module Part2 where

import Commons
import Data.HashMap.Internal.Strict (keys, (!))


getStarts :: [(String, Instruction)] -> [String]
getStarts [] = []
getStarts (([a, b, 'A'], ILeft): t) = [a, b, 'A']: getStarts t
getStarts (_: t) = getStarts t

getDistanceToEnd :: [Instruction] -> Network -> String -> Int
getDistanceToEnd [] network start = getDistanceToEnd (instructions network) network start
getDistanceToEnd  _ _ [_, _, 'Z'] = 0
getDistanceToEnd (ih: t) network start = 1 + getDistanceToEnd t network (nodes network ! (start, ih))

getAllDistances :: Network -> [Int]
getAllDistances network = map (getDistanceToEnd [] network) . getStarts . keys $ nodes network

getSteps :: Network -> Int
getSteps = foldr lcm 1 . getAllDistances