import static org.apache.commons.lang3.StringUtils.isBlank;

import java.util.Base64;

import javax.crypto.Cipher;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;

/**
 * Helper encryption function.
 */
public class EncryptUtils {

    private final static String KEY = "AWTyTh4cjqo5uMdXb0JHkj2q0xf719uE";
    private final static String ALGO = "AES/CBC/PKCS5Padding";

    public static String encrypt(String clearTxt) {
        if (isBlank(clearTxt)) {
            throw new IllegalArgumentException("Impossible to encrypt an empty string");
        }

        try {
            final SecretKeySpec secretKey = new SecretKeySpec(KEY.getBytes(), "AES");
            Cipher cipher = Cipher.getInstance(ALGO);
            cipher.init(Cipher.ENCRYPT_MODE, secretKey, new IvParameterSpec(new byte[16]));
            byte[] encrypted = cipher.doFinal(clearTxt.getBytes());
            return Base64.getEncoder().encodeToString(encrypted);
        } catch (Exception e) {
            throw new SecurityException("Something went wrong with the encrypt function...", e);
        }
    }

    public static String decrypt(String encryptedTxt) {
        if (isBlank(encryptedTxt)) {
            throw new IllegalArgumentException("Impossible to decrypt an empty string");
        }

        try {
            final SecretKeySpec secretKey = new SecretKeySpec(KEY.getBytes(), "AES");
            Cipher cipher = Cipher.getInstance(ALGO);
            cipher.init(Cipher.DECRYPT_MODE, secretKey, new IvParameterSpec(new byte[16]));
            byte[] decrypted = cipher.doFinal(Base64.getDecoder().decode(encryptedTxt));
            return new String(decrypted);
        } catch (Exception e) {
            throw new SecurityException("Something went wrong with the decrypt function...", e);
        }
    }
}