{-# LANGUAGE TemplateHaskell #-}
{-# OPTIONS_GHC -fno-warn-missing-signatures #-}

module Main (main) where

import Data.Time
import Data.Time.Zones
import Test.Tasty.TH
import Test.Tasty.HUnit

case_utcTZ_is_utc = timeZoneForPOSIX utcTZ 0 @?= utc

case_utcTZ_zero_diff = diffForPOSIX utcTZ 0 @?= 0

case_DB_utc_is_utc = do
  tz <- loadTZFromDB "UTC"
  tz @?= utcTZ

mkLocal y m d hh mm ss
  = LocalTime (fromGregorian y m d) (TimeOfDay hh mm ss)

mkUTC y m d hh mm ss
  = UTCTime (fromGregorian y m d) (timeOfDayToTime $ TimeOfDay hh mm ss)

case_Budapest_LocalToUTC = do
  tz <- loadTZFromDB "Europe/Budapest"
  let zWinter = TimeZone 60 False "CET"
      zSummer = TimeZone 120 True "CEST"
  -- Handle std times:
  localTimeToUTCFull tz (mkLocal 1970 01 01  01 00 00) @?=
    LTUUnique (mkUTC 1970 01 01  00 00 00) zWinter
  localTimeToUTCFull tz (mkLocal 2014 03 23  00 15 15.15) @?=
    LTUUnique (mkUTC 2014 03 22  23 15 15.15) zWinter

  -- Handle time in winter->summer transition:
  localTimeToUTCFull tz (mkLocal 2014 03 30  02 15 15) @?=
    LTUNone (mkUTC 2014 03 30  01 15 15) zWinter
  -- That utc time is acually in dst already:
  localTimeToUTCFull tz (mkLocal 2014 03 30  03 15 15) @?=
    LTUUnique (mkUTC 2014 03 30  01 15 15) zSummer

  -- Handle dst times:
  localTimeToUTCFull tz (mkLocal 2014 04 05  06 07 08.987654321999) @?=
    LTUUnique (mkUTC 2014 04 05  04 07 08.987654321999) zSummer

  -- Handle time in summer->winter transition:
  localTimeToUTCFull tz (mkLocal 2013 10 27  02 15 15) @?=
    LTUAmbiguous (mkUTC 2013 10 27  00 15 15) (mkUTC 2013 10 27  01 15 15)
      zSummer zWinter

-- Local->UTC, test for time zones that stop having DST.
-- Bug reported in #8
case_Moscow_LocalToUTC = do
  tz <- loadTZFromDB "Europe/Moscow"
  let zMoscow = TimeZone 180 False "MSK"
  localTimeToUTCFull tz (mkLocal 2015 11 23  00 00 00) @?=
    LTUUnique (mkUTC 2015 11 22  21 00 00) zMoscow

case_UTC_diffForAbbr = do
  tz <- loadTZFromDB "UTC"
  diffForAbbr tz "UTC" @?= Just 0
  diffForAbbr tz "XYZ" @?= Nothing

case_Paris_diffForAbbr = do
  tz <- loadTZFromDB "Europe/Paris"
  diffForAbbr tz "CET" @?= Just 3600
  diffForAbbr tz "CEST" @?= Just 7200
  diffForAbbr tz "WET" @?= Just 0
  diffForAbbr tz "LMT" @?= Just 561
  diffForAbbr tz "XYZ" @?= Nothing

main :: IO ()
main = $defaultMainGenerator