That's a huge commit if you ask me

src/router/index.ts

@@ -1,5 +1,13 @@
 import { createRouter, createWebHistory } from 'vue-router'
 import GroupSelection from '@/views/GroupSelection.vue'
+import { doc, getDoc } from "firebase/firestore"
+import { db } from '@/utils/firestore'
+import { useSessionStore } from '@/stores/useSessionStore'
+
+async function isGroupOk(id: string): Promise<boolean> {
+	const docSnap = await getDoc(doc(db, "groups", id))
+	return docSnap.exists()
+}
 
 const router = createRouter({
 	history: createWebHistory(import.meta.env.BASE_URL),
@@ -10,12 +18,15 @@ const router = createRouter({
 			component: GroupSelection
 		},
 		{
-			path: '/group',
+			path: '/group/:groupId',
 			name: 'Group',
-			component: GroupSelection,
-			// beforeEnter: (to, from) => {
-			// 	return '/'
-			// }
+			component: () => import('@/views/Chat.vue'),
+			beforeEnter: async (to, from) => {
+				const sessionStore = useSessionStore()
+				const userAllowed = await isGroupOk(to.params.groupId as string)
+				if (!userAllowed) return '/'
+				sessionStore.groupId = to.params.groupId as string
+			}
 		},
 	]
 })