from sklearn.naive_bayes import GaussianNB
from sklearn.metrics import confusion_matrix, accuracy_score
import pandas as pd
import numpy as np
import pickle, os
import typing

class Bayes:
    def __init__(self, path: str):
        self.path = path
        self.model_exists = False
        if os.path.isfile(self.path):
            self.model_exists = True
            with open(self.path, 'rb') as file:
                self.classifier = pickle.load(file)
        else:
            self.classifier = GaussianNB()


    def train(self, X: pd.DataFrame, Y: pd.Series) -> None:
        self.classifier.fit(X, Y)
        with open(self.path, 'wb') as file:
            pickle.dump(self.classifier, file)
        self.model_exists = True


    def predict(self, X: pd.DataFrame) -> np.ndarray:
        predictions = self.classifier.predict(X)
        return predictions


    def eval(self, Y: pd.Series, Y_pred: np.ndarray) -> typing.Tuple[np.ndarray, np.float64]:
        cm = confusion_matrix(Y, Y_pred)
        ac = accuracy_score(Y, Y_pred)
        return (cm, ac)