#!/usr/bin/env python3

import random

class Markov(object):
    def __init__(self, text=None):
        self.cache = {}
        self.words = []
        if text is None:
            text = ""
        self.words = text.split()
        self.word_size = len(self.words)
        self.database()

    def triples(self):
        """ Generates triples from the given data string. So if our string were
                "What a lovely day", we'd generate (What, a, lovely) and then
                (a, lovely, day).
        """

        if len(self.words) < 3:
            return

        for i in range(len(self.words) - 2):
            yield (self.words[i], self.words[i+1], self.words[i+2])

    def database(self):
        for w1, w2, w3 in self.triples():
            key = (w1, w2)
            if key in self.cache:
                self.cache[key].append(w3)
            else:
                self.cache[key] = [w3]

    def generate_markov_text(self, size=50):
        seed = random.randint(0, self.word_size-3)
        seed_word, next_word = self.words[seed], self.words[seed+1]
        while "!kvl" in seed_word:
            seed = random.randint(0, self.word_size-3)
            seed_word, next_word = self.words[seed], self.words[seed+1]
        w1, w2 = seed_word, next_word
        gen_words = []
        for i in range(size):
            gen_words.append(w1)
            if "!kvl" in w2 or not (w1, w2) in self.cache:
                print("Generated text")
                break
            else:
                w1, w2 = w2, random.choice(self.cache[(w1, w2)])
        return ' '.join(gen_words)