import Data.List
import qualified Data.Map.Strict as DMS
import Control.Monad.State.Lazy

type Path = [String]
type FilesizeEntry = (Path, Int)

path :: FilesizeEntry -> Path
path (p,_) = p

filesize :: FilesizeEntry -> Int
filesize (_,i) = i

normalizePath l|("..":_:r)<-l=r|let=l

traversePath :: Path -> [String] -> [FilesizeEntry]
traversePath currentPath (line:input)
        |"$ cd .." == line = traversePath (tail currentPath) input
        |("$ cd ",directory)<-splitAt 5 line,normalizedPath<-directory:currentPath = traversePath normalizedPath input
        |[(filesize, "")]<-reads$fst$head$lex line, (_, filename) <- span (/=' ') line = (tail filename:currentPath,filesize):traversePath currentPath input
        |let=traversePath currentPath input
traversePath _ [] = []

recFiles :: Path -> [FilesizeEntry] -> [Int]
recFiles directory = map filesize.filter(\entry->directory `isSuffixOf` path entry)

allDirectories = nub.map (tail.path)
gather :: [FilesizeEntry] -> [FilesizeEntry]
gather directoryFileEntries = [ (uniqueDirectory,sum$recFiles uniqueDirectory directoryFileEntries) | uniqueDirectory<-allDirectories directoryFileEntries]
sumsmall :: [FilesizeEntry] -> Int
sumsmall l=sum[f|(d,f)<-l, f<=100000]
main=interact$pprint[].take 20.traversePath [].lines

updateOrInsert :: Int -> Maybe Int -> Maybe Int
updateOrInsert a (Just x) = Just (x+a)
updateOrInsert a _ = Just (a)

files2folders :: [FilesizeEntry] -> State (DMS.Map Path Int) ()
files2folders [] = return ()
files2folders ((_:path, size):xs) = do
        forM (init$tails path) (\part -> modify $ DMS.alter (updateOrInsert size) part)
        files2folders xs
                 
        

pprint _ [] = []
pprint cur (entry:list)
 |cur == (tail $ path entry) = show(filesize entry) ++ " " ++ (head$path entry) ++ "\n" ++ pprint cur list
 |otherwise = (tail$concat$intersperse "/"$reverse$tail$path entry) ++ "\n" ++ pprint (tail $ path entry) (entry:list)
-- t = map(\(h,t)->(h,sum t))
-- t l=groupBy(\(i,_)(j,_)->i==j)$[(o,i)|(e,_)<-l,(o,i)<-l,isPrefixOf e o]
-- main=interact$show.map(foldr1(\(d,i)(c,j)->(d,i+j))).t.sort.x.lines
--

input = readFile "day7long"

prepare = input >>= (return.traversePath [].lines)