(core) Migrate to Stripe v8 + implement discount codes

Summary:
New plan signups now include a discount code field in
the signup form. If a valid discount code is entered, a
discount will be applied on the confirmation page.

Test Plan: Browser and server tests.

Reviewers: dsagal

Reviewed By: dsagal

Subscribers: jarek

Differential Revision: https://phab.getgrist.com/D3076

app/client/models/BillingModel.ts

@@ -1,7 +1,7 @@
 import {AppModel, getHomeUrl, reportError} from 'app/client/models/AppModel';
 import {urlState} from 'app/client/models/gristUrlState';
 import {IFormData} from 'app/client/ui/BillingForm';
-import {BillingAPI, BillingAPIImpl, BillingSubPage, BillingTask} from 'app/common/BillingAPI';
+import {BillingAPI, BillingAPIImpl, BillingSubPage, BillingTask, IBillingCoupon} from 'app/common/BillingAPI';
 import {IBillingCard, IBillingPlan, IBillingSubscription} from 'app/common/BillingAPI';
 import {FullUser} from 'app/common/LoginSessionAPI';
 import {bundleChanges, Computed, Disposable, Observable} from 'grainjs';
@@ -47,6 +47,8 @@ export interface BillingModel {
   // Triggered when submit is clicked on the payment page. Performs the API billing account
   // management call based on currentTask, signupPlan and whether an address/tokenId was submitted.
   submitPaymentPage(formData?: IFormData): Promise<void>;
+  // Fetches coupon information for a valid `discountCode`.
+  fetchSignupCoupon(discountCode: string): Promise<IBillingCoupon>;
   // Fetches the effective tax rate for the address in the given form.
   fetchSignupTaxRate(formData: IFormData): Promise<void>;
   // Fetches subscription data associated with the given org, if the pages are associated with an
@@ -133,6 +135,10 @@ export class BillingModelImpl extends Disposable implements BillingModel {
     return this._billingAPI.isDomainAvailable(domain);
   }
 
+  public async fetchSignupCoupon(discountCode: string): Promise<IBillingCoupon> {
+    return await this._billingAPI.getCoupon(discountCode);
+  }
+
   public async submitPaymentPage(formData: IFormData = {}): Promise<void> {
     const task = this.currentTask.get();
     const planId = this.signupPlanId.get();
@@ -145,7 +151,8 @@ export class BillingModelImpl extends Disposable implements BillingModel {
         if (!formData.token) { throw new Error('BillingPage _submit error: no card submitted'); }
         if (!formData.address) { throw new Error('BillingPage _submit error: no address submitted'); }
         if (!formData.settings) { throw new Error('BillingPage _submit error: no settings submitted'); }
-        const o = await this._billingAPI.signUp(planId, formData.token, formData.address, formData.settings);
+        const {token, address, settings, coupon} = formData;
+        const o = await this._billingAPI.signUp(planId, token, address, settings, coupon?.promotion_code);
         if (o && o.domain) {
           await urlState().pushUrl({ org: o.domain, billing: 'billing', params: undefined });
         } else {

app/client/ui/BillingForm.ts

@@ -1,9 +1,11 @@
 import {get as getBrowserGlobals} from 'app/client/lib/browserGlobals';
 import {reportError} from 'app/client/models/AppModel';
+import {BillingModel} from 'app/client/models/BillingModel';
 import * as css from 'app/client/ui/BillingPageCss';
 import {colors, vars} from 'app/client/ui2018/cssVars';
 import {IOption, select} from 'app/client/ui2018/menus';
-import {IBillingAddress, IBillingCard, IBillingOrgSettings} from 'app/common/BillingAPI';
+import {IBillingAddress, IBillingCard, IBillingCoupon, IBillingOrgSettings,
+        IFilledBillingAddress} from 'app/common/BillingAPI';
 import {checkSubdomainValidity} from 'app/common/orgNameUtils';
 import * as roles from 'app/common/roles';
 import {Organization} from 'app/common/UserAPI';
@@ -20,10 +22,11 @@ const states = [
 ];
 
 export interface IFormData {
-  address?: IBillingAddress;
+  address?: IFilledBillingAddress;
   card?: IBillingCard;
   token?: string;
   settings?: IBillingOrgSettings;
+  coupon?: IBillingCoupon;
 }
 
