-- | Miscellaneous helper functions that don't fit anywhere else
module Data.QRCodes.Utils where

import qualified Data.ByteString.Char8 as BS
import Data.Char (toLower, toUpper)
import Data.List.Utils (replace)
import Data.Word (Word8)

-- | function applied to byteStrings before saving to QR code so that uppercase/lowercase signatures can be preserverd
preserveUpper :: BS.ByteString -> BS.ByteString
preserveUpper = lift pU
    where pU = concatMap (\c -> if c `elem` ['A'..'Z'] then ((toLower c) : "!") else return c)

-- | resolve coded string to string with uppercase
resolveUpper :: BS.ByteString -> BS.ByteString
resolveUpper = lift rU
    where rU = foldr (.) id (map (\s -> replace (s : "!") ((pure . toUpper) s)) ['a'..'z'])

-- | given a function on strings, make it act on byteStrings
lift :: (String -> String) -> (BS.ByteString -> BS.ByteString)
lift f = BS.pack . f . BS.unpack

-- | helper function to life Either values to IO in our case
liftEither :: (Show b, Monad m) => (t -> m a) -> Either b t -> m a
liftEither = either (error . show)

swapWord :: Word8 -> Word8
swapWord 1 = 0
swapWord 0 = 1