ord9nummake.hs

{-# LANGUAGE OverloadedStrings #-}

module Main where

import System.Environment (getArgs)
import Data.String.Utils (split)
import Data.Char (digitToInt, intToDigit, isDigit)
import Data.List (sort, permutations)
import Data.Maybe (listToMaybe)

-- |
-- >>> parseInput "13:01167"
--     (13, [0, 1, 1, 6, 7] )
-- >>> parseInput ""
--     *** Exception: Invalid Input: ""
-- >>> parseInput ":"
--     *** Exception: Invalid Input: ":"
-- >>> parseInput ":1"
--     *** Exception: Invalid Input: ":1"
-- >>> parseInput "1:"
--     *** Exception: Invalid Input: "1:"
-- >>> parseInput "1:123"
--     *** Exception: Invalid Input: "1:123"
parseInput :: String -> (Int, [Int])
parseInput s = parseInputList $ split ":" s
  where
    parseInputList (s1:s2:[])
      | isDigits s1 && isDigits s2 && length s2 == 4 = ( read s1 :: Int, map digitToInt s2 )
      | otherwise = invalidInput
    parseInputList _ = invalidInput
    invalidInput = error $ "Invalid Input: " ++ show s

solve :: Int -> [Int] -> Maybe [Int]
solve i is = i `thElemOf` fourDigits
  where
    is' = sort is
    fourDigits = filter ( (4 ==) . length ) $ permutationsWithoutZeroHead is'
    permutationsWithoutZeroHead is'' = do
      overZero <- overZeros
      let without_a_OverZero = undefined
      map (without_a_OverZero:) $ permutations without_a_OverZero
      where
        overZeros = filter (0 /=) is''

-- |
-- >>> 2 `thElemOf` [1..2]
--     Just 2
-- >>> 1 `thElemOf` [1]
--     Just 1
-- >>> 0 `thElemOf` [1]
--     Nothing
thElemOf :: Int -> [a] -> Maybe a
thElemOf i = listToMaybe . drop ( i - 1 )

-- |
-- >>> solveFromInput "13:01167"
--     "1109"
-- >>> solveFromInput "1:1234"
--     "1234"
-- >>> solveFromInput "2:1234"
--     "1243"
-- >>> solveFromInput "7:1234"
--     "2134"
-- >>> solveFromInput "24:1234"
--     "4321"
-- >>> solveFromInput "25:1234"
--     "-"
-- >>> solveFromInput "2:1116"
--     "1119"
-- >>> solveFromInput "2:0116"
--     "1019"
-- >>> solveFromInput "3:6666"
--     "6696"
-- >>> solveFromInput "16:6666"
--     "9999"
-- >>> solveFromInput "10:01267"
--     "1097"
-- >>> solveFromInput "14:111167"
--     "1671"
-- >>> solveFromInput "1:1111"
--     "1111"
-- >>> solveFromInput "2:1111"
--     "-"
-- >>> solveFromInput "1:666633"
--     "3366"
-- >>> solveFromInput "72:666611"
--     "9999"
-- >>> solveFromInput "73:666622"
--     "-"
-- >>> solveFromInput "1:666600"
--     "6006"
-- >>> solveFromInput "52:666600"
--     "9999"
-- >>> solveFromInput "53:666600"
--     "-"
-- >>> solveFromInput "25:06688"
--     "8086"
-- >>> solveFromInput "93:02566"
--     "6502"
-- >>> solveFromInput "11:06688"
--     "6809"
-- >>> solveFromInput "169:01268"
--     "9801"
-- >>> solveFromInput "174:01268"
--     "9821"
-- >>> solveFromInput "66:012288"
--     "8201"
solveFromInput :: String -> String
solveFromInput s = maybe "-" (map intToDigit) $ uncurry solve $ parseInput s

isDigits :: String -> Bool
isDigits = all isDigit

main :: IO ()
main = do
  (input:_) <- getArgs
  putStrLn $ solveFromInput input