 
@@ -34,6 +37,7 @@ interface IAutofill {
   // Note that the card name is the only value that may be initialized, since the other card
   // information is sensitive.
   card?: Partial<IBillingCard>;
+  coupon?: Partial<IBillingCoupon>;
 }
 
 // An object containing a function to check the validity of its observable value.
@@ -47,13 +51,14 @@ interface IValidated<T> {
 
 export class BillingForm extends Disposable {
   private readonly _address: BillingAddressForm|null;
+  private readonly _discount: BillingDiscountForm|null;
   private readonly _payment: BillingPaymentForm|null;
   private readonly _settings: BillingSettingsForm|null;
 
   constructor(
     org: Organization|null,
-    isDomainAvailable: (domain: string) => Promise<boolean>,
+    billingModel: BillingModel,
-    options: {payment: boolean, address: boolean, settings: boolean, domain: boolean},
+    options: {payment: boolean, address: boolean, settings: boolean, domain: boolean, discount: boolean},
     autofill: IAutofill = {}
   ) {
     super();
@@ -63,12 +68,17 @@ export class BillingForm extends Disposable {
       .reduce((acc, x) => acc + (x ? 1 : 0), 0);
 
     // Org settings form.
-    this._settings = options.settings ? new BillingSettingsForm(org, isDomainAvailable, {
+    this._settings = options.settings ? new BillingSettingsForm(billingModel, org, {
       showHeader: count > 1,
       showDomain: options.domain,
       autofill: autofill.settings
     }) : null;
 
+    // Discount form.
+    this._discount = options.discount ? new BillingDiscountForm(billingModel, {
+      autofill: autofill.coupon
+    }) : null;
+
     // Address form.
     this._address = options.address ? new BillingAddressForm({
       showHeader: count > 1,
@@ -85,6 +95,7 @@ export class BillingForm extends Disposable {
   public buildDom() {
     return [
       this._settings ? this._settings.buildDom() : null,
+      this._discount ? this._discount.buildDom() : null,
       this._address ? this._address.buildDom() : null,
       this._payment ? this._payment.buildDom() : null
     ];
@@ -95,9 +106,11 @@ export class BillingForm extends Disposable {
     const settings = this._settings ? await this._settings.getSettings() : undefined;
     const address = this._address ? await this._address.getAddress() : undefined;
     const cardInfo = this._payment ? await this._payment.getCardAndToken() : undefined;
+    const coupon = this._discount ? await this._discount.getCoupon() : undefined;
     return {
       settings,
       address,
+      coupon,
       token: cardInfo ? cardInfo.token : undefined,
       card: cardInfo ? cardInfo.card : undefined
     };
@@ -344,7 +357,7 @@ class BillingAddressForm extends BillingSubForm {
   // Throws if any value is invalid. Returns a customer address as accepted by the customer
   // object in stripe.
   // For reference: https://stripe.com/docs/api/customers/object#customer_object-address
-  public async getAddress(): Promise<IBillingAddress|undefined> {
+  public async getAddress(): Promise<IFilledBillingAddress|undefined> {
     try {
       return {
         line1: await this._address1.get(),
@@ -371,8 +384,8 @@ class BillingSettingsForm extends BillingSubForm {
     this._options.showDomain ? d => this._verifyDomain(d) : () => undefined);
 
   constructor(
+    private readonly _billingModel: BillingModel,
     private readonly _org: Organization|null,
-    private readonly _isDomainAvailable: (domain: string) => Promise<boolean>,
     private readonly _options: {
       showHeader: boolean;
       showDomain: boolean;
@@ -444,11 +457,72 @@ class BillingSettingsForm extends BillingSubForm {
     // OK to retain current domain.
     if (domain === this._options.autofill?.domain) { return; }
     checkSubdomainValidity(domain);
-    const isAvailable = await this._isDomainAvailable(domain);
+    const isAvailable = await this._billingModel.isDomainAvailable(domain);
     if (!isAvailable) { throw new Error('Domain is already taken.'); }
   }
 }
 
