dynamicweb2/hosting/models.py

import unicodedata
import logging
import random
import os

from django.db import models
from django.contrib.auth.models import AbstractBaseUser, BaseUserManager, PermissionsMixin
from django.contrib.sites.models import Site
from django.core.exceptions import ValidationError
from django.utils.translation import gettext_lazy as _
from django.conf import settings
from django.contrib.auth.hashers import make_password
from django.urls import reverse
from django.db import IntegrityError, models
from guardian.shortcuts import assign_perm

from .fields import CountryField
from .mailer import BaseEmail
from dynamicweb2.ldap_manager import LdapManager
from dynamicweb2.stripe_utils import StripeUtils
from django.utils.crypto import get_random_string
from Crypto.PublicKey import RSA

from django.utils.functional import cached_property

# Create your models here.

logger = logging.getLogger(__name__)


def get_validation_slug():
    return make_password(None)


def validate_name(value):
    valid_chars = [char for char in value if (char.isalpha() or char == "-" or char == " ")]
    if len(valid_chars) < len(value):
        raise ValidationError(
            _('%(value)s is not a valid name. A valid name can only include letters, spaces or -'),
            params={'value': value},
        )


class MyUserManager(BaseUserManager):
    def create_user(self, email, name, password=None):
        """
        Creates and saves a User with the given email,name and password.
        """

        if not email:
            raise ValueError('Users must have an email address')

        user = self.model(
            email=self.normalize_email(email),
            name=name,
            validation_slug=make_password(None)
        )
        user.is_admin = False
        user.set_password(password)
        user.save(using=self._db)
        user.create_ldap_account(password)
        return user

    def create_superuser(self, email, name, password):
        """
        Creates and saves a superuser with the given email, name and password.
        """
        user = self.create_user(email,
                                password=password,
                                name=name,
                                )
        user.is_admin = True
        user.is_active = True
        user.is_superuser = True
        user.save(using=self._db)
        return user


class CustomUser(AbstractBaseUser, PermissionsMixin):
    VALIDATED_CHOICES = ((0, 'Not validated'), (1, 'Validated'))
    site = models.ForeignKey(Site, default=1, on_delete=models.CASCADE)
    name = models.CharField(max_length=50, validators=[validate_name])
    email = models.EmailField(unique=True)
    username = models.CharField(max_length=60, unique=True, null=True)
    validated = models.IntegerField(choices=VALIDATED_CHOICES, default=0)
    in_ldap = models.BooleanField(default=False)
    # By default, we initialize the validation_slug with appropriate value
    # This is required for User(page) admin
    validation_slug = models.CharField(
        db_index=True, unique=True, max_length=50,
        default=get_validation_slug
    )
    is_admin = models.BooleanField(
        _('staff status'),
        default=False,
        help_text=_(
            'Designates whether the user can log into this admin site.'),
    )
    import_stripe_bill_remark = models.TextField(
        default="",
        help_text="Indicates any issues while importing stripe bills"
    )

    objects = MyUserManager()

    USERNAME_FIELD = "email"
    REQUIRED_FIELDS = ['name', 'password']

    # Define the groups field with a related_name to avoid clash
    groups = models.ManyToManyField(
        'auth.Group',
        related_name='custom_user_set',  # Define a unique related_name
        blank=True,
        verbose_name='groups',
        help_text='The groups this user belongs to.',
    )

    # Define the user_permissions field with a related_name to avoid clash
    user_permissions = models.ManyToManyField(
        'auth.Permission',
        related_name='custom_user_permission_set',  # Define a unique related_name
        blank=True,
        verbose_name='user permissions',
        help_text='Specific permissions for this user.',
    )

