#!/usr/bin/env python3
import os
import pandas as pd
import glob

from sklearn import preprocessing
from sklearn.metrics import f1_score, precision_score, recall_score, make_scorer
from sklearn.model_selection import GridSearchCV

from sklearn.neural_network import MLPClassifier
from sklearn.naive_bayes import GaussianNB
from sklearn.svm import SVC
from sklearn.tree import DecisionTreeClassifier
from sklearn.ensemble import RandomForestClassifier

DIR: str = os.path.dirname(os.path.realpath(__file__))
IN_DIR: str = DIR + '/metrics'
OUT_DIR: str = DIR + '/models'
RANDOM: int = 42


def clean_output():
    filelist = glob.glob(OUT_DIR + '/models.csv')
    for f in filelist:
        os.remove(f)


def get_classifiers() -> list:
    return [
        (GaussianNB(), {}),
        (SVC(), {
            'kernel': ['linear', 'poly', 'rbf', 'sigmoid'],
            'gamma': ['scale', 'auto']
        }),
        (DecisionTreeClassifier(), {
            'criterion': ['gini', 'entropy'],
            'splitter': ['best', 'random']
        }),
        (RandomForestClassifier(), {
            'criterion': ['gini', 'entropy'],
            'max_features': ['sqrt', 'log2'],
            'class_weight': ['balanced', 'balanced_subsample']
        }),
        (MLPClassifier(), {
            'max_iter': [2000],
            'hidden_layer_sizes': [(10,), (50,), (100, 20,)],
            'activation':  ['identity', 'logistic', 'tanh', 'relu'],
            'solver': ['lbfgs', 'sgd', 'adam'],
            'learning_rate': ['constant', 'invscaling', 'adaptive']
        })
    ]


def main():
    clean_output()

    # load dataset
    df = pd.read_csv(IN_DIR + '/feature_vectors_labeled.csv')
    df = df.drop('class_name', axis=1)

    X = df.iloc[:, :-1].to_numpy()
    y = df.iloc[:, -1].to_numpy()

    scaler = preprocessing.StandardScaler().fit(X)
    X_scaled = scaler.transform(X)

    df = None

    for classifier, grid in get_classifiers():
        # cross-validation splits are same across calls as data is not shuffled
        # see: https://scikit-learn.org/stable/modules/generated/sklearn.model_selection.GridSearchCV.html
        clf = GridSearchCV(classifier, grid, cv=5, scoring={
            'precision': make_scorer(precision_score, average='binary', zero_division=0),
            'recall': make_scorer(recall_score, average='binary'),
            'f1': make_scorer(f1_score, average='binary')
        }, refit='f1')

        clf.fit(X_scaled, y)

        df_classifier = pd.DataFrame(clf.cv_results_)
        df_classifier['classifier'] = type(classifier).__name__

        df = df_classifier if df is None else pd.concat(
            [df, df_classifier], ignore_index=True)

    df.to_csv(OUT_DIR + '/models.csv', index=False)


if __name__ == '__main__':
    main()