{-# LANGUAGE MagicHash #-}
module Hcompta.Format.Ledger.Date.Write where

import           Data.Char (Char)
import           Data.Eq (Eq(..))
import           Data.Ord (Ord(..))
import qualified Data.Text as Text
import qualified Data.Time.LocalTime as Time
import           GHC.Exts (Int(..))
import           GHC.Integer.Logarithms (integerLogBase#)
import           Prelude (($), (.), Integer, Num(..), RealFrac(..), Show(..))

import           Hcompta.Date (Date)
import qualified Hcompta.Date as Date
import           Hcompta.Lib.Leijen (Doc, (<>))
import qualified Hcompta.Lib.Leijen as W

-- * Write 'Date'

date :: Date -> Doc
date dat = do
	let (y, mo, d) = Date.gregorian dat
	(if y == 0 then W.empty else W.integer y <> sep '/') <> do
	int2 mo <> do
	sep '/' <> int2 d <> do
	(case Date.tod dat of
	 Time.TimeOfDay 0 0 0 -> W.empty
	 Time.TimeOfDay h m s ->
		sep '_' <> int2 h <> do
		sep ':' <> int2 m <> do
		(case s of
		 0 -> W.empty
		 _ -> sep ':' <> do
			(if s < 10 then W.char '0' else W.empty) <> do
			W.strict_text $ Text.pack $ show $ (truncate s::Integer)))
	-- (case tz_min of
	--  0 -> W.empty
	--  _ | tz_name /= "" -> W.space <> do W.strict_text $ Text.pack tz_name
	--  _ -> W.space <> do W.strict_text $ Text.pack $ Time.timeZoneOffsetString tz)
	where
		int2 :: Int -> Doc
		int2 i = if i < 10 then W.char '0' <> W.int i else W.int i
		sep :: Char -> Doc
		sep = W.bold . W.dullblack . W.char

-- ** Measure 'Date'

date_length :: Date -> Int
date_length dat = do
	let (y, _, _) = Date.gregorian dat
	(case y of
	 0 -> 0
	 _ ->
		(if y < 0 then 1 else 0) -- sign
		+ (1 + (I# (integerLogBase# 10 (abs y)))) -- year
		+ 1) -- /
	+ 2 -- month
	+ 1 -- /
	+ 2 -- dom
	+ (case Date.tod dat of
	 Time.TimeOfDay 0 0 0 -> 0
	 Time.TimeOfDay _ _ s ->
		1 -- _
		+ 2 -- hour
		+ 1 -- :
		+ 2 -- min
		+ (case s of
		 0 -> 0
		 _ -> 1 + 2 -- : sec
		)
	)