import lilliput_ae_1
import lilliput_ae_2


N_BYTES = 15


def _checkInputs(key, 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 len(nonce) != N_BYTES:
        raise ValueError('nonce must be {}-byte long'.format(N_BYTES))


def mainEnc(plaintext, adata, key, nonce, mode):
    _checkInputs(key, nonce)

    A = adata
    M = plaintext
    N = nonce

    if(mode == 1) :
        return lilliput_ae_1.OCB3Enc(A, M, N, key)
    if(mode == 2) :
        return lilliput_ae_2.SCT2Enc(A, M, N, key)


def mainDec(ciphertext, tag, adata, key, nonce, mode):
    _checkInputs(key, nonce)

    A = adata
    C = ciphertext
    N = nonce
    tag = list(tag)

    if(mode == 1) :
        return lilliput_ae_1.OCB3Dec(A, C, N, tag, key)
    if(mode == 2) :
        return lilliput_ae_2.SCT2Dec(A, C, N, tag, key)