import os.path
import atexit

import ujson
import markovify

from config import config


class Markov:
    def __init__(self):
        self.counter = 0

        self.corpus = []
        self.chain = None

        self.load()

        atexit.register(self.save)

    @property
    def is_ready(self):
        return self.chain is not None

    def generate(self):
        words = self.chain.walk()
        if not words:
            return self.generate()

        return " ".join(words)

    def rebuild(self):
        self.chain = markovify.Chain(self.corpus, config.MARKOV_STATE_SIZE).compile()

    def extend_corpus(self, text):
        text = text.strip()
        if not text:
            return

        text = text.replace("\n", " ")
        text = text.split(" ")
        text = map(lambda word: word.strip(), text)
        text = filter(bool, text)
        text = list(text)

        self.corpus.insert(0, text)

        if len(self.corpus) > config.MARKOV_CORPUS_SIZE:
            self.corpus = self.corpus[: config.MARKOV_CORPUS_SIZE]

        self.counter += 1

        if self.counter % config.MARKOV_REBUILD_RATE == 0:
            self.counter = 0

            self.rebuild()

    def load(self):
        if os.path.isfile(config.MARKOV_CHAIN_PATH):
            with open(config.MARKOV_CHAIN_PATH, "r") as f:
                self.chain = markovify.Chain.from_json(f.read())

        if os.path.isfile(config.MARKOV_CORPUS_PATH):
            with open(config.MARKOV_CORPUS_PATH, "r") as f:
                self.corpus = ujson.load(f)

    def save(self):
        if self.chain:
            with open(config.MARKOV_CHAIN_PATH, "w") as f:
                f.write(self.chain.to_json())

        with open(config.MARKOV_CORPUS_PATH, "w") as f:
            ujson.dump(self.corpus, f)