import os
import numpy as np
import pandas as pd

import matplotlib.pyplot as plt
import seaborn as sns

from sklearn import cluster, mixture
from sklearn.decomposition import PCA
from sklearn.cluster import KMeans, DBSCAN, OPTICS
from sklearn.preprocessing import StandardScaler
from sklearn.metrics.pairwise import cosine_similarity
from sklearn.neighbors import kneighbors_graph
from itertools import cycle, islice

import warnings
warnings.simplefilter('ignore')


def generate_clustering_algorithms(Z, n_clusters, m):
    # Generate clustering algorithms:
    # m = 'MeanShift', 'KMeans', 'MiniBatchKMeans'

    # The minimal percentage of similarity of the clustered feature with "Survived" for inclusion in the final dataset
    limit_opt = 0.7

    params = {'quantile': .2,
              'eps': .3,
              'damping': .9,
              'preference': -200,
              'n_neighbors': 10,
              'n_clusters': n_clusters,
              'min_samples': 3,
              'xi': 0.05,
              'min_cluster_size': 0.05}

    # estimate bandwidth for mean shift
    bandwidth = cluster.estimate_bandwidth(Z, quantile=params['quantile'])

    # connectivity matrix for structured Ward
    connectivity = kneighbors_graph(
        Z, n_neighbors=params['n_neighbors'], include_self=False)

    # make connectivity symmetric
    connectivity = 0.5 * (connectivity + connectivity.T)

    # ============
    # Create cluster objects
    # ============
    if m == 'MeanShift':
        cl = cluster.MeanShift(bandwidth=bandwidth, bin_seeding=True)
    elif m == 'KMeans':
        cl = cluster.KMeans(n_clusters=n_clusters, random_state = 1000)
    elif m == 'MiniBatchKMeans':
        cl = cluster.MiniBatchKMeans(n_clusters=n_clusters)

    return cl


def clustering_df(X, n, m, output_hist, title='clusters_by'):

    # Standardization
    X_columns = X.columns
    scaler = StandardScaler()
    scaler.fit(X)
    X = pd.DataFrame(scaler.transform(X), columns = X_columns)
    cl = generate_clustering_algorithms(X, n, m)
    cl.fit(X)
    if hasattr(cl, 'labels_'):
        labels = cl.labels_.astype(np.uint8)
    else:
        labels = cl.predict(X)
    clusters=pd.concat([X, pd.DataFrame({'cluster':labels})], axis=1)

    # Inverse Standardization
    X_inv = pd.DataFrame(scaler.inverse_transform(X), columns = X_columns)
    clusters_inv=pd.concat([X_inv, pd.DataFrame({'cluster':labels})], axis=1)

    # Number of points in clusters
    print("Number of points in clusters:\n", clusters['cluster'].value_counts())

    # Data in clusters - thanks to https://www.kaggle.com/sabanasimbutt/clustering-visualization-of-clusters-using-pca
    if output_hist:
        for c in clusters:
            grid = sns.FacetGrid(clusters_inv, col='cluster')
            grid.map(plt.hist, c)

    plt.savefig(f'{title}_by_method_{m}.png')

    return clusters, clusters_inv


def plot_draw(X, title, m):
    # Drawing a plot with clusters on the plane (using PCA transformation)
    # Thanks to https://www.kaggle.com/sabanasimbutt/clustering-visualization-of-clusters-using-pca

    dist = 1 - cosine_similarity(X)

    # PCA transform
    pca = PCA(2)
    pca.fit(dist)
    X_PCA = pca.transform(dist)

    # Generate point numbers and colors for clusters
    hsv = plt.get_cmap('hsv')
    n_clusters = max(X['cluster'].value_counts().index)-min(X['cluster'].value_counts().index)+2
    colors = list(hsv(np.linspace(0, 1, n_clusters)))
    colors_num = list(np.linspace(min(X['cluster'].value_counts().index), max(X['cluster'].value_counts().index), n_clusters))
    colors_num = [int(x) for x in colors_num]
    colors_str = [str(x) for x in colors_num]
    names_dict = dict(zip(colors_num, colors_str))
    colors_dict = dict(zip(colors_num, colors))

    # Visualization
    x, y = X_PCA[:, 0], X_PCA[:, 1]

    df = pd.DataFrame({'x': x, 'y':y, 'label':X['cluster'].tolist()})
    groups = df.groupby('label')

    fig, ax = plt.subplots(figsize=(12, 8))

    for name, group in groups:
        ax.plot(group.x, group.y, marker='o', linestyle='', ms=10,
                color=colors_dict[name],
                label=names_dict[name],
                mec='none')
        ax.set_aspect('auto')
        ax.tick_params(axis='x',which='both',bottom='off',top='off',labelbottom='off')
        ax.tick_params(axis= 'y',which='both',left='off',top='off',labelleft='off')

    ax.legend(loc='upper right')
    ax.set_title(f"{title} by method {m}")
    plt.savefig(f'{title}_by_method_{m}.png')
    plt.show()


if __name__ == "__main__":
    data = pd.read_csv("..//heart_disease_uci.csv")
    data = data.drop_duplicates().reset_index(drop=True)

    print(data.select_dtypes(include='object').columns.tolist())
    for column in data.select_dtypes(include='object').columns.tolist():
        data[column] = pd.factorize(data[column])[0]
        # print(pd.factorize(data[column])[0])

    methods_all = ['KMeans', 'MiniBatchKMeans', 'MeanShift']
    n_default = 6

    data = data[data.notna().all(axis=1)]

    res = dict(zip(methods_all, [False]*len(methods_all)))
    n_clust = dict(zip(methods_all, [1]*len(methods_all)))
    for method in methods_all:
        print(f"Method - {method}")
        Y, Y_inv = clustering_df(data.copy(), n_default, method, True)

        # If the number of clusters is less than 2, then the clustering is not successful
        n_cl = len(Y['cluster'].value_counts())
        if n_cl > 1:
            res[method] = True
            n_clust[method] = n_cl

            plot_draw(Y, "Data clustering", method)
        else:
            print('Clustering is not successful because all data is in one cluster!\n')