anagram.ls

fs = require \fs
{count-by, group-by, last, filter, reject, obj-to-pairs, pairs-to-obj, unique, sort, map, foldl1} = require \prelude-ls

const primes = [2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 101, 103, 107, 109, 113]
const alphabet = [\a to \z] ++ <[ å ä ö é ]>
const alpha_indices = pairs-to-obj alphabet.map (c, i) -> [c, i]
const filepath = (langcode, wordlist, length) -> "./words/#langcode/#wordlist/#length.txt"

class AnagramFinder

    get_prime_product: (word) ->
        prime_product = 1
        for char in word.toLowerCase()
            if char in alphabet 
                prime_product *= primes[ alpha_indices[char] ]
        return prime_product

    find_anagrams_among_words: (target_word, words) ->

        target_prime_product = @get_prime_product target_word
        anagrams = []
    
        for word in words
            prime_product =  @get_prime_product word
            if prime_product is target_prime_product
                anagrams ++= word

        return anagrams |> filter (.toLowerCase() isnt target_word.toLowerCase())

    get_anagrams: (word, wordlists, langcode, callback) ->

        console.log langcode

        wordlists .= split ','
        wordlength = word |> (.split '') |> reject (not in alphabet) |> (.length)

        if wordlength < 2 then return callback []

        found_anagrams = []
        read_wordlist_files = 0

        for let wordlist in wordlists

            error, words <~ fs.readFile (filepath langcode, wordlist, wordlength), encoding:\utf8

            if error then console.log error
            else
                words .= split \\n
                anagrams = @find_anagrams_among_words word, words
                found_anagrams ++= anagrams |> map (anagram) -> language:langcode, wordlist:wordlist, word:anagram

            read_wordlist_files += 1
            if read_wordlist_files == wordlists.length then callback found_anagrams


module.exports = new AnagramFinder()