disable if not all are present

frontend/app/components/Primitives.tsx

@@ -97,6 +97,7 @@ const MyThreadScrollToBottom: FC = () => {
 
 interface MyComposerProps {
   messages: BaseMessage[];
+  submitDisabled: boolean;
 }
 
 const MyComposer: FC<MyComposerProps> = (props: MyComposerProps) => {
@@ -117,7 +118,7 @@ const MyComposer: FC<MyComposerProps> = (props: MyComposerProps) => {
         className="placeholder:text-gray-400 text-gray-100 max-h-40 flex-1 resize-none border-none bg-transparent px-2 py-2 text-sm outline-none focus:ring-0 disabled:cursor-not-allowed"
       />
       <div className="flex-shrink-0">
-        <ThreadPrimitive.If running={false}>
+        <ThreadPrimitive.If running={false} disabled={props.submitDisabled}>
           <ComposerPrimitive.Send asChild>
             <TooltipIconButton
               tooltip="Send"

frontend/app/hooks/useGraph.tsx

@@ -6,7 +6,7 @@ import { v4 as uuidv4 } from "uuid";
 
 import { Client } from "@langchain/langgraph-sdk";
 import { getCookie, setCookie } from "../utils/cookies";
-import { ThreadActual } from "./useThreads";
+import { ThreadActual, useThreads } from "./useThreads";
 
 export const createClient = () => {
   const apiUrl = process.env.NEXT_PUBLIC_API_URL ?? "http://localhost:3000/api";
@@ -53,20 +53,41 @@ export interface GraphInput {
 
 export function useGraph(userId: string | undefined) {
   const { toast } = useToast();
+  const { getThreadById } = useThreads(userId);
   const [messages, setMessages] = useState<BaseMessage[]>([]);
   const [assistantId, setAssistantId] = useState<string>();
   const [threadId, setThreadId] = useState<string>();
 
   useEffect(() => {
     if (threadId || typeof window === "undefined" || !userId) return;
-    createThread(userId);
+    searchOrCreateThread(userId);
   }, [userId]);
 
   useEffect(() => {
     if (assistantId || typeof window === "undefined") return;
     getOrCreateAssistant();
   }, []);
 
+  const searchOrCreateThread = async (id: string) => {
+    const threadIdCookie = getCookie("clc_py_thread_id");
+    if (!threadIdCookie) {
+      await createThread(id);
+      return;
+    }
+    // Thread ID is in cookies.
+
+    const thread = await getThreadById(threadIdCookie);
+    if (!thread.values) {
+      // No values = no activity. Can keep.
+      setThreadId(threadIdCookie);
+      return;
+    } else {
+      // Current thread has activity. Create a new thread.
+      await createThread(id);
+      return;
+    }
+  };
+
   const createThread = async (id: string) => {
     setMessages([]);
     const client = createClient();
@@ -81,6 +102,7 @@ export function useGraph(userId: string | undefined) {
         throw new Error("Thread creation failed.");
       }
       setThreadId(thread.thread_id);
+      setCookie("clc_py_thread_id", thread.thread_id);
     } catch (e) {
       console.error("Error creating thread", e);
       toast({

frontend/app/hooks/useThreads.tsx

@@ -43,7 +43,13 @@ export function useThreads(userId: string | undefined) {
     }
   };
 
+  const getThreadById = async (id: string) => {
+    const client = createClient();
+    return (await client.threads.get(id)) as Awaited<ThreadActual>;
+  };
+
   return {
     userThreads,
+    getThreadById,
   };
 }

frontend/app/new/page.tsx

@@ -19,8 +19,10 @@ import { useGraph } from "../hooks/useGraph";
 import { ThreadHistory } from "../components/ThreadHistory";
 import { useUser } from "../hooks/useUser";
 import { useThreads } from "../hooks/useThreads";
+import { useToast } from "../hooks/use-toast";
 
 export default function ContentComposerChatInterface(): React.ReactElement {
+  const { toast } = useToast();
   const { userId } = useUser();
   const {
     messages,
@@ -34,7 +36,25 @@ export default function ContentComposerChatInterface(): React.ReactElement {
   const { userThreads } = useThreads(userId);
   const [isRunning, setIsRunning] = useState(false);
 
+  const isSubmitDisabled = !userId || !assistantId || !currentThread;
+
   async function onNew(message: AppendMessage): Promise<void> {
+    if (isSubmitDisabled) {
+      let description = "";
+      if (!userId) {
+        description = "Unable to find user ID. Please try again later.";
+      } else if (!assistantId) {
+        description = "Unable to find assistant ID. Please try again later.";
+      } else if (!currentThread) {
+        description =
+          "Unable to find current thread ID. Please try again later.";
+      }
+      toast({
+        title: "Failed to send message",
+        description,
+      });
+      return;
+    }
     if (message.content[0]?.type !== "text") {
       throw new Error("Only text messages are supported");
     }
@@ -83,7 +103,7 @@ export default function ContentComposerChatInterface(): React.ReactElement {
       </div>
       <div className="w-full h-full overflow-hidden">
         <AssistantRuntimeProvider runtime={runtime}>
-          <MyThread messages={messages} />
+          <MyThread submitDisabled={isSubmitDisabled} messages={messages} />
         </AssistantRuntimeProvider>
       </div>
       <Toaster />