--module SortNet where
import Data.List
import Control.Parallel
import System.Environment
import System.Random

main = do args <- getArgs
          if ((length args) < 2) 
            then putStrLn usage 
            else 
            let inp = rand(2^(read (args !! 1)))
                res :: [Int]
                res | (args !! 0 == "1") = sortNet inp
                    | (args !! 0 == "2") = sortNetPar inp
                    | otherwise          = sortNetParD (if (length args) < 3 then 3 else read (read (args !! 2))) inp
                output' =  (if (length args) < 3 
                            then (read (args !! 3)) == 1 
                            else False)
                output | output'    = print res
                       | otherwise  = length res `pseq` putStrLn "done"
            in output
                    
usage = "2-4 Parameter werden benötigt: \n" ++
        " 1. Version (sortNet,sortNetPar,sortNetParD)\n"++
        " 2. Liste der Länge 2^N (N anzugeben)\n"++
        " 3. Parallele Tiefe für sortNetParD (default 3)\n"++
        " 4. Ausgabe der Ergebnisliste, 1 meint Ausgabe (default 0)"

comparator :: Ord a => a -> a -> [a]
comparator _ _ = error ""

    
nToNMerge :: Ord a => [a] -> [a] -> [a]
    
nToNMerge _ _ = error "input length: no power of 2"
    
sortNet :: Ord a => [a] -> [a]
sortNet _ = error ""

sortNetPar :: Ord a => [a] -> [a]
sortNetPar _ = error ""

sortNetParD :: Ord a => Int -> [a] -> [a]
sortNetParD _ _ = error ""
               

-- | Round robin distribution - inverse to shuffle
-- 
unshuffle :: Int      -- ^number of sublists
             -> [a]   -- ^input list
             -> [[a]] -- ^distributed output


unshuffle n xs = [takeEach n (drop i xs) | i <- [0..n-1]]
takeEach :: Int -> [a] -> [a] 
takeEach n [] = []
takeEach n (x:xs) = x : takeEach n (drop (n-1) xs)


-- | Simple shuffling - inverse to round robin distribution
shuffle :: [[a]]  -- ^ sublists
           -> [a] -- ^ shuffled sublists
shuffle = concat . transpose


rand :: Int -> [Int]
rand i = take i $ randomRs (1,10000) (mkStdGen 2)