module Reflex.Vty.Test.Common
  ( subscribeDynamic
  , readDynamic
  , checkSingle
  , checkSingleMaybe
  , checkNothing
  )
where

import           Relude

import           Test.HUnit

import           Reflex
import           Reflex.Host.Class


subscribeDynamic :: (MonadSubscribeEvent t m) => Dynamic t a -> m (EventHandle t a, Behavior t a)
subscribeDynamic d = do
  eh <- subscribeEvent $ updated d
  return (eh, current d)

readDynamic :: forall t m a. (MonadReadEvent t m, MonadSample t m) => (EventHandle t a, Behavior t a) -> m a
readDynamic (evh, b) = do
  v <- readEvent evh
  case v of
    Nothing -> sample b
    Just x -> x



checkSingle :: (Eq a, Show a) => [a] -> a -> Assertion
checkSingle values a = case nonEmpty values of
  Nothing -> assertFailure "empty list"
  Just x  -> a @=? head x

checkSingleMaybe :: (Eq a, Show a) => [Maybe a] -> a -> Assertion
checkSingleMaybe values a = case nonEmpty values of
  Nothing -> assertFailure "empty list"
  Just x  -> Just a @=? head x

checkNothing :: [Maybe a] -> Assertion
checkNothing values = case nonEmpty values of
  Nothing -> assertFailure "empty list"
  -- TODO prob check that all elts in list are Nothing
  Just x  -> True @=? isNothing (head x)