# -*- coding: utf-8 -*-
__all__ = ['aes_encrypt', 'key_expansion', 'aes_ctr_decrypt', 'aes_cbc_decrypt', 'aes_decrypt_text']

import base64
from math import ceil

#from .utils import bytes_to_intlist, intlist_to_bytes
def bytes_to_intlist(bs):
	if not bs:
		return []
	if isinstance(bs[0], int): # Python 3
		return list(bs)
	else:
		return [ord(c) for c in bs]

def intlist_to_bytes(xs):
	if not xs:
		return b''
	if isinstance(chr(0), bytes): # Python 2
		return ''.join([chr(x) for x in xs])
	else:
		return bytes(xs)

BLOCK_SIZE_BYTES = 16

def aes_ctr_decrypt(data, key, counter):
	"""
	Decrypt with aes in counter mode

	@param {int[]} data		cipher
	@param {int[]} key		 16/24/32-Byte cipher key
	@param {instance} counter  Instance whose next_value function (@returns {int[]}  16-Byte block)
							   returns the next counter block
	@returns {int[]}		   decrypted data
	"""
	expanded_key = key_expansion(key)
	block_count = int(ceil(float(len(data)) / BLOCK_SIZE_BYTES))

	decrypted_data=[]
	for i in range(block_count):
		counter_block = counter.next_value()
		block = data[i*BLOCK_SIZE_BYTES : (i+1)*BLOCK_SIZE_BYTES]
		block += [0]*(BLOCK_SIZE_BYTES - len(block))

		cipher_counter_block = aes_encrypt(counter_block, expanded_key)
		decrypted_data += xor(block, cipher_counter_block)
	decrypted_data = decrypted_data[:len(data)]

	return decrypted_data

def aes_cbc_decrypt(data, key, iv):
	"""
	Decrypt with aes in CBC mode

	@param {int[]} data		cipher
	@param {int[]} key		 16/24/32-Byte cipher key
	@param {int[]} iv		  16-Byte IV
	@returns {int[]}		   decrypted data
	"""
	expanded_key = key_expansion(key)
	block_count = int(ceil(float(len(data)) / BLOCK_SIZE_BYTES))

	decrypted_data=[]
	previous_cipher_block = iv
	for i in range(block_count):
		block = data[i*BLOCK_SIZE_BYTES : (i+1)*BLOCK_SIZE_BYTES]
		block += [0]*(BLOCK_SIZE_BYTES - len(block))

		decrypted_block = aes_decrypt(block, expanded_key)
		decrypted_data += xor(decrypted_block, previous_cipher_block)
		previous_cipher_block = block
	decrypted_data = decrypted_data[:len(data)]

	return decrypted_data

def key_expansion(data):
	"""
	Generate key schedule

	@param {int[]} data  16/24/32-Byte cipher key
	@returns {int[]}	 176/208/240-Byte expanded key
	"""
	data = data[:] # copy
	rcon_iteration = 1
	key_size_bytes = len(data)
	expanded_key_size_bytes = (key_size_bytes // 4 + 7) * BLOCK_SIZE_BYTES

	while len(data) < expanded_key_size_bytes:
		temp = data[-4:]
		temp = key_schedule_core(temp, rcon_iteration)
		rcon_iteration += 1
		data += xor(temp, data[-key_size_bytes : 4-key_size_bytes])

		for _ in range(3):
			temp = data[-4:]
			data += xor(temp, data[-key_size_bytes : 4-key_size_bytes])

		if key_size_bytes == 32:
			temp = data[-4:]
			temp = sub_bytes(temp)
			data += xor(temp, data[-key_size_bytes : 4-key_size_bytes])

		for _ in range(3 if key_size_bytes == 32  else 2 if key_size_bytes == 24 else 0):
			temp = data[-4:]
			data += xor(temp, data[-key_size_bytes : 4-key_size_bytes])
	data = data[:expanded_key_size_bytes]

