content: {-
    Copyright 2020 The CodeWorld Authors. All rights reserved.
  
    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.
  -}
  
  -- |
  -- Functions for generating, reading and writing secrets for use with
  -- local authentication method
  module CodeWorld.Auth.Secret
    ( Secret (..),
      generateSecret,
      readSecret,
      writeSecret,
    )
  where
  
  import Crypto.Random (getRandomBytes)
  import Data.ByteString (ByteString)
  import qualified Data.ByteString as ByteString (readFile, writeFile)
  import qualified Data.ByteString.Base64 as Base64 (decode, encode)
  
  data Secret = Secret ByteString deriving (Eq)
  
  -- | Generates a new, random secret
  generateSecret ::
    -- | Secret
    IO Secret
  generateSecret = Secret <$> getRandomBytes 32
  
  -- | Writes a secret to a file
  writeSecret ::
    -- | File path
    FilePath ->
    -- | Secret
    Secret ->
    -- | Result
    IO ()
  writeSecret path (Secret bytes) = ByteString.writeFile path (Base64.encode bytes)
  
  -- | Reads a secret from a file
  readSecret ::
    -- | File path
    FilePath ->
    -- | Result
    IO Secret
  readSecret path = do
    s <- ByteString.readFile path
    case Base64.decode s of
      Left e -> error e
      Right bytes -> return $ Secret bytes
  