{-# LANGUAGE DeriveDataTypeable #-}
module Hcompta.Model.Amount.Style where

import Data.Data
import Data.Word (Word8)
import Data.Typeable ()

-- * The 'Style' type

data Style
 =   Style
 { decimal_point :: Maybe Char
 , format :: Maybe Format
 , precision :: Word8
 , unit_side :: Maybe Side
 , unit_spaced :: Maybe Bool
 } deriving (Data, Eq, Ord, Read, Show, Typeable)

data Side
 =   Side_Left
 |   Side_Right
 deriving (Data, Eq, Ord, Read, Show, Typeable)

data Format
 =   Format Char [Int]
 deriving (Data, Eq, Ord, Read, Show, Typeable)

-- * Constructors

null :: Style
null =
	Style
	 { decimal_point = Nothing
	 , format = Nothing
	 , precision = 0
	 , unit_side = Nothing
	 , unit_spaced = Nothing
	 }

-- * Operators

union :: Style -> Style -> Style
union
 style@Style
 { decimal_point=decimal_point_
 , format=format_
 , precision=precision_
 , unit_side=side
 , unit_spaced=spaced
 }
 style'@Style
 { decimal_point=decimal_point'
 , format=format_'
 , precision=precision'
 , unit_side=side'
 , unit_spaced=spaced'
 } =
	if style == style'
	then style'
	else
		Style
		 { decimal_point=maybe decimal_point' (const decimal_point_) decimal_point_
		 , format=maybe format_' (const format_) format_
		 , precision=max precision_ precision'
		 , unit_side=maybe side' (const side) side
		 , unit_spaced=maybe spaced' (const spaced) spaced
		 }