feat: add subscription middleware

Made-with: Cursor

src/plugins/subscription.ts

@@ -0,0 +1,71 @@
+import type { FastifyInstance, FastifyRequest, FastifyReply } from 'fastify';
+import fp from 'fastify-plugin';
+import { eq } from 'drizzle-orm';
+import { subscriptions } from '../db/schema/subscriptions.js';
+import { forbidden } from '../utils/errors.js';
+
+export type SubscriptionInfo = {
+  plan: 'free' | 'pro';
+  status: 'active' | 'trialing' | 'cancelled' | 'expired';
+  isPro: boolean;
+  expiresAt: Date | null;
+};
+
+declare module 'fastify' {
+  interface FastifyRequest {
+    subscription?: SubscriptionInfo | null;
+  }
+  interface FastifyInstance {
+    withSubscription: (req: FastifyRequest, reply: FastifyReply) => Promise<void>;
+    requirePro: (req: FastifyRequest, reply: FastifyReply) => Promise<void>;
+  }
+}
+
+async function loadSubscription(db: FastifyInstance['db'], userId: string): Promise<SubscriptionInfo | null> {
+  const [sub] = await db
+    .select()
+    .from(subscriptions)
+    .where(eq(subscriptions.userId, userId))
+    .limit(1);
+
+  if (!sub) return null;
+
+  const now = new Date();
+  const isExpired = sub.expiresAt && sub.expiresAt < now;
+  const isPro =
+    sub.plan === 'pro' &&
+    (sub.status === 'active' || sub.status === 'trialing') &&
+    !isExpired;
+
+  return {
+    plan: sub.plan as 'free' | 'pro',
+    status: sub.status as SubscriptionInfo['status'],
+    isPro,
+    expiresAt: sub.expiresAt,
+  };
+}
+
+export async function requirePro(req: FastifyRequest, _reply: FastifyReply): Promise<void> {
+  const sub = req.subscription;
+
+  if (!sub?.isPro) {
+    throw forbidden('Pro subscription required');
+  }
+}
+
+const subscriptionPlugin = async (app: FastifyInstance) => {
+  app.decorateRequest('subscription', undefined);
+
+  app.decorate('withSubscription', async (req: FastifyRequest, _reply: FastifyReply) => {
+    if (!req.user?.id) return;
+    const sub = await loadSubscription(app.db, req.user.id);
+    req.subscription = sub;
+  });
+
+  app.decorate('requirePro', requirePro);
+};
+
+export default fp(subscriptionPlugin, {
+  name: 'subscription',
+  dependencies: ['database', 'auth'],
+});