#!/usr/bin/runghc

import Data.HashSet (HashSet)
import Data.List
import Data.Maybe
import Debug.Trace (trace)
import DetectEnglish
import TranspositionDecrypt
import TranspositionEncrypt

-- This is a monolithing recursive way of solving the problem:

-- |
-- >>> hackTransposition ["HI", "THERE"] 0.2 (encryptString 6 "hi there transposition")
-- "hi there transposition  "
hackTransposition :: HashSet String -> Float -> String -> (Int, String)
hackTransposition = hackTranspositionRec 1

-- |
-- >>> hackTranspositionRec 1 ["HI", "THERE"] 0.2 (encryptString 6 "hi there transposition")
-- "hi there transposition  "
hackTranspositionRec :: Int -> HashSet String -> Float -> String -> (Int, String)
hackTranspositionRec key wordList threshold message =
  let decrypted = decryptString (numOfColumns key message) message
      english = isEnglish wordList threshold decrypted
   in if english
        then (key, decrypted)
        else trace (show (key, decrypted)) $ hackTranspositionRec (key + 1) wordList threshold message

-- The above design does not have a "not-found" condition.
-- An alternative design is below:
-- use `find` with decryptSuccess predicate for single message, across [1..]

-- |
-- >>> decryptSuccess 6 ["HI", "THERE"] 0.2 (encryptString 6 "hi there transposition")
-- Just (6,"hi there transposition  ")

-- |
-- >>> decryptSuccess 1 ["HI", "THERE"] 0.2 (encryptString 6 "hi there transposition")
-- Nothing
decryptSuccess :: Int -> HashSet String -> Float -> String -> Bool
decryptSuccess key wordList threshold message =
  let decrypted = decryptString (numOfColumns key message) message
   in isEnglish wordList threshold decrypted

main :: IO ()
main = do
  hashDict <- importDictionary
  let encryptedMessage = encryptString 6 "This is a long message that is in English, and it will be cracked."
  print (hackTransposition hashDict 0.2 encryptedMessage)
  putStrLn "Another method, key was: "
  case find (\x -> decryptSuccess x hashDict 0.2 encryptedMessage) [1 ..] of
    Just crackedKey -> print (crackedKey, decryptString (numOfColumns crackedKey encryptedMessage) encryptedMessage)
    Nothing -> putStrLn "No key found"