import Data.List.Split
import Data.List.Unique
import Data.Char as Char
import Data.List as List
import Data.Either as Either
import Debug.Trace as Trace
import Data.Maybe

main = do
    mapIn <-  lines <$> getContents
    let robot = Robot mapIn [((5,1),64)] (5,1) 1
    let resultRobots = (runRobot robot )
    let connections = concat $ [(getConnections mapIn a b) | a <-"@abcdefghijklmnop", b <- "@abcdefghijklmnop", a /= b]
    let state = StatePath connections '@' []
    let result = getPath2 [state]
    --let nextKey = head (sortBy sortLength reachablePoints) 
    --let newMap = openGate mapIn nextKey
    --let aRobotLength = List.minimum( map (length . points) $ aRobots)
    --let aRobotWin = filter(\(Robot brain points position direction) -> length points == aRobotLength) aRobots 
    --let winRobots = filter(\(Robot br pts pos dir) -> elem 2 (map(\(p,c) -> c) pts))resultRobots
    --let winRobotsLength = map(\(Robot br pts pos dir) -> length (filter(\(p,c) -> c == 1)pts))winRobots
    --let winRobot = (map(\(Robot br pts pos dir) -> Robot br [] pos 1) winRobots) !! 0
    --let part2Robots = (runRobot winRobot)
    --let part2Length = map(\(Robot br pts pos dir) -> length (filter(\(p,c) -> c == 1)pts))part2Robots
    --putStrLn(show winRobotsLength)
    --putStrLn(show $ List.maximum( part2Length))
    mapM putStrLn(map show mapIn)
    mapM putStrLn(map show connections)
    putStrLn(show  result)
    
    --putStrLn(printKey nextKey)
    --mapM putStrLn(map show resultRobots)

data Robot = Robot{ brain:: [[Char]]
                    ,points:: [((Int,Int),Int)]
                    ,position:: (Int,Int)
                    ,direction :: Int
                    } deriving Show

data Key = Key { id :: Int,
                 pos :: (Int,Int),
                 way :: Int
               } deriving (Show, Eq)

data State = State { m :: [[Char]],
                     posi :: (Int,Int),
                     keys :: [Key]
                   } deriving Show

data StatePath = StatePath { connection :: [Connection],
                             p :: Char,
                             path :: [(Char,Int)]
                           } deriving (Show, Eq)


data Connection =Connection { key1 :: Char,
                               key2 :: Char,
                               l :: Int,
                               block :: [Char]
                              } deriving (Show, Eq)

getPath2 :: [StatePath] -> Int
getPath2 states = do
        let choose = (sortBy sortL( filter(\state -> getLength state < (min)) possible))
        if null choose
	   then min
           else do 
             let newChoose = (getPath (head choose) min)
             getPath2 ((delete (head choose) states) ++ (newChoose))
        where min = if length completed /= 0 then List.minimum( map(getLength) completed)
                                             else 999 
              completed = filter(\state -> length (path state) == 16) states
              possible = states \\ completed
              longest =List.maximum $ map(\state -> length (path state)) states

sortL :: StatePath -> StatePath -> Ordering
sortL s1 s2 
       | length (path s1) > length (path s2) = LT
       | length (path s1) < length (path s2) = GT
       | getLength s1 < getLength s2 = LT
       | getLength s1 > getLength s2 = GT
       | otherwise = EQ 

getPath :: StatePath -> Int -> [StatePath]
getPath(StatePath conn id path) minIn 
       |length path >= 16 =  [ (StatePath conn id path) ]
       |length possible == 1 = do
               let c = head possible
               let newState = stepPath (StatePath conn id path) c
               if getLength newState > minIn
                  then [newState]
                  else getPath newState minIn     
       |otherwise  = do
               let newStates = map(\c -> stepPath (StatePath conn id path) c) possible
               newStates              
       where possible = filter(\(Connection k1 k2 _ bs) -> k1 == id && length bs == 0) conn

stepPath :: StatePath -> Connection -> StatePath
stepPath (StatePath conn id path) c = do 
        let newConn' = map(\(Connection k1 k2 l b) -> (Connection k1 k2 l (delete (toUpper (key2 c)) b))) conn
        let newConn = filter(\(Connection k1 k2 l b) -> (k1 /= (key1 c)) && (k2 /= (key1 c)) ) newConn'
        let newId = key2 c
        let newPath = (newId, l c):path  
        StatePath ( newConn ) newId newPath

getCoordinate :: [[Char]] -> Char -> (Int,Int)
getCoordinate mapIn id = do
        let yAxis = head $ filter(\y -> elem  id y) mapIn
        let yAxisV = fromJust $ elemIndex yAxis mapIn
        let xAxisV = fromJust $ elemIndex id yAxis
        (xAxisV,yAxisV)

