{-# LANGUAGE
    CPP,
    DataKinds,
    DeriveGeneric,
    FlexibleContexts,
    FlexibleInstances,
    LambdaCase,
    TypeFamilies,
    UndecidableInstances #-}

import Control.Monad (replicateM)
import Control.DeepSeq (NFData, force)
import GHC.Generics (Generic)
import System.Timeout (timeout)

import Test.QuickCheck

import Generic.Random

newtype T a = W a deriving (Generic, Show)

instance (Arbitrary a, BaseCase (T a)) => Arbitrary (T a) where
  arbitrary = genericArbitrary' uniform

instance NFData a => NFData (T a)

data NTree = Leaf | Node [NTree] deriving (Generic, Show)

instance Arbitrary NTree where
  arbitrary = genericArbitraryU'

instance NFData NTree

eval :: NFData a => String -> Gen a -> IO ()
eval name g = do
  x <- timeout (10 ^ (6 :: Int)) $ do
    xs <- generate (replicateM 100 g)
    return $! force xs
  case x of
    Just _ -> return ()
    Nothing -> fail $ name ++ ": did not finish on time"

#if __GLASGOW_HASKELL__ >= 800
-- Tests for ConstrGen

data Tree2 = Leaf2 Int | Node2 Tree2 Tree2 deriving (Generic, Show)

instance Arbitrary Tree2 where
  arbitrary = genericArbitraryUG ((ConstrGen (Leaf2 <$> arbitrary) :: ConstrGen "Node2" 1 Tree2))

isLeftBiased :: Tree2 -> Bool
isLeftBiased (Leaf2 _) = True
isLeftBiased (Node2 t (Leaf2 _)) = isLeftBiased t
isLeftBiased _ = False
#endif

main :: IO ()
main = do
  eval "T" (arbitrary :: Gen (T (T Int)))
  eval "NTree" (arbitrary :: Gen NTree)
#if __GLASGOW_HASKELL__ >= 800
  quickCheck . whenFail (putStrLn "Tree2") $ isLeftBiased
#endif