import datetime
from base64 import urlsafe_b64encode
import json
from Crypto.Cipher import AES
from Crypto.Random import get_random_bytes
from Crypto.Hash import SHA256, HMAC
class ShopifyMultipass:
    def __init__(self, secret):
        pass

    def generateShopifyUrl(self, secret, customerDataHash, url):
        key = SHA256.new(secret.encode('utf-8')).digest()

        self.encryptionKey = key[0:16]
        self.signatureKey = key[16:32]

        currentDate = datetime.datetime.utcnow().isoformat()
        customerDataHash['created_at'] = currentDate
        plainText = json.dumps(customerDataHash)
        plainText2 = plainText + (AES.block_size - len(plainText) % AES.block_size) * chr(
            AES.block_size - len(plainText) % AES.block_size)
        iv = get_random_bytes(AES.block_size)
        cipher = AES.new(self.encryptionKey, AES.MODE_CBC, iv)
        cipherText = iv + cipher.encrypt(plainText2.encode('utf-8'))
        signedText = HMAC.new(self.signatureKey, secret.encode('utf-8'), SHA256).digest()
        token = urlsafe_b64encode(cipherText + signedText).decode('utf-8')
        return '{0}/account/login/multipass/{1}'.format(url, token)

from shopifymultipass import ShopifyMultipass
multipass = ShopifyMultipass()
customerData = {
        'email': 'amol@mydomain.com',
        'return_to': 'https://ourshop.myshopify.com/collections/all',
        'first_name': 'Amol',
        'last_name': 'Chakane' }

    url = multipass.generateShopifyUrl('Shopify_Multipass_Secret', customerData, 'http://ourshop.myshopify.com');