frontend/src/app/api/auth/[...nextauth]/route.ts

import NextAuth, { type NextAuthOptions } from "next-auth";
import GoogleProvider from "next-auth/providers/google";

const apiBase = process.env.NEXT_PUBLIC_API_BASE_URL ?? "http://127.0.0.1:8000";
const googleClientId = process.env.GOOGLE_CLIENT_ID ?? "";
const googleClientSecret = process.env.GOOGLE_CLIENT_SECRET ?? "";

export const authOptions: NextAuthOptions = {
  providers:
    googleClientId && googleClientSecret
      ? [
          GoogleProvider({
            clientId: googleClientId,
            clientSecret: googleClientSecret,
          }),
        ]
      : [],
  session: { strategy: "jwt" as const },
  callbacks: {
    async signIn({ account }) {
      if (account?.provider === "google" && account.id_token) {
        try {
          const response = await fetch(`${apiBase}/auth/google`, {
            method: "POST",
            headers: { "Content-Type": "application/json" },
            body: JSON.stringify({ id_token: account.id_token }),
          });
          if (!response.ok) {
            console.error("Google verification failed", await response.text());
            return false;
          }
          const payload = await response.json();
          const enrichedAccount = account as Record<string, unknown>;
          enrichedAccount.userId = payload.user_id;
          enrichedAccount.userEmail = payload.email;
          enrichedAccount.userName = payload.display_name;
        } catch (error) {
          console.error("Google auth request failed", error);
          return false;
        }
      }
      return true;
    },
    async jwt({ token, account }) {
      if (account) {
        const enrichedAccount = account as Record<string, unknown>;
        token.userId = (enrichedAccount.userId as string | undefined) ?? token.userId;
        token.email = (enrichedAccount.userEmail as string | undefined) ?? token.email;
        token.name = (enrichedAccount.userName as string | undefined) ?? token.name;
      }
      return token;
    },
    async session({ session, token }) {
      if (session.user) {
        session.user.id = token.userId;
      }
      return session;
    },
  },
  pages: {
    signIn: "/",
  },
  secret: process.env.NEXTAUTH_SECRET,
};

const handler = NextAuth(authOptions);

export { handler as GET, handler as POST };