') >= 0:
            line = line.replace('*', '/')
        if line.startswith('||'):
            line = line.lstrip('||')
        elif line.startswith('|'):
            line = line.lstrip('|')
        elif line.startswith('.'):
            line = line.lstrip('.')
        if line.startswith('!'):
            continue
        elif line.startswith('['):
            continue
        elif line.startswith('@'):
            # ignore white list
            continue
        add_domain_to_set(domains, line)
    return domains


def reduce_domains(domains):
    # reduce 'www.google.com' to 'google.com'
    # remove invalid domains
    with open('./tld.txt', 'rb') as f:
            tld_content = f.read()
    tlds = set(tld_content.splitlines(False))
    new_domains = set()
    for domain in domains:
        domain_parts = domain.split('.')
        last_root_domain = None
        for i in xrange(0, len(domain_parts)):
            root_domain = '.'.join(domain_parts[len(domain_parts) - i - 1:])
            if i == 0:
                if not tlds.__contains__(root_domain):
                    # root_domain is not a valid tld
                    break
            last_root_domain = root_domain
            if tlds.__contains__(root_domain):
                continue
            else:
                break
        if last_root_domain is not None:
            new_domains.add(last_root_domain)

    uni_domains = set()
    for domain in new_domains:
        domain_parts = domain.split('.')
        for i in xrange(0, len(domain_parts)-1):
            root_domain = '.'.join(domain_parts[len(domain_parts) - i - 1:])
            if domains.__contains__(root_domain):
                break
        else:
            uni_domains.add(domain)
    return uni_domains


def generate_pac_fast(domains, proxy, direct_domains, cnips, local_tlds):
    # render the pac file
    with open('./pac-template', 'rb') as f:
        proxy_content = f.read()
    domains_dict = {}
    for domain in domains:
        domains_dict[domain] = 1
    proxy_content = proxy_content.replace('__PROXY__', json.dumps(str(proxy)))
    proxy_content = proxy_content.replace(
        '__DOMAINS__',
        json.dumps(domains_dict, indent=2, sort_keys=True)
    )

    direct_domains_dict = {}
    for domain in direct_domains:
        direct_domains_dict[domain] = 1
    proxy_content = proxy_content.replace(
        '__DIRECT_DOMAINS__',
        json.dumps(direct_domains_dict, indent=2, sort_keys=True)
    )

    proxy_content = proxy_content.replace(
        '__CN_IPS__',
        json.dumps(cnips, indent=2, sort_keys=False)
    )

    tlds_dict = {}
    for domain in local_tlds:
        tlds_dict[domain] = 1
    proxy_content = proxy_content.replace(
        '__LOCAL_TLDS__',
        json.dumps(tlds_dict, indent=2, sort_keys=True)
    )

    return proxy_content


def generate_pac_precise(rules, proxy):
    def grep_rule(rule):
        if rule:
            if rule.startswith('!'):
                return None
            if rule.startswith('['):
                return None
            return rule
        return None
    # render the pac file
    proxy_content = pkgutil.get_data('gfwlist2pac', './abp.js')
    rules = filter(grep_rule, rules)
    proxy_content = proxy_content.replace('__PROXY__', json.dumps(str(proxy)))
    proxy_content = proxy_content.replace('__RULES__',
                                          json.dumps(rules, indent=2))
    return proxy_content


def main():
    args = parse_args()
    user_rule = None
    direct_rule = None
    localtld_rule = None
    if (args.input):
        with open(args.input, 'rb') as f:
            content = f.read()
    else:
        print 'Downloading gfwlist from %s' % gfwlist_url
        content = urllib2.urlopen(gfwlist_url, timeout=10).read()
    if args.user_rule:
        userrule_parts = urlparse.urlsplit(args.user_rule)
        if not userrule_parts.scheme or not userrule_parts.netloc:
            # It's not an URL, deal it as local file
            with open(args.user_rule, 'rb') as f:
                user_rule = f.read()
        else:
            # Yeah, it's an URL, try to download it
            print 'Downloading user rules file from %s' % args.user_rule
            user_rule = urllib2.urlopen(args.user_rule, timeout=10).read()

    if args.direct_rule:
        directrule_parts = urlparse.urlsplit(args.direct_rule)
        if not directrule_parts.scheme or not directrule_parts.netloc:
            # It's not an URL, deal it as local file
            with open(args.direct_rule, 'rb') as f:
                direct_rule = f.read()
        else:
            # Yeah, it's an URL, try to download it
            print 'Downloading user rules file from %s' % args.user_rule
            direct_rule = urllib2.urlopen(args.direct_rule, timeout=10).read()
        direct_rule = direct_rule.splitlines(False)
    else:
        direct_rule = []

    if args.localtld_rule:
        tldrule_parts = urlparse.urlsplit(args.localtld_rule)
        if not tldrule_parts.scheme or not tldrule_parts.netloc:
            # It's not an URL, deal it as local file
            with open(args.localtld_rule, 'rb') as f:
                localtld_rule = f.read()
        else:
            # Yeah, it's an URL, try to download it
            print 'Downloading local tlds rules file from %s' % args.user_rule
            localtld_rule = urllib2.urlopen(args.localtld_rule, timeout=10).read()
        localtld_rule = localtld_rule.splitlines(False)
    else:
        localtld_rule = []

    cnips = fetch_ip_data()

    content = decode_gfwlist(content)
    gfwlist = combine_lists(content, user_rule)

    domains = parse_gfwlist(gfwlist)
    domains = reduce_domains(domains)
    pac_content = generate_pac_fast(domains, args.proxy, direct_rule, cnips, localtld_rule)

    with open(args.output, 'wb') as f:
        f.write(pac_content)


if __name__ == '__main__':
    main()