getConnections :: [[Char]] -> Char -> Char -> [Connection]
getConnections mapIn id goal =  conn 
        where robot = Robot (mapIn) [((a,b),64)] (a,b) 1
              resultRobots = (runRobot robot (ord goal))
              conn = (getConnection  (resultRobots) id goal)
              (a,b) = getCoordinate mapIn id
              

getConnection :: [Robot] -> Char -> Char -> [Connection]
getConnection robots startKey goal = conn
        where paths = map (\(Robot brain points position direction) -> points) robots
              pkPair = map(\ps -> ((snd (last ps)),ps)) paths
              gPkPair = filter(\(k,pth) -> (chr k) == goal) pkPair
              conn = map(\(k,pth) -> Connection startKey (chr k) (length pth) (blocks pth)) gPkPair
              blocks xs = map(\(_,c) -> (chr c)) $ filter(\(_,c) -> between 65 c 90) xs

getLength :: StatePath -> Int
getLength (StatePath _ _ path) = do
        let keyL = map(\(_,a) -> a - 1) path
        sum (keyL)


stepKey :: State -> Key -> State
stepKey (State mapIn (a,b) keys) nextKey = do
	let newMap = openGate mapIn (nextKey)
        let newKeys = nextKey:keys 	
        State newMap (pos nextKey) newKeys

sortLength :: Key -> Key -> Ordering
sortLength (Key _ _ way1) (Key _ _ way2) 
	| way1 == way2 = EQ
        | way1 < way2 = LT
        | way1 > way2 = GT

openGate :: [[Char]] -> Key -> [[Char]]
openGate mapIn (Key id (a,b) _) = result
        where result' = map( map(\c -> if c==(chr id) then '.' else c)) mapIn 
	      result = map( map(\c -> if c==(chr (id-32)) then '.' else c)) result'

printKey :: Key -> [Char]
printKey (Key id pos way) = (show id)++" :"++(show pos)++(show way)

getBrain :: Robot -> [[Char]]
getBrain (Robot brain points poisition direction)  = brain


getNextKey :: [Robot] -> [Key]
getNextKey robots = nub minPts
          where kPts = map(\(Robot brain points position direction) ->(Key (snd(last points)) (fst(last points)) (length points))) robots
                minPts = map(\(Key id pos way) ->(Key id pos (min id))) keyWPr 
                min x = List.minimum  $ map(\(Key id pos way) -> way) $ filter(\(Key id pos way) -> id == x) keyWPr
                keys = filter(\(Key id pos way) -> id /= 46 && id /= 64 && between 97 id 122) kPts
                keyWPr = keys 

min :: [Int] -> Int
min xs = foldr1 (\x y -> if x < y then x else y) xs

runRobot :: Robot -> Int -> [Robot]
runRobot robot goal
  | (length move) == 0 = [robot]
  | (length move) == 1 = do
          let newRobot = stepRobot robot ( move!!0 ) goal
          runRobot newRobot goal
  | otherwise = do
               let newRobots = map(\mv -> stepRobot robot mv goal) move
               foldl (++) [] $ map(\robot ->  runRobot robot goal) newRobots
  where move = getNextMove robot  

stepRobot :: Robot -> Int -> Int -> Robot 
stepRobot (Robot brain points position direction) newDirection goal = do
        let newPos = move position newDirection 
        let statusResponse = ord ((brain!! (snd newPos))!! (fst newPos)) 
        let newPoints = (points) ++ [(newPos,  statusResponse)]
	if statusResponse == 35 || statusResponse == goal
          then Robot brain newPoints position newDirection
          else Robot brain newPoints newPos newDirection

between :: Int -> Int -> Int -> Bool
between x y z 
  |x <= y = y <= z
  |otherwise = False

move :: (Int,Int) -> Int -> (Int,Int)
move (x,y) direction 
               | direction == 1 = (x,y-1)
               | direction == 2 = (x+1,y)
               | direction == 3 = (x,y+1)
               | direction == 4 = (x-1,y)

getNextMove :: Robot -> [Int]
getNextMove (Robot brain points position direction) 
            |length points > 0 && (snd $ last points) == 2 = [] 
            |otherwise = do
                    filterMoves (Robot brain points position direction) [1,2,3,4]
                                        
filterMoves :: Robot -> [Int] -> [Int] 
filterMoves robot moves = filter(\x -> checkVisit robot x && checkWall robot x) moves

checkVisit :: Robot -> Int -> Bool
checkVisit (Robot brain points position direction) mv = do
        let newPos = move position mv
        let visits = map(\(pos,c) -> pos) points
        notElem newPos visits

checkWall :: Robot -> Int -> Bool
checkWall (Robot brain points position direction) mv = do
        let newPos = (move position mv)
	let mvResult = ( ord ((brain!! (snd newPos))!! (fst newPos)))
        not (mvResult == 35 ) 
        
getList :: String -> [Int]
getList = map Prelude.read . splitOn ","