+/**
+ * Creates the billing discount form.
+ */
+class BillingDiscountForm extends BillingSubForm {
+  private _isExpanded = Observable.create(this, false);
+  private readonly _discountCode: IValidated<string> = createValidated(this, () => undefined);
+
+  constructor(
+    private readonly _billingModel: BillingModel,
+    private readonly _options: { autofill?: Partial<IBillingCoupon>; }
+  ) {
+    super();
+    if (this._options.autofill) {
+      const { promotion_code } = this._options.autofill;
+      this._discountCode.value.set(promotion_code ?? '');
+      this._isExpanded.set(Boolean(promotion_code));
+    }
+  }
+
+  public buildDom() {
+    return dom.domComputed(this._isExpanded, isExpanded => [
+      !isExpanded ?
+        css.paymentBlock(
+          css.paymentRow(
+            css.billingText('Have a discount code?', testId('discount-code-question')),
+            css.billingTextBtn(
+              css.billingIcon('Settings'),
+              'Apply',
+              dom.on('click', () => this._isExpanded.set(true)),
+              testId('apply-discount-code')
+            )
+          )
+        ) :
+        css.paymentBlock(
+          css.paymentRow(
+            css.paymentField(
+              css.paymentLabel('Discount Code'),
+              this.billingInput(this._discountCode, testId('discount-code')),
+            )
+          ),
+          css.inputError(
+            dom.text(this.formError),
+            testId('discount-form-error')
+          )
+        )
+    ]);
+  }
+
+  public async getCoupon() {
+    const discountCode = await this._discountCode.get();
+    if (discountCode.trim() === '') { return undefined; }
+
+    try {
+      return await this._billingModel.fetchSignupCoupon(discountCode);
+    } catch (e) {
+      this.formError.set('Invalid or expired discount code.');
+      throw e;
+    }
+  }
+}
+
 function checkFunc(func: (val: string) => boolean, message: string) {
   return (val: string) => {
     if (!func(val)) { throw new Error(message); }

