#!/usr/bin/env python
# coding: utf-8

# # RNN을 이용한 창작 (작곡) - 1
# - https://tykimos.github.io/2017/04/09/RNN_Layer_Talk/

# ## 0. 코딩환경준비

# conda create -n tf20 python==3.7 <br/>
# conda activate tf20 <br/>
# pip install jupyter <br/>
# pip install matplotlib <br/>
# pip install scipy <br/>
# pip install music21 <br/>
# pip install tensorflow==2.0.0-alpha0

# - Musescore2 다운로드 및 설치 
#   - https://musescore.org/ko/download#older-versions

# In[1]:


import tensorflow as tf
print(tf.__version__)


# In[4]:


import numpy as np
from tensorflow.keras.models import Sequential
from tensorflow.keras.layers import Dense, LSTM
import tensorflow.keras.utils as utils
import os


# In[5]:


#http://web.mit.edu/music21/doc/usersGuide/usersGuide_08_installingMusicXML.html
import music21


# ## 1. 데이터 준비하기

# ### 시퀀스 데이터 정의

# In[7]:


seq = ['g8', 'e8', 'e4', 'f8', 'd8', 'd4', 'c8', 'd8', 'e8', 'f8', 'g8', 'g8', 'g4',
       'g8', 'e8', 'e8', 'e8', 'f8', 'd8', 'd4', 'c8', 'e8', 'g8', 'g8', 'e8', 'e8', 'e4',
       'd8', 'd8', 'd8', 'd8', 'd8', 'e8', 'f4', 'e8', 'e8', 'e8', 'e8', 'e8', 'f8', 'g4',
       'g8', 'e8', 'e4', 'f8', 'd8', 'd4', 'c8', 'e8', 'g8', 'g8', 'e8', 'e8', 'e4']

print("length of seq: {0}".format(len(seq)))


# In[8]:


note_seq = ""
for note in seq:
    note_seq += note + " "
    
m = music21.converter.parse("2/4 " + note_seq, format='tinyNotation')

m.show("midi")


# In[9]:


m.show()


# ### 코드 사전 정의

# In[10]:


code2idx = {'c4': 0, 'd4': 1, 'e4': 2, 'f4': 3, 'g4': 4, 'a4': 5, 'b4': 6,
            'c8': 7, 'd8': 8, 'e8': 9, 'f8': 10, 'g8': 11, 'a8': 12, 'b8': 13}

idx2code = {0: 'c4', 1: 'd4', 2: 'e4', 3: 'f4', 4: 'g4', 5: 'a4', 6: 'b4',
            7: 'c8', 8: 'd8', 9: 'e8', 10: 'f8', 11: 'g8', 12: 'a8', 13: 'b8'}


# ## 2. 데이터셋 생성하기

# ### 데이터셋 생성 함수
# 

# In[11]:


def seq2dataset(seq, window_size):
    dataset = []
    
    for i in range(len(seq) - window_size):
        subset = seq[i: (i + window_size + 1)]
        dataset.append([code2idx[item] for item in subset])
    return np.array(dataset)


# In[9]:


test_seq = ['c4', 'd4', 'e4', 'f4', 'g4', 'd8', 'b8']
dataset = seq2dataset(seq=test_seq, window_size=4)
print(dataset)


# ###  생성

# In[12]:


n_steps = 4
n_inputs = 1

dataset = seq2dataset(seq, window_size=n_steps)

print("dataset.shape: {0}".format(dataset.shape))


# ### 입력(X)과 출력(Y) 변수로 분리하기

# In[13]:


x_train = dataset[:, 0: n_steps]
y_train = dataset[:, n_steps]
print("x_train: {0}".format(x_train.shape))
print("y_train: {0}".format(y_train.shape))
print(x_train[0])
print(y_train[0])


# In[14]:


max_idx_value = len(code2idx) - 1

print("max_idx_value: {0}".format(max_idx_value))


# ### 입력값 정규화 시키기

# In[15]:


x_train = x_train / float(max_idx_value)


# ### 입력을 (샘플 수, 타입스텝, 특성 수)로 형태 변환

# In[16]:


x_train = np.reshape(x_train, (x_train.shape[0], x_train.shape[1], n_inputs))


# ### 라벨값에 대한 one-hot 인코딩 수행

# In[17]:


y_train = utils.to_categorical(y_train)


