# Pastebin dUC7zGuy
module Day2Gqplox where

data Shape = Rock | Paper | Scissors deriving (Show, Ord, Eq, Enum)

data Outcome = Win | Draw | Lose deriving (Show, Ord, Eq, Enum)

shapeScore :: Shape -> Int
shapeScore = succ . fromEnum

score :: Shape -> Outcome -> Int
score opp Win = 6 + (shapeScore . wrappedSucc) opp
score opp Draw = 3 + shapeScore opp
score opp Lose = 0 + (shapeScore . wrappedPred) opp

wrappedSucc :: Shape -> Shape
wrappedSucc Scissors = Rock
wrappedSucc s = succ s

wrappedPred :: Shape -> Shape
wrappedPred = wrappedSucc . wrappedSucc

parseShape :: Char -> Shape
parseShape 'A' = Rock
parseShape 'B' = Paper
parseShape 'C' = Scissors

parseOutcome :: Char -> Outcome
parseOutcome 'X' = Lose
parseOutcome 'Y' = Draw
parseOutcome 'Z' = Win

solve :: [(Shape, Outcome)] -> Int
solve = sum . map (uncurry score)

parse :: String -> (Shape, Outcome)
parse str = case str of
            [s, ' ', o] -> (parseShape s, parseOutcome o)
            _ -> error "errors are bad"

part2 :: IO Int
part2 = solve . map parse . lines <$> readFile "input/day2"