refactor: split auth module into separate files and fix imports

- Created auth_types.ts for type definitions
- Created auth_shared.ts for utility functions and endpoints
- Updated auth.ts to focus on session management
- Fixed all auth import statements throughout codebase
- Updated login redirect to use Auth_tinyauth_public_endpoint properly

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <[email protected]>

5 files changed, 44 insertions, 39 deletions

diff --git a/frontend/app/api/upload/route.ts b/frontend/app/api/upload/route.ts
index 07ab908..5ce0640 100644
--- a/frontend/app/api/upload/route.ts
+++ b/frontend/app/api/upload/route.ts
@@ -3,7 +3,8 @@ import { writeFile, unlink } from 'fs/promises'
 import { tmpdir } from 'os'
 import { join } from 'path'
 import { randomUUID } from 'crypto'
-import { Auth_get_user, Auth_user_can_upload } from '@/lib/auth'
+import { Auth_get_user } from '@/lib/auth'
+import { Auth_user_can_upload } from '@/lib/auth_shared'
 import { Drive_import } from '@/lib/drive_server'
 import { UPLOAD_MAX_FILE_SIZE } from '@/lib/constants'
 
diff --git a/frontend/components/drive/DriveDirectoryClient.tsx b/frontend/components/drive/DriveDirectoryClient.tsx
index d64fb5d..d48be61 100644
--- a/frontend/components/drive/DriveDirectoryClient.tsx
+++ b/frontend/components/drive/DriveDirectoryClient.tsx
@@ -3,7 +3,7 @@
 import type React from "react"
 import { useState, useRef } from "react"
 import Link from "next/link"
-import { Auth_tinyauth_public_endpoint } from "@/lib/auth"
+import { Auth_tinyauth_public_endpoint } from "@/lib/auth_shared"
 import {
   ChevronRight,
   File,
diff --git a/frontend/lib/auth.ts b/frontend/lib/auth.ts
index 015fddf..55255fc 100644
--- a/frontend/lib/auth.ts
+++ b/frontend/lib/auth.ts
@@ -1,20 +1,7 @@
 import { cookies } from 'next/headers';
 import { Env_is_development } from './env';
-import { Elsie } from 'next/font/google';
+import type { UserSessionCookie, UserAuth } from './auth_types';
 
-export interface UserSessionCookie {
-  name: string,
-  value: string,
-}
-
-export interface UserAuth {
-  isLoggedIn: boolean,
-  username: string,
-  name: string,
-  email: string,
-  provider: string,
-  oauth: boolean,
-}
 
 export async function Auth_extract_session_cookie(): Promise<UserSessionCookie | null> {
   const cookieStore = await cookies();
@@ -47,6 +34,7 @@ export async function Auth_get_user(): Promise<UserAuth> {
   }
 
   const cookie = await Auth_extract_session_cookie();
+  const { Auth_tinyauth_endpoint } = await import('./auth_shared');
   const endpoint = Auth_tinyauth_endpoint();
 
   try {
@@ -94,26 +82,3 @@ export async function Auth_get_user(): Promise<UserAuth> {
   }
 }
 
-export function Auth_user_can_upload(user: UserAuth): boolean {
-  if (!user.isLoggedIn)
-    return false;
-
-  if (Env_is_development())
-    return true;
-
-  return user.oauth && user.email.endsWith("@campus.fct.unl.pt");
-}
-
-function Auth_tinyauth_endpoint(): string {
-  const endpoint = process.env.TINYAUTH_ENDPOINT;
-  if (endpoint == undefined)
-    throw new Error(`env var TINYAUTH_ENDPOINT not defined`);
-  return endpoint;
-}
-
-export function Auth_tinyauth_public_endpoint(): string {
-  const endpoint = process.env.TINYAUTH_PUBLIC_ENDPOINT;
-  if (endpoint == undefined)
-    throw new Error(`env var TINYAUTH_PUBLIC_ENDPOINT not defined`);
-  return endpoint;
-}
diff --git a/frontend/lib/auth_shared.ts b/frontend/lib/auth_shared.ts
new file mode 100644
index 0000000..b23b046
--- /dev/null
+++ b/frontend/lib/auth_shared.ts
@@ -0,0 +1,26 @@
+import { Env_is_development } from './env';
+import type { UserAuth } from './auth_types';
+
+export function Auth_user_can_upload(user: UserAuth): boolean {
+  if (!user.isLoggedIn)
+    return false;
+
+  if (Env_is_development())
+    return true;
+
+  return user.oauth && user.email.endsWith("@campus.fct.unl.pt");
+}
+
+export function Auth_tinyauth_endpoint(): string {
+  const endpoint = process.env.TINYAUTH_ENDPOINT;
+  if (endpoint == undefined)
+    throw new Error(`env var TINYAUTH_ENDPOINT not defined`);
+  return endpoint;
+}
+
+export function Auth_tinyauth_public_endpoint(): string {
+  const endpoint = process.env.TINYAUTH_PUBLIC_ENDPOINT;
+  if (endpoint == undefined)
+    throw new Error(`env var TINYAUTH_PUBLIC_ENDPOINT not defined`);
+  return endpoint;
+}
diff --git a/frontend/lib/auth_types.ts b/frontend/lib/auth_types.ts
new file mode 100644
index 0000000..fca1122
--- /dev/null
+++ b/frontend/lib/auth_types.ts
@@ -0,0 +1,13 @@
+export interface UserSessionCookie {
+  name: string,
+  value: string,
+}
+
+export interface UserAuth {
+  isLoggedIn: boolean,
+  username: string,
+  name: string,
+  email: string,
+  provider: string,
+  oauth: boolean,
+}