refactor(payment): centralize route lifecycle

src/app/subscription/page.tsx

@@ -1,45 +1,50 @@
-import type { PayChannel } from "@/data/dto/payment";
 import {
   PAYMENT_ANALYTICS_ENTRY_PARAM,
   PAYMENT_ANALYTICS_REASON_PARAM,
   parsePaymentAnalyticsContext,
 } from "@/lib/analytics/payment_analytics_context";
+import {
+  getFirstPaymentSearchParam,
+  parsePaymentReturnSearchParams,
+  type PaymentSearchParams,
+} from "@/lib/payment/payment_search_params";
 
 import {
   SubscriptionScreen,
   type SubscriptionType,
 } from "./subscription-screen";
 
-type SubscriptionSearchParams = Record<string, string | string[] | undefined>;
-
 export default async function SubscriptionPage({
   searchParams,
 }: {
-  searchParams: Promise<SubscriptionSearchParams>;
+  searchParams: Promise<PaymentSearchParams>;
 }) {
   const query = await searchParams;
-  const subscriptionType = toSubscriptionType(firstSearchParam(query.type));
+  const paymentReturn = parsePaymentReturnSearchParams(query);
+  const subscriptionType = toSubscriptionType(
+    getFirstPaymentSearchParam(query.type),
+  );
   const analyticsContext = parsePaymentAnalyticsContext({
-    entryPoint: firstSearchParam(query[PAYMENT_ANALYTICS_ENTRY_PARAM]),
-    triggerReason: firstSearchParam(query[PAYMENT_ANALYTICS_REASON_PARAM]),
+    entryPoint: getFirstPaymentSearchParam(
+      query[PAYMENT_ANALYTICS_ENTRY_PARAM],
+    ),
+    triggerReason: getFirstPaymentSearchParam(
+      query[PAYMENT_ANALYTICS_REASON_PARAM],
+    ),
     subscriptionType,
   });
 
   return (
     <SubscriptionScreen
       subscriptionType={subscriptionType}
-      shouldResumePendingOrder={firstSearchParam(query.paymentReturn) === "1"}
-      returnTo={toReturnTo(firstSearchParam(query.returnTo))}
-      initialPayChannel={toPayChannel(firstSearchParam(query.payChannel))}
+      shouldResumePendingOrder={paymentReturn.shouldResumePendingOrder}
+      returnTo={toReturnTo(getFirstPaymentSearchParam(query.returnTo))}
+      initialPayChannel={paymentReturn.initialPayChannel}
       analyticsContext={analyticsContext}
     />
   );
 }
 
-function firstSearchParam(value: string | string[] | undefined): string | null {
-  return Array.isArray(value) ? (value[0] ?? null) : (value ?? null);
-}
-
 function toSubscriptionType(value: string | null): SubscriptionType {
   return value === "topup" ? "topup" : "vip";
 }
@@ -47,7 +52,3 @@ function toSubscriptionType(value: string | null): SubscriptionType {
 function toReturnTo(value: string | null): "chat" | null {
   return value === "chat" ? "chat" : null;
 }
-
-function toPayChannel(value: string | null): PayChannel | null {
-  return value === "ezpay" || value === "stripe" ? value : null;
-}