	return data

def aes_encrypt(data, expanded_key):
	"""
	Encrypt one block with aes

	@param {int[]} data		  16-Byte state
	@param {int[]} expanded_key  176/208/240-Byte expanded key
	@returns {int[]}			 16-Byte cipher
	"""
	rounds = len(expanded_key) // BLOCK_SIZE_BYTES - 1

	data = xor(data, expanded_key[:BLOCK_SIZE_BYTES])
	for i in range(1, rounds+1):
		data = sub_bytes(data)
		data = shift_rows(data)
		if i != rounds:
			data = mix_columns(data)
		data = xor(data, expanded_key[i*BLOCK_SIZE_BYTES : (i+1)*BLOCK_SIZE_BYTES])

	return data

def aes_decrypt(data, expanded_key):
	"""
	Decrypt one block with aes

	@param {int[]} data		  16-Byte cipher
	@param {int[]} expanded_key  176/208/240-Byte expanded key
	@returns {int[]}			 16-Byte state
	"""
	rounds = len(expanded_key) // BLOCK_SIZE_BYTES - 1

	for i in range(rounds, 0, -1):
		data = xor(data, expanded_key[i*BLOCK_SIZE_BYTES : (i+1)*BLOCK_SIZE_BYTES])
		if i != rounds:
			data = mix_columns_inv(data)
		data = shift_rows_inv(data)
		data = sub_bytes_inv(data)
	data = xor(data, expanded_key[:BLOCK_SIZE_BYTES])

	return data

def aes_decrypt_text(data, password, key_size_bytes):
	"""
	Decrypt text
	- The first 8 Bytes of decoded 'data' are the 8 high Bytes of the counter
	- The cipher key is retrieved by encrypting the first 16 Byte of 'password'
	  with the first 'key_size_bytes' Bytes from 'password' (if necessary filled with 0's)
	- Mode of operation is 'counter'

	@param {str} data					Base64 encoded string
	@param {str,unicode} password		Password (will be encoded with utf-8)
	@param {int} key_size_bytes		  Possible values: 16 for 128-Bit, 24 for 192-Bit or 32 for 256-Bit
	@returns {str}					   Decrypted data
	"""
	NONCE_LENGTH_BYTES = 8

	data = bytes_to_intlist(base64.b64decode(data))
	password = bytes_to_intlist(password.encode('utf-8'))

	key = password[:key_size_bytes] + [0]*(key_size_bytes - len(password))
	key = aes_encrypt(key[:BLOCK_SIZE_BYTES], key_expansion(key)) * (key_size_bytes // BLOCK_SIZE_BYTES)

	nonce = data[:NONCE_LENGTH_BYTES]
	cipher = data[NONCE_LENGTH_BYTES:]

	class Counter:
		__value = nonce + [0]*(BLOCK_SIZE_BYTES - NONCE_LENGTH_BYTES)
		def next_value(self):
			temp = self.__value
			self.__value = inc(self.__value)
			return temp

	decrypted_data = aes_ctr_decrypt(cipher, key, Counter())
	plaintext = intlist_to_bytes(decrypted_data)

