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

    Dectect Binary and decode it
"""
import time
import os
import redis
import base64
from hashlib import sha1
import magic
import json
import datetime

from pubsublogger import publisher

from Helper import Process
from packages import Item

from lib import Decoded

import re
import signal

class TimeoutException(Exception):
    pass

def timeout_handler(signum, frame):
    raise TimeoutException

signal.signal(signal.SIGALRM, timeout_handler)

def hex_decoder(hexStr):
    #hexStr = ''.join( hex_string.split(" ") )
    return bytes(bytearray([int(hexStr[i:i+2], 16) for i in range(0, len(hexStr), 2)]))

def binary_decoder(binary_string):
    return bytes(bytearray([int(binary_string[i:i+8], 2) for i in range(0, len(binary_string), 8)]))

def base64_decoder(base64_string):
    return base64.b64decode(base64_string)

def decode_string(content, item_id, item_date, encoded_list, decoder_name, encoded_min_size):
    find = False
    for encoded in encoded_list:
        if len(encoded) >=  encoded_min_size:
            decoded_file = decoder_function[decoder_name](encoded)
            find = True

            sha1_string = sha1(decoded_file).hexdigest()
            mimetype = Decoded.get_file_mimetype(file_content)
            Decoded.save_decoded_file_content(sha1_string, decoded_file, item_date, mimetype=mimetype)
            Decoded.save_item_relationship(sha1_string, item_id)
            Decoded.create_decoder_matadata(sha1_string, item_id, decoder_name)

            #remove encoded from item content
            content = content.replace(encoded, '', 1)
    if(find):
        set_out_item(decoder_name, message)

    return content

def set_out_item(decoder_name, message):
    publisher.warning(decoder_name+' decoded')
    #Send to duplicate
    p.populate_set_out(message, 'Duplicate')

    msg = 'infoleak:automatic-detection="'+decoder_name+'";{}'.format(message)
    p.populate_set_out(msg, 'Tags')


if __name__ == '__main__':
    # If you wish to use an other port of channel, do not forget to run a subscriber accordingly (see launch_logs.sh)
    # Port of the redis instance used by pubsublogger
    publisher.port = 6380
    # Script is the default channel used for the modules.
    publisher.channel = 'Script'

    # Section name in bin/packages/modules.cfg
    config_section = 'Decoder'

    # Setup the I/O queues
    p = Process(config_section)

    serv_metadata = redis.StrictRedis(
        host=p.config.get("ARDB_Metadata", "host"),
        port=p.config.getint("ARDB_Metadata", "port"),
        db=p.config.getint("ARDB_Metadata", "db"),
        decode_responses=True)

    # Sent to the logging a description of the module
    publisher.info("Decoder started")

    regex_binary = '[0-1]{40,}'
    #regex_hex = '(0[xX])?[A-Fa-f0-9]{40,}'
    regex_hex = '[A-Fa-f0-9]{40,}'
    regex_base64 = '(?:[A-Za-z0-9+/]{4}){2,}(?:[A-Za-z0-9+/]{2}[AEIMQUYcgkosw048]=|[A-Za-z0-9+/][AQgw]==)'

    re.compile(regex_binary)
    re.compile(regex_hex)
    re.compile(regex_base64)

    # map decoder function
    decoder_function = {'binary':binary_decoder,'hexadecimal':hex_decoder, 'base64':base64_decoder}

    hex_max_execution_time = p.config.getint("Hex", "max_execution_time")
    binary_max_execution_time = p.config.getint("Binary", "max_execution_time")
    base64_max_execution_time = p.config.getint("Base64", "max_execution_time")

    # list all decoder yith regex,
    decoder_binary = {'name': 'binary', 'regex': regex_binary, 'encoded_min_size': 300, 'max_execution_time': binary_max_execution_time}
    decoder_hexadecimal = {'name': 'hexadecimal', 'regex': regex_hex, 'encoded_min_size': 300, 'max_execution_time': hex_max_execution_time}
    decoder_base64 = {'name': 'base64', 'regex': regex_base64, 'encoded_min_size': 40, 'max_execution_time': base64_max_execution_time}

    decoder_order = [ decoder_base64, decoder_binary, decoder_hexadecimal, decoder_base64]

    for decoder in decoder_order:
        serv_metadata.sadd('all_decoder', decoder['name'])

    # Endless loop getting messages from the input queue
    while True:
        # Get one message from the input queue
        message = p.get_from_set()
        if message is None:

            publisher.debug("{} queue is empty, waiting".format(config_section))
            time.sleep(1)
            continue

        obj_id = Item.get_item_id(message)

        # Do something with the message from the queue
        content = Item.get_item_content(obj_id)
        date = Item.get_item_date(obj_id)

        for decoder in decoder_order: # add threshold and size limit

            # max execution time on regex
            signal.alarm(decoder['max_execution_time'])
            try:
                encoded_list = re.findall(decoder['regex'], content)
            except TimeoutException:
                encoded_list = []
                p.incr_module_timeout_statistic() # add encoder type
                print ("{0} processing timeout".format(obj_id))
                continue
            else:
                signal.alarm(0)

                if(len(encoded_list) > 0):
                    content = decode_string(content, message, date, encoded_list, decoder['name'], decoder['encoded_min_size'])