billing: Do subscription management in-house instead of with Stripe B…

…illing.

This is a major rewrite of the billing system. It moves subscription
information off of stripe Subscriptions and into a local CustomerPlan
table.

To keep this manageable, it leaves several things unimplemented
(downgrading, etc), and a variety of other TODOs in the code. There are also
some known regressions, e.g. error-handling on /upgrade is broken.

analytics/views.py

@@ -495,21 +495,12 @@ def realm_summary_table(realm_minutes: Dict[str, float]) -> str:
     # estimate annual subscription revenue
     total_amount = 0
     if settings.BILLING_ENABLED:
-        from corporate.lib.stripe import estimate_customer_arr
-        from corporate.models import Customer
-        stripe.api_key = get_secret('stripe_secret_key')
-        estimated_arr = {}
-        try:
-            for stripe_customer in stripe.Customer.list(limit=100):
-                # TODO: could do a select_related to get the realm.string_id, potentially
-                customer = Customer.objects.filter(stripe_customer_id=stripe_customer.id).first()
-                if customer is not None:
-                    estimated_arr[customer.realm.string_id] = estimate_customer_arr(stripe_customer)
-        except stripe.error.StripeError:
-            pass
+        from corporate.lib.stripe import estimate_annual_recurring_revenue_by_realm
+        estimated_arrs = estimate_annual_recurring_revenue_by_realm()
         for row in rows:
-            row['amount'] = estimated_arr.get(row['string_id'], None)
-        total_amount = sum(estimated_arr.values())
+            if row['string_id'] in estimated_arrs:
+                row['amount'] = estimated_arrs[row['string_id']]
+        total_amount += sum(estimated_arrs.values())
 
     # augment data with realm_minutes
     total_hours = 0.0

corporate/migrations/0003_customerplan.py

@@ -0,0 +1,35 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.11.16 on 2018-12-22 21:05
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('corporate', '0002_customer_default_discount'),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='CustomerPlan',
+            fields=[
+                ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('licenses', models.IntegerField()),
+                ('automanage_licenses', models.BooleanField(default=False)),
+                ('charge_automatically', models.BooleanField(default=False)),
+                ('price_per_license', models.IntegerField(null=True)),
+                ('fixed_price', models.IntegerField(null=True)),
+                ('discount', models.DecimalField(decimal_places=4, max_digits=6, null=True)),
+                ('billing_cycle_anchor', models.DateTimeField()),
+                ('billing_schedule', models.SmallIntegerField()),
+                ('billed_through', models.DateTimeField()),
+                ('next_billing_date', models.DateTimeField(db_index=True)),
+                ('tier', models.SmallIntegerField()),
+                ('status', models.SmallIntegerField(default=1)),
+                ('customer', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to='corporate.Customer')),
+            ],
+        ),
+    ]

corporate/models.py

@@ -9,17 +9,52 @@
 class Customer(models.Model):
     realm = models.OneToOneField(Realm, on_delete=models.CASCADE)  # type: Realm
     stripe_customer_id = models.CharField(max_length=255, unique=True)  # type: str
-    # Becomes True the first time a payment successfully goes through, and never
-    # goes back to being False
+    # Deprecated .. delete once everyone is migrated to new billing system
     has_billing_relationship = models.BooleanField(default=False)  # type: bool
     default_discount = models.DecimalField(decimal_places=4, max_digits=7, null=True)  # type: Optional[Decimal]
 
     def __str__(self) -> str:
         return "<Customer %s %s>" % (self.realm, self.stripe_customer_id)
 