    @classmethod
    def register(cls, name, password, email, app='digital_glarus',
                 base_url=None, send_email=True, account_details=None):
        user = cls.objects.filter(email=email).first()
        if not user:
            user = cls.objects.create_user(name=name, email=email,
                                           password=password)
            if user:
                if app == 'dcl':
                    dcl_text = settings.DCL_TEXT
                    user.is_active = False
                    if send_email is True:
                        email_data = {
                            'subject': '{dcl_text} {account_activation}'.format(
                                dcl_text=dcl_text,
                                account_activation=_('Account Activation')
                            ),
                            'from_address': settings.DCL_SUPPORT_FROM_ADDRESS,
                            'to': user.email,
                            'context': {'base_url': base_url,
                                        'activation_link': reverse(
                                            'hosting:validate',
                                            kwargs={
                                                'validate_slug': user.validation_slug}),
                                        'dcl_text': dcl_text
                                        },
                            'template_name': 'user_activation',
                            'template_path': 'hosting/emails/'
                        }
                        if account_details:
                            email_data['context'][
                                'account_details'] = account_details
                        email = BaseEmail(**email_data)
                        email.send()
                return user
            else:
                return None
        else:
            return None

    @classmethod
    def get_all_members(cls):
        return cls.objects.filter(
            stripecustomer__membershiporder__isnull=False)

    @classmethod
    def validate_url(cls, validation_slug):
        user = cls.objects.filter(validation_slug=validation_slug).first()
        if user:
            user.validated = 1
            user.save()
            return True
        return False

    @classmethod
    def get_random_password(cls):
        return get_random_string(24)

    def is_superuser(self):
        return False

    def get_full_name(self):
        # The user is identified by their email address
        return self.email

    def get_short_name(self):
        # The user is identified by their email address
        return self.email

    def get_first_and_last_name(self, full_name):
        first_name, *last_name = full_name.split(" ")
        last_name = " ".join(last_name)
        return first_name, last_name

    def assign_username(self, user):
        if not user.username:
            ldap_manager = LdapManager()

            # Try to come up with a username
            first_name, last_name = self.get_first_and_last_name(user.name)
            user.username = unicodedata.normalize('NFKD', first_name + last_name)
            user.username = "".join([char for char in user.username if char.isalnum()]).lower()
            exist = True
            while exist:
                # Check if it exists
                exist, entries = ldap_manager.check_user_exists(user.username)
                if exist:
                    # If username exists in ldap, come up with a new user name and check it again
                    user.username = user.username + str(random.randint(0, 2 ** 10))
                else:
                    # If username does not exists in ldap, try to save it in database
                    try:
                        user.save()
                    except IntegrityError:
                        # If username exists in database then come up with a new username
                        user.username = user.username + str(random.randint(0, 2 ** 10))
                        exist = True

    def create_ldap_account(self, password):
        # create ldap account for user if it does not exists already.
        if self.in_ldap:
            return
        self.assign_username(self)
        ldap_manager = LdapManager()
        try:
            user_exists_in_ldap, entries = ldap_manager.check_user_exists(self.username)
        except Exception:
            logger.exception("Exception occur while searching for user in LDAP")
        else:
            if not user_exists_in_ldap:
                # IF no ldap account
                first_name, last_name = self.get_first_and_last_name(self.name)
                if not last_name:
                    last_name = first_name
                ldap_manager.create_user(self.username, password=password,
                                         firstname=first_name, lastname=last_name,
                                         email=self.email)
            else:
                # User exists already in LDAP, but with a dummy credential
                # We are here implies that the user has successfully
                # authenticated against Django db, and a corresponding user
                # exists in LDAP.
                # We just update the LDAP credentials once again, assuming it
                # was set to a dummy value while migrating users from Django to
                # LDAP
                ldap_manager.change_password(self.username, password)
            self.in_ldap = True
            self.save()

    def __str__(self):  # __unicode__ on Python 2
        return self.email

    # def has_perm(self, perm, obj=None):
    #     "Does the user have a specific permission?"
    #     # Simplest possible answer: Yes, always
    #     return self.is_admin

    def has_module_perms(self, app_label):
        "Does the user have permissions to view the app `app_label`?"
        # Simplest possible answer: Yes, always
        return self.is_admin

    @property
    def is_staff(self):
        "Is the user a member of staff?"
        # Simplest possible answer: All admins are staff
        return self.is_admin

    @is_staff.setter
    def is_staff(self, value):
        self._is_staff = value


class StripeCustomer(models.Model):
    user = models.OneToOneField(CustomUser, on_delete=models.CASCADE)
    stripe_id = models.CharField(unique=True, max_length=100)

    def __str__(self):
        return "%s - %s" % (self.stripe_id, self.user.email)

