#!/usr/bin/env python3
# This directly follows the OAuth login flow that is opaquely described
# https://github.com/openid/AppAuth-Android
# A really nice walk through of how it works is:
# https://auth0.com/docs/get-started/authentication-and-authorization-flow/call-your-api-using-the-authorization-code-flow-with-pkce
import requests
from urllib.parse import urlparse, parse_qs, urlencode
from lxml import html
import io
import re
import sys
import json
from time import time
from base64 import b64decode as base64_decode
from base64 import urlsafe_b64encode as base64url_encode
from Crypto.Random import get_random_bytes
from Crypto.Hash import SHA256
from zipfile import ZipFile

email = sys.argv[1]
password = sys.argv[2]

base_url = 'https://api.home-connect.com/security/oauth/'
asset_url = 'https://prod.reu.rest.homeconnectegw.com/'

# The app_id and scope are hardcoded in the application
app_id = '9B75AC9EC512F36C84256AC47D813E2C1DD0D6520DF774B020E1E6E2EB29B1F3'
scope = ["ReadAccount","Settings","IdentifyAppliance","Control","DeleteAppliance","WriteAppliance","ReadOrigApi","Monitor","WriteOrigApi","Images"]

def b64(b):
	return re.sub(r'=', '', base64url_encode(b).decode('UTF-8'))
def b64random(num):
	return b64(base64url_encode(get_random_bytes(num)))

verifier = b64(get_random_bytes(32))

login_query = {
	"response_type": "code",
	"prompt": "login",
	"code_challenge": b64(SHA256.new(verifier.encode('UTF-8')).digest()),
	"code_challenge_method": "S256",
	"client_id": app_id,
	"scope": ' '.join(scope),
	"nonce": b64random(16),
	"state": b64random(16),
	"redirect_uri": 'hcauth://auth/prod',
}

loginpage_url = base_url + 'authorize?' + urlencode(login_query)
auth_url = base_url + 'login'
token_url = base_url + 'token'

r = requests.get(loginpage_url)
if r.status_code != requests.codes.ok:
	print("error fetching login url!", file=sys.stderr)
	exit(1)
loginpage = r.text

#print('--------- got login page ----------')

#with open("login.html") as fd:
#	loginpage = fd.read()

tree = html.fromstring(loginpage)

# add in the email and password
auth_fields = {
	"email": email,
	"password": password,
	"code_challenge": login_query["code_challenge"],
	"code_challenge_method": login_query["code_challenge_method"],
	"redirect_uri": login_query["redirect_uri"],
}

for form in tree.forms:
	if form.attrib.get("id") != "login_form":
		continue
	for field in form.fields:
		if field not in auth_fields:
			auth_fields[field] = form.fields.get(field)

#print(auth_fields)

# try to submit the form and get the redirect URL with the token
r = requests.post(auth_url, data=auth_fields, allow_redirects=False)
if r.status_code != 302:
	print("Did not get a redirect; wrong username/password?", file=sys.stderr)
	exit(1)

# Yes!
location = r.headers["location"]
url = urlparse(location)
query = parse_qs(url.query)
#print("response:", location, query)
code = query.get("code")
if not code:
	print("Unable to find code in response?", location, file=sys.stderr)
	sys.exit(1)

#print('--------- got code page ----------')

token_fields = {
	"grant_type": "authorization_code",
	"client_id": app_id,
	"code_verifier": verifier,
	"code": code[0],
	"redirect_uri": login_query["redirect_uri"],
}

#print(token_fields)

r = requests.post(token_url, data=token_fields, allow_redirects=False)
if r.status_code != requests.codes.ok:
	print("Bad code?", file=sys.stderr)
	print(r.headers, r.text)
	exit(1)

#print('--------- got token page ----------')

# Yes!
#print(r.text)

token = json.loads(r.text)["access_token"]
headers = {
	"Authorization": "Bearer " + token,
}

# now we can fetch the rest of the account info
r = requests.get(asset_url + "account/details", headers=headers)
if r.status_code != requests.codes.ok:
	print("unable to fetch account details", file=sys.stderr)
	print(r.headers, r.text)
	exit(1)

#print(r.text)
account = json.loads(r.text)
configs = []

for app in account["data"]["homeAppliances"]:
	app_brand = app["brand"]
	app_type = app["type"]
	app_id = app["identifier"]

	config = {
		"name": app_type.lower(),
	}

	configs.append(config)

	if "tls" in app:
		# fancy machine with TLS support
		config["host"] =app_brand + "-" + app_type + "-" + app_id
		config["key"] = app["tls"]["key"]
	else:
		# less fancy machine with HTTP support
		config["host"] = app_id
		config["key"] = app["aes"]["key"]
		config["iv"] = app["aes"]["iv"]

	# Fetch the XML zip file for this device
	app_url = asset_url + "api/iddf/v1/iddf/" + app_id
	print("fetching", app_url)
	r = requests.get(app_url, headers=headers)
	if r.status_code != requests.codes.ok:
		print(app_id, ": unable to fetch machine description?")
		next

	# we now have a zip file with XML, let's unpack them
	z = ZipFile(io.BytesIO(r.content))
	print(z.infolist())


print(configs)