import itertools
import re

from dictionary import Dictionary


def candidates(letters, dictionary: Dictionary, excludes, min=2):
    possibilities = []
    for length in range(min, len(letters) + 1):
        for comb in itertools.combinations(letters, length):
            for perm in itertools.permutations(comb):
                word = "".join(perm)
                possibilities.append(word)
    return dictionary.filter(possibilities, excludes)


def filter_possibilities(possibilities, regex):
    return set(filter(regex.match, possibilities))