export const runtime = "nodejs";

import { NextResponse } from "next/server";

/**
 * Proxies multipart POSTs (file + method) to the bgbye upstream.
 * Set BG_BYE_UPSTREAM to the FULL endpoint that accepts the form:
 *   e.g. http://127.0.0.1:8010/process
 *        http://localhost:8010/api/removebg
 */
export async function POST(req: Request) {
    const upstream = process.env.BG_BYE_UPSTREAM;
    if (!upstream) {
        return NextResponse.json(
            { error: "BG_BYE_UPSTREAM is not configured on the server" },
            { status: 500 }
        );
    }

    try {
        const form = await req.formData();

        // Forward the form as-is to the upstream
        const ures = await fetch(upstream, {
            method: "POST",
            body: form,
            // Let undici set boundary; don't set Content-Type manually
        });

        const contentType = ures.headers.get("content-type") || "application/octet-stream";
        const status = ures.status;

        // Stream/buffer back to the client preserving content-type
        const ab = await ures.arrayBuffer();
        return new Response(Buffer.from(ab), {
            status,
            headers: {
                "content-type": contentType,
                // Allow the client to see error text if upstream returns text
                "cache-control": "no-store",
            },
        });
    } catch (err: any) {
        const msg = err?.message || String(err);
        return NextResponse.json({ error: `Proxy error: ${msg}` }, { status: 502 });
    }
}