v4.0: Fix /api/chat — call Gradio Space chatbot endpoint

web/app/api/chat/route.ts

@@ -1,36 +1,68 @@
 import { NextRequest, NextResponse } from "next/server";
 
-const API_URL = process.env.CLAUSEGUARD_API_URL || "https://gaurv007-clauseguard-api.hf.space";
+const GRADIO_URL = process.env.CLAUSEGUARD_GRADIO_URL || "https://gaurv007-clauseguard.hf.space";
 
 export async function POST(req: NextRequest) {
   try {
     const body = await req.json();
-    const { message, session_id, history } = body;
+    const { message, history } = body;
 
-    if (!message || !session_id) {
+    if (!message) {
       return NextResponse.json(
-        { error: "message and session_id are required" },
+        { error: "message is required" },
         { status: 400 }
       );
     }
 
-    const response = await fetch(`${API_URL}/api/chat`, {
+    // The Gradio ChatInterface endpoint is /chat
+    // It accepts: message (str), then the additional_inputs are handled by Gradio state
+    // We need to call the Gradio API with the message
+    const submitRes = await fetch(`${GRADIO_URL}/gradio_api/call/chat`, {
       method: "POST",
       headers: { "Content-Type": "application/json" },
-      body: JSON.stringify({ message, session_id, history: history || [] }),
+      body: JSON.stringify({ data: [message] }),
     });
 
-    if (!response.ok) {
-      const err = await response.text().catch(() => "");
-      throw new Error(err || `Backend error: ${response.status}`);
+    if (!submitRes.ok) {
+      const errText = await submitRes.text().catch(() => "");
+      throw new Error(`Chat submit failed (${submitRes.status}): ${errText}`);
     }
 
-    const result = await response.json();
-    return NextResponse.json(result);
+    const { event_id } = await submitRes.json();
+    if (!event_id) throw new Error("No event_id from Gradio chat");
+
+    // Poll for streaming result
+    const resultRes = await fetch(
+      `${GRADIO_URL}/gradio_api/call/chat/${event_id}`,
+      { headers: { Accept: "text/event-stream" } }
+    );
+
+    if (!resultRes.ok) {
+      throw new Error(`Chat result failed: ${resultRes.status}`);
+    }
+
+    const resultText = await resultRes.text();
+
+    // Find the complete event data
+    const dataMatch = resultText.match(/event:\s*complete\s*\ndata:\s*(.+)/);
+    if (!dataMatch) {
+      // Check for error
+      const errMatch = resultText.match(/event:\s*error\s*\ndata:\s*(.+)/);
+      if (errMatch) {
+        throw new Error(`Chat error: ${errMatch[1]}`);
+      }
+      throw new Error("No response from chatbot. Analyze a contract first in the Gradio Space, then try chatting.");
+    }
+
+    const responseData = JSON.parse(dataMatch[1]);
+    // The ChatInterface returns the response as a string
+    const responseText = typeof responseData === "string" ? responseData : responseData[0] || "";
+
+    return NextResponse.json({ response: responseText });
   } catch (error: any) {
     console.error("Chat error:", error.message);
     return NextResponse.json(
-      { error: error.message || "Chat failed. Try again." },
+      { error: error.message || "Chat failed. Make sure you analyzed a contract in the Gradio Space first." },
       { status: 500 }
     );
   }