Add fake payment API

README.md

@@ -4,3 +4,20 @@ This is a template project with best-practice modules:
 - Winterspec for defining the API
 - bun testing
 - Zustand store with zod definition for database state
+
+## Fake Payments API
+
+The fake payment routes model the lifecycle needed by bounty-style flows without
+contacting a real payment provider.
+
+- `POST /payments/send`: create a pending fake payment. Accepts `recipient`,
+  `amount`, optional `currency`, bounty metadata, and optional
+  `idempotency_key`.
+- `GET /payments/list`: list payments, optionally filtered by `recipient`,
+  `repository`, or `status`.
+- `GET /payments/get?payment_id=pay_0`: fetch one payment by id.
+- `POST /payments/complete`: mark a pending payment as completed.
+
+When `idempotency_key` is supplied to `/payments/send`, repeated requests return
+the original payment with `idempotent_replay: true` instead of creating duplicate
+fake transfers.

lib/db/db-client.ts

@@ -1,17 +1,36 @@
-import { createStore, type StoreApi } from "zustand/vanilla"
+import { type HoistedStoreApi, hoist } from "zustand-hoist"
 import { immer } from "zustand/middleware/immer"
-import { hoist, type HoistedStoreApi } from "zustand-hoist"
+import { type StoreApi, createStore } from "zustand/vanilla"
 
-import { databaseSchema, type DatabaseSchema, type Thing } from "./schema.ts"
 import { combine } from "zustand/middleware"
+import {
+  type DatabaseSchema,
+  type Payment,
+  type PaymentStatus,
+  type Thing,
+  databaseSchema,
+} from "./schema.ts"
 
 export const createDatabase = () => {
   return hoist(createStore(initializer))
 }
 
 export type DbClient = ReturnType<typeof createDatabase>
 
-const initializer = combine(databaseSchema.parse({}), (set) => ({
+type CreatePaymentInput = Omit<
+  Payment,
+  "payment_id" | "status" | "created_at" | "updated_at"
+> & {
+  status?: PaymentStatus
+}
+
+const terminalStatuses = new Set<PaymentStatus>([
+  "completed",
+  "canceled",
+  "failed",
+])
+
+const initializer = combine(databaseSchema.parse({}), (set, get) => ({
   addThing: (thing: Omit<Thing, "thing_id">) => {
     set((state) => ({
       things: [
@@ -21,4 +40,82 @@ const initializer = combine(databaseSchema.parse({}), (set) => ({
       idCounter: state.idCounter + 1,
     }))
   },
+  createPayment: (input: CreatePaymentInput) => {
+    const existingPayment = input.idempotency_key
+      ? get().payments.find(
+          (payment) => payment.idempotency_key === input.idempotency_key,
+        )
+      : undefined
+
+    if (existingPayment) {
+      return { payment: existingPayment, idempotentReplay: true }
+    }
+
+    const timestamp = new Date().toISOString()
+    const payment: Payment = {
+      ...input,
+      payment_id: `pay_${get().paymentCounter}`,
+      currency: input.currency || "USD",
+      status: input.status || "pending",
+      created_at: timestamp,
+      updated_at: timestamp,
+    }
+
+    set((state) => ({
+      payments: [...state.payments, payment],
+      paymentCounter: state.paymentCounter + 1,
+    }))
+
+    return { payment, idempotentReplay: false }
+  },
+  findPaymentById: (paymentId: string) => {
+    return (
+      get().payments.find((payment) => payment.payment_id === paymentId) ?? null
+    )
+  },
+  listPayments: (filters?: {
+    recipient?: string
+    repository?: string
+    status?: PaymentStatus
+  }) => {
+    return get().payments.filter((payment) => {
+      if (filters?.recipient && payment.recipient !== filters.recipient) {
+        return false
+      }
+      if (filters?.repository && payment.repository !== filters.repository) {
+        return false
+      }
+      if (filters?.status && payment.status !== filters.status) {
+        return false
+      }
+      return true
+    })
+  },
+  updatePaymentStatus: (paymentId: string, status: PaymentStatus) => {
+    const existingPayment = get().payments.find(
+      (payment) => payment.payment_id === paymentId,
+    )
+
+    if (!existingPayment) {
+      return null
+    }
+
+    if (terminalStatuses.has(existingPayment.status)) {
+      return existingPayment
+    }
+
+    const updatedPayment: Payment = {
+      ...existingPayment,
+      status,
+      updated_at: new Date().toISOString(),
+    }
+
+    set((state) => ({
+      payments: state.payments.map((payment) =>
+        payment.payment_id === paymentId ? updatedPayment : payment,
+      ),
+    }))
+
+    return updatedPayment
+  },
 }))

lib/db/schema.ts

@@ -9,8 +9,33 @@ export const thingSchema = z.object({
 })
 export type Thing = z.infer<typeof thingSchema>
 
+export const paymentStatusSchema = z.enum([
+  "pending",
+  "completed",
+  "canceled",
+  "failed",
+])
+export type PaymentStatus = z.infer<typeof paymentStatusSchema>
+
+export const paymentSchema = z.object({
+  payment_id: z.string(),
+  recipient: z.string(),
+  amount: z.number(),
+  currency: z.string(),
+  status: paymentStatusSchema,
+  bounty_id: z.string().optional(),
+  issue_number: z.number().optional(),
+  repository: z.string().optional(),
+  idempotency_key: z.string().optional(),
+  created_at: z.string(),
+  updated_at: z.string(),
+})
+export type Payment = z.infer<typeof paymentSchema>
+
 export const databaseSchema = z.object({
   idCounter: z.number().default(0),
+  paymentCounter: z.number().default(0),
   things: z.array(thingSchema).default([]),
+  payments: z.array(paymentSchema).default([]),
 })
 export type DatabaseSchema = z.infer<typeof databaseSchema>