# In[18]:


one_hot_vec_size = y_train.shape[1]

print("one hot encoding vector size is {0}".format(one_hot_vec_size))
print("After pre-processing")
print("x_train: {0}".format(x_train.shape))
print("y_train: {0}".format(y_train.shape))


# ## 3. 모델 구성하기

# In[19]:


model = Sequential()
model.add(LSTM(
    units=128,
    kernel_initializer='glorot_normal',
    bias_initializer='zero',
    batch_input_shape=(1, n_steps, n_inputs), 
    stateful=True
))
model.add(Dense(
    units=one_hot_vec_size, 
    kernel_initializer='glorot_normal',
    bias_initializer='zero',    
    activation='softmax'
))


# ## 4. 모델 학습과정 설정하기

# In[20]:


model.compile(
    loss='categorical_crossentropy',
    optimizer='adam',
    metrics=['accuracy']
)


# ## 5. 모델 학습시키기

# ### 손실 이력 클래스 정의

# In[21]:


class LossHistory(tf.keras.callbacks.Callback):
    def init(self):
        self.epoch = 0
        self.losses = []

    def on_epoch_end(self, batch, logs={}):
        self.losses.append(logs.get('loss'))
        
        if self.epoch % 100 == 0:
            print("epoch: {0} - loss: {1:8.6f}".format(self.epoch, logs.get('loss')))
            
        self.epoch += 1


# ### 학습

# In[20]:


num_epochs = 1500
history = LossHistory()  # 손실 이력 객체 생성

history.init()

for epoch_idx in range(num_epochs + 1):
    model.fit(
        x=x_train,
        y=y_train,
        epochs=1,
        batch_size=1,
        verbose=0,
        shuffle=False,
        callbacks=[history]
    )
    if history.losses[-1] < 1e-5:
        print("epoch: {0} - loss: {1:8.6f}".format(epoch_idx, history.losses[-1]))
        model.reset_states()    
        break
    model.reset_states()


# ## 6. 학습과정 살펴보기

# In[21]:


import matplotlib.pyplot as plt
get_ipython().run_line_magic('matplotlib', 'inline')

plt.plot(history.losses)
plt.ylabel('loss')
plt.xlabel('epoch')
plt.legend(['train'], loc='upper right')
plt.show()


# ## 7. 모델 평가하기

# In[22]:


scores = model.evaluate(x_train, y_train, batch_size=1)
print("{0}: {1}".format(model.metrics_names[1], scores[1]*100))
model.reset_states()


# ## 8. 모델 사용하기

# ### 한 스텝 예측

# In[23]:


pred_count = 50  # 최대 예측 개수 정의

# 한 스텝 예측
seq_out = ['g8', 'e8', 'e4', 'f8']
pred_out = model.predict(x_train)

for i in range(pred_count):
    idx = np.argmax(pred_out[i])  # one-hot 인코딩을 인덱스 값으로 변환
    seq_out.append(idx2code[idx])  # seq_out는 최종 악보이므로 인덱스 값을 코드로 변환하여 저장

model.reset_states()

print("one step prediction : ", seq_out)


# ### 곡 전체 예측

# In[24]:


seq_in = ['g8', 'c8', 'f4', 'e8']
seq_out = seq_in
seq_in = [code2idx[note] / float(max_idx_value) for note in seq_in]  # 코드를 인덱스값으로 변환

for i in range(pred_count):
    sample_in = np.array(seq_in)
    sample_in = np.reshape(sample_in, (1, n_steps, n_inputs))  # 샘플 수, 타입스텝 수, 속성 수
    pred_out = model.predict(sample_in)
    idx = np.argmax(pred_out)
    seq_out.append(idx2code[idx])
    seq_in.append(idx / float(max_idx_value))
    seq_in.pop(0)

model.reset_states()

print("full song prediction : ")

for note in seq_out:
    print(note, end=" ")


# In[25]:


#http://web.mit.edu/music21/doc/usersGuide/usersGuide_08_installingMusicXML.html
import music21

note_seq = ""
for note in seq_out:
    note_seq += note + " "
    
conv_midi = music21.converter.subConverters.ConverterMidi()

m = music21.converter.parse("2/4 " + note_seq, format='tinyNotation')

m.show("midi")


# In[26]:


m.show()


# In[27]:


m.write("midi", fp="./new_music.mid")