(core) link AppSumo activations with stripe, and support upgrades/downgrades

Summary:
This links AppSumo sign-ups with Stripe subscriptions
and our billing pages. Different AppSumo tiers are supported by
different coupons on the standard plan. Configuration of this
is in stripe, and then cached in the database.

The front end is tweaked just enough to make completing a sign-up
possible. It is not yet friendly.

Not covered includes:
 * Streamlining landing page.
 * Making billing pages git clearer summaries of AppSumo states.
 * Making flow through Cognito as graceful as possible - default
   probably doesn't meet AppSumo requirements.
 * Disabling site on cancellation/refund.
 * Downgrades when more seats in use than lower tier allows.

Test Plan: api-level tests added. No front-end tests yet.

Reviewers: dsagal

Reviewed By: dsagal

Differential Revision: https://phab.getgrist.com/D2878

app/client/models/BillingModel.ts

@@ -175,6 +175,19 @@ export class BillingModelImpl extends Disposable implements BillingModel {
           }
           // If there is an org update, re-initialize the org in the client.
           if (newSettings) { this._appModel.topAppModel.initialize(); }
+        } else if (task === 'signUpLite') {
+          // This is a sign up variant where payment info is handled externally.
+          // All that can change here is company name, and domain.
+          const org = this._appModel.currentOrg;
+          const name = formData.settings && formData.settings.name;
+          const domain = formData.settings && formData.settings.domain;
+          const newSettings = org && (name !== org.name || domain !== org.domain) && formData.settings;
+          // If the address or settings have a new value, run the update.
+          if (newSettings) {
+            await this._billingAPI.updateAddress(undefined, newSettings || undefined);
+          }
+          // If there is an org update, re-initialize the org in the client.
+          if (newSettings) { this._appModel.topAppModel.initialize(); }
         } else {
           throw new Error('BillingPage _submit error: no task in progress');
         }

app/client/ui/BillingPage.ts

@@ -25,7 +25,8 @@ const taskActions = {
   updatePlan:    'Update Plan',
   addCard:       'Add Payment Method',
   updateCard:    'Update Payment Method',
-  updateAddress: 'Update Address'
+  updateAddress: 'Update Address',
+  signUpLite:    'Complete Sign Up'
 };
 
 /**
@@ -310,10 +311,10 @@ export class BillingPage extends Disposable {
     // If there is an immediate charge required, require re-entering the card info.
     // Show all forms on sign up.
     this._form = new BillingForm(org, (...args) => this._model.isDomainAvailable(...args), {
-      payment: task !== 'updateAddress',
-      address: task === 'signUp' || task === 'updateAddress',
-      settings: task === 'signUp' || task === 'updateAddress',
-      domain: task === 'signUp'
+      payment: ['signUp', 'updatePlan', 'addCard', 'updateCard'].includes(task),
+      address: ['signUp', 'updateAddress'].includes(task),
+      settings: ['signUp', 'signUpLite', 'updateAddress'].includes(task),
+      domain: ['signUp', 'signUpLite'].includes(task)
     }, { address: currentAddress, settings: currentSettings, card: this._formData.card });
     return dom('div',
       dom.onDispose(() => {
@@ -447,6 +448,8 @@ export class BillingPage extends Disposable {
   }
 
   private _buildDomainSummary(domain: string|null) {
+    const task = this._model.currentTask.get();
+    if (task === 'signUpLite') { return null; }
     return css.summaryItem(
       css.summaryHeader(
         css.billingBoldText('Billing Info'),

app/common/BillingAPI.ts

@@ -10,7 +10,7 @@ export type BillingSubPage = typeof BillingSubPage.type;
 export const BillingPage = StringUnion(...BillingSubPage.values, 'billing');
 export type BillingPage = typeof BillingPage.type;
 
-export const BillingTask = StringUnion('signUp', 'updatePlan', 'addCard', 'updateCard', 'updateAddress');
+export const BillingTask = StringUnion('signUp', 'signUpLite', 'updatePlan', 'addCard', 'updateCard', 'updateAddress');
 export type BillingTask = typeof BillingTask.type;
 
 // Note that IBillingPlan includes selected fields from the Stripe plan object along with

app/gen-server/lib/HomeDBManager.ts

@@ -1673,7 +1673,8 @@ export class HomeDBManager extends EventEmitter {
       // Pick out properties that are allowed to be changed, to prevent accidental updating
       // of other information.
       const updated = pick(billingAccountCopy, 'inGoodStanding', 'status', 'stripeCustomerId',
-        'stripeSubscriptionId', 'stripePlanId', 'product');
+                           'stripeSubscriptionId', 'stripePlanId', 'product', 'externalId',
+                           'externalOptions');
       billingAccount.paid = undefined;  // workaround for a typeorm bug fixed upstream in
                                         // https://github.com/typeorm/typeorm/pull/4035
       await transaction.save(Object.assign(billingAccount, updated));