	return plaintext

RCON = (0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36)
SBOX = (0x63, 0x7C, 0x77, 0x7B, 0xF2, 0x6B, 0x6F, 0xC5, 0x30, 0x01, 0x67, 0x2B, 0xFE, 0xD7, 0xAB, 0x76,
		0xCA, 0x82, 0xC9, 0x7D, 0xFA, 0x59, 0x47, 0xF0, 0xAD, 0xD4, 0xA2, 0xAF, 0x9C, 0xA4, 0x72, 0xC0,
		0xB7, 0xFD, 0x93, 0x26, 0x36, 0x3F, 0xF7, 0xCC, 0x34, 0xA5, 0xE5, 0xF1, 0x71, 0xD8, 0x31, 0x15,
		0x04, 0xC7, 0x23, 0xC3, 0x18, 0x96, 0x05, 0x9A, 0x07, 0x12, 0x80, 0xE2, 0xEB, 0x27, 0xB2, 0x75,
		0x09, 0x83, 0x2C, 0x1A, 0x1B, 0x6E, 0x5A, 0xA0, 0x52, 0x3B, 0xD6, 0xB3, 0x29, 0xE3, 0x2F, 0x84,
		0x53, 0xD1, 0x00, 0xED, 0x20, 0xFC, 0xB1, 0x5B, 0x6A, 0xCB, 0xBE, 0x39, 0x4A, 0x4C, 0x58, 0xCF,
		0xD0, 0xEF, 0xAA, 0xFB, 0x43, 0x4D, 0x33, 0x85, 0x45, 0xF9, 0x02, 0x7F, 0x50, 0x3C, 0x9F, 0xA8,
		0x51, 0xA3, 0x40, 0x8F, 0x92, 0x9D, 0x38, 0xF5, 0xBC, 0xB6, 0xDA, 0x21, 0x10, 0xFF, 0xF3, 0xD2,
		0xCD, 0x0C, 0x13, 0xEC, 0x5F, 0x97, 0x44, 0x17, 0xC4, 0xA7, 0x7E, 0x3D, 0x64, 0x5D, 0x19, 0x73,
		0x60, 0x81, 0x4F, 0xDC, 0x22, 0x2A, 0x90, 0x88, 0x46, 0xEE, 0xB8, 0x14, 0xDE, 0x5E, 0x0B, 0xDB,
		0xE0, 0x32, 0x3A, 0x0A, 0x49, 0x06, 0x24, 0x5C, 0xC2, 0xD3, 0xAC, 0x62, 0x91, 0x95, 0xE4, 0x79,
		0xE7, 0xC8, 0x37, 0x6D, 0x8D, 0xD5, 0x4E, 0xA9, 0x6C, 0x56, 0xF4, 0xEA, 0x65, 0x7A, 0xAE, 0x08,
		0xBA, 0x78, 0x25, 0x2E, 0x1C, 0xA6, 0xB4, 0xC6, 0xE8, 0xDD, 0x74, 0x1F, 0x4B, 0xBD, 0x8B, 0x8A,
		0x70, 0x3E, 0xB5, 0x66, 0x48, 0x03, 0xF6, 0x0E, 0x61, 0x35, 0x57, 0xB9, 0x86, 0xC1, 0x1D, 0x9E,
		0xE1, 0xF8, 0x98, 0x11, 0x69, 0xD9, 0x8E, 0x94, 0x9B, 0x1E, 0x87, 0xE9, 0xCE, 0x55, 0x28, 0xDF,
		0x8C, 0xA1, 0x89, 0x0D, 0xBF, 0xE6, 0x42, 0x68, 0x41, 0x99, 0x2D, 0x0F, 0xB0, 0x54, 0xBB, 0x16)
SBOX_INV = (0x52, 0x09, 0x6a, 0xd5, 0x30, 0x36, 0xa5, 0x38, 0xbf, 0x40, 0xa3, 0x9e, 0x81, 0xf3, 0xd7, 0xfb,
			0x7c, 0xe3, 0x39, 0x82, 0x9b, 0x2f, 0xff, 0x87, 0x34, 0x8e, 0x43, 0x44, 0xc4, 0xde, 0xe9, 0xcb,
			0x54, 0x7b, 0x94, 0x32, 0xa6, 0xc2, 0x23, 0x3d, 0xee, 0x4c, 0x95, 0x0b, 0x42, 0xfa, 0xc3, 0x4e,
			0x08, 0x2e, 0xa1, 0x66, 0x28, 0xd9, 0x24, 0xb2, 0x76, 0x5b, 0xa2, 0x49, 0x6d, 0x8b, 0xd1, 0x25,
			0x72, 0xf8, 0xf6, 0x64, 0x86, 0x68, 0x98, 0x16, 0xd4, 0xa4, 0x5c, 0xcc, 0x5d, 0x65, 0xb6, 0x92,
			0x6c, 0x70, 0x48, 0x50, 0xfd, 0xed, 0xb9, 0xda, 0x5e, 0x15, 0x46, 0x57, 0xa7, 0x8d, 0x9d, 0x84,