app/client/ui/BillingPage.ts

@@ -14,7 +14,8 @@ import {cssBreadcrumbs, cssBreadcrumbsLink, separator} from 'app/client/ui2018/b
 import {bigBasicButton, bigBasicButtonLink, bigPrimaryButton} from 'app/client/ui2018/buttons';
 import {loadingSpinner} from 'app/client/ui2018/loaders';
 import {confirmModal} from 'app/client/ui2018/modals';
-import {BillingSubPage, BillingTask, IBillingAddress, IBillingCard, IBillingPlan} from 'app/common/BillingAPI';
+import {BillingSubPage, BillingTask, IBillingAddress, IBillingCard, IBillingCoupon,
+        IBillingPlan} from 'app/common/BillingAPI';
 import {capitalize} from 'app/common/gutil';
 import {Organization} from 'app/common/UserAPI';
 import {Disposable, dom, IAttrObj, IDomArgs, makeTestId, Observable} from 'grainjs';
@@ -145,8 +146,10 @@ export class BillingPage extends Disposable {
       const planId = validPlan ? sub.activePlan.id : sub.lastPlanId;
       // If on a "Tier" coupon, present information differently, emphasizing the coupon
       // name and minimizing the plan.
-      const tier = sub.discountName && sub.discountName.includes(' Tier ');
+      const discountName = sub.discount && sub.discount.name;
-      const planName = tier ? sub.discountName! : sub.activePlan.nickname;
+      const discountEnd = sub.discount && sub.discount.end_timestamp_ms;
+      const tier = discountName && discountName.includes(' Tier ');
+      const planName = tier ? discountName! : sub.activePlan.nickname;
       const invoiceId = this._appModel.currentOrg?.billingAccount?.externalOptions?.invoiceId;
       return [
         css.summaryFeatures(
@@ -172,12 +175,18 @@ export class BillingPage extends Disposable {
           moneyPlan.amount ? [
             makeSummaryFeature([`Your team site has `, `${sub.userCount}`,
                                 ` member${sub.userCount > 1 ? 's' : ''}`]),
-            tier ? this.buildAppSumoPlanNotes(sub.discountName!) : null,
+            tier ? this.buildAppSumoPlanNotes(discountName!) : null,
             // Currently the subtotal is misleading and scary when tiers are in effect.
             // In this case, for now, just report what will be invoiced.
             !tier ? makeSummaryFeature([`Your ${moneyPlan.interval}ly subtotal is `,
                                         getPriceString(moneyPlan.amount * sub.userCount)]) : null,
-            (sub.discountName && !tier) ? makeSummaryFeature([`You receive the `, sub.discountName]) : null,
+            (discountName && !tier) ?
+              makeSummaryFeature([
+                `You receive the `,
+                discountName,
+                ...(discountEnd !== null ? [' (until ', dateFmtFull(discountEnd), ')'] : []),
+              ]) :
+              null,
             // When on a free trial, Stripe reports trialEnd time, but it seems to always
             // match periodEnd for a trialing subscription, so we just use that.
             sub.isInTrial ? makeSummaryFeature(['Your free trial ends on ', dateFmtFull(sub.periodEnd)]) : null,
@@ -366,12 +375,23 @@ export class BillingPage extends Disposable {
     const pageText = taskActions[task];
     // 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), {
+    this._form = new BillingForm(
+      org,
+      this._model,
+      {
         payment: ['signUp', 'updatePlan', 'addCard', 'updateCard'].includes(task),
+        discount: ['signUp'].includes(task),
         address: ['signUp', 'updateAddress'].includes(task),
         settings: ['signUp', 'signUpLite', 'updateAddress', 'updateDomain'].includes(task),
         domain: ['signUp', 'signUpLite', 'updateDomain'].includes(task)
-    }, { address: currentAddress, settings: currentSettings, card: this._formData.card });
+      },
+      {
+        address: currentAddress,
+        settings: currentSettings,
+        card: this._formData.card,
+        coupon: this._formData.coupon
+      }
+    );
     return dom('div',
       dom.onDispose(() => {
         if (this._form) {
@@ -665,8 +685,6 @@ export class BillingPage extends Disposable {
       } else if (!sub) {
         const planPriceStr = getPriceString(plan.amount);
         const subtotal = plan.amount * (stubSub?.userCount || 1);
-        const subTotalPriceStr = getPriceString(subtotal);
-        const totalPriceStr = getPriceString(subtotal, stubSub?.taxRate || 0);
         // This is a new subscription, either a fresh sign ups, or renewal after cancellation.
         // The server will allow the trial period only for fresh sign ups.
         const trialSummary = (plan.trial_period_days && task === 'signUp') ?
@@ -674,8 +692,16 @@ export class BillingPage extends Disposable {
         return [
           makeSummaryFeature(['You are changing to the ', plan.nickname, ' plan']),
           dom.domComputed(this._showConfirmPage, confirmPage => {
+            const subTotalOptions = {coupon: confirmPage ? this._formData.coupon : undefined};
+            const subTotalPriceStr = getPriceString(subtotal, subTotalOptions);
+            const totalPriceStr = getPriceString(subtotal, {...subTotalOptions, taxRate: stubSub?.taxRate ?? 0});
             if (confirmPage) {
               return [
+                this._formData.coupon ?
+                  makeSummaryFeature([
+                    'You applied the ',
+                    this._formData.coupon.name + ` (${getDiscountAmountString(this._formData.coupon)}) `,
+                  ]) : null,
                 makeSummaryFeature([`Your ${plan.interval}ly subtotal is `, subTotalPriceStr]),
                 // Note that on sign up, the number of users in the new org is always one.
                 trialSummary || makeSummaryFeature(['You will be charged ', totalPriceStr, ' to start'])
@@ -692,15 +718,29 @@ export class BillingPage extends Disposable {
         ];
       } else if (plan.amount > sub.activePlan.amount) {
         const refund = sub.valueRemaining || 0;
+        const subtotal = plan.amount * sub.userCount;
+        const taxRate = sub.taxRate;
+
         // User is upgrading their plan.
         return [
           makeSummaryFeature(['You are changing to the ', plan.nickname, ' plan']),
-          makeSummaryFeature([`Your ${plan.interval}ly subtotal is `,
+          dom.domComputed(this._showConfirmPage, confirmPage => {
-            getPriceString(plan.amount * sub.userCount)]),
+            const subTotalOptions = {coupon: confirmPage ? this._formData.coupon : undefined};
-          makeSummaryFeature(['You will be charged ',
+            const subTotalPriceStr = getPriceString(subtotal, subTotalOptions);
-            getPriceString((plan.amount * sub.userCount) - refund, sub.taxRate), ' to start']),
+            const startPriceStr = getPriceString(subtotal, {...subTotalOptions, taxRate, refund});
+
+            return [
+              confirmPage && this._formData.coupon ?
+                makeSummaryFeature([
+                  'You applied the ',
+                  this._formData.coupon.name + ` (${getDiscountAmountString(this._formData.coupon)}) `,
+                ]) : null,
+              makeSummaryFeature([`Your ${plan.interval}ly subtotal is `, subTotalPriceStr]),
+              makeSummaryFeature(['You will be charged ', startPriceStr, ' to start']),
               refund > 0 ? makeSummaryFeature(['Your charge is prorated based on the remaining plan time']) : null,
             ];
+          }),
+        ];
       } else {
         // User is cancelling their decision to downgrade their plan.
         return [
@@ -799,7 +839,35 @@ function getSubscriptionProblem(sub: ISubscriptionModel) {
   return result.map(msg => makeSummaryFeature(msg, {isBad: true}));
 }
 
