import matplotlib.pyplot as plt

import numpy as np

import segmentation_models_pytorch.utils.losses as vanilla_losses

import torch.optim.optimizer

from torch.utils.data import DataLoader

from data.etis import EtisDataset

from data.hyperkvasir import KvasirSegmentationDataset

from models import segmentation_models

from evaluation.metrics import iou

from losses.consistency_losses import NakedConsistencyLoss, ConsistencyLoss

from perturbation.model import ModelOfNaturalVariation

from utils import logging

class VanillaTrainer:

    def __init__(self, id, config):

        """

        :param model: String describing the model type. Can be DeepLab, TriUnet, ... TODO

        :param config: Contains hyperparameters : lr, epochs, batch_size, T_0, T_mult

        """

        self.config = config

        self.device = config["device"]

        self.lr = config["lr"]

        self.batch_size = config["batch_size"]

        self.epochs = config["epochs"]

        self.model = None

        self.id = id

        self.model_str = config["model"]

        self.mnv = ModelOfNaturalVariation(T0=1).to(self.device)

        self.nakedcloss = NakedConsistencyLoss()

        self.closs = ConsistencyLoss()

        if self.model_str == "DeepLab":

            self.model = segmentation_models.DeepLab().to(self.device)

        elif self.model_str == "TriUnet":

            self.model = segmentation_models.TriUnet().to(self.device)

        elif self.model_str == "Unet":

            self.model = segmentation_models.Unet().to(self.device)

        elif self.model_str == "FPN":

            self.model = segmentation_models.FPN().to(self.device)

        elif self.model_str == "InductiveNet":

            self.model = segmentation_models.InductiveNet().to(self.device)

        else:

            raise AttributeError("model_str not valid; choices are DeepLab, TriUnet, InductiveNet, FPN, Unet")

        self.optimizer = torch.optim.Adam(self.model.parameters(), self.lr)

        self.criterion = vanilla_losses.JaccardLoss()

        self.scheduler = torch.optim.lr_scheduler.CosineAnnealingWarmRestarts(self.optimizer, T_0=50, T_mult=2)

        self.train_set = KvasirSegmentationDataset("Datasets/HyperKvasir", split="train", augment=False)

        self.val_set = KvasirSegmentationDataset("Datasets/HyperKvasir", split="val", augment=False)

        self.test_set = KvasirSegmentationDataset("Datasets/HyperKvasir", split="test", augment=False)

        self.train_loader = DataLoader(self.train_set, batch_size=self.batch_size, shuffle=True)

        self.val_loader = DataLoader(self.val_set)

        self.test_loader = DataLoader(self.test_set)

    def train_epoch(self):

        self.model.train()

        losses = []

        for x, y, fname in self.train_loader:

            image = x.to("cuda")

            mask = y.to("cuda")

            self.optimizer.zero_grad()

            output = self.model(image)

            loss = self.criterion(output, mask)

            loss.backward()

            self.optimizer.step()

            losses.append(np.abs(loss.item()))

        return np.mean(losses)

    def train(self):

        best_val_loss = 10

        print("Starting Segmentation training")

        best_closs = 100

        for i in range(self.epochs):

            training_loss = np.abs(self.train_epoch())

            val_loss, ious, closs = self.validate(epoch=i, plot=False)

            gen_ious = self.validate_generalizability(epoch=i, plot=False)

            mean_iou = float(torch.mean(ious))

            gen_iou = float(torch.mean(gen_ious))

            consistency = 1 - np.mean(closs)

            test_ious = np.mean(self.test().numpy())

            self.config["lr"] = [group['lr'] for group in self.optimizer.param_groups]

            logging.log_full(epoch=i, id=self.id, config=self.config, result_dict=

            {"train_loss": training_loss, "val_loss": val_loss,

             "iid_val_iou": mean_iou, "iid_test_iou": test_ious, "ood_iou": gen_iou,

             "consistency": consistency}, type="vanilla")

            self.scheduler.step(i)

            print(

                f"Epoch {i} of {self.epochs} \t"

                f" lr={[group['lr'] for group in self.optimizer.param_groups]} \t"

                f" loss={training_loss} \t"

                f" val_loss={val_loss} \t"

                f" ood_iou={gen_iou}\t"

                f" val_iou={mean_iou} \t"

                f" gen_prop={gen_iou / mean_iou}"

