Harden auth and outbound admin surfaces

frontend/app/lib/auth.ts

@@ -1,27 +1,53 @@
+const AUTH_STATE_COOKIE = 'magent_logged_in'
+
 export const getApiBase = () => process.env.NEXT_PUBLIC_API_BASE ?? '/api'
 
-export const getToken = () => {
-  if (typeof window === 'undefined') return null
-  return window.localStorage.getItem('magent_token')
+const setCookie = (name: string, value: string, maxAgeSeconds: number) => {
+  if (typeof document === 'undefined') return
+  document.cookie = `${name}=${value}; Max-Age=${maxAgeSeconds}; Path=/; SameSite=Lax`
 }
 
-export const setToken = (token: string) => {
-  if (typeof window === 'undefined') return
-  window.localStorage.setItem('magent_token', token)
+const clearCookie = (name: string) => {
+  if (typeof document === 'undefined') return
+  document.cookie = `${name}=; Max-Age=0; Path=/; SameSite=Lax`
+}
+
+export const getToken = () => {
+  if (typeof document === 'undefined') return null
+  const cookies = document.cookie.split(';').map((entry) => entry.trim())
+  const marker = cookies.find((entry) => entry.startsWith(`${AUTH_STATE_COOKIE}=`))
+  if (!marker) return null
+  const [, value] = marker.split('=', 2)
+  return value || null
+}
+
+export const setToken = (_token: string) => {
+  setCookie(AUTH_STATE_COOKIE, '1', 60 * 60 * 12)
 }
 
 export const clearToken = () => {
+  clearCookie(AUTH_STATE_COOKIE)
   if (typeof window === 'undefined') return
-  window.localStorage.removeItem('magent_token')
+  const baseUrl = getApiBase()
+  void fetch(`${baseUrl}/auth/logout`, {
+    method: 'POST',
+    credentials: 'include',
+    keepalive: true,
+  }).catch(() => undefined)
+}
+
+export const logout = async () => {
+  const baseUrl = getApiBase()
+  clearCookie(AUTH_STATE_COOKIE)
+  await fetch(`${baseUrl}/auth/logout`, {
+    method: 'POST',
+    credentials: 'include',
+  })
 }
 
 export const authFetch = (input: RequestInfo | URL, init?: RequestInit) => {
-  const token = getToken()
   const headers = new Headers(init?.headers || {})
-  if (token) {
-    headers.set('Authorization', `Bearer ${token}`)
-  }
-  return fetch(input, { ...init, headers })
+  return fetch(input, { ...init, headers, credentials: 'include' })
 }
 
 export const getEventStreamToken = async () => {