#%%
from __future__ import absolute_import, division, print_function, unicode_literals

import pathlib
import os
os.environ['TF_CPP_MIN_LOG_LEVEL'] = '2'


import matplotlib.pyplot as plt
import pandas as pd
import seaborn as sns
 
import tensorflow as tf

from tensorflow import keras
from tensorflow.keras import layers, losses

print(tf.__version__)


# 在线下载汽车效能数据集
dataset_path = keras.utils.get_file("auto-mpg.data", "http://archive.ics.uci.edu/ml/machine-learning-databases/auto-mpg/auto-mpg.data")

# 效能（公里数每加仑），气缸数，排量，马力，重量
# 加速度，型号年份，产地
column_names = ['MPG','Cylinders','Displacement','Horsepower','Weight',
                'Acceleration', 'Model Year', 'Origin']
raw_dataset = pd.read_csv(dataset_path, names=column_names,
                      na_values = "?", comment='\t',
                      sep=" ", skipinitialspace=True)

dataset = raw_dataset.copy()
# 查看部分数据
dataset.tail()
dataset.head()
dataset
#%%


#%%

# 统计空白数据,并清除
dataset.isna().sum()
dataset = dataset.dropna()
dataset.isna().sum()
dataset
#%%

# 处理类别型数据，其中origin列代表了类别1,2,3,分布代表产地：美国、欧洲、日本
# 其弹出这一列
origin = dataset.pop('Origin')
# 根据origin列来写入新列
dataset['USA'] = (origin == 1)*1.0
dataset['Europe'] = (origin == 2)*1.0
dataset['Japan'] = (origin == 3)*1.0
dataset.tail()


# 切分为训练集和测试集
train_dataset = dataset.sample(frac=0.8,random_state=0)
test_dataset = dataset.drop(train_dataset.index) 


#%% 统计数据
sns.pairplot(train_dataset[["Cylinders", "Displacement", "Weight", "MPG"]], 
diag_kind="kde")
#%%
# 查看训练集的输入X的统计数据
train_stats = train_dataset.describe()
train_stats.pop("MPG")
train_stats = train_stats.transpose()
train_stats


# 移动MPG油耗效能这一列为真实标签Y
train_labels = train_dataset.pop('MPG')
test_labels = test_dataset.pop('MPG')


# 标准化数据
def norm(x):
  return (x - train_stats['mean']) / train_stats['std']
normed_train_data = norm(train_dataset)
normed_test_data = norm(test_dataset)
#%%

print(normed_train_data.shape,train_labels.shape)
print(normed_test_data.shape, test_labels.shape)
#%%

class Network(keras.Model):
    # 回归网络
    def __init__(self):
        super(Network, self).__init__()
        # 创建3个全连接层
        self.fc1 = layers.Dense(64, activation='relu')
        self.fc2 = layers.Dense(64, activation='relu')
        self.fc3 = layers.Dense(1)

    def call(self, inputs, training=None, mask=None):
        # 依次通过3个全连接层
        x = self.fc1(inputs)
        x = self.fc2(x)
        x = self.fc3(x)

        return x

model = Network()
model.build(input_shape=(None, 9))
model.summary()
optimizer = tf.keras.optimizers.RMSprop(0.001)
train_db = tf.data.Dataset.from_tensor_slices((normed_train_data.values, train_labels.values))
train_db = train_db.shuffle(100).batch(32)

# # 未训练时测试
# example_batch = normed_train_data[:10]
# example_result = model.predict(example_batch)
# example_result


train_mae_losses = []
test_mae_losses = []
for epoch in range(200):
    for step, (x,y) in enumerate(train_db):

        with tf.GradientTape() as tape:
            out = model(x)
            loss = tf.reduce_mean(losses.MSE(y, out))
            mae_loss = tf.reduce_mean(losses.MAE(y, out)) 

        if step % 10 == 0:
            print(epoch, step, float(loss))

        grads = tape.gradient(loss, model.trainable_variables)
        optimizer.apply_gradients(zip(grads, model.trainable_variables))

    train_mae_losses.append(float(mae_loss))
    out = model(tf.constant(normed_test_data.values))
    test_mae_losses.append(tf.reduce_mean(losses.MAE(test_labels, out)))


plt.figure()
plt.xlabel('Epoch')
plt.ylabel('MAE')
plt.plot(train_mae_losses,  label='Train')

plt.plot(test_mae_losses, label='Test')
plt.legend()
 
# plt.ylim([0,10])
plt.legend()
plt.savefig('auto.svg')
plt.show() 




#%%