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

import           Control.Monad
import           Network.HTTP.Lucu.Parser
import           Network.HTTP.Lucu.Parser.Http
import           Network.HTTP.Lucu.Utils


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

instance Show ETag where
    show (ETag isWeak token) = (if isWeak then
                                    "W/"
                                else
                                    "")
                               ++
                               quoteStr token


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


strongETag :: String -> ETag
strongETag = ETag False


weakETag :: String -> ETag
weakETag = ETag True


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


eTagListP :: Parser [ETag]
eTagListP = allowEOF
            $ do xs <- listOf eTagP
                 when (null xs)
                          $ fail ""
                 return xs