import tensorflow as tf
import os
from matplotlib import pyplot as plt
from PIL import Image
import numpy as np

mnist = tf.keras.datasets.mnist

(x_train, y_train), (x_test, y_test) = mnist.load_data()
x_train, x_test = x_train/255.0, x_test/255.0

def creat_model():
    model = tf.keras.models.Sequential([
        tf.keras.layers.Flatten(),
        tf.keras.layers.Dense(128, activation='relu'),
        tf.keras.layers.Dense(10, activation='softmax')
    ])

    model.compile(optimizer='adam',
                  loss=tf.keras.losses.SparseCategoricalCrossentropy(from_logits=False),
                  metrics=["sparse_categorical_accuracy"])
    return model
def model_fit(model,check_save_path):

    if os.path.exists(check_save_path+'.index'):
        print("load modals...")
        model.load_weights(check_save_path)

    cp_callback = tf.keras.callbacks.ModelCheckpoint(filepath=check_save_path,
                                                    save_weights_only=True,
                                                    save_best_only=True)

    history = model.fit(x_train, y_train, batch_size=32, epochs=5, validation_split=0.15, validation_freq=1, callbacks=[cp_callback])
    model.summary()

    final_loss, final_acc = model.evaluate(x_test, y_test, verbose=2)
    print("Model accuracy: ", final_acc, ", model loss: ", final_loss)

    acc = history.history['sparse_categorical_accuracy']
    val_acc = history.history['val_sparse_categorical_accuracy']
    loss = history.history['loss']
    val_loss = history.history['val_loss']

    plt.subplot(1, 2, 1)
    plt.plot(acc, label='Training Accuracy')
    plt.plot(val_acc, label='Validation Accuracy')
    plt.title('Training and Validation Accuracy')
    plt.legend()

    plt.subplot(1, 2, 2)
    plt.plot(loss, label='Training Loss')
    plt.plot(val_loss, label='Validation Loss')
    plt.title('Training and Validation Loss')
    plt.legend()
    plt.show()

def eva_acc(str, model):
    model.load_weights(str)
    final_loss, final_acc = model.evaluate(x_test, y_test, verbose=2)
    print("Model accuracy: ", final_acc, ", model loss: ", final_loss)

if __name__=="__main__":
    check_save_path = "./checkpoint/mnist.ckpt"
    model = creat_model()
    model_fit(model, check_save_path)
    eva_acc(check_save_path, model)