{-# LANGUAGE DeriveAnyClass        #-}
{-# LANGUAGE DeriveDataTypeable    #-}
{-# LANGUAGE DeriveGeneric         #-}
{-# LANGUAGE FlexibleInstances     #-}
{-# LANGUAGE MultiParamTypeClasses #-}

module Operator.Binary.Logical
  ( BinaryLogicalOperator()
  , getBinaryLogicalSymbol
  , getBinaryLogicalOperator
  , fromBinaryLogicalFunction
  ) where

import Control.DeepSeq
import Data.Data
import Data.Monoid ()
import Data.Semigroup
import GHC.Generics
import Test.QuickCheck        hiding (generate)
import Test.SmallCheck.Series


data  BinaryLogicalOperator
    = AlwaysFalse
    | LogicalNOR
    | ConverseNonImplication
    | NotFirstArgument
    | NonImplication
    | NotSecondArgument
    | LogicalXOR
    | LogicalNAND
    | LogicalAND
    | LogicalXNOR
    | SecondArgument
    | Implication
    | FirstArgument
    | ConverseImplication
    | LogicalOR
    | AlwaysTrue
    deriving (Data, Eq, Ord, Generic, NFData, Typeable)


instance Arbitrary BinaryLogicalOperator where

    arbitrary = arbitraryBoundedEnum


instance Bounded BinaryLogicalOperator where

    minBound = AlwaysFalse

    maxBound = AlwaysTrue


instance CoArbitrary BinaryLogicalOperator where

    coarbitrary = coarbitraryEnum


instance Enum BinaryLogicalOperator where

    toEnum n =
        case n `rem` 16 of
          0  -> AlwaysFalse
          1  -> LogicalNOR
          2  -> ConverseNonImplication
          3  -> NotFirstArgument
          4  -> NonImplication
          5  -> NotSecondArgument
          6  -> LogicalXOR
          7  -> LogicalNAND
          8  -> LogicalAND
          9  -> LogicalXNOR
          10 -> SecondArgument
          11 -> Implication
          12 -> FirstArgument
          13 -> ConverseImplication
          14 -> LogicalOR
          _  -> AlwaysTrue

    fromEnum x =
        case x of
          AlwaysFalse            -> 0
          LogicalNOR             -> 1
          ConverseNonImplication -> 2
          NotFirstArgument       -> 3
          NonImplication         -> 4
          NotSecondArgument      -> 5
          LogicalXOR             -> 6
          LogicalNAND            -> 7
          LogicalAND             -> 8
          LogicalXNOR            -> 9
          SecondArgument         -> 10
          Implication            -> 11
          FirstArgument          -> 12
          ConverseImplication    -> 13
          LogicalOR              -> 14
          AlwaysTrue             -> 15

    succ x =
        case x of
          AlwaysFalse            -> LogicalNOR
          LogicalNOR             -> ConverseNonImplication
          ConverseNonImplication -> NotFirstArgument
          NotFirstArgument       -> NonImplication
          NonImplication         -> NotSecondArgument
          NotSecondArgument      -> LogicalXOR
          LogicalXOR             -> LogicalNAND
          LogicalNAND            -> LogicalAND
          LogicalAND             -> LogicalXNOR
          LogicalXNOR            -> SecondArgument
          SecondArgument         -> Implication
          Implication            -> FirstArgument
          FirstArgument          -> ConverseImplication
          ConverseImplication    -> LogicalOR
          LogicalOR              -> AlwaysTrue
          AlwaysTrue             -> AlwaysFalse

    pred x =
        case x of
          AlwaysFalse            -> AlwaysTrue
          LogicalNOR             -> AlwaysFalse
          ConverseNonImplication -> LogicalNOR
          NotFirstArgument       -> ConverseNonImplication
          NonImplication         -> NotFirstArgument
          NotSecondArgument      -> NonImplication
          LogicalXOR             -> NotSecondArgument
          LogicalNAND            -> LogicalXOR
          LogicalAND             -> LogicalNAND
          LogicalXNOR            -> LogicalAND
          SecondArgument         -> LogicalXNOR
          Implication            -> SecondArgument
          FirstArgument          -> Implication
          ConverseImplication    -> FirstArgument
          LogicalOR              -> ConverseImplication
          AlwaysTrue             -> LogicalOR