			0x90, 0xd8, 0xab, 0x00, 0x8c, 0xbc, 0xd3, 0x0a, 0xf7, 0xe4, 0x58, 0x05, 0xb8, 0xb3, 0x45, 0x06,
			0xd0, 0x2c, 0x1e, 0x8f, 0xca, 0x3f, 0x0f, 0x02, 0xc1, 0xaf, 0xbd, 0x03, 0x01, 0x13, 0x8a, 0x6b,
			0x3a, 0x91, 0x11, 0x41, 0x4f, 0x67, 0xdc, 0xea, 0x97, 0xf2, 0xcf, 0xce, 0xf0, 0xb4, 0xe6, 0x73,
			0x96, 0xac, 0x74, 0x22, 0xe7, 0xad, 0x35, 0x85, 0xe2, 0xf9, 0x37, 0xe8, 0x1c, 0x75, 0xdf, 0x6e,
			0x47, 0xf1, 0x1a, 0x71, 0x1d, 0x29, 0xc5, 0x89, 0x6f, 0xb7, 0x62, 0x0e, 0xaa, 0x18, 0xbe, 0x1b,
			0xfc, 0x56, 0x3e, 0x4b, 0xc6, 0xd2, 0x79, 0x20, 0x9a, 0xdb, 0xc0, 0xfe, 0x78, 0xcd, 0x5a, 0xf4,
			0x1f, 0xdd, 0xa8, 0x33, 0x88, 0x07, 0xc7, 0x31, 0xb1, 0x12, 0x10, 0x59, 0x27, 0x80, 0xec, 0x5f,
			0x60, 0x51, 0x7f, 0xa9, 0x19, 0xb5, 0x4a, 0x0d, 0x2d, 0xe5, 0x7a, 0x9f, 0x93, 0xc9, 0x9c, 0xef,
			0xa0, 0xe0, 0x3b, 0x4d, 0xae, 0x2a, 0xf5, 0xb0, 0xc8, 0xeb, 0xbb, 0x3c, 0x83, 0x53, 0x99, 0x61,
			0x17, 0x2b, 0x04, 0x7e, 0xba, 0x77, 0xd6, 0x26, 0xe1, 0x69, 0x14, 0x63, 0x55, 0x21, 0x0c, 0x7d)
MIX_COLUMN_MATRIX = ((0x2,0x3,0x1,0x1),
					 (0x1,0x2,0x3,0x1),
					 (0x1,0x1,0x2,0x3),
					 (0x3,0x1,0x1,0x2))
MIX_COLUMN_MATRIX_INV = ((0xE,0xB,0xD,0x9),
						 (0x9,0xE,0xB,0xD),
						 (0xD,0x9,0xE,0xB),
						 (0xB,0xD,0x9,0xE))
RIJNDAEL_EXP_TABLE = (0x01, 0x03, 0x05, 0x0F, 0x11, 0x33, 0x55, 0xFF, 0x1A, 0x2E, 0x72, 0x96, 0xA1, 0xF8, 0x13, 0x35,
					  0x5F, 0xE1, 0x38, 0x48, 0xD8, 0x73, 0x95, 0xA4, 0xF7, 0x02, 0x06, 0x0A, 0x1E, 0x22, 0x66, 0xAA,
					  0xE5, 0x34, 0x5C, 0xE4, 0x37, 0x59, 0xEB, 0x26, 0x6A, 0xBE, 0xD9, 0x70, 0x90, 0xAB, 0xE6, 0x31,
					  0x53, 0xF5, 0x04, 0x0C, 0x14, 0x3C, 0x44, 0xCC, 0x4F, 0xD1, 0x68, 0xB8, 0xD3, 0x6E, 0xB2, 0xCD,
					  0x4C, 0xD4, 0x67, 0xA9, 0xE0, 0x3B, 0x4D, 0xD7, 0x62, 0xA6, 0xF1, 0x08, 0x18, 0x28, 0x78, 0x88,
					  0x83, 0x9E, 0xB9, 0xD0, 0x6B, 0xBD, 0xDC, 0x7F, 0x81, 0x98, 0xB3, 0xCE, 0x49, 0xDB, 0x76, 0x9A,
					  0xB5, 0xC4, 0x57, 0xF9, 0x10, 0x30, 0x50, 0xF0, 0x0B, 0x1D, 0x27, 0x69, 0xBB, 0xD6, 0x61, 0xA3,
					  0xFE, 0x19, 0x2B, 0x7D, 0x87, 0x92, 0xAD, 0xEC, 0x2F, 0x71, 0x93, 0xAE, 0xE9, 0x20, 0x60, 0xA0,
					  0xFB, 0x16, 0x3A, 0x4E, 0xD2, 0x6D, 0xB7, 0xC2, 0x5D, 0xE7, 0x32, 0x56, 0xFA, 0x15, 0x3F, 0x41,
					  0xC3, 0x5E, 0xE2, 0x3D, 0x47, 0xC9, 0x40, 0xC0, 0x5B, 0xED, 0x2C, 0x74, 0x9C, 0xBF, 0xDA, 0x75,
