const crypto = require('crypto');

// The encryption key must be exactly 32 bytes for AES-256
const getEncryptionKey = () => {
    const key = process.env.ENCRYPTION_KEY || 'default_secret_key_needs_32_bytes!';
    // Ensure it's 32 bytes by hashing it if it's not exactly 32 bytes
    if (key.length !== 32) {
        return crypto.createHash('sha256').update(key).digest();
    }
    return Buffer.from(key);
};

const algorithm = 'aes-256-cbc';

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

module.exports = { encrypt, decrypt };