#!/usr/bin/env python3
# -*-coding:UTF-8 -*

"""
The Mails Module
======================

This module is consuming the Redis-list created by the Categ module.

It apply mail regexes on item content and warn if above a threshold.

"""

import os
import re
import sys
import redis
import time
import datetime

import dns.resolver
import dns.exception

from pubsublogger import publisher
from Helper import Process

from pyfaup.faup import Faup

## REGEX TIMEOUT ##
import signal

class TimeoutException(Exception):
    pass

def timeout_handler(signum, frame):
    raise TimeoutException

signal.signal(signal.SIGALRM, timeout_handler)
max_execution_time = 30
## -- ##

sys.path.append(os.path.join(os.environ['AIL_BIN'], 'packages'))
import Item

sys.path.append(os.path.join(os.environ['AIL_BIN'], 'lib/'))
import ConfigLoader

## LOAD CONFIG ##
config_loader = ConfigLoader.ConfigLoader()
server_statistics = config_loader.get_redis_conn("ARDB_Statistics")
r_serv_cache = config_loader.get_redis_conn("Redis_Cache")

dns_server = config_loader.get_config_str('Mail', 'dns')

config_loader = None
## -- ##
def extract_all_email(email_regex, item_content):
    return re.findall(email_regex, item_content)

def is_mxdomain_in_cache(mxdomain):
    return r_serv_cache.exists('mxdomain:{}'.format(mxdomain))

def save_mxdomain_in_cache(mxdomain):
    r_serv_cache.setex(mxdomain, 1, datetime.timedelta(days=1))

def check_mx_record(set_mxdomains, dns_server):
    """Check if emails MX domains are responding.

    :param adress_set: -- (set) This is a set of emails domains
    :return: (int) Number of adress with a responding and valid MX domains

    """
    resolver = dns.resolver.Resolver()
    resolver.nameservers = [dns_server]
    resolver.timeout = 5.0
    resolver.lifetime = 2.0

    valid_mxdomain = []
    for mxdomain in set_mxdomains:

        # check if is in cache
        # # TODO:
        if is_mxdomain_in_cache(mxdomain):
            valid_mxdomain.append(mxdomain)
        else:

            # DNS resolution
            try:
                answers = resolver.query(mxdomain, rdtype=dns.rdatatype.MX)
                if answers:
                    save_mxdomain_in_cache(mxdomain)
                    valid_mxdomain.append(mxdomain)
                    # DEBUG
                    # print('---')
                    # print(answers.response)
                    # print(answers.qname)
                    # print(answers.rdtype)
                    # print(answers.rdclass)
                    # print(answers.nameserver)
                    # print()

            except dns.resolver.NoNameservers:
                publisher.debug('NoNameserver, No non-broken nameservers are available to answer the query.')
                print('NoNameserver, No non-broken nameservers are available to answer the query.')
            except dns.resolver.NoAnswer:
                publisher.debug('NoAnswer, The response did not contain an answer to the question.')
                print('NoAnswer, The response did not contain an answer to the question.')
            except dns.name.EmptyLabel:
                publisher.debug('SyntaxError: EmptyLabel')
                print('SyntaxError: EmptyLabel')
            except dns.resolver.NXDOMAIN:
                #save_mxdomain_in_cache(mxdomain)
                publisher.debug('The query name does not exist.')
                print('The query name does not exist.')
            except dns.name.LabelTooLong:
                publisher.debug('The Label is too long')
                print('The Label is too long')
            except dns.exception.Timeout:
                print('dns timeout')
                #save_mxdomain_in_cache(mxdomain)
            except Exception as e:
                print(e)
    return valid_mxdomain

if __name__ == "__main__":
    publisher.port = 6380
    publisher.channel = "Script"

    config_section = 'Mail'

    faup = Faup()

    p = Process(config_section)

    publisher.info("Mails module started")

    # Numbers of Mails needed to Tags
    mail_threshold = 10

    email_regex = "[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,6}"

    while True:
        message = p.get_from_set()

        if message is not None:
            item_id, score = message.split()

            item_content = Item.get_item_content(item_id)
            item_date = Item.get_item_date(item_id)

            # Get all emails address
            signal.alarm(max_execution_time)
            try:
                all_emails = extract_all_email(email_regex, item_content)
            except TimeoutException:
                p.incr_module_timeout_statistic()
                err_mess = "Mails: processing timeout: {}".format(item_id)
                print(err_mess)
                publisher.info(err_mess)
                continue
            signal.alarm(0)

            # filtering duplicate
            all_emails = set(all_emails)

            # get MXdomains
            set_mxdomains = set()
            dict_mxdomains_email = {}
            for email in all_emails:
                mxdomain = email.split('@')[1].lower()
                if not mxdomain in dict_mxdomains_email:
                    dict_mxdomains_email[mxdomain] = []
                    set_mxdomains.add(mxdomain)
                dict_mxdomains_email[mxdomain].append(email)

                ## TODO: add MAIL trackers

            valid_mx = check_mx_record(set_mxdomains, dns_server)

            num_valid_email = 0
            for domain_mx in valid_mx:
                num_valid_email += len(dict_mxdomains_email[domain_mx])

                for email in dict_mxdomains_email[domain_mx]:
                    msg = 'mail;{};{};{}'.format(1, email, item_date)
                    p.populate_set_out(msg, 'ModuleStats')

                    # Create country stats
                    faup.decode(email)
                    tld = faup.get()['tld']
                    try:
                        tld = tld.decode()
                    except:
                        pass
                    server_statistics.hincrby('mail_by_tld:{}'.format(item_date), tld, 1)

            msg = 'Mails;{};{};{};Checked {} e-mail(s);{}'.format(Item.get_source(item_id), item_date, Item.get_item_basename(item_id), num_valid_email, item_id)

            if num_valid_email > mail_threshold:
                print('{}    Checked {} e-mail(s)'.format(item_id, num_valid_email))
                publisher.warning(msg)
                #Send to duplicate
                p.populate_set_out(item_id, 'Duplicate')
                #tags
                msg = 'infoleak:automatic-detection="mail";{}'.format(item_id)
                p.populate_set_out(msg, 'Tags')
            else:
                publisher.info(msg)

        else:
            time.sleep(10)