refactor(payment): centralize route lifecycle

src/lib/payment/__tests__/payment_search_params.test.ts

@@ -0,0 +1,38 @@
+import { describe, expect, it } from "vitest";
+
+import {
+  getFirstPaymentSearchParam,
+  parsePaymentPayChannel,
+  parsePaymentReturnSearchParams,
+} from "../payment_search_params";
+
+describe("payment search params", () => {
+  it("takes the first value from repeated query parameters", () => {
+    expect(getFirstPaymentSearchParam(["first", "second"])).toBe("first");
+    expect(getFirstPaymentSearchParam([])).toBeNull();
+  });
+
+  it("accepts only supported payment channels", () => {
+    expect(parsePaymentPayChannel("stripe")).toBe("stripe");
+    expect(parsePaymentPayChannel(["ezpay", "stripe"])).toBe("ezpay");
+    expect(parsePaymentPayChannel("paypal")).toBeNull();
+    expect(parsePaymentPayChannel(undefined)).toBeNull();
+  });
+
+  it("parses the shared payment return context", () => {
+    expect(
+      parsePaymentReturnSearchParams({
+        payChannel: ["ezpay", "stripe"],
+        paymentReturn: "1",
+      }),
+    ).toEqual({
+      initialPayChannel: "ezpay",
+      shouldResumePendingOrder: true,
+    });
+
+    expect(parsePaymentReturnSearchParams({ paymentReturn: "0" })).toEqual({
+      initialPayChannel: null,
+      shouldResumePendingOrder: false,
+    });
+  });
+});

src/lib/payment/payment_search_params.ts

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+import type { PayChannel } from "@/data/dto/payment";
+
+export type PaymentSearchParamValue = string | string[] | undefined;
+export type PaymentSearchParams = Record<string, PaymentSearchParamValue>;
+
+export interface PaymentReturnSearchParams {
+  initialPayChannel: PayChannel | null;
+  shouldResumePendingOrder: boolean;
+}
+
+export function getFirstPaymentSearchParam(
+  value: PaymentSearchParamValue,
+): string | null {
+  return Array.isArray(value) ? (value[0] ?? null) : (value ?? null);
+}
+
+export function parsePaymentPayChannel(
+  value: PaymentSearchParamValue,
+): PayChannel | null {
+  const channel = getFirstPaymentSearchParam(value);
+  return channel === "ezpay" || channel === "stripe" ? channel : null;
+}
+
+export function parsePaymentReturnSearchParams(
+  searchParams: PaymentSearchParams,
+): PaymentReturnSearchParams {
+  return {
+    initialPayChannel: parsePaymentPayChannel(searchParams.payChannel),
+    shouldResumePendingOrder:
+      getFirstPaymentSearchParam(searchParams.paymentReturn) === "1",
+  };
+}