import Data.Time.Clock
import Data.Time.LocalTime
import Data.Time.ZoneInfo

import System.IO.Unsafe

import Test.QuickCheck
import Text.Printf

prop_init = do
  -- Use TZDIR environment variable.
  -- Example:
  -- TZDIR=/usr/etc/zoneinfo runhaskell Setup test
  initZoneInfo Nothing
  return True

prop_show = do
  zi <- newZoneInfo "America/New_York"
  return (showZoneInfo zi == "America/New_York")

prop_minutes = do
  zi <- newZoneInfo "America/New_York"
  est <- getZoneMinutes zi False
  edt <- getZoneMinutes zi True
  return (est == -300 && edt == -240)

prop_inverse = do
  zi <- newZoneInfo "America/Chicago"
  ut <- getCurrentTime
  zt <- utcToZonedTime' zi ut
  (ut', _) <- localToUTCZoned zi (zonedTimeToLocalTime zt)
  return (ut == ut')

quickCheckUnsafe =
    quickCheck . unsafePerformIO

tests = [("init", quickCheckUnsafe prop_init),
         ("show", quickCheckUnsafe prop_show),
         ("minutes", quickCheckUnsafe prop_minutes),
         ("inverse", quickCheckUnsafe prop_inverse)]

main = mapM_ (\(s, a) -> printf "%-25s: " s >> a) tests