feat: add reasoning model (#750)

Co-authored-by: Matt Apperson <me@mattapperson.com>

app/(chat)/chat/[id]/page.tsx

@@ -3,10 +3,10 @@ import { notFound } from 'next/navigation';
 
 import { auth } from '@/app/(auth)/auth';
 import { Chat } from '@/components/chat';
-import { DEFAULT_MODEL_NAME, models } from '@/lib/ai/models';
 import { getChatById, getMessagesByChatId } from '@/lib/db/queries';
 import { convertToUIMessages } from '@/lib/utils';
 import { DataStreamHandler } from '@/components/data-stream-handler';
+import { DEFAULT_CHAT_MODEL } from '@/lib/ai/models';
 
 export default async function Page(props: { params: Promise<{ id: string }> }) {
   const params = await props.params;
@@ -34,17 +34,29 @@ export default async function Page(props: { params: Promise<{ id: string }> }) {
   });
 
   const cookieStore = await cookies();
-  const modelIdFromCookie = cookieStore.get('model-id')?.value;
-  const selectedModelId =
-    models.find((model) => model.id === modelIdFromCookie)?.id ||
-    DEFAULT_MODEL_NAME;
+  const chatModelFromCookie = cookieStore.get('chat-model');
+
+  if (!chatModelFromCookie) {
+    return (
+      <>
+        <Chat
+          id={chat.id}
+          initialMessages={convertToUIMessages(messagesFromDb)}
+          selectedChatModel={DEFAULT_CHAT_MODEL}
+          selectedVisibilityType={chat.visibility}
+          isReadonly={session?.user?.id !== chat.userId}
+        />
+        <DataStreamHandler id={id} />
+      </>
+    );
+  }
 
   return (
     <>
       <Chat
         id={chat.id}
         initialMessages={convertToUIMessages(messagesFromDb)}
-        selectedModelId={selectedModelId}
+        selectedChatModel={chatModelFromCookie.value}
         selectedVisibilityType={chat.visibility}
         isReadonly={session?.user?.id !== chat.userId}
       />