import { createServerClient } from "@supabase/ssr";
import { NextResponse } from "next/server";

export async function GET(request) {
  const requestUrl = new URL(request.url);
  const code = requestUrl.searchParams.get("code");

  // Derive redirect origin from proxy-forwarded headers when present,
  // falling back to the direct request origin for local/direct access.
  const forwardedHost = request.headers.get("x-forwarded-host");
  const forwardedProto = request.headers.get("x-forwarded-proto");
  let origin;

  if (forwardedHost && forwardedProto) {
    // Nginx Proxy Manager (and similar proxies) set these headers.
    // x-forwarded-host may contain host:port or just hostname; use as-is.
    origin = `${forwardedProto}://${forwardedHost}`;
  } else {
    origin = requestUrl.origin;
  }

  const response = NextResponse.redirect(new URL("/", origin));

  if (code) {
    const supabase = createServerClient(
      process.env.NEXT_PUBLIC_SUPABASE_URL,
      process.env.NEXT_PUBLIC_SUPABASE_ANON_KEY,
      {
        cookies: {
          getAll: () => request.cookies.getAll(),
          setAll(cookiesToSet) {
            cookiesToSet.forEach(({ name, value, options }) => response.cookies.set(name, value, options));
          },
        },
      },
    );
    await supabase.auth.exchangeCodeForSession(code);
  }

  return response;
}