# -*- coding: utf-8 -*-
""" Set of methods used to retrieve access tokens by simulating the official VK application for Android.
This is a Python port of the PHP module developed by Vodka2 to retrieve VK audio tokens. More info at https://github.com/vodka2/vk-audio-token
This module, as a Python port, just tries to get the tokens by using the Official VK app's tokens. I did not implemented the Kate mobile functionality as it involves a lot of more work and is not giving any advantage over the official way.
there are a lot of features pending to be applied. Hopefully later I can make it working more efficiently and OOP based.
"""
import random
import requests
import logging
from hashlib import md5
from .wxUI import two_factor_auth, bad_password

log = logging.getLogger("authenticator.official")

class AuthenticationError(Exception):
    pass

# Data extracted from official VK android APP.
client_id = "2274003"
client_secret = "hHbZxrka2uZ6jB1inYsH"
api_ver="5.93"
scope = "nohttps,all"
user_agent = "VKAndroidApp/5.23-2978 (Android 4.4.2; SDK 19; x86; unknown Android SDK built for x86; en; 320x240)"

api_url = "https://api.vk.com/method/"

def get_device_id():
	""" Generate a random device ID, consisting in 16 alphanumeric characters."""
	return "".join(random.choice(["1", "2", "3", "4", "5", "6", "7", "8", "9", "0", "a", "b", "c", "d", "e", "f"]) for _ in range(16))

def get_sig(method, values, secret):
	""" Create a signature for parameters passed to VK API. """
	postdata = ""
	for key in values:
		# None values should be excluded from SIG, otherwise VK won't validate it correctly.
		if values[key] != None:
			postdata = postdata + "{key}={value}&".format(key=key, value=values[key])
	# Remove the last "&" character.
	postdata = postdata[:-1]
	sig = md5(b"/method/"+method.encode("utf-8")+b"?"+postdata.encode("utf-8")+secret.encode("utf-8"))
	return sig.hexdigest()

def perform_request(method, postdata, secret):
	""" Send a request to VK servers by signing the data with the 'sig' parameter."""
	url = api_url+method
	sig = get_sig(method, postdata, secret)
	postdata.update(sig=sig)
	headers = {'User-Agent': user_agent}
	r = requests.post(url, data=postdata, headers=headers)
	return r.json()

def get_non_refreshed(login, password, scope=scope):
	""" Retrieves a non-refreshed token, this should be the first token needed to authenticate in VK.
	returns the access_token which still needs to be refreshed, device_id, and secret code, needed to sign all petitions in VK."""
	if not (login or password):
		raise ValueError("Both user and password are required.")
	device_id = get_device_id()
	# Let's authenticate.
	url = "https://oauth.vk.com/token"
	params = dict(grant_type="password",
		client_id=client_id, client_secret=client_secret, username=login,
		password=password, v=api_ver, scope=scope, lang="en", device_id=device_id, force_sms=1)
	# Add two factor auth later due to python's syntax.
	params["2fa_supported"] = 1
	headers = {'User-Agent': user_agent}
	r = requests.get(url, params=params, headers=headers)
	# Let's print this into logs as exceptions so we can catch future errors.
	log.exception(r.json())
	# If a 401 error is raised, we need to use 2FA here.
	# see https://vk.com/dev/auth_direct (switch lang to russian, english docs are very incomplete in the matter)
	# ToDo: this needs testing after implemented official VK tokens.
	if r.status_code == 401 and "phone_mask" in r.text:
		t = r.json()
		log.exception(t)
		validation_sid = t["validation_sid"]
		url = "https://api.vk.com/method/auth.validatePhone"
		params = dict(v="5.95", sid=validation_sid)
		validated = requests.get(url, params=params, headers=headers)
		log.exception(validated.json())
		code, remember = two_factor_auth()
		url = "https://oauth.vk.com/token"
		params = dict(grant_type="password", lang="en",
			client_id=client_id, client_secret=client_secret, username=login,
			password=password, v=api_ver, scope=scope, device_id=device_id, code=code)
		r = requests.get(url, params=params, headers=headers)
	if r.status_code == 200 and 'access_token' in r.text:
		res = r.json()
		# Retrieve access_token and secret.
		access_token = res['access_token']
		secret = res['secret']
		return access_token, secret, device_id
	else:
		raise AuthenticationError(r.text)

def refresh_token(token, secret, device_id):
	method = "execute.getUserInfo"
	postdata = dict(v=api_ver, https=1, androidVersion=19, androidModel="Android SDK built for x86", info_fields="audio_ads,audio_background_limit,country,discover_design_version,discover_preload,discover_preload_not_seen,gif_autoplay,https_required,inline_comments,intro,lang,menu_intro,money_clubs_p2p,money_p2p,money_p2p_params,music_intro,audio_restrictions,profiler_settings,raise_to_record_enabled,stories,masks,subscriptions,support_url,video_autoplay,video_player,vklive_app,community_comments,webview_authorization,story_replies,animated_stickers,community_stories,live_section,playlists_download,calls,security_issue,eu_user,wallet,vkui_community_create,vkui_profile_edit,vkui_community_manage,vk_apps,stories_photo_duration,stories_reposts,live_streaming,live_masks,camera_pingpong,role,video_discover", device_id=device_id, lang="en", func_v=11, androidManufacturer="unknown", fields="photo_100,photo_50,exports,country,sex,status,bdate,first_name_gen,last_name_gen,verified,trending", access_token=token)
	perform_request(method, postdata, secret)
	method = "auth.refreshToken"
	postdata = dict(v=api_ver, https=1, timestamp=0, receipt2="", device_id=device_id, receipt="", lang="en", nonce="", access_token=token)
	return perform_request(method, postdata, secret)

def login(user, password):
	try:
		access_token, secret, device_id = get_non_refreshed(user, password)
		response = refresh_token(access_token, secret, device_id)
	except AuthenticationError:
		bad_password()
		raise AuthenticationError("")
	try:
		return response["response"]["token"], secret, device_id
	except KeyError:
		log.exception("An exception has occurred while attempting to authenticate. Printing response returned by vk...")
		log.exception(response)