-class CustomerPlan(object):
+class CustomerPlan(models.Model):
+    customer = models.ForeignKey(Customer, on_delete=models.CASCADE)  # type: Customer
+    licenses = models.IntegerField()  # type: int
+    automanage_licenses = models.BooleanField(default=False)  # type: bool
+    charge_automatically = models.BooleanField(default=False)  # type: bool
+
+    # Both of these are in cents. Exactly one of price_per_license or
+    # fixed_price should be set. fixed_price is only for manual deals, and
+    # can't be set via the self-serve billing system.
+    price_per_license = models.IntegerField(null=True)  # type: Optional[int]
+    fixed_price = models.IntegerField(null=True)  # type: Optional[int]
+
+    # A percentage, like 85
+    discount = models.DecimalField(decimal_places=4, max_digits=6, null=True)  # type: Optional[Decimal]
+
+    billing_cycle_anchor = models.DateTimeField()  # type: datetime.datetime
     ANNUAL = 1
     MONTHLY = 2
+    billing_schedule = models.SmallIntegerField()  # type: int
+
+    # This is like analytic's FillState, but for billing
+    billed_through = models.DateTimeField()  # type: datetime.datetime
+    next_billing_date = models.DateTimeField(db_index=True)  # type: datetime.datetime
+
+    STANDARD = 1
+    PLUS = 2  # not available through self-serve signup
+    ENTERPRISE = 10
+    tier = models.SmallIntegerField()  # type: int
+
+    ACTIVE = 1
+    ENDED = 2
+    NEVER_STARTED = 3
+    # You can only have 1 active subscription at a time
+    status = models.SmallIntegerField(default=ACTIVE)  # type: int
+
+    # TODO maybe override setattr to ensure billing_cycle_anchor, etc are immutable
+
+def get_active_plan(customer: Customer) -> Optional[CustomerPlan]:
+    return CustomerPlan.objects.filter(customer=customer, status=CustomerPlan.ACTIVE).first()
 
 # Everything below here is legacy
 

corporate/tests/stripe_fixtures/billing_page_permissions:Charge.create.1.json

@@ -0,0 +1,75 @@
+{
+  "amount": 64000,
+  "amount_refunded": 0,
+  "application": null,
+  "application_fee": null,
+  "balance_transaction": "txn_NORMALIZED00000000000001",
+  "captured": true,
+  "created": 1000000000,
+  "currency": "usd",
+  "customer": "cus_NORMALIZED0001",
+  "description": "Upgrade to Zulip Standard, $80.0 x 8",
+  "destination": null,
+  "dispute": null,
+  "failure_code": null,
+  "failure_message": null,
+  "fraud_details": {},
+  "id": "ch_NORMALIZED00000000000001",
+  "invoice": null,
+  "livemode": false,
+  "metadata": {},
+  "object": "charge",
+  "on_behalf_of": null,
+  "order": null,
+  "outcome": {
+    "network_status": "approved_by_network",
+    "reason": null,
+    "risk_level": "normal",
+    "risk_score": 00,
+    "seller_message": "Payment complete.",
+    "type": "authorized"
+  },
+  "paid": true,
+  "payment_intent": null,
+  "receipt_email": "[email protected]",
+  "receipt_number": null,
+  "refunded": false,
+  "refunds": {
+    "data": [],
+    "has_more": false,
+    "object": "list",
+    "total_count": 0,
+    "url": "/v1/charges/ch_NORMALIZED00000000000001/refunds"
+  },
+  "review": null,
+  "shipping": null,
+  "source": {
+    "address_city": "Pacific",
+    "address_country": "United States",
+    "address_line1": "Under the sea,",
+    "address_line1_check": "pass",
+    "address_line2": null,
+    "address_state": null,
+    "address_zip": "33333",
+    "address_zip_check": "pass",
+    "brand": "Visa",
+    "country": "US",
+    "customer": "cus_NORMALIZED0001",
+    "cvc_check": "pass",
+    "dynamic_last4": null,
+    "exp_month": 3,
+    "exp_year": 2033,
+    "fingerprint": "NORMALIZED000001",
+    "funding": "credit",
+    "id": "card_NORMALIZED00000000000001",
+    "last4": "4242",
+    "metadata": {},
+    "name": "Ada Starr",
+    "object": "card",
+    "tokenization_method": null
+  },
+  "source_transfer": null,
+  "statement_descriptor": "Zulip Standard",
+  "status": "succeeded",
+  "transfer_group": null
+}