import { NextResponse } from "next/server";
import { getToken } from "next-auth/jwt";
import { signIn } from "@/app/(auth)/auth";
import { isDevelopmentEnvironment } from "@/lib/constants";

export async function GET(request: Request) {
  const requestUrl = new URL(request.url);
  const { searchParams } = requestUrl;
  const redirectUrl = searchParams.get("redirectUrl") || "/";

  const token = await getToken({
    req: request,
    secret: process.env.AUTH_SECRET,
    secureCookie: !isDevelopmentEnvironment,
  });

  if (token) {
    const baseUrl = process.env.AUTH_URL || requestUrl.origin;
    return NextResponse.redirect(new URL("/", baseUrl));
  }

  const baseUrl = process.env.AUTH_URL || requestUrl.origin;

  // 规范化 redirectUrl：
  // 1. 无论是相对路径还是带 localhost 的绝对地址，
  // 2. 最终都转换为以 AUTH_URL/baseUrl 为 origin 的完整 URL，保证端口正确。
  let finalRedirectUrl = `${baseUrl}/`;
  try {
    const candidate = new URL(redirectUrl, baseUrl);
    // 只保留路径和查询参数，强制使用外网域名和端口
    const normalized = new URL(
      `${candidate.pathname}${candidate.search}${candidate.hash}`,
      baseUrl,
    );
    finalRedirectUrl = normalized.toString();
  } catch {
    // ignore, 使用默认的 baseUrl
  }

  return signIn("guest", { redirect: true, redirectTo: finalRedirectUrl });
}