Wired trial days to stripe checkout session

refs https://github.com/TryGhost/Team/issues/1724

- wires trial days stored on a tier to stripe checkout session creation
- removes deprecated `trial_from_plan` if trial days is set

ghost/members-api/lib/controllers/router.js

@@ -214,6 +214,11 @@ module.exports = class RouterController {
         const priceId = price.get('stripe_price_id');
 
         const product = await this._productRepository.get({stripe_price_id: priceId});
+        let trialDays;
+
+        if (this.labsService.isSet('freeTrial')) {
+            trialDays = product.get('trial_days');
+        }
 
         if (product.get('active') !== true) {
             throw new NoPermissionError({
@@ -257,6 +262,7 @@ module.exports = class RouterController {
                 coupon: couponId,
                 successUrl,
                 cancelUrl,
+                trialDays,
                 customerEmail: req.body.customerEmail,
                 metadata: metadata
             });
@@ -311,6 +317,7 @@ module.exports = class RouterController {
                 coupon: couponId,
                 successUrl,
                 cancelUrl,
+                trialDays,
                 metadata: metadata
             });
             const publicKey = this._stripeAPIService.getPublicKey();

ghost/members-api/lib/repositories/product.js

@@ -288,6 +288,7 @@ class ProductRepository {
      * @param {string} data.id
      * @param {string} data.name
      * @param {string} data.description
+     * @param {number} data.trial_days
      * @param {'public'|'none'} data.visibility
      * @param {string} data.welcome_page_url
      * @param {BenefitInput[]} data.benefits
@@ -345,9 +346,14 @@ class ProductRepository {
             productData.active = data.active;
         }
 
+        if (Reflect.has(data, 'trial_days')) {
+            productData.trial_days = data.trial_days;
+        }
+
         if (existingProduct.get('type') === 'free') {
             delete productData.name;
             delete productData.active;
+            delete productData.trial_days;
         }
 
         if (existingProduct.get('active') === true && productData.active === false) {

ghost/stripe/lib/StripeAPI.js

@@ -360,6 +360,7 @@ module.exports = class StripeAPI {
      * @param {string} options.successUrl
      * @param {string} options.cancelUrl
      * @param {string} options.customerEmail
+     * @param {number} options.trialDays
      * @param {string} [options.coupon]
      *
      * @returns {Promise<import('stripe').Stripe.Checkout.Session>}
@@ -372,6 +373,22 @@ module.exports = class StripeAPI {
         if (options.coupon) {
             discounts = [{coupon: options.coupon}];
         }
+
+        const subscriptionData = {
+            trial_from_plan: true,
+            items: [{
+                plan: priceId
+            }]
+        };
+
+        /**
+         * `trial_from_plan` is deprecated.
+         * Replaces it in favor of custom trial period days stored in Ghost
+         */
+        if (!isNaN(options.trialDays)) {
+            delete subscriptionData.trial_from_plan;
+            subscriptionData.trial_period_days = options.trialDays;
+        }
         const session = await this._stripe.checkout.sessions.create({
             payment_method_types: ['card'],
             success_url: options.successUrl || this._config.checkoutSessionSuccessUrl,
@@ -390,12 +407,7 @@ module.exports = class StripeAPI {
             // It should be replaced with the line_items entry above when possible,
             // however, this would lose the "trial from plan" feature which has also
             // been deprecated by Stripe
-            subscription_data: {
-                trial_from_plan: true,
-                items: [{
-                    plan: priceId
-                }]
-            }
+            subscription_data: subscriptionData
         });
 
         return session;

ghost/stripe/test/unit/lib/StripeAPI.test.js

@@ -42,4 +42,22 @@ describe('StripeAPI', function () {
         should.exist(mockStripe.checkout.sessions.create.firstCall.firstArg.success_url);
         should.exist(mockStripe.checkout.sessions.create.firstCall.firstArg.cancel_url);
     });
+
+    it('createCheckoutSetupSession uses trialDays', async function (){
+        await api.createCheckoutSession('priceId', null, {
+            trialDays: 12
+        });
+
+        should.not.exist(mockStripe.checkout.sessions.create.firstCall.firstArg.subscription_data.trial_from_plan);
+        should.exist(mockStripe.checkout.sessions.create.firstCall.firstArg.subscription_data.trial_period_days);
+        should.equal(mockStripe.checkout.sessions.create.firstCall.firstArg.subscription_data.trial_period_days, 12);
+    });
+
+    it('createCheckoutSetupSession uses trial_from_plan without trialDays', async function (){
+        await api.createCheckoutSession('priceId', null, {});
+
+        should.exist(mockStripe.checkout.sessions.create.firstCall.firstArg.subscription_data.trial_from_plan);
+        should.equal(mockStripe.checkout.sessions.create.firstCall.firstArg.subscription_data.trial_from_plan, true);
+        should.not.exist(mockStripe.checkout.sessions.create.firstCall.firstArg.subscription_data.trial_period_days);
+    });
 });