    @classmethod
    def create_stripe_api_customer(cls, email=None, id_payment_method=None,
                                   customer_name=None):
        """
            This method creates a Stripe API customer with the given
            email, token and customer_name. This is different from
            get_or_create method below in that it does not create a
            CustomUser and associate the customer created in stripe
            with it, while get_or_create does that before creating the
            stripe user.
        """
        stripe_utils = StripeUtils()
        stripe_data = stripe_utils.create_customer(
            id_payment_method, email, customer_name)
        if stripe_data.get('response_object'):
            stripe_cus_id = stripe_data.get('response_object').get('id')
            return stripe_cus_id
        else:
            return None

    @classmethod
    def get_or_create(cls, email=None, token=None, id_payment_method=None):
        """
            Check if there is a registered stripe customer with that email
            or create a new one
        """
        try:
            stripe_utils = StripeUtils()
            stripe_customer = cls.objects.get(user__email=email)
            # check if user is not in stripe but in database
            customer = stripe_utils.check_customer(stripe_customer.stripe_id,
                                                   stripe_customer.user, token)
            if "deleted" in customer and customer["deleted"]:
                raise StripeCustomer.DoesNotExist()
            return stripe_customer
        except StripeCustomer.DoesNotExist:
            user = CustomUser.objects.get(email=email)
            stripe_utils = StripeUtils()
            stripe_data = stripe_utils.create_customer(token, email, user.name)
            if stripe_data.get('response_object'):
                stripe_cus_id = stripe_data.get('response_object').get('id')
                if hasattr(user, 'stripecustomer'):
                    # User already had a Stripe account and we are here
                    # because the account was deleted in dashboard
                    # So, we simply update the stripe_id
                    user.stripecustomer.stripe_id = stripe_cus_id
                    user.stripecustomer.save()
                    stripe_customer = user.stripecustomer
                else:
                    # The user never had an associated Stripe account
                    # So, create one
                    stripe_customer = StripeCustomer.objects.create(
                        user=user, stripe_id=stripe_cus_id
                    )
                return stripe_customer
            else:
                return None


class BaseBillingAddress(models.Model):
    cardholder_name = models.CharField(max_length=100, default="")
    street_address = models.CharField(max_length=100)
    city = models.CharField(max_length=50)
    postal_code = models.CharField(max_length=50)
    country = CountryField()
    vat_number = models.CharField(max_length=100, default="", blank=True)
    stripe_tax_id = models.CharField(max_length=100, default="", blank=True)
    vat_number_validated_on = models.DateTimeField(blank=True, null=True)
    vat_validation_status = models.CharField(max_length=25, default="",
                                             blank=True)

    class Meta:
        abstract = True


class BillingAddress(BaseBillingAddress):
    def __str__(self):
        if self.vat_number:
            return "%s, %s, %s, %s, %s, %s %s %s %s" % (
                self.cardholder_name, self.street_address, self.city,
                self.postal_code, self.country, self.vat_number,
                self.stripe_tax_id, self.vat_number_validated_on,
                self.vat_validation_status
            )
        else:
            return "%s, %s, %s, %s, %s" % (
                self.cardholder_name, self.street_address, self.city,
                self.postal_code, self.country
            )


class UserBillingAddress(BaseBillingAddress):
    user = models.ForeignKey(CustomUser, related_name='billing_addresses', on_delete=models.CASCADE)
    current = models.BooleanField(default=True)

    def __str__(self):
        if self.vat_number:
            return "%s, %s, %s, %s, %s, %s %s %s %s" % (
                self.cardholder_name, self.street_address, self.city,
                self.postal_code, self.country, self.vat_number,
                self.stripe_tax_id, self.vat_number_validated_on,
                self.vat_validation_status
            )
        else:
            return "%s, %s, %s, %s, %s" % (
                self.cardholder_name, self.street_address, self.city,
                self.postal_code, self.country
            )

    def to_dict(self):
        return {
            'Cardholder Name': self.cardholder_name,
            'Street Address': self.street_address,
            'City': self.city,
            'Postal Code': self.postal_code,
            'Country': self.country,
            'VAT Number': self.vat_number
        }


