-- Copyright 2018 Google LLC
--
-- 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
--
--     https://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.

{-# LANGUAGE OverloadedStrings #-}

module Codec.Crypto.HKDFTests (tests) where

import Data.ByteString (ByteString)
import qualified Data.ByteString as ByteString
import qualified Data.ByteString.Base16 as ByteString.Base16
import qualified Data.ByteString.Char8 as ByteString.Char8
import Test.Tasty (TestTree, testGroup)
import Test.Tasty.HUnit ((@?=), testCase)

import Codec.Crypto.HKDF (AssociatedData(AssociatedData), Salt(Salt), SecretKey(SecretKey), noSalt)
import qualified Codec.Crypto.HKDF as HKDF
import Data.Digest (sha1, sha256)

tests :: TestTree
tests = testGroup "Codec.Crypto.HKDF" [testRFC5869]

-- | Tests from RFC 5869.
testRFC5869 = testGroup "RFC 5869 examples"
  [ t "test case 1"
      sha256
      (SecretKey $ ByteString.replicate 22 0x0b)
      (Salt $ ByteString.pack [0x00 .. 0x0c])
      (AssociatedData $ ByteString.pack [0xf0 .. 0xf9])
      42
      (SecretKey $ hex "077709362c2e32df0ddc3f0dc47bba6390b6c73bb50f9c3122ec844ad7c2b3e5")
      (SecretKey $ hex "3cb25f25faacd57a90434f64d0362f2a2d2d0a90cf1a5a4c5db02d56ecc4c5bf34007208d5b887185865")
  , t "test case 2"
      sha256
      (SecretKey $ ByteString.pack [0x00 .. 0x4f])
      (Salt $ ByteString.pack [0x60 .. 0xaf])
      (AssociatedData $ ByteString.pack [0xb0 .. 0xff])
      82
      (SecretKey $ hex "06a6b88c5853361a06104c9ceb35b45cef760014904671014a193f40c15fc244")
      (SecretKey $ hex "b11e398dc80327a1c8e7f78c596a49344f012eda2d4efad8a050cc4c19afa97c59045a99cac7827271cb41c65e590e09da3275600c2f09b8367793a9aca3db71cc30c58179ec3e87c14c01d5c1f3434f1d87")
  , t "test case 3"
      sha256
      (SecretKey $ ByteString.replicate 22 0x0b)
      (Salt "")
      (AssociatedData "")
      42
      (SecretKey $ hex "19ef24a32c717b167f33a91d6f648bdf96596776afdb6377ac434c1c293ccb04")
      (SecretKey $ hex "8da4e775a563c18f715f802a063c5a31b8a11f5c5ee1879ec3454e5f3c738d2d9d201395faa4b61a96c8")
  , t "test case 4"
      sha1
      (SecretKey $ ByteString.replicate 11 0x0b)
      (Salt $ ByteString.pack [0x00 .. 0x0c])
      (AssociatedData $ ByteString.pack [0xf0 .. 0xf9])
      42
      (SecretKey $ hex "9b6c18c432a7bf8f0e71c8eb88f4b30baa2ba243")
      (SecretKey $ hex "085a01ea1b10f36933068b56efa5ad81a4f14b822f5b091568a9cdd4f155fda2c22e422478d305f3f896")
  , t "test case 5"
      sha1
      (SecretKey $ ByteString.pack [0x00 .. 0x4f])
      (Salt $ ByteString.pack [0x60 .. 0xaf])
      (AssociatedData $ ByteString.pack [0xb0 .. 0xff])
      82
      (SecretKey $ hex "8adae09a2a307059478d309b26c4115a224cfaf6")
      (SecretKey $ hex "0bd770a74d1160f7c9f12cd5912a06ebff6adcae899d92191fe4305673ba2ffe8fa3f1a4e5ad79f3f334b3b202b2173c486ea37ce3d397ed034c7f9dfeb15c5e927336d0441f4c4300e2cff0d0900b52d3b4")
  , t "test case 6"
      sha1
      (SecretKey $ ByteString.replicate 22 0x0b)
      (Salt "")
      (AssociatedData "")
      42
      (SecretKey $ hex "da8c8a73c7fa77288ec6f5e7c297786aa0d32d01")
      (SecretKey $ hex "0ac1af7002b3d761d1e55298da9d0506b9ae52057220a306e07b6b87e8df21d0ea00033de03984d34918")
  , t "test case 7"
      sha1
      (SecretKey $ ByteString.replicate 22 0x0c)
      noSalt
      (AssociatedData "")
      42
      (SecretKey $ hex "2adccada18779e7c2077ad2eb19d3f3e731385dd")
      (SecretKey $ hex "2c91117204d745f3500d636a62f64f0ab3bae548aa53d423b0d1f27ebba6f5e5673a081d70cce7acfc48")
  ]
  where
    t name hash ikm salt info len prk okm =
      testGroup name [ testCase "extract" $ HKDF.extract hash salt ikm @?= prk
                     , testCase "expand" $ HKDF.expand hash info len prk @?= okm
                     ]

hex :: ByteString -> ByteString
hex s =
  case ByteString.Base16.decode s of
    (r, "") -> r
    _ -> error $ "invalid hex string " ++ ByteString.Char8.unpack s