Add Lemon Squeezy Billing System

packages/billing/stripe/src/services/create-stripe-checkout.ts

@@ -0,0 +1,88 @@
+import type { Stripe } from 'stripe';
+import { z } from 'zod';
+
+import { CreateBillingCheckoutSchema } from '@kit/billing/schema';
+
+/**
+ * @name createStripeCheckout
+ * @description Creates a Stripe Checkout session, and returns an Object
+ * containing the session, which you can use to redirect the user to the
+ * checkout page
+ */
+export async function createStripeCheckout(
+  stripe: Stripe,
+  params: z.infer<typeof CreateBillingCheckoutSchema>,
+) {
+  // in MakerKit, a subscription belongs to an organization,
+  // rather than to a user
+  // if you wish to change it, use the current user ID instead
+  const clientReferenceId = params.accountId;
+
+  // we pass an optional customer ID, so we do not duplicate the Stripe
+  // customers if an organization subscribes multiple times
+  const customer = params.customerId ?? undefined;
+
+  // docs: https://stripe.com/docs/billing/subscriptions/build-subscription
+  const mode: Stripe.Checkout.SessionCreateParams.Mode =
+    params.plan.paymentType === 'recurring' ? 'subscription' : 'payment';
+
+  // this should only be set if the mode is 'subscription'
+  const subscriptionData:
+    | Stripe.Checkout.SessionCreateParams.SubscriptionData
+    | undefined =
+    mode === 'subscription'
+      ? {
+          trial_period_days: params.trialDays,
+          metadata: {
+            accountId: params.accountId,
+          },
+        }
+      : undefined;
+
+  const urls = getUrls({
+    returnUrl: params.returnUrl,
+  });
+
+  // we use the embedded mode, so the user does not leave the page
+  const uiMode = 'embedded';
+
+  const customerData = customer
+    ? {
+        customer,
+      }
+    : {
+        customer_email: params.customerEmail,
+      };
+
+  const lineItems = params.plan.lineItems.map((item) => {
+    if (item.type === 'metered') {
+      return {
+        price: item.id,
+      };
+    }
+
+    return {
+      price: item.id,
+      quantity: 1,
+    };
+  });
+
+  return stripe.checkout.sessions.create({
+    mode,
+    ui_mode: uiMode,
+    line_items: lineItems,
+    client_reference_id: clientReferenceId,
+    subscription_data: subscriptionData,
+    customer_creation: 'always',
+    ...customerData,
+    ...urls,
+  });
+}
+
+function getUrls(params: { returnUrl: string }) {
+  const returnUrl = `${params.returnUrl}?session_id={CHECKOUT_SESSION_ID}`;
+
+  return {
+    return_url: returnUrl,
+  };
+}