from data_provider.data_factory import data_provider
from exp.exp_basic import Exp_Basic
from utils.tools import EarlyStopping, adjust_learning_rate, visual
from utils.metrics import metric
import torch
import torch.nn as nn
from torch import optim
import os
import time
import warnings
import numpy as np
from utils.dtw_metric import dtw, accelerated_dtw

warnings.filterwarnings("ignore")


class Exp_Long_Term_Forecast(Exp_Basic):
    def __init__(self, args):
        super(Exp_Long_Term_Forecast, self).__init__(args)

    def _get_data(self, flag):
        data_set, data_loader = data_provider(self.args, flag)
        return data_set, data_loader

    def _select_optimizer(self):
        model_optim = optim.Adam(self.model.parameters(), lr=self.args.learning_rate)
        return model_optim

    def _select_criterion(self):
        criterion = nn.MSELoss()
        return criterion

    def vali(self, vali_data, vali_loader, criterion):
        total_loss = []
        self.model.eval()
        with torch.no_grad():
            for i, (batch_x, batch_y, batch_x_mark, batch_y_mark) in enumerate(
                vali_loader
            ):
                batch_x = batch_x.float().to(self.device)
                batch_y = batch_y.float()

                # encoder - decoder
                if self.args.use_amp:
                    with torch.cuda.amp.autocast():
                        outputs = self.model(batch_x)
                else:
                    outputs = self.model(batch_x)
                f_dim = -1 if self.args.features == "MS" else 0
                outputs = outputs[:, -self.args.pred_len :, f_dim:]
                batch_y = batch_y[:, -self.args.pred_len :, f_dim:].to(self.device)

                pred = outputs.detach().cpu()
                true = batch_y.detach().cpu()

                loss = criterion(pred, true)

                total_loss.append(loss)
        total_loss = np.average(total_loss)
        self.model.train()
        return total_loss

    def train(self, setting):
        """进行模型训练"""
        # 获得训练使用的训练集，验证集，测试集
        train_data, train_loader = self._get_data(flag="train")
        vali_data, vali_loader = self._get_data(flag="val")
        test_data, test_loader = self._get_data(flag="test")

        path = os.path.join(self.args.checkpoints, setting)
        if not os.path.exists(path):
            os.makedirs(path)

        # 获取当前的时间
        time_now = time.time()

        train_steps = len(train_loader)
        early_stopping = EarlyStopping(patience=self.args.patience, verbose=True)

        model_optim = self._select_optimizer()
        criterion = self._select_criterion()

        if self.args.use_amp:
            scaler = torch.cuda.amp.GradScaler()

        for epoch in range(self.args.train_epochs):
            iter_count = 0
            train_loss = []

            self.model.train()
            # 每个Epoch所用的时间
            epoch_time = time.time()
            for i, (batch_x, batch_y, batch_x_mark, batch_y_mark) in enumerate(
                train_loader
            ):
                iter_count += 1
                model_optim.zero_grad()
                batch_x = batch_x.float().to(self.device)
                batch_y = batch_y.float().to(self.device)

                # encoder - decoder
                if self.args.use_amp:
                    with torch.cuda.amp.autocast():
                        outputs = self.model(batch_x)

                        f_dim = -1 if self.args.features == "MS" else 0
                        outputs = outputs[:, -self.args.pred_len :, f_dim:]
                        batch_y = batch_y[:, -self.args.pred_len :, f_dim:].to(
                            self.device
                        )
                        loss = criterion(outputs, batch_y)
                        train_loss.append(loss.item())
                else:
                    outputs = self.model(batch_x)

                    f_dim = -1 if self.args.features == "MS" else 0
                    outputs = outputs[:, -self.args.pred_len :, f_dim:]
                    batch_y = batch_y[:, -self.args.pred_len :, f_dim:].to(self.device)
                    loss = criterion(outputs, batch_y)
                    train_loss.append(loss.item())

                if (i + 1) % 100 == 0:
                    print(
                        "\titers: {0}, epoch: {1} | loss: {2:.7f}".format(
                            i + 1, epoch + 1, loss.item()
                        )
                    )
                    speed = (time.time() - time_now) / iter_count
                    left_time = speed * (
                        (self.args.train_epochs - epoch) * train_steps - i
                    )
                    print(
                        "\tspeed: {:.4f}s/iter; left time: {:.4f}s".format(
                            speed, left_time
                        )
                    )
                    iter_count = 0
                    time_now = time.time()

                if self.args.use_amp:
                    scaler.scale(loss).backward()
                    scaler.step(model_optim)
                    scaler.update()
                else:
                    loss.backward()
                    model_optim.step()

