module Main where

import Data.Char
import Data.List
import Control.Monad
import qualified Data.Set as Set

import Debug.Trace

indexof :: (Eq a) => [a] -> a -> Int
indexof l x = indexof' l x 0

indexof' :: (Eq a) => [a] -> a -> Int -> Int
indexof' (x:xs) v n | x == v = n
indexof' (_:xs) v n = indexof' xs v (n+1)

contains :: (Eq a) => [a] -> a -> Bool
contains [] _ = False
contains (x:xs) v = if x == v then True else contains xs v

collectnames :: [[String]] -> [String]
collectnames l = Set.toList $ collectnames' l

collectnames' :: [[String]] -> Set.Set String
collectnames' [] = Set.empty
collectnames' ((a:_:b:_):xs) = Set.insert a $ Set.insert b $ collectnames' xs

setinarr :: [a] -> Int -> a -> [a]
setinarr a i v = pre ++ v : post
    where spl = splitAt i a
          pre = fst spl
          post = tail $ snd spl

setinarr2 :: [[a]] -> (Int,Int) -> a -> [[a]]
setinarr2 a (i,j) v = pre ++ setinarr line j v : post
    where spl = splitAt i a
          pre = fst spl
          ([line],post) = splitAt 1 $ snd spl

parse :: [[String]] -> [[Int]]
parse ll = parse' ll names $ replicate numn (replicate numn 0)
    where names = collectnames ll
          numn = length names

parse' :: [[String]] -> [String] -> [[Int]] -> [[Int]]
parse' [] _ adj = adj
parse' ([as,_,bs,_,ds]:ls) ns adj = parse' ls ns $ setinarr2 (setinarr2 adj (b,a) d) (a,b) d
    where a = indexof ns as
          b = indexof ns bs
          d = read ds :: Int

pathlen :: [Int] -> Int
pathlen = sum

genpaths :: [[Int]] -> [[Int]]
genpaths adj = map todists $ concat [genpaths' adj [from] | from <- [0..(length adj - 1)]]
    where todists (a:b:cs) = adj!!a!!b : todists (b:cs)
          todists _ = []

genpaths' :: [[Int]] -> [Int] -> [[Int]]
genpaths' adj pat  -- = -- subl syntax
    | length pat == length adj = [pat]
    | otherwise = {-traceShow pat $-} concat [genpaths' adj (from:pat) | from <- [0..(length adj - 1)], adj!!(head pat)!!from /= 0 && not (contains pat from)]

day9 :: IO ()
day9 = do
    input <- liftM (map words . lines) $ readFile "day09.txt"
    print $ collectnames input
    --print $ parse input
    --print $ genpaths $ parse input
    print $ minimum [pathlen $ path | path <- genpaths $ parse input]

main = day9