from __future__ import absolute_import
from __future__ import division
from __future__ import print_function

import numpy as np
import sklearn.preprocessing as prep
import tensorflow as tf
from tensorflow.examples.tutorials.mnist import input_data

from autoencoder_models.VariationalAutoencoder import VariationalAutoencoder

mnist = input_data.read_data_sets('MNIST_data', one_hot=True)


def min_max_scale(X_train, X_test):
    preprocessor = prep.MinMaxScaler().fit(X_train)
    X_train = preprocessor.transform(X_train)
    X_test = preprocessor.transform(X_test)
    return X_train, X_test


def get_random_block_from_data(data, batch_size):
    start_index = np.random.randint(0, len(data) - batch_size)
    return data[start_index:(start_index + batch_size)]


X_train, X_test = min_max_scale(mnist.train.images, mnist.test.images)

n_samples = int(mnist.train.num_examples)
training_epochs = 20
batch_size = 128
display_step = 1

autoencoder = VariationalAutoencoder(
    n_input=784,
    n_hidden=200,
    optimizer=tf.train.AdamOptimizer(learning_rate = 0.001))

for epoch in range(training_epochs):
    avg_cost = 0.
    total_batch = int(n_samples / batch_size)
    # Loop over all batches
    for i in range(total_batch):
        batch_xs = get_random_block_from_data(X_train, batch_size)

        # Fit training using batch data
        cost = autoencoder.partial_fit(batch_xs)
        # Compute average loss
        avg_cost += cost / n_samples * batch_size

    # Display logs per epoch step
    if epoch % display_step == 0:
        print("Epoch:", '%d,' % (epoch + 1),
              "Cost:", "{:.9f}".format(avg_cost))

print("Total cost: " + str(autoencoder.calc_total_cost(X_test)))
