module Part2 where

import Commons
import Data.Array (Array, array, (!), (//), assocs, listArray)


type Hashmap = Array Int [Instruction]


initHashmap :: Hashmap
initHashmap = listArray (0, 255) [[] | _ <- [0..255]]

applyInstructionToList :: [Instruction] -> Instruction -> [Instruction]
applyInstructionToList [] i | iType i == Set = [i]
                            | otherwise      = []
applyInstructionToList (h: t) i | iType i == Set && label h == label i    = i: t
                                | iType i == Remove && label h == label i = t
                                | otherwise                               = h: applyInstructionToList t i

applyInstruction :: Hashmap -> Instruction -> Hashmap
applyInstruction m i = let hash = getHash 0 (label i)
                       in m // [(hash, applyInstructionToList (m ! hash) i)]

applyInstructions :: [Instruction] -> Hashmap
applyInstructions = foldl applyInstruction initHashmap

getFocusingPowerFromList :: Int -> Int -> [Instruction] -> [Int]
getFocusingPowerFromList _ _ [] = []
getFocusingPowerFromList i slot (h: t) = i * slot * focal h: getFocusingPowerFromList i (slot + 1) t

getFocusingPower :: Hashmap -> [Int]
getFocusingPower = concatMap (\ (i, h) -> getFocusingPowerFromList (i + 1) 1 h) . assocs

getAllFocusingPower :: [Instruction] -> [Int]
getAllFocusingPower = getFocusingPower . applyInstructions