{-# LANGUAGE FlexibleContexts, NoMonomorphismRestriction #-}
{-# LANGUAGE TypeOperators, DataKinds #-}
{-# LANGUAGE TemplateHaskell #-}

module Control.Eff.NdetEff.Test (testGroups) where

import Test.HUnit hiding (State)
import Control.Applicative
import Control.Eff
import Control.Eff.Lift
import Control.Eff.NdetEff
import Control.Eff.Writer.Strict
import Control.Monad (msum, guard, mzero, mplus)
import Utils

import Test.Framework.TH
import Test.Framework.Providers.HUnit

testGroups = [ $(testGroupGenerator) ]

case_NdetEff_testCA :: Assertion
case_NdetEff_testCA = [2, 4..10] @=? (run $ makeChoiceA testCA)
  where
    testCA :: (Integral a) => Eff (NdetEff ': r) a
    testCA = do
      i <- msum . fmap return $ [1..10]
      guard (i `mod` 2 == 0)
      return i

case_NdetEff_ifte :: Assertion
case_NdetEff_ifte =
  let primes = ifte_test_run
  in
    assertEqual "NdetEff: test ifte using primes"
    [2,3,5,7,11,13,17,19,23,29] primes
  where
    ifte_test = do
      n <- gen
      ifte (do
               d <- gen
               guard $ d < n && n `mod` d == 0
               -- _ <- trace ("d: " ++ show d) (return ())
           )
        (\_ -> mzero)
        (return n)
        where gen = msum . fmap return $ [2..30]

    ifte_test_run :: [Int]
    ifte_test_run = run . makeChoiceA $ ifte_test


-- called reflect in the LogicT paper
case_NdetEff_reflect :: Assertion
case_NdetEff_reflect =
  let tsplitr10 = run $ runListWriter $ makeChoiceA tsplit
      tsplitr11 = run $ runListWriter $ makeChoiceA (msplit tsplit >>= unmsplit)
      tsplitr20 = run $ makeChoiceA $ runListWriter tsplit
      tsplitr21 = run $ makeChoiceA $ runListWriter (msplit tsplit >>= unmsplit)
  in
    assertEqual "tsplitr10" expected1 tsplitr10
    >> assertEqual "tsplitr11" expected1 tsplitr11
    >> assertEqual "tsplitr20" expected2 tsplitr20
    >> assertEqual "tsplitr21" expected21 tsplitr21
  where
    expected1 = ([1, 2],["begin", "end"])
    expected2 = [(1, ["begin"]), (2, ["end"])]
    expected21 = [(1, ["begin"]), (2, ["begin", "end"])]

    unmsplit :: Member NdetEff r => (Maybe (a, Eff r a)) -> Eff r a
    unmsplit Nothing      = mzero
    unmsplit (Just (a,m)) = return a `mplus` m

    tsplit =
      (tell "begin" >> return 1) `mplus`
      (tell "end"   >> return 2)

case_NdetEff_monadBaseControl :: Assertion
case_NdetEff_monadBaseControl = runLift (makeChoiceA $ doThing (return 1 <|> return 2)) @=? Just [1,2]