#%%
import pandas as pd
from collections import defaultdict, Counter

from sqlalchemy import true
from nltk import trigrams, word_tokenize, bigrams
import csv

#%%
class Model:
    def __init__(self):
        self.model = defaultdict(lambda: defaultdict(lambda: 0))
        self.model_bi = defaultdict(lambda: defaultdict(lambda: 0))
        train_in = pd.read_csv("train/in.tsv.xz", sep='\t', header=None, encoding="UTF-8", on_bad_lines="skip", quoting=csv.QUOTE_NONE)[[6, 7]]
        train_expected = pd.read_csv("train/expected.tsv", sep='\t', header=None, encoding="UTF-8", on_bad_lines="skip", quoting=csv.QUOTE_NONE)
        data = pd.concat([train_in, train_expected], axis=1)
        self.data = data[6] + data[0] + data[7]
        self.data = self.data.apply(self.clean)

    def clean(self, text):
        text = str(text).lower().strip().replace("’", "'").replace('\\n', " ").replace("'t", " not").replace("'s", " is").replace("'ll", " will").replace("'m", " am").replace("'ve", " have").replace(",", "").replace("-", "")
        return text

    def train(self):
        alpha = 0.7
        vocab = set()
        for text in model.data:
            words = word_tokenize(text)
            for w1, w2, w3 in trigrams(words, pad_left=True, pad_right=True):
                self.model[w1, w2][w3] += 1
                vocab.add(w1)
                vocab.add(w2)
                vocab.add(w3)
            for w1, w2 in bigrams(words, pad_left=True, pad_right=True):
                self.model_bi[w1][w2] +=1
        for w1, w2 in self.model:
            total_count = float(sum(self.model[w1, w2].values()))
            denominator = total_count * len(vocab)
            for w in self.model[w1, w2]:
                self.model[w1, w2][w] = self.model[w1, w2][w] / denominator * alpha
        for w1 in self.model_bi:
            total_count = float(sum(self.model_bi[w1].values()))
            denominator = total_count * len(vocab)
            for w in self.model_bi[w1]:
                self.model_bi[w1][w] = self.model_bi[w1][w] / denominator * (1-alpha)

    def predict(self, words):
        trigrams = Counter(dict(self.model[words]))
        bigrams = Counter(dict(self.model_bi[words[-1]]))
        predictions = dict((trigrams + bigrams).most_common(6))
        total_prob = 0
        
        result = ""
        for word, prob in predictions.items():
            total_prob += prob
            result += f"{word}:{prob} "

        if len(result) == 0:
            return "a:0.2 the:0.2 to:0.2 of:0.1 and:0.1 of:0.1 :0.1"
        return result + f":{max(1-total_prob, 0.01)}"

model = Model()

#%%
model.data
model.train()

#%%
def predict(model, path, result_path):
    data = pd.read_csv(path, sep='\t', header=None, encoding="UTF-8", on_bad_lines="skip", quoting=csv.QUOTE_NONE)[7]
    with open(result_path, "w+", encoding="UTF-8") as f:
        for text in data:
            words = word_tokenize(model.clean(text))
            if len(words) < 2:
                prediction = "a:0.2 the:0.2 to:0.2 of:0.1 and:0.1 of:0.1 :0.1"
            else:
                prediction = model.predict((words[-2], words[-1]))
            f.write(prediction + "\n")

predict(model, "dev-0/in.tsv.xz", "dev-0/out.tsv")
predict(model, "test-A/in.tsv.xz", "test-A/out.tsv")