feat: add customer schemas and contracts

Add customer endpoint support for subscription management:
- CustomerSchema with subscriptions and hasActiveSubscription
- CustomerSubscriptionSchema for subscription summaries
- GetCustomerInputSchema with externalId/email/customerId lookup
- customer.get ORPC contract

Author: NatElkins

src/contracts/customer.ts

@@ -0,0 +1,10 @@
+import { oc } from "@orpc/contract";
+import { CustomerSchema, GetCustomerInputSchema } from "../schemas/customer";
+
+export const getCustomerContract = oc
+	.input(GetCustomerInputSchema)
+	.output(CustomerSchema);
+
+export const customer = {
+	get: getCustomerContract,
+};

src/index.ts

@@ -1,4 +1,5 @@
 import { checkout } from "./contracts/checkout";
+import { customer } from "./contracts/customer";
 import { onboarding } from "./contracts/onboarding";
 import { products } from "./contracts/products";
 import { subscription } from "./contracts/subscription";
@@ -23,6 +24,7 @@ export type {
 	CreateRenewalCheckout,
 	GetSubscriptionInput,
 } from "./contracts/subscription";
+export type { GetCustomerInput } from "./schemas/customer";
 export type { Checkout } from "./schemas/checkout";
 export { CheckoutSchema } from "./schemas/checkout";
 export type { Currency } from "./schemas/currency";
@@ -47,8 +49,23 @@ export {
 	SubscriptionWebhookEventSchema,
 	SubscriptionWebhookPayloadSchema,
 } from "./schemas/subscription";
+export type {
+	Customer,
+	CustomerSubscription,
+} from "./schemas/customer";
+export {
+	CustomerSchema,
+	CustomerSubscriptionSchema,
+	GetCustomerInputSchema,
+} from "./schemas/customer";
 
-export const contract = { checkout, onboarding, products, subscription };
+export const contract = {
+	checkout,
+	customer,
+	onboarding,
+	products,
+	subscription,
+};
 
 export type { MetadataValidationError } from "./validation/metadata-validation";
 export {

src/schemas/customer.ts

@@ -0,0 +1,62 @@
+import { z } from "zod";
+import { CurrencySchema } from "./currency";
+import {
+	RecurringIntervalSchema,
+	SubscriptionStatusSchema,
+} from "./subscription";
+
+/**
+ * Summary of a subscription for the customer response.
+ * Contains the essential fields needed for displaying subscription status.
+ */
+export const CustomerSubscriptionSchema = z.object({
+	id: z.string(),
+	productId: z.string(),
+	status: SubscriptionStatusSchema,
+	currentPeriodStart: z.string(), // ISO date
+	currentPeriodEnd: z.string(), // ISO date
+	cancelAtPeriodEnd: z.boolean().optional(),
+	amount: z.number(),
+	currency: CurrencySchema,
+	recurringInterval: RecurringIntervalSchema,
+});
+
+/**
+ * Customer data with their subscriptions.
+ * Returned by the customer.get endpoint.
+ */
+export const CustomerSchema = z.object({
+	id: z.string(),
+	email: z.string().nullable().optional(),
+	name: z.string().nullable().optional(),
+	externalId: z.string().nullable().optional(),
+	subscriptions: z.array(CustomerSubscriptionSchema),
+	hasActiveSubscription: z.boolean(),
+});
+
+/**
+ * Input for getting a customer.
+ * Requires exactly one of: externalId, email, or customerId.
+ */
+export const GetCustomerInputSchema = z
+	.object({
+		externalId: z.string().optional(),
+		email: z.string().optional(),
+		customerId: z.string().optional(),
+	})
+	.refine(
+		(data) => {
+			const fields = [data.externalId, data.email, data.customerId].filter(
+				Boolean,
+			);
+			return fields.length === 1;
+		},
+		{
+			message:
+				"Exactly one of externalId, email, or customerId must be provided",
+		},
+	);
+
+export type CustomerSubscription = z.infer<typeof CustomerSubscriptionSchema>;
+export type Customer = z.infer<typeof CustomerSchema>;
+export type GetCustomerInput = z.infer<typeof GetCustomerInputSchema>;