import pandas as pd
import nltk
from collections import Counter, defaultdict
from utils import get_csv, check_prerequisites, ENCODING, clean_text


def main():
    check_prerequisites()

    data = get_csv("train/in.tsv.xz")

    train_words = get_csv("train/expected.tsv")

    train_data = data[[7, 6]]
    train_data = pd.concat([train_data, train_words], axis=1)

    train_data[760] = train_data[7] + train_data[0] + train_data[6]

    model = defaultdict(lambda: defaultdict(lambda: 0))

    train_model(train_data, model)

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


def train_model(data, model):
    for _, row in data.iterrows():
        words = nltk.word_tokenize(clean_text(row[760]))
        for w1, w2 in nltk.bigrams(words, pad_left=True, pad_right=True):
            if w1 and w2:
                model[w2][w1] += 1
    for w2 in model:
        total_count = float(sum(model[w2].values()))
        for w1 in model[w2]:
            model[w2][w1] /= total_count


def predict(word, model):
    predictions = dict(model[word])
    most_common = dict(Counter(predictions).most_common(5))

    total_prob = 0.0
    str_prediction = ""

    for word, prob in most_common.items():
        total_prob += prob
        str_prediction += f"{word}:{prob} "

    if not total_prob:
        return "the:0.2 be:0.2 to:0.2 of:0.1 and:0.1 a:0.1 :0.1"

    if 1 - total_prob >= 0.01:
        str_prediction += f":{1-total_prob}"
    else:
        str_prediction += f":0.01"

    return str_prediction


def predict_data(read_path, save_path, model):
    data = get_csv(read_path)

    with open(save_path, "w", encoding=ENCODING) as f:
        for _, row in data.iterrows():
            words = nltk.word_tokenize(clean_text(row[7]))
            if len(words) < 3:
                prediction = "the:0.2 be:0.2 to:0.2 of:0.1 and:0.1 a:0.1 :0.1"
            else:
                prediction = predict(words[-1], model)
            f.write(prediction + "\n")


if __name__ == "__main__":
    main()