{-# LANGUAGE OverloadedStrings #-}
-- |
-- Module      :  HaskDeep.Computation
-- Copyright   :  Mauro Taraborelli 2012
-- License     :  BSD3
--
-- Maintainer  :  maurotaraborelli@gmail.com
-- Stability   :  experimental
-- Portability :  unknown
--
-- Computes hashes traversing recursively through a directory structure.
-- Uses a list of known hashes to audit a set of files.
--
-- Internal module.

module HaskDeep.ComputationMode
    (
     -- * Computation modes
     ComputationMode (..)
    ,md5hash
    ,sha1hash
    ,sha256hash
    ,skein512hash
    )
where

import           Crypto.Hash.CryptoAPI (MD5, SHA1, SHA256, Skein512_512)
import           Data.ByteString (ByteString)
import qualified Data.ByteString.Base16 as BB16
import qualified Data.Serialize as S
import qualified Data.Text as T

-- | Algorithm to compute hash.
data ComputationMode a = ComputationMode
    { symbol         :: T.Text           -- ^ Computation mode symbol
    , runComputation :: a -> ByteString  -- ^ Computation function
    }

-- | MD5 computation.
md5hash  :: ComputationMode MD5
md5hash  = ComputationMode "md5" (BB16.encode . S.encode)

-- | SHA1 computation.
sha1hash :: ComputationMode SHA1
sha1hash = ComputationMode "sha1" (BB16.encode . S.encode)

-- | SHA256 computation.
sha256hash :: ComputationMode SHA256
sha256hash = ComputationMode "sha256" (BB16.encode . S.encode)

-- | Skein512 computation.
skein512hash :: ComputationMode Skein512_512
skein512hash = ComputationMode "skein512" (BB16.encode . S.encode)