from enum import Enum

import lilliput_ae_1
import lilliput_ae_2
from constants import NONCE_BYTES


class LilliputAeMode(Enum):
    lilliput_1 = lilliput_ae_1
    lilliput_2 = lilliput_ae_2


def _checkInputs(key, mode, nonce):
    valid_key_lengths = (128, 192, 256)

    if len(key)*8 not in valid_key_lengths:
        raise ValueError('invalid key size: {} not in {}'.format(len(key)*8, valid_key_lengths))

    if mode.name not in LilliputAeMode.__members__:
        raise ValueError('invalid mode: use a member of the LilliputAeMode enumeration')

    if len(nonce) != NONCE_BYTES:
        raise ValueError('nonce must be {}-byte long'.format(NONCE_BYTES))


def encrypt(plaintext, adata, key, nonce, mode):
    _checkInputs(key, mode, nonce)
    return mode.value.encrypt(adata, plaintext, nonce, key)


def decrypt(ciphertext, tag, adata, key, nonce, mode):
    _checkInputs(key, mode, nonce)
    return mode.value.decrypt(adata, ciphertext, nonce, tag, key)