i think i finally fixed the state management awfulness

src/routes/callback/+page.js

@@ -1,20 +1,5 @@
-import { Client } from '$lib/client/client.js';
-import { goto } from '$app/navigation';
-import { error } from '@sveltejs/kit';
-import { get } from 'svelte/store';
-
-export const ssr = false;
-
-export async function load({ params, url }) {
-    const client = get(Client.get());
-    let auth_code = url.searchParams.get("code");
-    if (auth_code) {
-        client.getToken(auth_code).then(() => {
-            client.save();
-            goto("/");
-        });
-    }
-    error(400, {
-        message: "Bad request"
-    });
+export async function load({ url }) {
+    return {
+        code: url.searchParams.get("code") || false
+    };
 }

src/routes/callback/+page.svelte

@@ -0,0 +1,35 @@
+<script>
+    import { client } from '$lib/client/client.js';
+    import { goto } from '$app/navigation';
+    import { error } from '@sveltejs/kit';
+    import { get } from 'svelte/store';
+
+    export let data;
+
+    let auth_code = data.code;
+
+    if (!auth_code) {
+        error(400, { message: "Bad request" });
+    } else {
+        get(client).getToken(auth_code).then(token => {
+            if (!token) {
+                error(400, { message: "Invalid auth code provided" });
+                return;
+            }
+
+            client.update(c => {
+                c.app.token = token;
+                c.save();
+                return c;
+            });
+
+            get(client).getUser().then(user => {
+                if (user) client.update(client => {
+                    client.user = user
+                    return client;
+                });
+                goto("/");
+            });
+        });
+    }
+</script>