					  0x9F, 0xBA, 0xD5, 0x64, 0xAC, 0xEF, 0x2A, 0x7E, 0x82, 0x9D, 0xBC, 0xDF, 0x7A, 0x8E, 0x89, 0x80,
					  0x9B, 0xB6, 0xC1, 0x58, 0xE8, 0x23, 0x65, 0xAF, 0xEA, 0x25, 0x6F, 0xB1, 0xC8, 0x43, 0xC5, 0x54,
					  0xFC, 0x1F, 0x21, 0x63, 0xA5, 0xF4, 0x07, 0x09, 0x1B, 0x2D, 0x77, 0x99, 0xB0, 0xCB, 0x46, 0xCA,
					  0x45, 0xCF, 0x4A, 0xDE, 0x79, 0x8B, 0x86, 0x91, 0xA8, 0xE3, 0x3E, 0x42, 0xC6, 0x51, 0xF3, 0x0E,
					  0x12, 0x36, 0x5A, 0xEE, 0x29, 0x7B, 0x8D, 0x8C, 0x8F, 0x8A, 0x85, 0x94, 0xA7, 0xF2, 0x0D, 0x17,
					  0x39, 0x4B, 0xDD, 0x7C, 0x84, 0x97, 0xA2, 0xFD, 0x1C, 0x24, 0x6C, 0xB4, 0xC7, 0x52, 0xF6, 0x01)
RIJNDAEL_LOG_TABLE = (0x00, 0x00, 0x19, 0x01, 0x32, 0x02, 0x1a, 0xc6, 0x4b, 0xc7, 0x1b, 0x68, 0x33, 0xee, 0xdf, 0x03,
					  0x64, 0x04, 0xe0, 0x0e, 0x34, 0x8d, 0x81, 0xef, 0x4c, 0x71, 0x08, 0xc8, 0xf8, 0x69, 0x1c, 0xc1,
					  0x7d, 0xc2, 0x1d, 0xb5, 0xf9, 0xb9, 0x27, 0x6a, 0x4d, 0xe4, 0xa6, 0x72, 0x9a, 0xc9, 0x09, 0x78,
					  0x65, 0x2f, 0x8a, 0x05, 0x21, 0x0f, 0xe1, 0x24, 0x12, 0xf0, 0x82, 0x45, 0x35, 0x93, 0xda, 0x8e,
					  0x96, 0x8f, 0xdb, 0xbd, 0x36, 0xd0, 0xce, 0x94, 0x13, 0x5c, 0xd2, 0xf1, 0x40, 0x46, 0x83, 0x38,
					  0x66, 0xdd, 0xfd, 0x30, 0xbf, 0x06, 0x8b, 0x62, 0xb3, 0x25, 0xe2, 0x98, 0x22, 0x88, 0x91, 0x10,
					  0x7e, 0x6e, 0x48, 0xc3, 0xa3, 0xb6, 0x1e, 0x42, 0x3a, 0x6b, 0x28, 0x54, 0xfa, 0x85, 0x3d, 0xba,
					  0x2b, 0x79, 0x0a, 0x15, 0x9b, 0x9f, 0x5e, 0xca, 0x4e, 0xd4, 0xac, 0xe5, 0xf3, 0x73, 0xa7, 0x57,
					  0xaf, 0x58, 0xa8, 0x50, 0xf4, 0xea, 0xd6, 0x74, 0x4f, 0xae, 0xe9, 0xd5, 0xe7, 0xe6, 0xad, 0xe8,
					  0x2c, 0xd7, 0x75, 0x7a, 0xeb, 0x16, 0x0b, 0xf5, 0x59, 0xcb, 0x5f, 0xb0, 0x9c, 0xa9, 0x51, 0xa0,
					  0x7f, 0x0c, 0xf6, 0x6f, 0x17, 0xc4, 0x49, 0xec, 0xd8, 0x43, 0x1f, 0x2d, 0xa4, 0x76, 0x7b, 0xb7,
					  0xcc, 0xbb, 0x3e, 0x5a, 0xfb, 0x60, 0xb1, 0x86, 0x3b, 0x52, 0xa1, 0x6c, 0xaa, 0x55, 0x29, 0x9d,
					  0x97, 0xb2, 0x87, 0x90, 0x61, 0xbe, 0xdc, 0xfc, 0xbc, 0x95, 0xcf, 0xcd, 0x37, 0x3f, 0x5b, 0xd1,
					  0x53, 0x39, 0x84, 0x3c, 0x41, 0xa2, 0x6d, 0x47, 0x14, 0x2a, 0x9e, 0x5d, 0x56, 0xf2, 0xd3, 0xab,
					  0x44, 0x11, 0x92, 0xd9, 0x23, 0x20, 0x2e, 0x89, 0xb4, 0x7c, 0xb8, 0x26, 0x77, 0x99, 0xe3, 0xa5,
					  0x67, 0x4a, 0xed, 0xde, 0xc5, 0x31, 0xfe, 0x18, 0x0d, 0x63, 0x8c, 0x80, 0xc0, 0xf7, 0x70, 0x07)

