{-# LANGUAGE OverloadedStrings #-}
module Data.CSS.Style.Selector.LowerWhere(
        WhereLowerer(..)
    ) where

import Data.CSS.Syntax.Selector
import Data.CSS.Style.Common

lowerSelector :: Selector -> Selector
lowerSelector (Element sel) = Element $ lowerSelector' sel
lowerSelector (Child sel x) = Child (lowerSelector sel) x
lowerSelector (Descendant sel x) = Descendant (lowerSelector sel) x
lowerSelector (Adjacent sel x) = Adjacent (lowerSelector sel) x
lowerSelector (Sibling sel x) = Sibling (lowerSelector sel) x

lowerSelector' :: [SimpleSelector] -> [SimpleSelector]
lowerSelector' (Psuedoclass c args:sel)
    | c `elem` ["is", "where"], ([Element arg'], []) <- parseSelectors args =
        arg' ++ lowerSelector' sel
lowerSelector' (test:tests) = test : lowerSelector' tests
lowerSelector' [] = []

data WhereLowerer s = WhereLowerer s

instance RuleStore s => RuleStore (WhereLowerer s) where
    new = WhereLowerer new
    addStyleRule (WhereLowerer self) priority rule =
        WhereLowerer $ addStyleRule self priority $ rule {
            inner = StyleRule (lowerSelector sel) props psuedo
        }
      where StyleRule sel props psuedo = inner rule
    lookupRules (WhereLowerer self) el = lookupRules self el