{-# LANGUAGE OverloadedStrings #-}
-----------------------------------------------------------------------------
-- |
-- Module      : Hasmin.Types.Shadow
-- Copyright   : (c) 2017 Cristian Adrián Ontivero
-- License     : BSD3
-- Stability   : experimental
-- Portability : non-portable
--
-----------------------------------------------------------------------------
module Hasmin.Types.Shadow (
      Shadow(..)
    ) where

import Control.Monad.Reader (ask)
import Data.Monoid ((<>))
import Data.Text.Lazy.Builder (singleton)
import Data.Bool (bool)

import Hasmin.Types.Class
import Hasmin.Types.Color
import Hasmin.Types.Dimension

data Shadow = Shadow { inset :: Bool
                     , sOffsetX :: Distance
                     , sOffsetY :: Distance
                     , blurRadius :: Maybe Distance
                     , spreadRadius :: Maybe Distance
                     , sColor :: Maybe Color
                     } deriving (Eq, Show)

instance ToText Shadow where
  toBuilder (Shadow i ox oy br sr c) =
      bool mempty "inset " i
      <> toBuilder ox <> singleton ' '
      <> toBuilder oy <> f br <> f sr <> f c
    where f x = maybe mempty (\y -> singleton ' ' <> toBuilder y) x -- don't eta reduce this!

instance Minifiable Shadow where
  minifyWith (Shadow i ox oy br sr c) = do
      conf <- ask
      x  <- minifyWith ox
      y  <- minifyWith oy
      nb <- mapM minifyWith br
      ns <- mapM minifyWith sr
      c2 <- mapM minifyWith c
      pure $ if True {- shouldMinifyShadows conf -}
                then let (a, b) = minifyBlurAndSpread nb ns
                     in Shadow i x y a b c2
                else Shadow i x y nb ns c2

minifyBlurAndSpread :: Maybe Distance -> Maybe Distance
             -> (Maybe Distance, Maybe Distance)
minifyBlurAndSpread (Just br) Nothing
    | br == Distance 0 Q = (Nothing, Nothing)
    | otherwise          = (Just br, Nothing)
minifyBlurAndSpread (Just br) (Just sr)
    | sr == Distance 0 Q = minifyBlurAndSpread (Just br) Nothing
    | otherwise          = (Just br, Just sr)
minifyBlurAndSpread x y = (x, y)