module Graphics.Text.Font.Choose.Range(Range(..), iRange) where

import Data.MessagePack (MessagePack(..), Object(..))
import qualified Data.Vector as V
import qualified Data.IntMap as IM

-- | Matches a numeric range.
data Range = Range Double Double deriving (Eq, Show, Ord)
-- | Matches an integral range.
iRange :: Int -> Int -> Range
iRange i j = toEnum i `Range` toEnum j

instance MessagePack Range where
    toObject (Range start end) = ObjectMap $ V.fromList [
        (ObjectInt 0, ObjectDouble start),
        (ObjectInt 1, ObjectDouble end)
      ]
    fromObject msg
        | Just msg' <- fromObject msg =
            Just (IM.findWithDefault 0 0 msg' `Range` IM.findWithDefault 0 1 msg')
        | otherwise = Nothing