class AssignPermissionsMixin(object):
    permissions = tuple()
    user = None
    obj = None
    kwargs = dict()

    def assign_permissions(self, user):
        for permission in self.permissions:
            assign_perm(permission, user, self)


class OrderDetail(AssignPermissionsMixin, models.Model):
    # vm_template = models.ForeignKey(
    #     VMTemplate, blank=True, null=True, default=None,
    #     on_delete=models.SET_NULL
    # )
    cores = models.IntegerField(default=0)
    memory = models.IntegerField(default=0)
    hdd_size = models.IntegerField(default=0)
    ssd_size = models.IntegerField(default=0)

    def __str__(self):
        return "Not available" if self.vm_template is None else (
                "%s - %s, %s cores, %s GB RAM, %s GB SSD" % (
            self.vm_template.name, self.vm_template.vm_type, self.cores,
            self.memory, self.ssd_size
        )
        )


class GenericProduct(AssignPermissionsMixin, models.Model):
    permissions = ('view_genericproduct',)
    product_name = models.CharField(max_length=128, default="")
    product_slug = models.SlugField(
        unique=True,
        help_text=(
            'An mandatory unique slug for the product'
        )
    )
    product_description = models.CharField(max_length=500, default="")
    created_at = models.DateTimeField(auto_now_add=True)
    product_price = models.DecimalField(max_digits=6, decimal_places=2)
    product_vat = models.DecimalField(max_digits=6, decimal_places=4, default=0)
    product_is_subscription = models.BooleanField(default=True)
    product_subscription_interval = models.CharField(
        max_length=10, default="month",
        help_text="Choose between `year` and `month`")
    exclude_vat_calculations = models.BooleanField(
        default=False,
        help_text="When checked VAT calculations are excluded for this product"
    )

    def __str__(self):
        return self.product_name

    def get_actual_price(self, vat_rate=None):
        if self.exclude_vat_calculations:
            return round(float(self.product_price), 2)
        else:
            VAT = vat_rate if vat_rate is not None else self.product_vat
            return round(
                float(self.product_price) + float(self.product_price) * float(VAT), 2
            )


class HostingOrder(AssignPermissionsMixin, models.Model):
    ORDER_APPROVED_STATUS = 'Approved'
    ORDER_DECLINED_STATUS = 'Declined'

    vm_id = models.IntegerField(default=0)
    customer = models.ForeignKey(StripeCustomer, on_delete=models.CASCADE)
    billing_address = models.ForeignKey(BillingAddress, on_delete=models.CASCADE)
    created_at = models.DateTimeField(auto_now_add=True)
    approved = models.BooleanField(default=False)
    last4 = models.CharField(max_length=4)
    cc_brand = models.CharField(max_length=128)
    stripe_charge_id = models.CharField(max_length=100, null=True)
    price = models.FloatField()
    subscription_id = models.CharField(max_length=100, null=True)
    # vm_pricing = models.ForeignKey(VMPricing)
    order_detail = models.ForeignKey(
        OrderDetail, null=True, blank=True, default=None,
        on_delete=models.SET_NULL
    )
    generic_product = models.ForeignKey(
        GenericProduct, null=True, blank=True, default=None,
        on_delete=models.SET_NULL
    )
    generic_payment_description = models.CharField(
        max_length=500, null=True
    )
    permissions = ('u_view_hostingorder',)

    class Meta:
        permissions = (
            ('u_view_hostingorder', 'View Hosting Order'),
        )

    def __str__(self):
        hosting_order_str = ("Order Nr: #{} - VM_ID: {} - {} - {} - "
                             "Specs: {} - Price: {}").format(
            self.id, self.vm_id, self.customer.user.email, self.created_at,
            self.order_detail, self.price
        )
        if self.generic_product_id is not None:
            hosting_order_str += " - Generic Payment"
            if self.stripe_charge_id is not None:
                hosting_order_str += " - One time charge"
            else:
                hosting_order_str += " - Recurring"
        return hosting_order_str

    @cached_property
    def status(self):
        return self.ORDER_APPROVED_STATUS if self.approved else self.ORDER_DECLINED_STATUS