routes/payments/complete.ts

@@ -0,0 +1,22 @@
+import { paymentSchema } from "lib/db/schema"
+import { withRouteSpec } from "lib/middleware/with-winter-spec"
+import { z } from "zod"
+
+export default withRouteSpec({
+  methods: ["POST"],
+  jsonBody: z.object({
+    payment_id: z.string().min(1),
+  }),
+  jsonResponse: z.object({
+    ok: z.boolean(),
+    payment: paymentSchema.nullable(),
+  }),
+})(async (req, ctx) => {
+  const { payment_id } = await req.json()
+  const payment = ctx.db.updatePaymentStatus(payment_id, "completed")
+
+  return ctx.json({
+    ok: Boolean(payment),
+    payment,
+  })
+})

routes/payments/get.ts

@@ -0,0 +1,17 @@
+import { paymentSchema } from "lib/db/schema"
+import { withRouteSpec } from "lib/middleware/with-winter-spec"
+import { z } from "zod"
+
+export default withRouteSpec({
+  methods: ["GET"],
+  jsonResponse: z.object({
+    payment: paymentSchema.nullable(),
+  }),
+})((req, ctx) => {
+  const url = new URL(req.url)
+  const paymentId = url.searchParams.get("payment_id")
+
+  return ctx.json({
+    payment: paymentId ? ctx.db.findPaymentById(paymentId) : null,
+  })
+})

routes/payments/list.ts

@@ -0,0 +1,23 @@
+import { paymentSchema, paymentStatusSchema } from "lib/db/schema"
+import { withRouteSpec } from "lib/middleware/with-winter-spec"
+import { z } from "zod"
+
+export default withRouteSpec({
+  methods: ["GET"],
+  jsonResponse: z.object({
+    payments: z.array(paymentSchema),
+  }),
+})((req, ctx) => {
+  const url = new URL(req.url)
+  const status = paymentStatusSchema
+    .optional()
+    .parse(url.searchParams.get("status") ?? undefined)
+
+  const payments = ctx.db.listPayments({
+    recipient: url.searchParams.get("recipient") ?? undefined,
+    repository: url.searchParams.get("repository") ?? undefined,
+    status,
+  })
+
+  return ctx.json({ payments })
+})

routes/payments/send.ts

@@ -0,0 +1,31 @@
+import { paymentSchema } from "lib/db/schema"
+import { withRouteSpec } from "lib/middleware/with-winter-spec"
+import { z } from "zod"
+
+export default withRouteSpec({
+  methods: ["POST"],
+  jsonBody: z.object({
+    recipient: z.string().min(1),
+    amount: z.number().positive(),
+    currency: z.string().min(1).optional(),
+    bounty_id: z.string().optional(),
+    issue_number: z.number().optional(),
+    repository: z.string().optional(),
+    idempotency_key: z.string().optional(),
+  }),
+  jsonResponse: z.object({
+    payment: paymentSchema,
+    idempotent_replay: z.boolean(),
+  }),
+})(async (req, ctx) => {
+  const body = await req.json()
+  const { payment, idempotentReplay } = ctx.db.createPayment({
+    ...body,
+    currency: body.currency || "USD",
+  })
+
+  return ctx.json({
+    payment,
+    idempotent_replay: idempotentReplay,
+  })
+})

tests/routes/payments.test.ts

@@ -0,0 +1,68 @@
+import { expect, test } from "bun:test"
+import { getTestServer } from "tests/fixtures/get-test-server"
+
+test("send, list, get, and complete a payment", async () => {
+  const { axios } = await getTestServer()
+
+  const sendResponse = await axios.post("/payments/send", {
+    recipient: "[email protected]",
+    amount: 10,
+    bounty_id: "bounty_1",
+    issue_number: 1,
+    repository: "tscircuit/fake-algora",
+  })
+
+  expect(sendResponse.data.idempotent_replay).toBe(false)
+  expect(sendResponse.data.payment).toMatchObject({
+    payment_id: "pay_0",
+    recipient: "[email protected]",
+    amount: 10,
+    currency: "USD",
+    status: "pending",
+    bounty_id: "bounty_1",
+    issue_number: 1,
+    repository: "tscircuit/fake-algora",
+  })
+
+  const listResponse = await axios.get(
+    "/payments/list?recipient=dev%40example.com&status=pending",
+  )
+
+  expect(listResponse.data.payments).toHaveLength(1)
+  expect(listResponse.data.payments[0].payment_id).toBe("pay_0")
+
+  const getResponse = await axios.get("/payments/get?payment_id=pay_0")
+  expect(getResponse.data.payment.payment_id).toBe("pay_0")
+
+  const completeResponse = await axios.post("/payments/complete", {
+    payment_id: "pay_0",
+  })
+
+  expect(completeResponse.data.ok).toBe(true)
+  expect(completeResponse.data.payment.status).toBe("completed")
+})
+
+test("send replays existing payment for matching idempotency key", async () => {
+  const { axios } = await getTestServer()
+
+  const firstResponse = await axios.post("/payments/send", {
+    recipient: "[email protected]",
+    amount: 5,
+    idempotency_key: "retry-safe-key",
+  })
+
+  const secondResponse = await axios.post("/payments/send", {
+    recipient: "[email protected]",
+    amount: 5,
+    idempotency_key: "retry-safe-key",
+  })
+
+  expect(firstResponse.data.idempotent_replay).toBe(false)
+  expect(secondResponse.data.idempotent_replay).toBe(true)
+  expect(secondResponse.data.payment.payment_id).toBe(
+    firstResponse.data.payment.payment_id,
+  )
+
+  const listResponse = await axios.get("/payments/list")
+  expect(listResponse.data.payments).toHaveLength(1)
+})