-function getPriceString(priceCents: number, taxRate: number = 0): string {
+interface PriceOptions {
+  taxRate?: number;
+  coupon?: IBillingCoupon;
+  refund?: number;
+}
+
+const defaultPriceOptions: PriceOptions = {
+  taxRate: 0,
+  coupon: undefined,
+  refund: 0,
+};
+
+function getPriceString(priceCents: number, options = defaultPriceOptions): string {
+  const {taxRate = 0, coupon, refund} = options;
+  if (coupon) {
+    if (coupon.amount_off) {
+      priceCents -= coupon.amount_off;
+    } else if (coupon.percent_off) {
+      priceCents -= (priceCents * (coupon.percent_off / 100));
+    }
+  }
+
+  if (refund) {
+    priceCents -= refund;
+  }
+
+  // Make sure we never display negative prices.
+  priceCents = Math.max(0, priceCents);
+
   // TODO: Add functionality for other currencies.
   return ((priceCents / 100) * (taxRate + 1)).toLocaleString('en-US', {
     style: "currency",
@@ -808,6 +876,14 @@ function getPriceString(priceCents: number, taxRate: number = 0): string {
   });
 }
 
+function getDiscountAmountString(coupon: IBillingCoupon): string {
+  if (coupon.amount_off !== null) {
+    return `${getPriceString(coupon.amount_off)} off`;
+  } else {
+    return `${coupon.percent_off!}% off`;
+  }
+}
+
 /**
  * Make summary feature to include in:
  * - Plan cards for describing features of the plan.

