import admin from 'firebase-admin';
import { FIREBASE_PROJECT_ID } from '../config.js';

// Service account JSON (raw or base64) in FIREBASE_SERVICE_ACCOUNT lets the generator write usage counts to Firestore.
// Without it the Admin SDK can still verify ID tokens, but Firestore writes fail outside Google Cloud.
function loadServiceAccount() {
    const raw = process.env.FIREBASE_SERVICE_ACCOUNT;
    if (!raw) return null;
    const json = raw.trim().startsWith('{') ? raw : Buffer.from(raw, 'base64').toString('utf8');
    return JSON.parse(json);
}

if (!admin.apps.length) {
    try {
        const serviceAccount = loadServiceAccount();
        admin.initializeApp({
            projectId: FIREBASE_PROJECT_ID,
            ...(serviceAccount && { credential: admin.credential.cert(serviceAccount) })
        });
        console.log(`[Firebase] Initialized generator for ${FIREBASE_PROJECT_ID} (${serviceAccount ? 'service account' : 'no service account: usage counting will fail'})`);
    } catch (err) {
        console.error('[Firebase] Init notice:', err.message);
    }
}

export { admin };