module Main where

import Debug.Trace
import System.Environment (getArgs)

main :: IO ()
main = do
  input <- readFile . head =<< getArgs
  print $ part1 input
  print $ part2 input

part1 :: String -> Int
part1 = sum . filter invalid . concat . map ids . map parse . splitOn ','

splitOn :: (Eq a) => a -> [a] -> [[a]]
splitOn delim xs = case dropWhile (== delim) xs of
  [] -> []
  s' -> xs' : splitOn delim s''
    where
      (xs', s'') = break (== delim) s'

parse :: String -> (Int, Int)
parse = group . map read . splitOn '-'
  where
    group :: (Show a) => [a] -> (a, a)
    group (x : y : []) = (x, y)
    group x = error $ "group: " ++ show x ++ "is not two elements"

ids :: (Int, Int) -> [Int]
ids (start, end) = [start .. end]

invalid :: Int -> Bool
invalid i =
  let s = show i
      len = length s
      half = take (len `div` 2) s
   in s == half ++ half

part2 :: String -> Int
part2 = sum . filter invalid2 . concat . map ids . map parse . splitOn ','

invalid2 :: Int -> Bool
invalid2 i =
  let s = show i
      len = length s
      facs = factors len
   in or [(repeatN (len `div` n) $ take n s) == s | n <- facs]

-- needs to get the primes instead of all factors
factors :: Int -> [Int]
factors i = filter ((== 0) . (mod i)) [1 .. i `div` 2]

repeatN :: Int -> [a] -> [a]
repeatN i = concat . replicate i

testInput = "11-22,95-115,998-1012,1188511880-1188511890,222220-222224,1698522-1698528,446443-446449,38593856-38593862,565653-565659,824824821-824824827,2121212118-2121212124"