            )

            if val_loss < best_val_loss:

                test_ious = self.test()

                best_val_loss = val_loss

                np.save(

                    f"experiments/Data/Normal-Pipelines/{self.model_str}/{self.id}",

                    test_ious)

                print(f"Saving new best model. IID test-set mean iou: {float(np.mean(test_ious.numpy()))}")

                torch.save(self.model.state_dict(),

                           f"Predictors/Vanilla/{self.model_str}/{self.id}")

                print("saved in: ", f"Predictors/Vanilla/{self.model_str}/{self.id}")

            if closs < best_closs:

                best_closs = closs

                torch.save(self.model.state_dict(),

                           f"Predictors/Vanilla/{self.model_str}/{self.id}-maximum-consistency")

        torch.save(self.model.state_dict(),

                   f"Predictors/Vanilla/{self.model_str}/{self.id}_last_epoch")

    def test(self):

        self.model.eval()

        ious = torch.empty((0,))

        with torch.no_grad():

            for x, y, fname in self.test_loader:

                image = x.to("cuda")

                mask = y.to("cuda")

                output = self.model(image)

                batch_ious = torch.Tensor([iou(output_i, mask_j) for output_i, mask_j in zip(output, mask)])

                ious = torch.cat((ious, batch_ious.flatten()))

        return ious

    def validate(self, epoch, plot=False):

        self.model.eval()

        losses = []

        closses = []

        ious = torch.empty((0,))

        with torch.no_grad():

            for x, y, fname in self.val_loader:

                image = x.to("cuda")

                mask = y.to("cuda")

                aug_img, aug_mask = self.mnv(image, mask)

                output = self.model(image)

                aug_output = self.model(aug_img)  # todo consider train on augmented vs non-augmented?

                batch_ious = torch.Tensor([iou(output_i, mask_j) for output_i, mask_j in zip(output, mask)])

                loss = self.closs(aug_mask, mask, aug_output, output, torch.mean(batch_ious))

                losses.append(np.abs(loss.item()))

                closses.append(self.nakedcloss(aug_mask, mask, aug_output, output).item())

                ious = torch.cat((ious, batch_ious.cpu().flatten()))

                if plot:

                    plt.imshow(y[0, 0].cpu().numpy(), alpha=0.5)

                    plt.imshow(image[0].permute(1, 2, 0).cpu().numpy())

                    plt.imshow((output[0, 0].cpu().numpy() > 0.5).astype(int), alpha=0.5)

                    plt.imshow(y[0, 0].cpu().numpy().astype(int), alpha=0.5)

                    plt.title("IoU {} at epoch {}".format(iou(output[0, 0], mask[0, 0]), epoch))

                    plt.show()

                    plot = False  # plot one example per epoch

        avg_val_loss = np.mean(losses)

        avg_closs = np.mean(closses)

        return avg_val_loss, ious, avg_closs

    def validate_generalizability(self, epoch, plot=False):

        self.model.eval()

        ious = torch.empty((0,))

        with torch.no_grad():

            for x, y, index in DataLoader(EtisDataset("Datasets/ETIS-LaribPolypDB")):

                image = x.to("cuda")

                mask = y.to("cuda")

                output = self.model(image)

                batch_ious = torch.Tensor([iou(output_i, mask_j) for output_i, mask_j in zip(output, mask)])

                ious = torch.cat((ious, batch_ious.flatten()))

                if plot:

                    plt.imshow(image[0].permute(1, 2, 0).cpu().numpy())

                    plt.imshow((output[0, 0].cpu().numpy() > 0.5).astype(int), alpha=0.5)

                    plt.title("IoU {} at epoch {}".format(iou(output[0, 0], mask[0, 0]), epoch))

                    plt.show()

                    plot = False  # plot one example per epoch (hacky, but works)

            return ious