module Day02 where

import Data.Maybe (fromMaybe)
import Text.Read (readMaybe)

data Move = Horizontal Int | Depth Int deriving Show

readDataLines:: (String -> Maybe a) -> String -> Either String [a]
readDataLines f s = case mapM f (lines s) of
                      Just xs -> Right xs
                      Nothing -> Left "Error parsing string"

day02Part1 :: String -> String
day02Part1 _ = "Day02 Part1"


day02Part2 :: String -> String
day02Part2 _ = "Day02 Part2"

readDirection ::String -> Maybe (Int -> Move)
readDirection "forward" = Just Horizontal
readDirection "down" = Just Depth
readDirection "up" = Just (Depth . negate)
readDirection _ = Nothing

readMove :: String -> Maybe Move
readMove s = case words s of
               [dirStr, distStr] -> readDirection dirStr <*> readMaybe distStr
               _ -> Nothing