#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""
Created on Sat Mar  5 12:57:32 2022

@author: tanu
"""

import os, sys
import pandas as pd
import numpy as np
from sklearn.linear_model import LogisticRegression
from sklearn.naive_bayes import BernoulliNB
from sklearn.neighbors import KNeighborsClassifier
from sklearn.svm import SVC
from sklearn.tree import DecisionTreeClassifier
from sklearn.ensemble import RandomForestClassifier, ExtraTreesClassifier
from sklearn.neural_network import MLPClassifier
from sklearn.pipeline import Pipeline
from xgboost import XGBClassifier
from sklearn.preprocessing import StandardScaler
from sklearn.preprocessing import MinMaxScaler
from sklearn.model_selection import train_test_split
from sklearn.metrics import accuracy_score, confusion_matrix, precision_score, recall_score, roc_auc_score, roc_curve, f1_score
from sklearn.model_selection import cross_validate
from sklearn.metrics import make_scorer
from sklearn.metrics import classification_report

from sklearn.feature_selection import RFE
from sklearn.feature_selection import RFECV

#%%
model= Pipeline(steps = [
    ('pre', MinMaxScaler()),
    ('reg', LogisticRegression(class_weight = 'balanced'))])

def precision(y_true,y_pred):
    return precision_score(y_true,y_pred,pos_label = 1)
def recall(y_true,y_pred):
    return recall_score(y_true, y_pred, pos_label = 1)
def f1(y_true,y_pred):
    return f1_score(y_true, y_pred, pos_label = 1)

acc  = make_scorer(accuracy_score)
prec = make_scorer(precision)
rec  = make_scorer(recall)
f1   = make_scorer(f1)

output = cross_validate(model, X_train, y_train
                        , scoring = {'acc' : acc
                                  ,'prec': prec
                                  ,'rec' : rec
                                  ,'f1'  : f1}
                        , cv = 10
                        , return_train_score = False)
pd.DataFrame(output).mean()

#%%
# classification_repor: lowest scores but does it give numbers for all your classes!
model.fit(X_train, y_train)
y_pred = model.predict(X_test)

f1_score(y_test, y_pred)
roc_auc_score (y_test, y_pred) # not sure!
#roc_curve(y_test, y_pred)
classification_report(y_test, y_pred)
target_names = {1:'Resistant', 0:'Sensitive'}
print(classification_report(y_test
                            , y_pred
                            #, target_names=y_test.map(target_names)
                            ))
#%%NOT SURE!
from itertools import combinations
def train(X):
    return cross_validate(model, X, y_train
                          #, scoring = make_scorer(accuracy_score)
                          , scoring = {'acc' : acc
                                    ,'prec'  : prec
                                    ,'rec'   : rec
                                    ,'f1'    : f1}
                          , cv = 10
                          , return_train_score = False)
                          #, return_estimator = True)['test_score']

scores = [train(X_train.loc[:,vars]) for vars in combinations(X_train.columns, len(X_train.columns))]
means = [score.mean() for score in scores]
means
#%%
# TO TRY
https://rasbt.github.io/mlxtend/

# stackoverflow
# informative post
https://datascience.stackexchange.com/questions/937/does-scikit-learn-have-a-forward-selection-stepwise-regression-algorithm
https://datascience.stackexchange.com/questions/24405/how-to-do-stepwise-regression-using-sklearn/24447#24447
https://stats.stackexchange.com/questions/204141/difference-between-selecting-features-based-on-f-regression-and-based-on-r2


# 0.24 version, it supports
https://scikit-learn.org/stable/auto_examples/release_highlights/plot_release_highlights_0_24_0.html#new-sequentialfeatureselector-transformer
https://scikit-learn.org/stable/modules/generated/sklearn.feature_selection.SelectFromModel.html
https://scikit-learn.org/stable/modules/generated/sklearn.feature_selection.SequentialFeatureSelector.html
https://scikit-learn.org/stable/modules/generated/sklearn.feature_selection.RFECV.html
https://scikit-learn.org/stable/modules/generated/sklearn.feature_selection.f_regression.html
https://www.scikit-yb.org/en/latest/api/model_selection/rfecv.html
#%% RFE: Feature selection in classification
# others in example
# https://towardsdatascience.com/feature-selection-techniques-for-classification-and-python-tips-for-their-application-10c0ddd7918b
# https://towardsdatascience.com/feature-selection-using-python-for-classification-problem-b5f00a1c7028

model_logistic = LogisticRegression(solver='lbfgs'
                                    , multi_class = 'multinomial'
                                    , max_iter = 1000)
model_logistic = LogisticRegression()

sel_rfe_logistic = RFE(estimator = model_logistic
                       , n_features_to_select = 4
                       , step = 1)

X_train_rfe_logistic = sel_rfe_logistic.fit_transform(X_train, y_train)
print(sel_rfe_logistic.get_support())

print(sel_rfe_logistic.ranking_)
#%% RFECV
# https://scikit-learn.org/stable/modules/generated/sklearn.feature_selection.RFECV.html

target = target1
target = target3
target = target4
X_train, X_test, y_train, y_test = train_test_split(X_vars1, 
                                                    target, 
                                                    test_size = 0.33, 
                                                    random_state = 42)

X_train, X_test, y_train, y_test = train_test_split(X_vars2, 
                                                    target, 
                                                    test_size = 0.33, 
                                                    random_state = 42)

X_train, X_test, y_train, y_test = train_test_split(X_vars3, 
                                                    target, 
                                                    test_size = 0.33, 
                                                    random_state = 42)

X_train, X_test, y_train, y_test = train_test_split(X_vars5, 
                                                    target, 
                                                    test_size = 0.33, 
                                                    random_state = 42)

X_train, X_test, y_train, y_test = train_test_split(X_vars11, 
                                                    target, 
                                                    test_size = 0.33, 
                                                    random_state = 42)

model_logistic = LogisticRegression()
sel_rfe_logistic = RFECV(estimator = model_logistic
                       , cv = 10
                       , step = 1)

X_train_rfe_logistic = sel_rfe_logistic.fit_transform(X_train, y_train)
print(sel_rfe_logistic.get_support())
X_train.columns

print(sel_rfe_logistic.ranking_)