--    enumFrom x = toEnum <$> [fromEnum x .. 15]

--    enumFromTo x y = 


instance Monad m => Serial m BinaryLogicalOperator where

    series = generate $ const [minBound .. maxBound]


instance Show BinaryLogicalOperator where

    show x = "f p q = " <> s
      where
        s = case x of
              AlwaysFalse            -> "False (Contradiction)"
              LogicalNOR             -> "¬p ∧ ¬q (Logical NOR)"
              ConverseNonImplication -> "¬p ∧ q (Converse Non-Implication)"
              NotFirstArgument       -> "¬p (Not First)"
              NonImplication         -> "p ∧ ¬q (Non-Implication)"
              NotSecondArgument      -> "¬q (Not Second)"
              LogicalXOR             -> "(p ∧ ¬q) ∨ (¬p ∧ q) (Logical XOR)"
              LogicalNAND            -> "¬p ∨ ¬q (Logical NAND)"
              LogicalAND             -> "p ∧ q (Logical AND)"
              LogicalXNOR            -> "(p ∧ q) ∨ (¬p ∧ ¬q) (Logical XNOR)"
              SecondArgument         -> "q (Second)"
              Implication            -> "¬p ∨ q (Implication)"
              FirstArgument          -> "p (First)"
              ConverseImplication    -> "p ∨ ¬q (Converse Implication)"
              LogicalOR              -> "p ∧ q (Logical OR)"
              AlwaysTrue             -> "True (Tautology)"


getBinaryLogicalOperator :: BinaryLogicalOperator -> Bool -> Bool -> Bool
getBinaryLogicalOperator x =
    case x of
      AlwaysFalse            -> const (const False)
      LogicalNOR             -> \p q -> not $ p || q
      ConverseNonImplication -> \p q -> not p &&     q
      NotFirstArgument       -> \p _ -> not p
      NonImplication         -> \p q ->     p && not q
      NotSecondArgument      -> \_ q ->          not q
      LogicalXOR             -> (/=)
      LogicalNAND            -> \p q -> not $ p && q
      LogicalAND             -> (&&)
      LogicalXNOR            -> (==)
      SecondArgument         -> \_ q ->              q
      Implication            -> \p q -> not p ||     q
      FirstArgument          -> const
      ConverseImplication    -> \p q ->     p || not q
      LogicalOR              -> (||)
      AlwaysTrue             -> const (const True)


getBinaryLogicalSymbol :: BinaryLogicalOperator -> String
getBinaryLogicalSymbol x =
    case x of
      AlwaysFalse            -> "(const False)"
      LogicalNOR             -> "(not . (||))"
      ConverseNonImplication -> "(</=)"
      NotFirstArgument       -> "(not . fst)"
      NonImplication         -> "(=/>)"
      NotSecondArgument      -> "(not . snd)"
      LogicalXOR             -> "(/=)"
      LogicalNAND            -> "(not . (&&))"
      LogicalAND             -> "(&&)"
      LogicalXNOR            -> "(==)"
      SecondArgument         -> "(snd)"
      Implication            -> "(==>)"
      FirstArgument          -> "(fst)"
      ConverseImplication    -> "(<==)"
      LogicalOR              -> "(||)"
      AlwaysTrue             -> "(const True)"


fromBinaryLogicalFunction :: (Bool -> Bool -> Bool) -> BinaryLogicalOperator
fromBinaryLogicalFunction f = 
    case (f True True, f True False, f False True, f False False) of
      (False, False, False, False) -> AlwaysFalse
      (False, False, False, True ) -> LogicalNOR
      (False, False, True , False) -> ConverseNonImplication
      (False, False, True , True ) -> NotFirstArgument
      (False, True , False, False) -> NonImplication
      (False, True , False, True ) -> NotSecondArgument
      (False, True , True , False) -> LogicalXOR
      (False, True , True , True ) -> LogicalNAND
      (True , False, False, False) -> LogicalAND
      (True , False, False, True ) -> LogicalXNOR
      (True , False, True , False) -> SecondArgument
      (True , False, True , True ) -> Implication
      (True , True , False, False) -> FirstArgument
      (True , True , False, True ) -> ConverseImplication
      (True , True , True , False) -> LogicalOR 
      (True , True , True , True ) -> AlwaysTrue