    @classmethod
    def create(cls, price=None, vm_id=0, customer=None,
               billing_address=None, vm_pricing=None):
        instance = cls.objects.create(
            price=price,
            vm_id=vm_id,
            customer=customer,
            billing_address=billing_address,
            vm_pricing=vm_pricing
        )
        instance.assign_permissions(customer.user)
        return instance

    def set_approved(self):
        self.approved = True
        self.save()

    def set_stripe_charge(self, stripe_charge):
        self.stripe_charge_id = stripe_charge.id
        if stripe_charge.source is None:
            self.last4 = stripe_charge.payment_method_details.card.last4
            self.cc_brand = stripe_charge.payment_method_details.card.brand
        else:
            self.last4 = stripe_charge.source.last4
            self.cc_brand = stripe_charge.source.brand
        self.save()

    def set_subscription_id(self, subscription_id, cc_details):
        """
        When creating a Stripe subscription, we have subscription id.
        We store this in the subscription_id field.
        This method sets the subscription id
        and the last4 and credit card brands used for this order.

        :param subscription_id: Stripe's subscription id
        :param cc_details: A dict containing card details
        {last4, brand}
        :return:
        """
        self.subscription_id = subscription_id
        self.last4 = cc_details.get('last4')
        self.cc_brand = cc_details.get('brand')
        self.save()

    def get_cc_data(self):
        return {
            'last4': self.last4,
            'cc_brand': self.cc_brand,
        } if self.last4 and self.cc_brand else None


class UserHostingKey(models.Model):
    user = models.ForeignKey(CustomUser, blank=True, null=True, on_delete=models.CASCADE)
    public_key = models.TextField()
    private_key = models.FileField(upload_to='private_keys', blank=True)
    created_at = models.DateTimeField(auto_now_add=True)
    name = models.CharField(max_length=100)

    @staticmethod
    def generate_RSA(bits=2048):
        '''
        Generate an RSA keypair with an exponent of 65537 in PEM format
        param: bits The key length in bits
        Return private key and public key
        '''
        new_key = RSA.generate(2048, os.urandom)
        public_key = new_key.publickey().exportKey("OpenSSH")
        private_key = new_key.exportKey("PEM")
        return private_key, public_key

    @classmethod
    def generate_keys(cls):
        private_key, public_key = cls.generate_RSA()
        # self.public_key = public_key
        # self.save(update_fields=['public_key'])
        return private_key, public_key

    def delete(self, *args, **kwargs):
        if bool(self.private_key) and os.path.isfile(self.private_key.path):
            logger.debug("Removing private key {}".format(self.private_key.path))
            os.remove(self.private_key.path)
        else:
            logger.debug("No private_key to remove")

        super(UserHostingKey, self).delete(*args, **kwargs)


def get_anonymous_user_instance(CustomUser):
    return CustomUser(email='anonymous@ungleich.ch')


class VATRates(AssignPermissionsMixin, models.Model):
    start_date = models.DateField(blank=True, null=True)
    stop_date = models.DateField(blank=True, null=True)
    territory_codes = models.TextField(blank=True, default='')
    currency_code = models.CharField(max_length=10)
    rate = models.FloatField()
    rate_type = models.TextField(blank=True, default='')
    description = models.TextField(blank=True, default='')


class StripeTaxRate(AssignPermissionsMixin, models.Model):
    tax_rate_id = models.CharField(max_length=100, unique=True)
    jurisdiction = models.CharField(max_length=10)
    inclusive = models.BooleanField(default=False)
    display_name = models.CharField(max_length=100)
    percentage = models.FloatField(default=0)
    description = models.CharField(max_length=100)


class IncompletePaymentIntents(AssignPermissionsMixin, models.Model):
    completed_at = models.DateTimeField(null=True)
    created_at = models.DateTimeField(auto_now_add=True)
    payment_intent_id = models.CharField(max_length=100)
    request = models.TextField()
    stripe_api_cus_id = models.CharField(max_length=30)
    card_details_response = models.TextField()
    stripe_subscription_id = models.CharField(max_length=100, null=True)
    stripe_charge_id = models.CharField(max_length=100, null=True)
    gp_details = models.TextField()
    billing_address_data = models.TextField()


