{-# language BangPatterns #-}
{-# language LambdaCase #-}
{-# language ScopedTypeVariables #-}
{-# language TypeApplications #-}

{-# OPTIONS_GHC -fno-warn-orphans #-}

import Data.Chunks (Chunks(ChunksCons,ChunksNil))
import Data.Primitive (SmallArray)
import Data.Proxy (Proxy(Proxy))
import Test.QuickCheck (Arbitrary,Gen,(===))
import Test.QuickCheck.Classes (eqLaws,semigroupLaws)
import Test.QuickCheck.Classes (monoidLaws,isListLaws,foldableLaws)
import Test.Tasty (defaultMain,testGroup,TestTree)
import qualified Data.Chunks as C
import qualified Data.Foldable as F
import qualified Data.List as L
import qualified GHC.Exts as Exts
import qualified Test.QuickCheck as QC
import qualified Test.QuickCheck.Classes as QCC
import qualified Test.Tasty.QuickCheck as TQC

main :: IO ()
main = defaultMain tests

tests :: TestTree
tests = testGroup "Chunks"
  [ lawsToTest (eqLaws (Proxy :: Proxy (Chunks Integer)))
  , lawsToTest (semigroupLaws (Proxy :: Proxy (Chunks Integer)))
  , lawsToTest (monoidLaws (Proxy :: Proxy (Chunks Integer)))
  , lawsToTest (isListLaws (Proxy :: Proxy (Chunks Integer)))
  , lawsToTest (foldableLaws (Proxy :: Proxy Chunks))
  , TQC.testProperty "concat" $ \(cs :: Chunks Integer) ->
      F.toList cs === Exts.toList (C.concat cs)
  , TQC.testProperty "concatReverse" $ \(cs :: Chunks Integer) ->
      Exts.toList (mconcat (L.reverse (Exts.toList cs)))
      ===
      Exts.toList (C.concatReverse cs)
  ]

lawsToTest :: QCC.Laws -> TestTree
lawsToTest (QCC.Laws name pairs) = testGroup name (map (uncurry TQC.testProperty) pairs)

instance Arbitrary a => Arbitrary (Chunks a) where
  arbitrary = QC.choose (0,3 :: Int) >>= \case
    0 -> pure ChunksNil
    1 -> do
      a <- arbitrarySmallArray
      pure (ChunksCons a ChunksNil)
    2 -> do
      a <- arbitrarySmallArray
      b <- arbitrarySmallArray
      pure (ChunksCons a (ChunksCons b ChunksNil))
    3 -> do
      a <- arbitrarySmallArray
      b <- arbitrarySmallArray
      c <- arbitrarySmallArray
      pure (ChunksCons a (ChunksCons b (ChunksCons c ChunksNil)))
    _ -> error "Chunks.arbitrary: not possible"

instance Arbitrary a => Arbitrary (SmallArray a) where
  arbitrary = arbitrarySmallArray

arbitrarySmallArray :: Arbitrary a => Gen (SmallArray a)
arbitrarySmallArray = do
  n <- QC.choose (0,2 :: Int)
  fmap Exts.fromList (QC.vectorOf n QC.arbitrary)