import time

import torch

import torch.nn as nn

from torch.autograd import Variable

import torch.optim as optim

import torchvision

from torchvision import datasets, models

from torchvision import transforms as T

from torch.utils.data import DataLoader, Dataset

import numpy as np

import matplotlib.pyplot as plt

import os

import time

import pandas as pd

from skimage import io, transform

import matplotlib.image as mpimg

from PIL import Image

from sklearn.metrics import roc_auc_score

import torch.nn.functional as F

import scipy

import random

import pickle

import scipy.io as sio

import itertools

from scipy.ndimage.interpolation import shift

import warnings

warnings.filterwarnings("ignore")

plt.ion()

from utils import *

def train_model_3d(model, optimizer,dataloader, data_sizes, batch_size, num_epochs = 100, verbose = False):

    since = time.time()

    best_loss = np.inf

    loss_hist = {'train':[],'validate':[]}

    dice_score_0_hist = {'train':[],'validate':[]}

    dice_score_1_hist = {'train':[],'validate':[]}

    dice_score_2_hist = {'train':[],'validate':[]}

    for i in range(num_epochs):

        for phase in ['train', 'validate']:

            running_loss = 0

            running_dice_score_class_0 = 0

            running_dice_score_class_1 = 0

            running_dice_score_class_2 = 0

            if phase == 'train':

                model.train(True)

            else:

                model.train(False)

            for data in dataloader[phase]:

                optimizer.zero_grad()

                input, target,_ = data

                input = Variable(input).cuda()

                true = Variable(torch.transpose(target,2,1).contiguous().view(-1,4,256,256)).cuda()

                output = model(input)

                output_reshaped = torch.transpose(output,2,1).contiguous().view(-1,4,256,256)

                loss = dice_loss(true,output_reshaped,p=2.5)

                if phase == 'train':

                    loss.backward()

                    optimizer.step()

                running_loss += loss.data[0] * batch_size

                dice_score_batch = dice_score(true,output_reshaped)

                running_dice_score_class_0 += dice_score_batch[0] * batch_size

                running_dice_score_class_1 += dice_score_batch[1] * batch_size

                running_dice_score_class_2 += dice_score_batch[2] * batch_size

            epoch_loss = running_loss/data_sizes[phase]

            loss_hist[phase].append(epoch_loss) 

            epoch_dice_score_0 = running_dice_score_class_0/data_sizes[phase]

            epoch_dice_score_1 = running_dice_score_class_1/data_sizes[phase]

            epoch_dice_score_2 = running_dice_score_class_2/data_sizes[phase]

            dice_score_0_hist[phase].append(epoch_dice_score_0)

            dice_score_1_hist[phase].append(epoch_dice_score_1)

            dice_score_2_hist[phase].append(epoch_dice_score_2)

            if verbose or i%10 == 0:

                print('Epoch: {}, Phase: {}, epoch loss: {:.4f}, Dice Score (class 0): {:.4f}, Dice Score (class 1): {:.4f},Dice Score (class 2): {:.4f}'.format(i,phase,epoch_loss, epoch_dice_score_0, epoch_dice_score_1, epoch_dice_score_2))

                print('-'*10)

        if phase == 'validate' and epoch_loss < best_loss:

            best_loss = epoch_loss

            best_model_wts = model.state_dict() 

    print('-'*50)    

    time_elapsed = time.time() - since

    print('Training complete in {:.0f}m {:.0f}s'.format(time_elapsed // 60, time_elapsed % 60))

    print('Best val dice loss: {:4f}'.format(best_loss))

    model.load_state_dict(best_model_wts)

    return model, loss_hist, dice_score_0_hist, dice_score_1_hist, dice_score_2_hist