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

import           Control.DeepSeq
import           Data.Data
import           Data.Eq (Eq(..))
import           Data.Ord (Ord(..))
import           Data.String (IsString)
import           Data.Text (Text)
import qualified Data.Text as Text
import           Data.Typeable ()
import           Prelude ((.), Int)
import           Text.Show (Show(..))

import qualified Hcompta.Unit as Unit

-- * Type 'Unit'

newtype Unit = Unit Text
 deriving (Data, Eq, IsString, Ord, Show, Typeable)
instance Unit.Unit Unit where
	unit_empty = Unit ""
	unit_text (Unit t) = t
instance NFData Unit where
	rnf (Unit t) = rnf t

unit_length :: Unit -> Int
unit_length = Text.length . Unit.unit_text

-- * Example 'Unit's

-- | 'Unit.unit_empty'.
scalar :: Unit
scalar = Unit.unit_empty

-- | <https://en.wikipedia.org/wiki/Swiss_franc Swiss franc> unit of currency.
chf :: Unit
chf = Unit "CHF"

-- | <https://en.wikipedia.org/wiki/Yuan Yuan> unit of currency.
cny :: Unit
cny = Unit "Ұ"

-- | <https://en.wikipedia.org/wiki/Euro Euro> unit of currency.
eur :: Unit
eur = Unit "€"

-- | <https://en.wikipedia.org/wiki/Pound_sterling Pound sterling> unit of currency.
gbp :: Unit
gbp = Unit "£"

-- | <https://en.wikipedia.org/wiki/Indian_rupee Indian rupee> unit of currency.
inr :: Unit
inr = Unit "₹"

-- | <https://en.wikipedia.org/wiki/Japanese_yen Japanese yen> unit of currency.
jpy :: Unit
jpy = Unit "¥"

-- | <https://en.wikipedia.org/wiki/Russian_ruble Russian ruble> unit of currency.
--
-- NOTE: Ꝑ (U+A750) is used as a replacement latin letter,
--       because GHC currently chokes on ₽ (U+20BD),
--       which is the recently (2014/02) assigned Unicode code-point
--       for this currency.
rub :: Unit
rub = Unit "Ꝑ"

-- | <https://en.wikipedia.org/wiki/United_States_dollar United States dollar> unit of currency.
usd :: Unit
usd = Unit "$"