class IncompleteSubscriptions(AssignPermissionsMixin, models.Model):
    created_at = models.DateTimeField(auto_now_add=True)
    completed_at = models.DateTimeField(null=True)
    subscription_id = models.CharField(max_length=100)
    subscription_status = models.CharField(max_length=30)
    name = models.CharField(max_length=50)
    email = models.EmailField()
    request = models.TextField()
    stripe_api_cus_id = models.CharField(max_length=30)
    card_details_response = models.TextField()
    stripe_subscription_obj = models.TextField()
    stripe_onetime_charge = models.TextField()
    gp_details = models.TextField()
    specs = models.TextField()
    vm_template_id = models.PositiveIntegerField(default=0)
    template = models.TextField()
    billing_address_data = models.TextField()


class UserCardDetail(AssignPermissionsMixin, models.Model):
    permissions = ('view_usercarddetail',)
    stripe_customer = models.ForeignKey(StripeCustomer)
    last4 = models.CharField(max_length=4)
    brand = models.CharField(max_length=128)
    card_id = models.CharField(max_length=100, blank=True, default='')
    fingerprint = models.CharField(max_length=100)
    exp_month = models.IntegerField(null=False)
    exp_year = models.IntegerField(null=False)
    preferred = models.BooleanField(default=False)

    class Meta:
        permissions = (
            ('view_usercarddetail', 'View User Card'),
        )

    @classmethod
    def create(cls, stripe_customer=None, last4=None, brand=None,
               fingerprint=None, exp_month=None, exp_year=None, card_id=None,
               preferred=False):
        instance = cls.objects.create(
            stripe_customer=stripe_customer, last4=last4, brand=brand,
            fingerprint=fingerprint, exp_month=exp_month, exp_year=exp_year,
            card_id=card_id, preferred=preferred
        )
        instance.assign_permissions(stripe_customer.user)
        return instance

    @classmethod
    def get_all_cards_list(cls, stripe_customer):
        """
        Get all the cards of the given customer as a list

        :param stripe_customer: The StripeCustomer object
        :return: A list of all cards; an empty list if the customer object is
                 None
        """
        cards_list = []
        if stripe_customer is None:
            return cards_list
        user_card_details = UserCardDetail.objects.filter(
            stripe_customer_id=stripe_customer.id
        ).order_by('-preferred', 'id')
        for card in user_card_details:
            cards_list.append({
                'last4': card.last4, 'brand': card.brand, 'id': card.id,
                'exp_year': card.exp_year,
                'exp_month': '{:02d}'.format(card.exp_month),
                'preferred': card.preferred
            })
        return cards_list

    @classmethod
    def get_or_create_user_card_detail(cls, stripe_customer, card_details):
        """
        A method that checks if a UserCardDetail object exists already
        based upon the given card_details and creates it for the given
        customer if it does not exist. It returns the UserCardDetail object
        matching the given card_details if it exists.

        :param stripe_customer: The given StripeCustomer object to whom the
                card object should belong to
        :param card_details: A dictionary identifying a given card
        :return: UserCardDetail object
        """
        try:
            if ('fingerprint' in card_details and 'exp_month' in card_details
                    and 'exp_year' in card_details):
                card_detail = UserCardDetail.objects.get(
                    stripe_customer=stripe_customer,
                    fingerprint=card_details['fingerprint'],
                    exp_month=card_details['exp_month'],
                    exp_year=card_details['exp_year']
                )
            else:
                raise UserCardDetail.DoesNotExist()
        except UserCardDetail.DoesNotExist:
            preferred = False
            if 'preferred' in card_details:
                preferred = card_details['preferred']
            card_detail = UserCardDetail.create(
                stripe_customer=stripe_customer,
                last4=card_details['last4'],
                brand=card_details['brand'],
                fingerprint=card_details['fingerprint'],
                exp_month=card_details['exp_month'],
                exp_year=card_details['exp_year'],
                card_id=card_details['card_id'],
                preferred=preferred
            )
        return card_detail

