{-# LANGUAGE CPP #-}
{-# LANGUAGE OverloadedStrings #-}

module Hash where

import Data.ByteString (ByteString)

import Control.Monad (forM_)
import Crypto.Hash (MD5, SHA1, SHA256, hash)
import qualified Data.ByteString.Base16      as B16
import qualified System.Nix.Base32           as B32
import qualified Data.ByteString.Base64.Lazy as B64
import qualified Data.ByteString.Lazy        as BSL


import System.Nix.Base
import System.Nix.Hash
import System.Nix.StorePath
import Test.Hspec

spec_hash :: Spec
spec_hash = do

  describe "hashing parity with nix-store" $ do

    it "produces (base32 . sha256) of \"nix-output:foo\" the same as Nix does at the moment for placeholder \"foo\"" $
      shouldBe (encodeDigestWith NixBase32 (hash @ByteString @SHA256 "nix-output:foo"))
               "1x0ymrsy7yr7i9wdsqy9khmzc1yy7nvxw6rdp72yzn50285s67j5"
    it "produces (base16 . md5) of \"Hello World\" the same as the thesis" $
      shouldBe (encodeDigestWith Base16 (hash @ByteString @MD5 "Hello World"))
               "b10a8db164e0754105b7a99be72e3fe5"
    it "produces (base32 . sha1) of \"Hello World\" the same as the thesis" $
      shouldBe (encodeDigestWith NixBase32 (hash @ByteString @SHA1 "Hello World"))
               "s23c9fs0v32pf6bhmcph5rbqsyl5ak8a"

    -- The example in question:
    -- https://nixos.org/nixos/nix-pills/nix-store-paths.html
    it "produces same base32 as nix pill flat file example" $ do
      shouldBe (encodeWith NixBase32 $ unStorePathHashPart $ mkStorePathHashPart @SHA256 "source:sha256:2bfef67de873c54551d884fdab3055d84d573e654efa79db3c0d7b98883f9ee3:/nix/store:myfile")
        "xv2iccirbrvklck36f1g7vldn5v58vck"

-- | Hash encoding conversion ground-truth.
-- Similiar to nix/tests/hash.sh
spec_nixhash :: Spec
spec_nixhash = do

  describe "hashing parity with nix-nash" $ do

    let
      samples = [
          ( "800d59cfcd3c05e900cb4e214be48f6b886a08df"
          , "vw46m23bizj4n8afrc0fj19wrp7mj3c0"
          , "gA1Zz808BekAy04hS+SPa4hqCN8="
          )
        , ( "ba7816bf8f01cfea414140de5dae2223b00361a396177a9cb410ff61f20015ad"
          , "1b8m03r63zqhnjf7l5wnldhh7c134ap5vpj0850ymkq1iyzicy5s"
          , "ungWv48Bz+pBQUDeXa4iI7ADYaOWF3qctBD/YfIAFa0="
          )
        , ( "204a8fc6dda82f0a0ced7beb8e08a41657c16ef468b228a8279be331a703c33596fd15c13b1b07f9aa1d3bea57789ca031ad85c7a71dd70354ec631238ca3445"
          , "12k9jiq29iyqm03swfsgiw5mlqs173qazm3n7daz43infy12pyrcdf30fkk3qwv4yl2ick8yipc2mqnlh48xsvvxl60lbx8vp38yji0"
          , "IEqPxt2oLwoM7XvrjgikFlfBbvRosiioJ5vjMacDwzWW/RXBOxsH+aodO+pXeJygMa2Fx6cd1wNU7GMSOMo0RQ=="
          )
        ]

    it "b16 encoded . b32 decoded should equal original b16" $
      forM_ samples $ \(b16, b32, _b64) -> shouldBe (B16.encode <$> B32.decode b32) (pure b16)

    it "b64 encoded . b32 decoded should equal original b64" $
      forM_ samples $ \(_b16, b32, b64) -> shouldBe (B64.encode . BSL.fromStrict <$> B32.decode b32) (pure b64)

    it "b32 encoded . b64 decoded should equal original b32" $
      forM_ samples $ \(_b16, b32, b64) -> shouldBe (B32.encode . BSL.toStrict <$> B64.decode b64 ) (pure b32)

    it "b16 encoded . b64 decoded should equal original b16" $
      forM_ samples $ \(b16, _b32, b64) -> shouldBe (B16.encode . BSL.toStrict <$> B64.decode b64 ) (pure b16)

    it "b32 encoded . b16 decoded should equal original b32" $
      forM_ samples $ \(b16, b32, _b64) -> shouldBe (B32.encode
#if MIN_VERSION_base16_bytestring(1,0,0)
        <$> B16.decode b16) (pure b32)
#else
        $ fst $ B16.decode b16) (b32)
#endif

    it "b64 encoded . b16 decoded should equal original b64" $
      forM_ samples $ \(b16, _b32, b64) -> shouldBe (B64.encode . BSL.fromStrict
#if MIN_VERSION_base16_bytestring(1,0,0)
        <$> B16.decode b16) (pure b64)
#else
        $ fst $ B16.decode b16 ) (b64)
#endif