#!/usr/bin/python
import re
import itertools
from spellchecker import SpellChecker
from concurrent.futures import ThreadPoolExecutor
POOL = ThreadPoolExecutor()
SPELL = None


def init_spell_checker():
    global SPELL
    SPELL = SpellChecker()
    SPELL.word_frequency.load_text_file('extra_words.txt')


future = POOL.submit(init_spell_checker)


def canidates(letters, min=2):
    pos = []
    for length in range(min, len(letters)+1):
        for comb in itertools.combinations(letters, length):
            for perm in itertools.permutations(comb):
                word = ''.join(perm)
                pos.append(word)
    return set(SPELL.known(pos))


def filter_pos(pos, regex):
    pat = re.compile(regex + '$')
    return set(filter(pat.match, pos))


if __name__ == "__main__":
    while True:
        letters = input('Enter letters: ')
        if letters == ":quit:":
            break
        if SPELL is None:
            future.result()
        pos = canidates(letters)
        inp = None
        guessed = set()
        while inp not in (":quit:", ":new:"):
            if inp == ":enter:":
                inp = None
                while inp != ":done:":
                    if inp is not None:
                        guessed.add(inp)
                    inp = input("Enter guessed word, :done: to exit: ")
            elif inp is not None:
                fpos = filter_pos(pos, inp)
                for word in fpos-guessed:
                    print('>>>', word)
            print('Letters: ', ','.join(letters))
            prompt = """\
Enter pattern,
':new:' for new letters,
':enter:' to fill in guessed words, or
':quit:' to exit: """
            inp = input(prompt)
        if inp == ":quit:":
            break