"""
    Lilliput TBC
"""
from constants import BLOCK_BYTES, Sbox
import multiplications

KEY_BITS = 128
TWEAK_BITS = 192
LANE_BITS = 64
LANE_BYTES = LANE_BITS / 8
LANES = int((TWEAK_BITS+KEY_BITS) / LANE_BITS)

TWEAKEY_BITS = KEY_BITS + TWEAK_BITS
KEY_BYTES = int(KEY_BITS / 8)
TWEAK_BYTES = int(TWEAK_BITS / 8)
TWEAKEY_BYTES = int(TWEAKEY_BITS / 8)

MultiplyM = multiplications.MultiplyM
MultiplyM2 = multiplications.MultiplyM2
MultiplyM3 = multiplications.MultiplyM3
MultiplyMR = multiplications.MultiplyMR
MultiplyMR2 = multiplications.MultiplyMR2
MultiplyMR3 = multiplications.MultiplyMR3

permutation = [14, 11, 12, 10, 8, 9, 13, 15, 3, 1, 4, 5, 6, 0, 2, 7]
permutationInv = [13, 9, 14, 8, 10, 11, 12, 15, 4, 5, 3, 1, 2, 6 ,0 ,7]

################################################################################

def BuildTweakey(tweak, key) :

    tweakey = [0 for byte in range(0, TWEAKEY_BYTES)]
    for byte in range(0, TWEAK_BYTES) :
        tweakey[byte] = tweak[byte]

    for byte in range(0, KEY_BYTES) :
        tweakey[byte + TWEAK_BYTES] = key[byte]

    return tweakey

#############################

def RoundTweakeySchedule(tweakey) :

    # Multiplication
    lanes = [tweakey[word * 8:(word+1) * 8] for word in range(0, LANES)]
    tweakey_multiplied = []
    for word in range(0, LANES) :
        if word == 0 :
            tweakey_multiplied += list(lanes[0])
        elif word == 1 :
            tweakey_multiplied += MultiplyM(lanes[1])
        elif word == 2 :
            tweakey_multiplied += MultiplyM2(lanes[2])
        elif word == 3 :
            tweakey_multiplied += MultiplyM3(lanes[3])
        elif word == 4 :
            tweakey_multiplied += MultiplyMR(lanes[4])
        elif word == 5 :
            tweakey_multiplied += MultiplyMR2(lanes[5])
        elif word == 6 :
            tweakey_multiplied += MultiplyMR3(lanes[6])

    return tweakey_multiplied ;


def SubTweakeyExtract(tweakey, Ci):
    subtweakey = [0 for byte in range(0, 8)]

    for byte in range(0, TWEAKEY_BYTES) :
        subtweakey[byte % 8] ^= tweakey[byte]

    subtweakey[0] ^= Ci

    return subtweakey


def TweakeyScheduleWhole(tweakey, r):
    # store main tweakey in TKs[0]
    # and corresponding RTKs[0]
    TKs = [tweakey]
    RTKs = [SubTweakeyExtract(TKs[0], 0)]

    for i in range(1, r) :
        TKs.append(RoundTweakeySchedule(TKs[i-1]))
        RTKs.append(SubTweakeyExtract(TKs[i], i))

    return RTKs


################################################################################

def NonLinearLayer(state, subtweakey) :

    variables_xored = [0 for byte in range(0, 8)]
    for byte in range(0,8) :
        variables_xored[byte] = state[byte] ^ subtweakey[byte]

    variables_sboxed = [0 for byte in range(0, 8)]
    for byte in range(0, 8) :
        variables_sboxed[byte] = Sbox[variables_xored[byte]]

    state_output = [0 for byte in range(0, BLOCK_BYTES)]
    for byte in range(0,BLOCK_BYTES) :
        state_output[byte] = state[byte]
    for byte in range(0, 8) :
        state_output[15 - byte] ^= variables_sboxed[byte]

    return state_output


def LinearLayer(state) :
    state_output = [0 for byte in range(0, BLOCK_BYTES)]
    for byte in range(0, BLOCK_BYTES) :
        state_output[byte] = state[byte]

    for byte in range(1, 8) :
        state_output[15] ^= state[byte]

    for byte in range(9, 15) :
        state_output[byte] ^= state[7]

    return state_output


def PermutationLayerEnc(state) :
    state_output = [0 for byte in range(0, BLOCK_BYTES)]
    for byte in range(0, BLOCK_BYTES) :
        state_output[byte] = state[permutation[byte]]

    return state_output

def PermutationLayerDec(state) :
    state_output = [0 for byte in range(0, BLOCK_BYTES)]
    for byte in range(0, BLOCK_BYTES) :
        state_output[byte] = state[permutationInv[byte]]

    return state_output


def OneRoundEGFNEnc(state, subtweakey) :
    state_non_linear = NonLinearLayer(state, subtweakey)
    state_linear = LinearLayer(state_non_linear)
    state_permutation = PermutationLayerEnc(state_linear)

    return state_permutation

def LastRoundEGFN(state, subtweakey) :
    state_non_linear = NonLinearLayer(state, subtweakey)
    state_linear = LinearLayer(state_non_linear)

    return state_linear


def OneRoundEGFNDec(state, subtweakey) :
    state_non_linear = NonLinearLayer(state, subtweakey)
    state_linear = LinearLayer(state_non_linear)
    state_permutation = PermutationLayerDec(state_linear)

    return state_permutation


def _rounds(key_bytes):
    rounds = {
        128: 32,
        192: 36,
        256: 42
    }
    return rounds[key_bytes*8]


################################################################################
# Lilliput TBC

def LilliputTBCEnc(tweak, key, message) :
    r = _rounds(len(key))

    tweakey = BuildTweakey(tweak, key)
    RTKs = TweakeyScheduleWhole(tweakey, r)

    state = [0 for byte in range(0, BLOCK_BYTES)]
    for byte in range(0, BLOCK_BYTES) :
        state[byte] = message[byte]

    for i in range(0, r-1) :
        state_output = OneRoundEGFNEnc(state, RTKs[i])

        for byte in range(0, BLOCK_BYTES) :
            state[byte] = state_output[byte]

    state_output = LastRoundEGFN(state, RTKs[r-1])

    return state_output


def LilliputTBCDec(tweak, key, cipher) :
    r = _rounds(len(key))

    tweakey = BuildTweakey(tweak, key)
    RTKs = TweakeyScheduleWhole(tweakey, r)

    state = [0 for byte in range(0, BLOCK_BYTES)]
    for byte in range(0, BLOCK_BYTES) :
        state[byte] = cipher[byte]

    for i in range(0, r-1) :
        state_output = OneRoundEGFNDec(state, RTKs[r-i-1])

        for byte in range(0, BLOCK_BYTES) :
            state[byte] = state_output[byte]

    state_output = LastRoundEGFN(state, RTKs[0])

    return state_output