-- | Parsing of unix timestamps
module Calamity.Types.UnixTimestamp (
    UnixTimestamp (..),
    unixToMilliseconds,
    millisecondsToUnix,
) where

import Calamity.Internal.Utils ()

import Control.Arrow

import Data.Aeson
import Data.Aeson.Encoding (word64)
import Data.Time
import Data.Time.Clock.POSIX
import Data.Word

import GHC.Generics

import Control.DeepSeq (NFData)
import TextShow
import qualified TextShow.Generic as TSG

newtype UnixTimestamp = UnixTimestamp
    { unUnixTimestamp :: UTCTime
    }
    deriving (Show, Eq, Generic)
    deriving newtype (NFData)
    deriving (TextShow) via TSG.FromGeneric UnixTimestamp

unixToMilliseconds :: UnixTimestamp -> Word64
unixToMilliseconds =
    unUnixTimestamp
        >>> utcTimeToPOSIXSeconds
        >>> toRational
        >>> (* 1000)
        >>> round

millisecondsToUnix :: Word64 -> UnixTimestamp
millisecondsToUnix =
    toRational
        >>> fromRational
        >>> (/ 1000)
        >>> posixSecondsToUTCTime
        >>> UnixTimestamp

instance ToJSON UnixTimestamp where
    toJSON =
        unUnixTimestamp
            >>> utcTimeToPOSIXSeconds
            >>> toRational
            >>> round
            >>> toJSON @Word64
    toEncoding =
        unUnixTimestamp
            >>> utcTimeToPOSIXSeconds
            >>> toRational
            >>> round
            >>> word64

instance FromJSON UnixTimestamp where
    parseJSON =
        withScientific "UnixTimestamp" $
            toRational
                >>> fromRational
                >>> posixSecondsToUTCTime
                >>> UnixTimestamp
                >>> pure