from collections import Counter
from dictionary import Dictionary, DICTS


def make_key(dictionary_name, letters):
    return (dictionary_name, frozenset(Counter(letters).items()))


def candidates(letters, dictionary: Dictionary, min=2, permutations=None):
    letters = "".join(letters)
    possibilities = []
    for word in filter(lambda word: len(word) > min, dictionary.word_frequency.keys()):
        letter_set = set(word)
        if all(word.count(letter) < letters.count(letter) for letter in letter_set):
            possibilities.append(word)
    return possibilities


class CandidateCache:
    def __init__(self, maxsize=5):
        self.maxsize = maxsize
        self.cache = {}
        self.keys = []

    def get(self, dictionary_name, letters):
        key = make_key(dictionary_name, letters)
        try:
            return self.cache[key]
        except KeyError:

            data = candidates(letters, DICTS[dictionary_name])

            self.create(key, data)
            return data

    def create(self, key, data):
        if len(self.keys) > self.maxsize:
            key = self.keys.pop()
            del self.cache[key]
        self.keys.insert(0, key)
        self.cache[key] = data