module Network.HTTP.Lucu.ETag
    ( ETag
    , mkETag    -- Bool -> String -> ETag
    , eTagP     -- Parser ETag
    , eTagListP -- Parser [ETag]
    )
    where

import           Network.HTTP.Lucu.Parser
import           Network.HTTP.Lucu.Parser.Http


data ETag = ETag {
      etagIsWeak :: Bool
    , etagToken  :: String
    } deriving (Eq)


instance Show ETag where
    show (ETag isWeak token) = (if isWeak then
                                    "W/"
                                else
                                    "")
                               ++
                               foldr (++) "" (["\""] ++ map quote token ++ ["\""])
        where
          quote :: Char -> String
          quote '"' = "\\\""
          quote c   = [c]


mkETag :: Bool -> String -> ETag
mkETag = ETag


eTagP :: Parser ETag
eTagP = do isWeak <- option False (string "W/" >> return True)
           str    <- quotedStr
           return $ mkETag isWeak str


eTagListP :: Parser [ETag]
eTagListP = allowEOF
            $ sepBy1 eTagP (do many sp
                               char ','
                               many sp)