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

import NextAuth, { NextAuthOptions } from "next-auth";
import KeycloakProvider from "next-auth/providers/keycloak";

interface KeycloakProfile {
  sub: string;
  email?: string;
  name?: string;
  roles?: string[];
  preferred_username?: string;
  given_name?: string;
  family_name?: string;
}

declare module "next-auth" {
  interface Session {
    user: {
      id: string;
      name?: string | null;
      email?: string | null;
      image?: string | null;
      username: string;
      first_name: string;
      last_name: string;
      role: string[];
    };
    accessToken: string;
  }

  interface JWT {
    sub?: string;
    accessToken: string;
    refreshToken: string;
    accessTokenExpires: number;
    role: string[];
    username: string;
    first_name: string;
    last_name: string;
    error?: string;
  }
}

function getRequiredEnvVar(name: string): string {
  const value = process.env[name];
  if (!value) {
    throw new Error(`Missing required environment variable: ${name}`);
  }
  return value;
}

async function refreshAccessToken(token: JWT) {
  try {
    const response = await fetch(`${process.env.KEYCLOAK_ISSUER}/protocol/openid-connect/token`, {
      headers: { "Content-Type": "application/x-www-form-urlencoded" },
      body: new URLSearchParams({
        client_id: process.env.KEYCLOAK_CLIENT_ID!,
        client_secret: process.env.KEYCLOAK_CLIENT_SECRET!,
        grant_type: "refresh_token",
        refresh_token: token.refreshToken,
      }),
      method: "POST",
    });

    const refreshedTokens = await response.json();

    if (!response.ok) {
      throw refreshedTokens;
    }

    return {
      ...token,
      accessToken: refreshedTokens.access_token,
      refreshToken: refreshedTokens.refresh_token ?? token.refreshToken,
      accessTokenExpires: Date.now() + refreshedTokens.expires_in * 1000,
    };
  } catch (error) {
    console.error("Error refreshing access token:", error);
    return {
      ...token,
      error: "RefreshAccessTokenError",
    };
  }
}

export const authOptions: NextAuthOptions = {
  providers: [
    KeycloakProvider({
      clientId: getRequiredEnvVar("KEYCLOAK_CLIENT_ID"),
      clientSecret: getRequiredEnvVar("KEYCLOAK_CLIENT_SECRET"),
      issuer: getRequiredEnvVar("KEYCLOAK_ISSUER"),
      profile(profile) {
        return {
          id: profile.sub,
          name: profile.name ?? profile.preferred_username,
          email: profile.email,
          first_name: profile.given_name ?? '',
          last_name: profile.family_name ?? '',
          username: profile.preferred_username ?? profile.email?.split('@')[0] ?? '',
          role: profile.groups ?? [],
        }
      },
    }),
  ],
  session: {
    strategy: "jwt",
    maxAge: 30 * 24 * 60 * 60, // 30 days
  },
  callbacks: {
    async jwt({ token, account, profile }) {
      if (account && profile) {
        const keycloakProfile = profile as KeycloakProfile;
        token.accessToken = account.access_token ?? '';
        token.refreshToken = account.refresh_token ?? '';
        token.accessTokenExpires = account.expires_at ?? 0;
        token.sub = keycloakProfile.sub;
        token.role = keycloakProfile.roles ?? [];
        token.username = keycloakProfile.preferred_username ?? '';
        token.first_name = keycloakProfile.given_name ?? '';
        token.last_name = keycloakProfile.family_name ?? '';
      }

      if (Date.now() < (token.accessTokenExpires as number) * 1000) {
        return token;
      }

      return refreshAccessToken(token);
    },
    async session({ session, token }) {
      if (token.error) {
        throw new Error(token.error);
      }

      session.user = {
        id: token.sub ?? '',
        email: token.email ?? null,
        name: token.name ?? null,
        image: null,
        username: token.username ?? '',
        first_name: token.first_name ?? '',
        last_name: token.last_name ?? '',
        role: token.role ?? [],
      };
      session.accessToken = token.accessToken;

      return session;
    }
  },
  pages: {
    signIn: '/signin',
    error: '/signin',
  },
  debug: process.env.NODE_ENV === 'development',
};

const handler = NextAuth(authOptions);
export { handler as GET, handler as POST };

interface JWT {
  accessToken: string;
  refreshToken: string;
  accessTokenExpires: number;
}

interface Profile {
  sub?: string;
  email?: string;
  name?: string;
  roles?: string[];
}