const crypto = require('crypto');
require('dotenv').config();

const algorithm = 'aes-256-cbc';
const secretKey = process.env.ENCRYPTION_KEY;

if (!secretKey || secretKey.length !== 64) {
    console.error('FATAL: ENCRYPTION_KEY must be exactly 64 hex characters (32 bytes).');
    process.exit(1);
}

const key = Buffer.from(secretKey, 'hex');

function encrypt(text) {
    const iv = crypto.randomBytes(16);
    const cipher = crypto.createCipheriv(algorithm, key, iv);
    let encrypted = cipher.update(text, 'utf8', 'hex');
    encrypted += cipher.final('hex');
    return {
        iv: iv.toString('hex'),
        encryptedData: encrypted
    };
}

function decrypt(encryptedData, ivHex) {
    const iv = Buffer.from(ivHex, 'hex');
    const decipher = crypto.createDecipheriv(algorithm, key, iv);
    let decrypted = decipher.update(encryptedData, 'hex', 'utf8');
    decrypted += decipher.final('utf8');
    return decrypted;
}

module.exports = { encrypt, decrypt };