{-# LANGUAGE DeriveDataTypeable #-}
{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE GeneralizedNewtypeDeriving #-}
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE StandaloneDeriving #-}
{-# LANGUAGE TypeFamilies #-}
{-# OPTIONS_GHC -fno-warn-orphans #-}
module Hcompta.Format.Ledger.Quantity where

-- import           Data.Data
import           Data.Decimal
-- import           Data.Eq (Eq(..))
-- import           Data.Maybe (Maybe(..))
-- import           Data.Ord (Ord(..))
import           Data.Typeable ()
import           Data.Word (Word8)
-- import           Prelude (Num(..))

-- import qualified Hcompta.Polarize as Polarize
-- import qualified Hcompta.Quantity as Quantity
import qualified Hcompta.Filter.Amount as Filter.Amount

-- * Type 'Quantity'
type Quantity = Filter.Amount.Quantity
{-
deriving instance Data Quantity

instance Quantity.Zero Quantity where
	quantity_zero = 0
	quantity_null = (==) 0 -- . decimalMantissa
instance Quantity.Addable Quantity where
	quantity_add = (+)
instance Quantity.Negable Quantity where
	quantity_neg = negate
instance Polarize.Polarizable Quantity where
	polarizable_negative q =
		case q of
		 _ | q < 0 -> Just q
		 _         -> Nothing
	polarizable_positive q =
		case q of
		 _ | q <= 0 -> Nothing
		 _          -> Just q
-}

quantity_round :: Word8 -> Quantity -> Quantity
quantity_round = Data.Decimal.roundTo