Add ability to return to older chat message state

app/lib/persistence/useChatHistory.ts

@@ -1,4 +1,4 @@
-import { useLoaderData, useNavigate } from '@remix-run/react';
+import { useLoaderData, useNavigate, useSearchParams } from '@remix-run/react';
 import { useState, useEffect } from 'react';
 import { atom } from 'nanostores';
 import type { Message } from 'ai';
@@ -24,6 +24,7 @@ export const description = atom<string | undefined>(undefined);
 export function useChatHistory() {
   const navigate = useNavigate();
   const { id: mixedId } = useLoaderData<{ id?: string }>();
+  const [searchParams] = useSearchParams();
 
   const [initialMessages, setInitialMessages] = useState<Message[]>([]);
   const [ready, setReady] = useState<boolean>(false);
@@ -44,7 +45,13 @@ export function useChatHistory() {
       getMessages(db, mixedId)
         .then((storedMessages) => {
           if (storedMessages && storedMessages.messages.length > 0) {
-            setInitialMessages(storedMessages.messages);
+            const rewindId = searchParams.get('rewindId');
+            const filteredMessages = rewindId 
+              ? storedMessages.messages.slice(0, 
+                  storedMessages.messages.findIndex(m => m.id === rewindId) + 1)
+              : storedMessages.messages;
+            
+            setInitialMessages(filteredMessages);
             setUrlId(storedMessages.urlId);
             description.set(storedMessages.description);
             chatId.set(storedMessages.id);