# Copyright 2013 Donald Stufft and individual contributors
#
# 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

from binascii import unhexlify

import pytest

import nacl.bindings
import nacl.encoding
import nacl.hashlib
from nacl.exceptions import UnavailableError


# Test vectors from rfc 7914, Page 13
#   scrypt (P="", S="",
#           N=16, r=1, p=1, dklen=64) =
#   77 d6 57 62 38 65 7b 20 3b 19 ca 42 c1 8a 04 97
#   f1 6b 48 44 e3 07 4a e8 df df fa 3f ed e2 14 42
#   fc d0 06 9d ed 09 48 f8 32 6a 75 3a 0f c8 1f 17
#   e8 d3 e0 fb 2e 0d 36 28 cf 35 e2 0c 38 d1 89 06
#
#   scrypt (P="password", S="NaCl",
#           N=1024, r=8, p=16, dkLen=64) =
#   fd ba be 1c 9d 34 72 00 78 56 e7 19 0d 01 e9 fe
#   7c 6a d7 cb c8 23 78 30 e7 73 76 63 4b 37 31 62
#   2e af 30 d9 2e 22 a3 88 6f f1 09 27 9d 98 30 da
#   c7 27 af b9 4a 83 ee 6d 83 60 cb df a2 cc 06 40
#
#   scrypt (P="pleaseletmein", S="SodiumChloride",
#           N=16384, r=8, p=1, dkLen=64) =
#   70 23 bd cb 3a fd 73 48 46 1c 06 cd 81 fd 38 eb
#   fd a8 fb ba 90 4f 8e 3e a9 b5 43 f6 54 5d a1 f2
#   d5 43 29 55 61 3f 0f cf 62 d4 97 05 24 2a 9a f9
#   e6 1e 85 dc 0d 65 1e 40 df cf 01 7b 45 57 58 87
#
#   scrypt (P="pleaseletmein", S="SodiumChloride",
#           N=1048576, r=8, p=1, dkLen=64) =
#   21 01 cb 9b 6a 51 1a ae ad db be 09 cf 70 f8 81
#   ec 56 8d 57 4a 2f fd 4d ab e5 ee 98 20 ad aa 47
#   8e 56 fd 8f 4b a5 d0 9f fa 1c 6d 92 7c 40 f4 c3
#   37 30 40 49 e8 a9 52 fb cb f4 5c 6f a7 7a 41 a4

RFC_7914_VECTORS = [
    (b"", b"", 16, 1, 1, 64, (
     b"77 d6 57 62 38 65 7b 20 3b 19 ca 42 c1 8a 04 97"
     b"f1 6b 48 44 e3 07 4a e8 df df fa 3f ed e2 14 42"
     b"fc d0 06 9d ed 09 48 f8 32 6a 75 3a 0f c8 1f 17"
     b"e8 d3 e0 fb 2e 0d 36 28 cf 35 e2 0c 38 d1 89 06")
     ),
    (b"password", b"NaCl", 1024, 8, 16, 64, (
     b"fd ba be 1c 9d 34 72 00 78 56 e7 19 0d 01 e9 fe"
     b"7c 6a d7 cb c8 23 78 30 e7 73 76 63 4b 37 31 62"
     b"2e af 30 d9 2e 22 a3 88 6f f1 09 27 9d 98 30 da"
     b"c7 27 af b9 4a 83 ee 6d 83 60 cb df a2 cc 06 40")
     ),
    (b"pleaseletmein", b"SodiumChloride", 16384, 8, 1, 64, (
     b"70 23 bd cb 3a fd 73 48 46 1c 06 cd 81 fd 38 eb"
     b"fd a8 fb ba 90 4f 8e 3e a9 b5 43 f6 54 5d a1 f2"
     b"d5 43 29 55 61 3f 0f cf 62 d4 97 05 24 2a 9a f9"
     b"e6 1e 85 dc 0d 65 1e 40 df cf 01 7b 45 57 58 87")
     ),
    (b"pleaseletmein", b"SodiumChloride", 1048576, 8, 1, 64, (
     b"21 01 cb 9b 6a 51 1a ae ad db be 09 cf 70 f8 81"
     b"ec 56 8d 57 4a 2f fd 4d ab e5 ee 98 20 ad aa 47"
     b"8e 56 fd 8f 4b a5 d0 9f fa 1c 6d 92 7c 40 f4 c3"
     b"37 30 40 49 e8 a9 52 fb cb f4 5c 6f a7 7a 41 a4"),
     )
]


@pytest.mark.skipif(not nacl.hashlib.SCRYPT_AVAILABLE,
                    reason="Requires full build of libsodium")
@pytest.mark.parametrize(('password', 'salt', 'n', 'r', 'p',
                          'dklen', 'expected'),
                         RFC_7914_VECTORS)
def test_hashlib_scrypt_api(password, salt, n, r, p, dklen, expected):
    _exp = unhexlify(expected.replace(b" ", b""))
    dgst = nacl.hashlib.scrypt(password, salt=salt, n=n, r=r, p=p,
                               dklen=dklen, maxmem=2 * (1024 ** 3))
    assert _exp == dgst


@pytest.mark.skipif(nacl.hashlib.SCRYPT_AVAILABLE,
                    reason="Requires minimal build of libsodium")
def test_hashlib_scrypt_unavailable():
    with pytest.raises(UnavailableError):
        nacl.hashlib.scrypt(b"")