From f8f6748bec1a9653a3efc80d0adffb11925c91fe Mon Sep 17 00:00:00 2001
From: Aidan Bleser <117548273+ieedan@users.noreply.github.com>
Date: Mon, 11 Aug 2025 05:51:27 -0500
Subject: [PATCH] feat: go back to last chat on back to chat button (#47)

---
 .../model-picker/model-picker.svelte          |  4 ++--
 src/lib/state/last-chat.svelte.ts             | 23 +++++++++++++++++++
 src/routes/+layout.svelte                     |  8 +++++++
 src/routes/account/+layout.svelte             |  7 +++++-
 4 files changed, 39 insertions(+), 3 deletions(-)
 create mode 100644 src/lib/state/last-chat.svelte.ts

diff --git a/src/lib/components/model-picker/model-picker.svelte b/src/lib/components/model-picker/model-picker.svelte
index 2bc8471..40c18cb 100644
--- a/src/lib/components/model-picker/model-picker.svelte
+++ b/src/lib/components/model-picker/model-picker.svelte
@@ -272,7 +272,7 @@
 
 		<Popover.Content
 			portalProps={{
-				disabled: isFirefox
+				disabled: isFirefox,
 			}}
 			align="start"
 			sideOffset={5}
@@ -524,7 +524,7 @@
 		</div>
 
 		<div
-			class="bg-popover absolute top-1 right-1 scale-75 rounded-md p-1 md:opacity-0 transition-all group-hover/item:scale-100 group-hover/item:opacity-100"
+			class="bg-popover absolute top-1 right-1 scale-75 rounded-md p-1 transition-all group-hover/item:scale-100 group-hover/item:opacity-100 md:opacity-0"
 		>
 			<Button
 				variant="ghost"
diff --git a/src/lib/state/last-chat.svelte.ts b/src/lib/state/last-chat.svelte.ts
new file mode 100644
index 0000000..ecc0026
--- /dev/null
+++ b/src/lib/state/last-chat.svelte.ts
@@ -0,0 +1,23 @@
+import { Context } from 'runed';
+
+class LastChatState {
+	constructor(readonly opts: { lastChat: string | null }) {}
+
+	get current() {
+		return this.opts.lastChat;
+	}
+
+	set current(chat: string | null) {
+		this.opts.lastChat = chat;
+	}
+}
+
+const ctx = new Context<LastChatState>('last-chat');
+
+export function setupLastChat() {
+	return ctx.set(new LastChatState({ lastChat: null }));
+}
+
+export function useLastChat() {
+	return ctx.get();
+}
diff --git a/src/routes/+layout.svelte b/src/routes/+layout.svelte
index 3b3e5b5..67ccfde 100644
--- a/src/routes/+layout.svelte
+++ b/src/routes/+layout.svelte
@@ -10,11 +10,19 @@
 	import { browser } from '$app/environment';
 	import { MetaTags } from 'svelte-meta-tags';
 	import { page } from '$app/state';
+	import { setupLastChat } from '$lib/state/last-chat.svelte';
 
 	let { children } = $props();
 
 	setupConvex(PUBLIC_CONVEX_URL);
+	const lastChat = setupLastChat();
 	models.init();
+
+	$effect(() => {
+		if (page.url.pathname.startsWith('/chat')) {
+			lastChat.current = page.params?.id ?? null;
+		}
+	});
 </script>
 
 <MetaTags
diff --git a/src/routes/account/+layout.svelte b/src/routes/account/+layout.svelte
index b2bc56d..271a8ca 100644
--- a/src/routes/account/+layout.svelte
+++ b/src/routes/account/+layout.svelte
@@ -12,6 +12,7 @@
 	import { session } from '$lib/state/session.svelte.js';
 	import { api } from '$lib/backend/convex/_generated/api.js';
 	import { cn } from '$lib/utils/utils.js';
+	import { useLastChat } from '$lib/state/last-chat.svelte.js';
 
 	let { data, children } = $props();
 
@@ -71,11 +72,15 @@
 
 		await goto('/login');
 	}
+
+	const lastChat = useLastChat();
+
+	const backToChat = $derived(lastChat.current ? `/chat/${lastChat.current}` : '/chat');
 </script>
 
 <div class="container mx-auto max-w-[1200px] space-y-8 pt-6 pb-24">
 	<header class="flex place-items-center justify-between px-4">
-		<Button href="/chat" variant="ghost" class="flex place-items-center gap-2 text-sm">
+		<Button href={backToChat} variant="ghost" class="flex place-items-center gap-2 text-sm">
 			<ArrowLeftIcon class="size-4" />
 			Back to Chat
 		</Button>