import numpy as np
from tqdm import tqdm
import paddle.fluid as fluid
from models import Classifier
import paddle
from sklearn.metrics import f1_score


def build_batch(word2id_dict, corpus, batch_size, epoch_num, max_seq_len, shuffle=True):
    # 模型将会接受的两个输入：
    # 1. 一个形状为[batch_size, max_seq_len]的张量，sentence_batch，代表了一个mini-batch的句子。
    # 2. 一个形状为[batch_size, 1]的张量，sentence_label_batch，
    #    每个元素都是非0即1，代表了每个句子的情感类别（正向或者负向）
    sentence_batch = []
    sentence_label_batch = []

    for _ in range(epoch_num):
        # 每个epcoh前都shuffle一下数据，有助于提高模型训练的效果
        # 但是对于预测任务，不要做数据shuffle
        if shuffle:
            np.random.shuffle(corpus)
        for sentence_label in corpus:
            sentence, label = sentence_label.rsplit(sep='\t', maxsplit=1)
            sentence = sentence.split(',')
            sentence_sample = sentence[:min(max_seq_len, len(sentence))]
            if len(sentence_sample) < max_seq_len:
                for _ in range(max_seq_len - len(sentence_sample)):
                    sentence_sample.append(word2id_dict['<pad>'])
            # 飞桨1.6.1要求输入数据必须是形状为[batch_size, max_seq_len，1]的张量
            # sentence_sample = [[word_id] for word_id in sentence_sample]
            sentence_batch.append(sentence_sample)
            sentence_label_batch.append([label])

            if len(sentence_batch) == batch_size:
                yield np.array(sentence_batch).astype("int64"), np.array(sentence_label_batch).astype("int64")
                sentence_batch = []
                sentence_label_batch = []

    if len(sentence_batch) == batch_size:
        yield np.array(sentence_batch).astype("int64"), np.array(sentence_label_batch).astype("int64")


def train(train_path, place):
    pass


def evaluate(dev_path, multi_classifier):
    dev_corpus = open(dev_path, 'r', encoding='utf8').readlines()
    # 载入模型参数、优化器参数和最后一个epoch保存的检查点
    layer_state_dict = paddle.load("models/multi_classifier.pdparams")
    opt_state_dict = paddle.load("models/adam.pdopt")
    # 将load后的参数与模型关联起来
    multi_classifier.set_state_dict(layer_state_dict)
    adam.set_state_dict(opt_state_dict)

    # 记录模型预测结果的f1 score
    dev_batch = build_batch(word2id_dict, dev_corpus, len(dev_corpus), 1, max_seq_len, shuffle=False)
    for sentences, labels in tqdm(dev_batch, desc='dev set batch'):
        sentences_var = fluid.dygraph.to_variable(sentences)
        labels_var = fluid.dygraph.to_variable(labels)
        # 获取模型对当前batch的输出结果
        pred, loss = multi_classifier(sentences_var, labels_var)
        # 把输出结果转换为numpy array的数据结构
        pred_labels = np.argmax(pred.numpy(), axis=1).reshape(labels.shape)
    print(f1_score(labels, pred_labels, average='macro'))


def predict(test_path, multi_classifier):
    test_corpus = open(test_path, 'r', encoding='utf8').readlines()
    # 载入模型参数、优化器参数和最后一个epoch保存的检查点
    layer_state_dict = paddle.load("models/multi_classifier.pdparams")
    opt_state_dict = paddle.load("models/adam.pdopt")
    # 将load后的参数与模型关联起来
    multi_classifier.set_state_dict(layer_state_dict)
    adam.set_state_dict(opt_state_dict)

    # 记录模型预测结果的f1 score
    dev_batch = build_batch(word2id_dict, test_corpus, len(test_corpus), 1, max_seq_len, shuffle=False)
    for sentences, labels in tqdm(dev_batch, desc='test set batch'):
        sentences_var = fluid.dygraph.to_variable(sentences)
        labels_var = fluid.dygraph.to_variable(labels)
        # 获取模型对当前batch的输出结果
        pred, loss = multi_classifier(sentences_var, labels_var)
        # 把输出结果转换为numpy array的数据结构
        pred_labels = np.argmax(pred.numpy(), axis=1).reshape(labels.shape)
    print(f1_score(labels, pred_labels, average='macro'))


if __name__ == '__main__':
    # 开始训练
    batch_size = 256
    epoch_num = 1
    embedding_size = 128
    learning_rate = 0.01
    max_seq_len = 500
    class_num = 15

    use_gpu = False
    place = fluid.CUDAPlace(0) if use_gpu else fluid.CPUPlace()

    with open('data/dict.txt', 'r', encoding='utf-8') as f_data:
        word2id_dict = eval(f_data.readlines()[0])
    word2id_dict = dict(word2id_dict)
    vocab_size = len(word2id_dict)
    train_corpus = open('data/Train_IDs.txt', 'r', encoding='utf8').readlines()

    # with open('datatest/vocab.json', 'r', encoding='utf-8') as f_data:
    #     word2id_dict = eval(f_data.readlines()[0])
    # word2id_dict = dict(word2id_dict)
    # vocab_size = len(word2id_dict)
    # train_corpus = open('datatest/train_idx.txt', 'r', encoding='utf8').readlines()

    step = 0
    with fluid.dygraph.guard():
        # 创建一个用于情感分类的网络实例，sentiment_classifier
        multi_classifier = Classifier(
            hidden_size=embedding_size,
            vocab_size=vocab_size,
            num_steps=max_seq_len,
            class_num=class_num
        )
        # 创建优化器AdamOptimizer，用于更新这个网络的参数
        adam = fluid.optimizer.AdamOptimizer(
            learning_rate=learning_rate,
            parameter_list=multi_classifier.parameters()
        )

        train_batch = build_batch(word2id_dict, train_corpus, batch_size, epoch_num, max_seq_len)
        for sentences, labels in tqdm(train_batch, desc='train set batch'):
            sentences_var = fluid.dygraph.to_variable(sentences)
            labels_var = fluid.dygraph.to_variable(labels)
            pred, loss = multi_classifier(sentences_var, labels_var)
            loss.backward()
            adam.minimize(loss)
            multi_classifier.clear_gradients()
            step += 1
            if step % 50 == 0:
                print("step %d, loss %.5f" % (step, loss.numpy()[0]))
            # print("Epoch {} batch {}: loss = {}".format(
            #     epoch_id, batch_id, np.mean(loss.numpy())))
        # 保存Layer参数
        paddle.save(multi_classifier.state_dict(), "models/multi_classifier.pdparams")
        # 保存优化器参数
        paddle.save(adam.state_dict(), "models/adam.pdopt")

    with fluid.dygraph.guard():
        multi_classifier = Classifier(
            hidden_size=embedding_size,
            vocab_size=vocab_size,
            num_steps=max_seq_len,
            class_num=class_num)
        evaluate('data/Val_IDs.txt', multi_classifier)