            print("Epoch: {} cost time: {}".format(epoch + 1, time.time() - epoch_time))
            train_loss = np.average(train_loss)
            vali_loss = self.vali(vali_data, vali_loader, criterion)
            test_loss = self.vali(test_data, test_loader, criterion)

            print(
                "Epoch: {0}, Steps: {1} | Train Loss: {2:.7f} Vali Loss: {3:.7f} Test Loss: {4:.7f}".format(
                    epoch + 1, train_steps, train_loss, vali_loss, test_loss
                )
            )
            early_stopping(vali_loss, self.model, path)
            if early_stopping.early_stop:
                print("Early stopping")
                break

            adjust_learning_rate(model_optim, epoch + 1, self.args)

        best_model_path = path + "/" + "checkpoint.pth"
        self.model.load_state_dict(torch.load(best_model_path))

        return self.model

    def test(self, setting, test=0):
        test_data, test_loader = self._get_data(flag="test")
        if test:
            print("loading model")
            self.model.load_state_dict(
                torch.load(os.path.join("./checkpoints/" + setting, "checkpoint.pth"))
            )

        preds = []
        trues = []
        folder_path = "./test_results/" + setting + "/"
        if not os.path.exists(folder_path):
            os.makedirs(folder_path)

        self.model.eval()
        with torch.no_grad():
            for i, (batch_x, batch_y, batch_x_mark, batch_y_mark) in enumerate(
                test_loader
            ):
                batch_x = batch_x.float().to(self.device)
                batch_y = batch_y.float().to(self.device)

                # encoder - decoder
                if self.args.use_amp:
                    with torch.cuda.amp.autocast():
                        outputs = self.model(batch_x)
                else:
                    outputs = self.model(batch_x)

                f_dim = -1 if self.args.features == "MS" else 0
                outputs = outputs[:, -self.args.pred_len :, :]
                batch_y = batch_y[:, -self.args.pred_len :, :].to(self.device)
                outputs = outputs.detach().cpu().numpy()
                batch_y = batch_y.detach().cpu().numpy()
                if test_data.scale and self.args.inverse:
                    shape = outputs.shape
                    outputs = test_data.inverse_transform(
                        outputs.reshape(shape[0] * shape[1], -1)
                    ).reshape(shape)
                    batch_y = test_data.inverse_transform(
                        batch_y.reshape(shape[0] * shape[1], -1)
                    ).reshape(shape)

                outputs = outputs[:, :, f_dim:]
                batch_y = batch_y[:, :, f_dim:]

                pred = outputs
                true = batch_y

                preds.append(pred)
                trues.append(true)
                if i % 20 == 0:
                    input = batch_x.detach().cpu().numpy()
                    if test_data.scale and self.args.inverse:
                        shape = input.shape
                        input = test_data.inverse_transform(
                            input.reshape(shape[0] * shape[1], -1)
                        ).reshape(shape)
                    gt = np.concatenate((input[0, :, -1], true[0, :, -1]), axis=0)
                    pd = np.concatenate((input[0, :, -1], pred[0, :, -1]), axis=0)
                    visual(gt, pd, os.path.join(folder_path, str(i) + ".pdf"))

        preds = np.concatenate(preds, axis=0)
        trues = np.concatenate(trues, axis=0)
        print("test shape:", preds.shape, trues.shape)
        preds = preds.reshape(-1, preds.shape[-2], preds.shape[-1])
        trues = trues.reshape(-1, trues.shape[-2], trues.shape[-1])
        print("test shape:", preds.shape, trues.shape)

        # result save
        folder_path = "./results/" + setting + "/"
        if not os.path.exists(folder_path):
            os.makedirs(folder_path)

        # dtw calculation
        if self.args.use_dtw:
            dtw_list = []
            manhattan_distance = lambda x, y: np.abs(x - y)
            for i in range(preds.shape[0]):
                x = preds[i].reshape(-1, 1)
                y = trues[i].reshape(-1, 1)
                if i % 100 == 0:
                    print("calculating dtw iter:", i)
                d, _, _, _ = accelerated_dtw(x, y, dist=manhattan_distance)
                dtw_list.append(d)
            dtw = np.array(dtw_list).mean()
        else:
            dtw = "not calculated"

        mae, mse, rmse, mape, mspe = metric(preds, trues)
        print("mse:{}, mae:{}, dtw:{}".format(mse, mae, dtw))
        f = open("result_long_term_forecast.txt", "a")
        f.write(setting + "  \n")
        f.write("mse:{}, mae:{}, dtw:{}".format(mse, mae, dtw))
        f.write("\n")
        f.write("\n")
        f.close()

        np.save(folder_path + "metrics.npy", np.array([mae, mse, rmse, mape, mspe]))
        np.save(folder_path + "pred.npy", preds)
        np.save(folder_path + "true.npy", trues)

        return