fix message reversing

src/providers/Runtime.tsx

@@ -1,13 +1,43 @@
-import { ReactNode } from "react";
+import { ReactNode, useEffect } from "react";
 import {
   useExternalStoreRuntime,
   AppendMessage,
   AssistantRuntimeProvider,
 } from "@assistant-ui/react";
-import { HumanMessage } from "@langchain/langgraph-sdk";
+import { HumanMessage, Message, ToolMessage } from "@langchain/langgraph-sdk";
 import { useStreamContext } from "./Stream";
 import { convertLangChainMessages } from "./convert-messages";
 
+function ensureToolCallsHaveResponses(messages: Message[]): Message[] {
+  const newMessages: ToolMessage[] = [];
+
+  messages.forEach((message, index) => {
+    if (message.type !== "ai" || message.tool_calls?.length === 0) {
+      // If it's not an AI message, or it doesn't have tool calls, we can ignore.
+      return;
+    }
+    // If it has tool calls, ensure the message which follows this is a tool message
+    const followingMessage = messages[index + 1];
+    if (followingMessage && followingMessage.type === "tool") {
+      // Following message is a tool message, so we can ignore.
+      return;
+    }
+
+    // Since the following message is not a tool message, we must create a new tool message
+    newMessages.push(
+      ...(message.tool_calls?.map((tc) => ({
+        type: "tool" as const,
+        tool_call_id: tc.id ?? "",
+        id: tc.id ?? "",
+        name: tc.name,
+        content: "Successfully handled tool call.",
+      })) ?? []),
+    );
+  });
+
+  return newMessages;
+}
+
 export function RuntimeProvider({
   children,
 }: Readonly<{
@@ -21,9 +51,20 @@ export function RuntimeProvider({
 
     const input = message.content[0].text;
     const humanMessage: HumanMessage = { type: "human", content: input };
-    stream.submit({ messages: [humanMessage] });
+    const newMessages = [
+      ...ensureToolCallsHaveResponses(stream.messages),
+      humanMessage,
+    ];
+    console.log("Sending new messages", newMessages);
+    stream.submit({
+      messages: newMessages,
+    });
   };
 
+  useEffect(() => {
+    console.log("useEffect - stream.messages", stream.messages);
+  }, [stream.messages]);
+
   const runtime = useExternalStoreRuntime({
     isRunning: stream.isLoading,
     messages: stream.messages,