    @staticmethod
    def set_default_card(stripe_api_cus_id, stripe_source_id):
        """
        Sets the given stripe source as the default source for the given
        Stripe customer
        :param stripe_api_cus_id: Stripe customer id
        :param stripe_source_id: The Stripe source id
        :return:
        """
        stripe_utils = StripeUtils()
        cus_response = stripe_utils.get_customer(stripe_api_cus_id)
        cu = cus_response['response_object']
        if stripe_source_id.startswith("pm"):
            # card is a payment method
            cu.invoice_settings.default_payment_method = stripe_source_id
        else:
            cu.default_source = stripe_source_id
        cu.save()
        UserCardDetail.save_default_card_local(
            stripe_api_cus_id, stripe_source_id
        )

    @staticmethod
    def set_default_card_from_stripe(stripe_api_cus_id):
        stripe_utils = StripeUtils()
        cus_response = stripe_utils.get_customer(stripe_api_cus_id)
        cu = cus_response['response_object']
        default_source = cu.default_source
        if default_source is not None:
            UserCardDetail.save_default_card_local(
                stripe_api_cus_id, default_source
            )

    @staticmethod
    def save_default_card_local(stripe_api_cus_id, card_id):
        stripe_cust = StripeCustomer.objects.get(stripe_id=stripe_api_cus_id)
        user_card_detail = UserCardDetail.objects.get(
            stripe_customer=stripe_cust, card_id=card_id
        )
        for card in stripe_cust.usercarddetail_set.all():
            card.preferred = False
            card.save()
        user_card_detail.preferred = True
        user_card_detail.save()

    @staticmethod
    def get_user_card_details(stripe_customer, card_details):
        """
        A utility function to check whether a StripeCustomer is already
        associated with the card having given details

        :param stripe_customer:
        :param card_details:
        :return: The UserCardDetails object if it exists, None otherwise
        """
        try:
            ucd = UserCardDetail.objects.get(
                stripe_customer=stripe_customer,
                fingerprint=card_details['fingerprint'],
                exp_month=card_details['exp_month'],
                exp_year=card_details['exp_year']
            )
            return ucd
        except UserCardDetail.DoesNotExist:
            return None


class VMPricing(models.Model):
    name = models.CharField(max_length=255, unique=True)
    vat_inclusive = models.BooleanField(default=True)
    vat_percentage = models.DecimalField(
        max_digits=7, decimal_places=5, blank=True, default=0
    )
    cores_unit_price = models.DecimalField(
        max_digits=7, decimal_places=5, default=0
    )
    ram_unit_price = models.DecimalField(
        max_digits=7, decimal_places=5, default=0
    )
    ssd_unit_price = models.DecimalField(
        max_digits=7, decimal_places=5, default=0
    )
    hdd_unit_price = models.DecimalField(
        max_digits=7, decimal_places=6, default=0
    )
    discount_name = models.CharField(max_length=255, null=True, blank=True)
    discount_amount = models.DecimalField(
        max_digits=6, decimal_places=2, default=0
    )
    stripe_coupon_id = models.CharField(max_length=255, null=True, blank=True)

    def __str__(self):
        display_str = self.name + ' => ' + ' - '.join([
            '{}/Core'.format(self.cores_unit_price.normalize()),
            '{}/GB RAM'.format(self.ram_unit_price.normalize()),
            '{}/GB SSD'.format(self.ssd_unit_price.normalize()),
            '{}/GB HDD'.format(self.hdd_unit_price.normalize()),
            '{}% VAT'.format(self.vat_percentage.normalize())
            if not self.vat_inclusive else 'VAT-Incl',
        ])
        if self.discount_amount:
            display_str = ' - '.join([
                display_str,
                '{} {}'.format(
                    self.discount_amount,
                    self.discount_name if self.discount_name else 'Discount'
                )
            ])
        return display_str

    @classmethod
    def get_vm_pricing_by_name(cls, name):
        try:
            pricing = VMPricing.objects.get(name=name)
        except Exception as e:
            logger.error(
                "Error getting VMPricing with name {name}. "
                "Details: {details}. Attempting to return default"
                "pricing.".format(name=name, details=str(e))
            )
            pricing = VMPricing.get_default_pricing()
        return pricing

    @classmethod
    def get_default_pricing(cls):
        """ Returns the default pricing or None """
        try:
            default_pricing = VMPricing.objects.get(name='default')
        except Exception as e:
            logger.error(str(e))
            default_pricing = None
        return default_pricing