app/common/BillingAPI.ts

@@ -41,19 +41,44 @@ export interface IBillingPlan {
 // Stripe customer address information. Used to maintain the company address.
 // For reference: https://stripe.com/docs/api/customers/object#customer_object-address
 export interface IBillingAddress {
-  line1: string;
+  line1: string|null;
-  line2?: string;
+  line2: string|null;
-  city?: string;
+  city: string|null;
-  state?: string;
+  state: string|null;
-  postal_code?: string;
+  postal_code: string|null;
-  country?: string;
+  country: string|null;
+}
+
+// Utility type that requires all properties to be non-nullish.
+type NonNullableProperties<T> = { [P in keyof T]: Required<NonNullable<T[P]>>; };
+
+// Filled address info from the client. Fields can be blank strings.
+export type IFilledBillingAddress = NonNullableProperties<IBillingAddress>;
+
+// Stripe promotion code and coupon information. Used by client to apply signup discounts.
+// For reference: https://stripe.com/docs/api/promotion_codes/object#promotion_code_object-coupon
+export interface IBillingCoupon {
+  id: string;
+  promotion_code: string;
+  name: string|null;
+  percent_off: number|null;
+  amount_off: number|null;
+}
+
+// Stripe subscription discount information.
+// For reference: https://stripe.com/docs/api/discounts/object
+export interface IBillingDiscount {
+  name: string|null;
+  percent_off: number|null;
+  amount_off: number|null;
+  end_timestamp_ms: number|null;
 }
 
 export interface IBillingCard {
-  funding?: 'credit'|'debit'|'prepaid'|'unknown';
+  funding?: string|null;
-  brand?: string;
+  brand?: string|null;
-  country?: string;         // uppercase two-letter ISO country code
+  country?: string|null;         // uppercase two-letter ISO country code
-  last4?: string;           // last 4 digits of the card number
+  last4?: string|null;           // last 4 digits of the card number
   name?: string|null;
 }
 
@@ -83,8 +108,8 @@ export interface IBillingSubscription {
   userCount: number;
   // The next total in cents that Stripe is going to charge (includes tax and discount).
   nextTotal: number;
-  // Name of the discount if any.
+  // Discount information, if any.
-  discountName: string|null;
+  discount: IBillingDiscount|null;
   // Last plan we had a subscription for, if any.
   lastPlanId: string|null;
   // Whether there is a valid plan in effect
@@ -111,6 +136,7 @@ export interface FullBillingAccount extends BillingAccount {
 
 export interface BillingAPI {
   isDomainAvailable(domain: string): Promise<boolean>;
+  getCoupon(promotionCode: string): Promise<IBillingCoupon>;
   getTaxRate(address: IBillingAddress): Promise<number>;
   getPlans(): Promise<IBillingPlan[]>;
   getSubscription(): Promise<IBillingSubscription>;
@@ -118,7 +144,7 @@ export interface BillingAPI {
   // The signUp function takes the tokenId generated when card data is submitted to Stripe.
   // See: https://stripe.com/docs/stripe-js/reference#stripe-create-token
   signUp(planId: string, tokenId: string, address: IBillingAddress,
-         settings: IBillingOrgSettings): Promise<OrganizationWithoutAccessInfo>;
+         settings: IBillingOrgSettings, promotionCode?: string): Promise<OrganizationWithoutAccessInfo>;
   setCard(tokenId: string): Promise<void>;
   removeCard(): Promise<void>;
   setSubscription(planId: string, options: {
@@ -143,6 +169,13 @@ export class BillingAPIImpl extends BaseAPI implements BillingAPI {
     return resp.json();
   }
 
+  public async getCoupon(promotionCode: string): Promise<IBillingCoupon> {
+    const resp = await this.request(`${this._url}/api/billing/coupon/${promotionCode}`, {
+      method: 'GET',
+    });
+    return resp.json();
+  }
+
   public async getTaxRate(address: IBillingAddress): Promise<number> {
     const resp = await this.request(`${this._url}/api/billing/tax`, {
       method: 'POST',
@@ -172,11 +205,12 @@ export class BillingAPIImpl extends BaseAPI implements BillingAPI {
     planId: string,
     tokenId: string,
     address: IBillingAddress,
-    settings: IBillingOrgSettings
+    settings: IBillingOrgSettings,
+    promotionCode?: string,
   ): Promise<OrganizationWithoutAccessInfo> {
     const resp = await this.request(`${this._url}/api/billing/signup`, {
       method: 'POST',
-      body: JSON.stringify({ tokenId, planId, address, settings })
+      body: JSON.stringify({ tokenId, planId, address, settings, promotionCode }),
     });
     const parsed = await resp.json();
     return parsed.data;