#!/usr/bin/env python
# Train a model from sample data
# Author: Vasil Zlatanov, Nunzio Pucci
# EE4 Pattern Recognition coursework

import matplotlib.pyplot as plt
import sys
import random
from random import randint

from sklearn.neighbors import KNeighborsClassifier
from sklearn.decomposition import PCA
from sklearn.discriminant_analysis import LinearDiscriminantAnalysis
from sklearn.model_selection import train_test_split
from sklearn.preprocessing import StandardScaler
from sklearn.metrics import confusion_matrix  
from sklearn.metrics import accuracy_score

import argparse
import numpy as np

from numpy import genfromtxt
from numpy import linalg as LA

# subtract the normal face from each row of the face matrix
def normalise_faces(average_face, faces):
    faces = np.subtract(faces, np.tile(average_face, (faces.shape[0],1)))
    return np.divide(faces.T, np.std(faces.T, axis=0)).T

# Split data into training and testing sets
def test_split(n_faces, raw_faces, split, seed):
    random.seed(seed)
    n_cases = 52
    n_pixels = 2576 
    
    raw_faces_split = np.split(raw_faces,n_cases)
    n_training_faces = int(round(n_cases*(1 - split)))
    n_test_faces = n_cases - n_training_faces
    faces_train = np.zeros((n_faces, n_training_faces, n_pixels))
    faces_test = np.zeros((n_faces, n_test_faces, n_pixels))
    target_train = np.repeat(np.arange(n_faces), n_training_faces)
    target_test = np.repeat(np.arange(n_faces), n_test_faces)
    
    for x in range (n_faces):
        samples = random.sample(range(n_cases), n_training_faces)
        faces_train[x] = [raw_faces[i+n_cases*x] for i in samples]
        faces_test[x] = [raw_faces[i+n_cases*x] for i in range (n_cases) if i not in samples]

    faces_train = faces_train.reshape(n_faces*n_training_faces, n_pixels)
    faces_test = faces_test.reshape(n_faces*n_test_faces, n_pixels)
    return faces_train, faces_test, target_train, target_test


# usage: train.py [-h] -i DATA -o MODEL [-m M]
parser = argparse.ArgumentParser()
parser.add_argument("-i", "--data", help="Input CSV file", required=True)
parser.add_argument("-m", "--eigen", help="Number of eigenvalues in model", type=int, default = 10 )
parser.add_argument("-n", "--neighbors", help="How many neighbors to use", type=int, default = 3)
parser.add_argument("-f", "--faces", help="Show faces", type=int, default = 0)
parser.add_argument("-c", "--principal", help="Show principal components", action='store_true')
parser.add_argument("-s", "--seed", help="Seed to use", type=int, default=0)
parser.add_argument("-t", "--split", help="Fractoin of data to use for testing", type=float, default=0.22)
### best split for lda = 22
### best plit for pca = 20
parser.add_argument("-2", "--grapheigen", help="Swow 2D graph of targets versus principal components", action='store_true')
parser.add_argument("-p", "--pca", help="Use PCA", action='store_true')
parser.add_argument("-l", "--lda", help="Use LDA", action='store_true')
args = parser.parse_args()

if args.pca and args.lda:
    sys.exit("Flags -p and -l are mutually exclusive")

M = args.eigen

raw_faces = genfromtxt(args.data, delimiter=',')
targets = np.repeat(np.arange(10),52)

n_faces = 10

faces_train, faces_test, target_train, target_test = test_split(n_faces, raw_faces, args.split, args.seed)

# This remove the mean and scales to unit variance
#sc = StandardScaler()
#faces_train = sc.fit_transform(faces_train)
#faces_test = sc.transform(faces_test)

explained_variances = ()
if args.lda:
    average_face = np.mean(faces_train, axis=0) 
    n_cases = 52

#    lda = LinearDiscriminantAnalysis(n_components=M)
#    faces_train = lda.fit_transform(faces_train, target_train)
#    faces_test = lda.transform(faces_test)
#    explained_variances = lda.explained_variance_ratio_
### FIND MEAN OF EACH CLASS
    n_training_faces = int(round(n_cases*(1 - args.split)))
    n_test_faces = n_cases - n_training_faces
    mean_vector = np.zeros(10) 
    for n in range (10):
        mean_acc = 0
        for x in range (int(np.divide(n_training_faces,10))):
            mean_acc = np.add(mean_acc, np.mean(faces_train[x + n*10], axis=0))
        mean_vector [n] = np.divide(mean_acc, np.divide(n_training_faces,10))
    print (mean_vector)
### SCATTER MATRIX
    for n in range (10)
        faces_train = normalise_faces(mean_vector[n], faces_train[ 
else:
    # faces_pca containcts the principial components or the M most variant eigenvectors
    average_face = np.mean(faces_train, axis=0) 
    faces_train = normalise_faces(average_face, faces_train)
    faces_test = normalise_faces(average_face, faces_test)
    e_vals, e_vecs = LA.eigh(np.cov(faces_train.T))
    e_vals = np.flip(e_vals)
    e_vecs = np.fliplr(e_vecs).T
    faces_train = np.dot(faces_train, e_vecs[:M].T)
    faces_test = np.dot(faces_test, e_vecs[:M].T)
    
# Plot the variances (eigenvalues) from the pca object
if args.faces:
    if args.lda:
        sys.exit("Can not plot eigenfaces when using LDA")
    for i in range(args.faces):
        ax = plt.subplot(2, args.faces/2, i + 1)
        ax.imshow(e_vecs[i].reshape([46, 56]).T, cmap = 'gist_gray')
    plt.show()

if args.principal:
    e_vals = np.multiply(np.divide(e_vals, np.sum(e_vals)), 100)
    plt.bar(np.arange(M), e_vals[:M])
    plt.ylabel('Varaiance ratio (%)');plt.xlabel('Eigenface Number')
    plt.show()

if args.grapheigen:
    # Colors for distinct individuals
    cols = ['#{:06x}'.format(randint(0, 0xffffff)) for i in range(10)]
    pltCol = [cols[int(k)] for k in target_train]
    plt.scatter(faces_train[:, 0], faces_train[:, 1], color=pltCol)
    plt.show()

classifier = KNeighborsClassifier(n_neighbors=args.neighbors)
classifier.fit(faces_train, target_train)
target_pred = classifier.predict(faces_test)

cm = confusion_matrix(target_test, target_pred)  
print(cm)  
print('Accuracy %fl' % accuracy_score(target_test, target_pred))