module Day4Lib
    ( day4,
      day4Alternate
    ) where

import Data.List (intersect, isSubsequenceOf)
import Data.List.Split (splitOn)

type SectionId = Int
type Range = (SectionId, SectionId)
type RangePair = (Range, Range)

checkRangePairForPartialOverlap :: RangePair -> Bool
checkRangePairForPartialOverlap (r1, r2) = intersection
    where
        processedR1 = processRange r1
        processedR2 = processRange r2
        -- Get the intersection, convert it into a bool based on if it's empty, then negate the bool
        intersection = not $ null $ processedR1 `intersect` processedR2

checkRangePairForFullOverlap :: RangePair -> Bool
checkRangePairForFullOverlap (r1, r2) = processedR1 `isSubsequenceOf` processedR2 || processedR2 `isSubsequenceOf` processedR1
    where
        processedR1 = processRange r1
        processedR2 = processRange r2

processRange :: Range -> [SectionId]
processRange (s, e) = [s..e]

tuplify2 :: [a] -> (a,a)
tuplify2 [x,y] = (x, y)

parseInput :: String -> [RangePair]
parseInput i = map tuplify2 $ map (map tuplify2) $ map (map (map readAsInt)) $ map (map splitOnDash) $ map splitOnComma $ lines i
    where
        inputAsLines = lines i
        splitOnComma = splitOn ","
        splitOnDash = splitOn "-"
        readAsInt r = read r :: Int

day4 :: String -> Int
day4 input = sum $ map fromEnum $ map checkRangePairForFullOverlap $ parseInput input

day4Alternate :: String -> Int
day4Alternate input = sum $ map fromEnum $ map checkRangePairForPartialOverlap $ parseInput input