{-# LANGUAGE CPP #-}
{-# OPTIONS_GHC -fno-warn-orphans #-}
{-
	Copyright (C) 2011 Dr. Alistair Ward

	This program is free software: you can redistribute it and/or modify
	it under the terms of the GNU General Public License as published by
	the Free Software Foundation, either version 3 of the License, or
	(at your option) any later version.

	This program is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
	GNU General Public License for more details.

	You should have received a copy of the GNU General Public License
	along with this program.  If not, see <http://www.gnu.org/licenses/>.
-}
{- |
 [@AUTHOR@]	Dr. Alistair Ward

 [@DESCRIPTION@]	Implements 'Test.QuickCheck.Arbitrary' and defines /QuickCheck/-properties for "Math.Implementations.Primes".
-}

module Factory.Test.QuickCheck.Primes(
-- * Functions
	quickChecks,
--	isPrime,
	upperBound
) where

import			Control.Applicative((<$>))
import qualified	Control.DeepSeq
import qualified	Data.Set
import qualified	Factory.Math.Implementations.Primality		as Math.Implementations.Primality
import qualified	Factory.Math.Implementations.PrimeFactorisation	as Math.Implementations.PrimeFactorisation
import qualified	Factory.Math.Implementations.Primes		as Math.Implementations.Primes
import qualified	Factory.Math.Primality				as Math.Primality
import qualified	Factory.Math.Primes				as Math.Primes
import qualified	Test.QuickCheck
import			Test.QuickCheck((==>))
import qualified	ToolShed.Defaultable				as Defaultable

instance Test.QuickCheck.Arbitrary Math.Implementations.Primes.Algorithm	where
	arbitrary	= Test.QuickCheck.oneof [
		return Math.Implementations.Primes.TurnersSieve,
		Math.Implementations.Primes.TrialDivision . (`mod` 10) <$> Test.QuickCheck.arbitrary,
		Math.Implementations.Primes.SieveOfEratosthenes . (`mod` 10) <$> Test.QuickCheck.arbitrary
	 ]
#if !(MIN_VERSION_QuickCheck(2,1,0))
	coarbitrary	= undefined	--CAVEAT: stops warnings from ghc.
#endif

isPrime :: (Control.DeepSeq.NFData i, Integral i) => i -> Bool
isPrime	= Math.Primality.isPrime primalityAlgorithm	where
	primalityAlgorithm :: Math.Implementations.Primality.Algorithm Math.Implementations.PrimeFactorisation.Algorithm
	primalityAlgorithm	= Defaultable.defaultValue

upperBound :: Math.Implementations.Primes.Algorithm -> Int -> Int
upperBound algorithm i	= mod i $ if algorithm == Math.Implementations.Primes.TurnersSieve
	then 8192
	else 65536

-- | Defines invariant properties.
quickChecks :: IO ()
quickChecks =
	Test.QuickCheck.quickCheck `mapM_` [prop_isPrime, prop_isComposite]
	>> Test.QuickCheck.quickCheck prop_consistency where
		prop_isPrime, prop_isComposite :: Math.Implementations.Primes.Algorithm -> Int -> Test.QuickCheck.Property
		prop_isPrime algorithm i	= Test.QuickCheck.label "prop_isPrime" . all isPrime . takeWhile (<= (upperBound algorithm i)) $ (Math.Primes.primes algorithm :: [Int])

		prop_isComposite algorithm i	= Test.QuickCheck.label "prop_isComposite" . not . any isPrime . Data.Set.toList . Data.Set.difference (
			Data.Set.fromList [2 .. upperBound algorithm i]
		 ) . Data.Set.fromList . takeWhile (<= (upperBound algorithm i)) $ Math.Primes.primes algorithm

		prop_consistency :: Math.Implementations.Primes.Algorithm -> Math.Implementations.Primes.Algorithm -> Int -> Test.QuickCheck.Property
		prop_consistency l r i = l /= r	==> Test.QuickCheck.label "prop_consistency" . and . take (i `mod` 4096) $ zipWith (==) (Math.Primes.primes l) (Math.Primes.primes r :: [Int])