module Anagram (anagramsFor) where

import Data.List (sort)
import Data.Char (toLower)

anagramsFor :: String -> [String] -> [String]
anagramsFor word candidates = filter (isAnagram word) candidates

isAnagram :: [Char] -> [Char] -> Bool
isAnagram word candidate
  | isOwnAnagram = False
  | otherwise    = normalize word == normalize candidate
  where normalize word' = sort $ lower word'
        lower word'     = map toLower word'
        isOwnAnagram    = lower word == lower candidate