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

import NextAuth from 'next-auth';
import Okta from 'next-auth/providers/okta';

// Okta環境変数が全て設定されているかチェック
const hasOktaConfig = process.env.OKTA_OAUTH2_ISSUER && process.env.OKTA_OAUTH2_CLIENT_ID && process.env.OKTA_OAUTH2_CLIENT_SECRET;

const authOptions = {
  providers: hasOktaConfig
    ? [
        Okta({
          clientId: process.env.OKTA_OAUTH2_CLIENT_ID as string,
          clientSecret: process.env.OKTA_OAUTH2_CLIENT_SECRET as string,
          issuer: process.env.OKTA_OAUTH2_ISSUER as string,
        }),
      ]
    : [],
  secret: process.env.SECRET as string,
};

const handler = NextAuth(authOptions);

export { handler as GET, handler as POST };