# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#    http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
# implied.
# See the License for the specific language governing permissions and
# limitations under the License.

from __future__ import absolute_import, division, print_function

import binascii

from cryptography.hazmat.backends import default_backend
from cryptography.hazmat.primitives.ciphers import base, algorithms, modes


def encrypt(mode, key, iv, plaintext):
    cipher = base.Cipher(
        algorithms.CAST5(binascii.unhexlify(key)),
        mode(binascii.unhexlify(iv)),
        default_backend()
    )
    encryptor = cipher.encryptor()
    ct = encryptor.update(binascii.unhexlify(plaintext))
    ct += encryptor.finalize()
    return binascii.hexlify(ct)


def build_vectors(mode, filename):
    vector_file = open(filename, "r")

    count = 0
    output = []
    key = None
    iv = None
    plaintext = None
    for line in vector_file:
        line = line.strip()
        if line.startswith("KEY"):
            if count != 0:
                output.append("CIPHERTEXT = {}".format(
                    encrypt(mode, key, iv, plaintext))
                )
            output.append("\nCOUNT = {}".format(count))
            count += 1
            name, key = line.split(" = ")
            output.append("KEY = {}".format(key))
        elif line.startswith("IV"):
            name, iv = line.split(" = ")
            iv = iv[0:16]
            output.append("IV = {}".format(iv))
        elif line.startswith("PLAINTEXT"):
            name, plaintext = line.split(" = ")
            output.append("PLAINTEXT = {}".format(plaintext))

    output.append("CIPHERTEXT = {}".format(encrypt(mode, key, iv, plaintext)))
    return "\n".join(output)


def write_file(data, filename):
    with open(filename, "w") as f:
        f.write(data)

cbc_path = "tests/hazmat/primitives/vectors/ciphers/AES/CBC/CBCMMT128.rsp"
write_file(build_vectors(modes.CBC, cbc_path), "cast5-cbc.txt")
ofb_path = "tests/hazmat/primitives/vectors/ciphers/AES/OFB/OFBMMT128.rsp"
write_file(build_vectors(modes.OFB, ofb_path), "cast5-ofb.txt")
cfb_path = "tests/hazmat/primitives/vectors/ciphers/AES/CFB/CFB128MMT128.rsp"
write_file(build_vectors(modes.CFB, cfb_path), "cast5-cfb.txt")
ctr_path = "tests/hazmat/primitives/vectors/ciphers/AES/CTR/aes-128-ctr.txt"
write_file(build_vectors(modes.CTR, ctr_path), "cast5-ctr.txt")