feat: support guest session (#919)

app/(auth)/auth.ts

@@ -1,14 +1,33 @@
 import { compare } from 'bcrypt-ts';
-import NextAuth, { type User, type Session } from 'next-auth';
+import NextAuth, { type DefaultSession } from 'next-auth';
 import Credentials from 'next-auth/providers/credentials';
-
-import { getUser } from '@/lib/db/queries';
-
+import { createGuestUser, getUser } from '@/lib/db/queries';
 import { authConfig } from './auth.config';
 import { DUMMY_PASSWORD } from '@/lib/constants';
+import type { DefaultJWT } from 'next-auth/jwt';
 
-interface ExtendedSession extends Session {
-  user: User;
+export type UserType = 'guest' | 'regular';
+
+declare module 'next-auth' {
+  interface Session extends DefaultSession {
+    user: {
+      id: string;
+      type: UserType;
+    } & DefaultSession['user'];
+  }
+
+  interface User {
+    id?: string;
+    email?: string | null;
+    type: UserType;
+  }
+}
+
+declare module 'next-auth/jwt' {
+  interface JWT extends DefaultJWT {
+    id: string;
+    type: UserType;
+  }
 }
 
 export const {
@@ -40,27 +59,31 @@ export const {
 
         if (!passwordsMatch) return null;
 
-        return user as any;
+        return { ...user, type: 'regular' };
+      },
+    }),
+    Credentials({
+      id: 'guest',
+      credentials: {},
+      async authorize() {
+        const [guestUser] = await createGuestUser();
+        return { ...guestUser, type: 'guest' };
       },
     }),
   ],
   callbacks: {
     async jwt({ token, user }) {
       if (user) {
-        token.id = user.id;
+        token.id = user.id as string;
+        token.type = user.type;
       }
 
       return token;
     },
-    async session({
-      session,
-      token,
-    }: {
-      session: ExtendedSession;
-      token: any;
-    }) {
+    async session({ session, token }) {
       if (session.user) {
-        session.user.id = token.id as string;
+        session.user.id = token.id;
+        session.user.type = token.type;
       }
 
       return session;