def sub_bytes(data):
	return [SBOX[x] for x in data]

def sub_bytes_inv(data):
	return [SBOX_INV[x] for x in data]

def rotate(data):
	return data[1:] + [data[0]]

def key_schedule_core(data, rcon_iteration):
	data = rotate(data)
	data = sub_bytes(data)
	data[0] = data[0] ^ RCON[rcon_iteration]
	return data

def xor(data1, data2):
	return [x^y for x, y in zip(data1, data2)]

def rijndael_mul(a, b):
	if(a==0 or b==0):
		return 0
	return RIJNDAEL_EXP_TABLE[(RIJNDAEL_LOG_TABLE[a] + RIJNDAEL_LOG_TABLE[b]) % 0xFF]

def mix_column(data, matrix):
	data_mixed = []
	for row in range(4):
		mixed = 0
		for column in range(4):
			# xor is (+) and (-)
			mixed ^= rijndael_mul(data[column], matrix[row][column])
		data_mixed.append(mixed)
	return data_mixed

def mix_columns(data, matrix=MIX_COLUMN_MATRIX):
	data_mixed = []
	for i in range(4):
		column = data[i*4 : (i+1)*4]
		data_mixed += mix_column(column, matrix)
	return data_mixed

def mix_columns_inv(data):
	return mix_columns(data, MIX_COLUMN_MATRIX_INV)

def shift_rows(data):
	data_shifted = []
	for column in range(4):
		for row in range(4):
			data_shifted.append( data[((column + row) & 0b11) * 4 + row] )
	return data_shifted

def shift_rows_inv(data):
	data_shifted = []
	for column in range(4):
		for row in range(4):
			data_shifted.append( data[((column - row) & 0b11) * 4 + row] )
	return data_shifted

def inc(data):
	data = data[:] # copy
	for i in range(len(data)-1,-1,-1):
		if data[i] == 255:
			data[i] = 0
		else:
			data[i] = data[i] + 1
			break
	return data