import streamlit as st
from PIL import Image
import cv2 as cv

import os
import glob
import time
import numpy as np
from PIL import Image
from pathlib import Path
from tqdm.notebook import tqdm
import matplotlib.pyplot as plt
from skimage.color import rgb2lab, lab2rgb

# pip install fastai==2.4

import torch
from torch import nn, optim
from torchvision import transforms
from torchvision.utils import make_grid
from torch.utils.data import Dataset, DataLoader
device = torch.device("cuda" if torch.cuda.is_available() else "cpu")
use_colab = None

SIZE = 256
class ColorizationDataset(Dataset):
    def __init__(self, paths, split='train'):
        if split == 'train':
            self.transforms = transforms.Compose([
                transforms.Resize((SIZE, SIZE),  Image.BICUBIC),
                transforms.RandomHorizontalFlip(), # A little data augmentation!
            ])
        elif split == 'val':
            self.transforms = transforms.Resize((SIZE, SIZE),  Image.BICUBIC)
        
        self.split = split
        self.size = SIZE
        self.paths = paths
    
    def __getitem__(self, idx):
        img = Image.open(self.paths[idx]).convert("RGB")
        img = self.transforms(img)
        img = np.array(img)
        img_lab = rgb2lab(img).astype("float32") # Converting RGB to L*a*b
        img_lab = transforms.ToTensor()(img_lab)
        L = img_lab[[0], ...] / 50. - 1. # Between -1 and 1
        ab = img_lab[[1, 2], ...] / 110. # Between -1 and 1
        
        return {'L': L, 'ab': ab}
    
    def __len__(self):
        return len(self.paths)

def make_dataloaders(batch_size=16, n_workers=4, pin_memory=True, **kwargs): # A handy function to make our dataloaders
    dataset = ColorizationDataset(**kwargs)
    dataloader = DataLoader(dataset, batch_size=batch_size, num_workers=n_workers,
                            pin_memory=pin_memory)
    return dataloader

class UnetBlock(nn.Module):
    def __init__(self, nf, ni, submodule=None, input_c=None, dropout=False,
                 innermost=False, outermost=False):
        super().__init__()
        self.outermost = outermost
        if input_c is None: input_c = nf
        downconv = nn.Conv2d(input_c, ni, kernel_size=4,
                             stride=2, padding=1, bias=False)
        downrelu = nn.LeakyReLU(0.2, True)
        downnorm = nn.BatchNorm2d(ni)
        uprelu = nn.ReLU(True)
        upnorm = nn.BatchNorm2d(nf)
        
        if outermost:
            upconv = nn.ConvTranspose2d(ni * 2, nf, kernel_size=4,
                                        stride=2, padding=1)
            down = [downconv]
            up = [uprelu, upconv, nn.Tanh()]
            model = down + [submodule] + up
        elif innermost:
            upconv = nn.ConvTranspose2d(ni, nf, kernel_size=4,
                                        stride=2, padding=1, bias=False)
            down = [downrelu, downconv]
            up = [uprelu, upconv, upnorm]
            model = down + up
        else:
            upconv = nn.ConvTranspose2d(ni * 2, nf, kernel_size=4,
                                        stride=2, padding=1, bias=False)
            down = [downrelu, downconv, downnorm]
            up = [uprelu, upconv, upnorm]
            if dropout: up += [nn.Dropout(0.5)]
            model = down + [submodule] + up
        self.model = nn.Sequential(*model)
    
    def forward(self, x):
        if self.outermost:
            return self.model(x)
        else:
            return torch.cat([x, self.model(x)], 1)

class Unet(nn.Module):
    def __init__(self, input_c=1, output_c=2, n_down=8, num_filters=64):
        super().__init__()
        unet_block = UnetBlock(num_filters * 8, num_filters * 8, innermost=True)
        for _ in range(n_down - 5):
            unet_block = UnetBlock(num_filters * 8, num_filters * 8, submodule=unet_block, dropout=True)
        out_filters = num_filters * 8
        for _ in range(3):
            unet_block = UnetBlock(out_filters // 2, out_filters, submodule=unet_block)
            out_filters //= 2
        self.model = UnetBlock(output_c, out_filters, input_c=input_c, submodule=unet_block, outermost=True)
    
    def forward(self, x):
        return self.model(x)

class PatchDiscriminator(nn.Module):
    def __init__(self, input_c, num_filters=64, n_down=3):
        super().__init__()
        model = [self.get_layers(input_c, num_filters, norm=False)]
        model += [self.get_layers(num_filters * 2 ** i, num_filters * 2 ** (i + 1), s=1 if i == (n_down-1) else 2) 
                          for i in range(n_down)] # the 'if' statement is taking care of not using
                                                  # stride of 2 for the last block in this loop
        model += [self.get_layers(num_filters * 2 ** n_down, 1, s=1, norm=False, act=False)] # Make sure to not use normalization or
                                                                                             # activation for the last layer of the model
        self.model = nn.Sequential(*model)                                                   
        
    def get_layers(self, ni, nf, k=4, s=2, p=1, norm=True, act=True): # when needing to make some repeatitive blocks of layers,
        layers = [nn.Conv2d(ni, nf, k, s, p, bias=not norm)]          # it's always helpful to make a separate method for that purpose
        if norm: layers += [nn.BatchNorm2d(nf)]
        if act: layers += [nn.LeakyReLU(0.2, True)]
        return nn.Sequential(*layers)
    
    def forward(self, x):
        return self.model(x)

