firebase-admin.ts

import {
    initializeApp,
    getApps,
    App,
    getApp,
    cert,
} from "firebase-admin/app";

import { getFirestore } from "firebase-admin/firestore";

let app: App;

if(getApps().length === 0){
    // Use environment variables for Firebase Admin configuration
    const serviceAccount = {
        type: "service_account",
        project_id: process.env.FIREBASE_PROJECT_ID,
        private_key_id: process.env.FIREBASE_PRIVATE_KEY_ID,
        private_key: process.env.FIREBASE_PRIVATE_KEY?.replace(/\\n/g, '\n'),
        client_email: process.env.FIREBASE_CLIENT_EMAIL,
        client_id: process.env.FIREBASE_CLIENT_ID,
        auth_uri: "https://accounts.google.com/o/oauth2/auth",
        token_uri: "https://oauth2.googleapis.com/token",
        auth_provider_x509_cert_url: "https://www.googleapis.com/oauth2/v1/certs",
        client_x509_cert_url: process.env.FIREBASE_CLIENT_X509_CERT_URL,
    };

    app = initializeApp({
        credential: cert(serviceAccount as any),
    });
} else{
    app = getApp();
}

const adminDb = getFirestore(app);
export {app as adminApp, adminDb};