frontend/src/app/api/upload/route.ts

import { NextRequest } from "next/server";

export const runtime = "nodejs";

export async function POST(request: NextRequest) {
  const backendBaseUrl = process.env.BACKEND_URL ?? "http://127.0.0.1:7860";
  const formData = await request.formData();
  const sessionId = request.nextUrl.searchParams.get("session_id") ?? "";

  const targetUrl = sessionId
    ? `${backendBaseUrl}/api/upload?session_id=${encodeURIComponent(sessionId)}`
    : `${backendBaseUrl}/api/upload`;

  const upstream = await fetch(targetUrl, {
    method: "POST",
    body: formData,
    cache: "no-store"
  });

  const payload = await upstream.text();
  return new Response(payload, {
    status: upstream.status,
    headers: {
      "Content-Type": upstream.headers.get("content-type") ?? "application/json"
    }
  });
}