class GANLoss(nn.Module):
    def __init__(self, gan_mode='vanilla', real_label=1.0, fake_label=0.0):
        super().__init__()
        self.register_buffer('real_label', torch.tensor(real_label))
        self.register_buffer('fake_label', torch.tensor(fake_label))
        if gan_mode == 'vanilla':
            self.loss = nn.BCEWithLogitsLoss()
        elif gan_mode == 'lsgan':
            self.loss = nn.MSELoss()
    
    def get_labels(self, preds, target_is_real):
        if target_is_real:
            labels = self.real_label
        else:
            labels = self.fake_label
        return labels.expand_as(preds)
    
    def __call__(self, preds, target_is_real):
        labels = self.get_labels(preds, target_is_real)
        loss = self.loss(preds, labels)
        return loss

def init_weights(net, init='norm', gain=0.02):
    
    def init_func(m):
        classname = m.__class__.__name__
        if hasattr(m, 'weight') and 'Conv' in classname:
            if init == 'norm':
                nn.init.normal_(m.weight.data, mean=0.0, std=gain)
            elif init == 'xavier':
                nn.init.xavier_normal_(m.weight.data, gain=gain)
            elif init == 'kaiming':
                nn.init.kaiming_normal_(m.weight.data, a=0, mode='fan_in')
            
            if hasattr(m, 'bias') and m.bias is not None:
                nn.init.constant_(m.bias.data, 0.0)
        elif 'BatchNorm2d' in classname:
            nn.init.normal_(m.weight.data, 1., gain)
            nn.init.constant_(m.bias.data, 0.)
            
    net.apply(init_func)
    print(f"model initialized with {init} initialization")
    return net

def init_model(model, device):
    model = model.to(device)
    model = init_weights(model)
    return model

class MainModel(nn.Module):
    def __init__(self, net_G=None, lr_G=2e-4, lr_D=2e-4, 
                 beta1=0.5, beta2=0.999, lambda_L1=100.):
        super().__init__()
        
        self.device = torch.device("cuda" if torch.cuda.is_available() else "cpu")
        self.lambda_L1 = lambda_L1
        
        if net_G is None:
            self.net_G = init_model(Unet(input_c=1, output_c=2, n_down=8, num_filters=64), self.device)
        else:
            self.net_G = net_G.to(self.device)
        self.net_D = init_model(PatchDiscriminator(input_c=3, n_down=3, num_filters=64), self.device)
        self.GANcriterion = GANLoss(gan_mode='vanilla').to(self.device)
        self.L1criterion = nn.L1Loss()
        self.opt_G = optim.Adam(self.net_G.parameters(), lr=lr_G, betas=(beta1, beta2))
        self.opt_D = optim.Adam(self.net_D.parameters(), lr=lr_D, betas=(beta1, beta2))
    
    def set_requires_grad(self, model, requires_grad=True):
        for p in model.parameters():
            p.requires_grad = requires_grad
        
    def setup_input(self, data):
        self.L = data['L'].to(self.device)
        self.ab = data['ab'].to(self.device)
        
    def forward(self):
        self.fake_color = self.net_G(self.L)
    
    def backward_D(self):
        fake_image = torch.cat([self.L, self.fake_color], dim=1)
        fake_preds = self.net_D(fake_image.detach())
        self.loss_D_fake = self.GANcriterion(fake_preds, False)
        real_image = torch.cat([self.L, self.ab], dim=1)
        real_preds = self.net_D(real_image)
        self.loss_D_real = self.GANcriterion(real_preds, True)
        self.loss_D = (self.loss_D_fake + self.loss_D_real) * 0.5
        self.loss_D.backward()
    
    def backward_G(self):
        fake_image = torch.cat([self.L, self.fake_color], dim=1)
        fake_preds = self.net_D(fake_image)
        self.loss_G_GAN = self.GANcriterion(fake_preds, True)
        self.loss_G_L1 = self.L1criterion(self.fake_color, self.ab) * self.lambda_L1
        self.loss_G = self.loss_G_GAN + self.loss_G_L1
        self.loss_G.backward()
    
    def optimize(self):
        self.forward()
        self.net_D.train()
        self.set_requires_grad(self.net_D, True)
        self.opt_D.zero_grad()
        self.backward_D()
        self.opt_D.step()
        
        self.net_G.train()
        self.set_requires_grad(self.net_D, False)
        self.opt_G.zero_grad()
        self.backward_G()
        self.opt_G.step()

class AverageMeter:
    def __init__(self):
        self.reset()
        
    def reset(self):
        self.count, self.avg, self.sum = [0.] * 3
    
    def update(self, val, count=1):
        self.count += count
        self.sum += count * val
        self.avg = self.sum / self.count

def create_loss_meters():
    loss_D_fake = AverageMeter()
    loss_D_real = AverageMeter()
    loss_D = AverageMeter()
    loss_G_GAN = AverageMeter()
    loss_G_L1 = AverageMeter()
    loss_G = AverageMeter()
    
    return {'loss_D_fake': loss_D_fake,
            'loss_D_real': loss_D_real,
            'loss_D': loss_D,
            'loss_G_GAN': loss_G_GAN,
            'loss_G_L1': loss_G_L1,
            'loss_G': loss_G}

def update_losses(model, loss_meter_dict, count):
    for loss_name, loss_meter in loss_meter_dict.items():
        loss = getattr(model, loss_name)
        loss_meter.update(loss.item(), count=count)

def lab_to_rgb(L, ab):
    """
    Takes a batch of images
    """
    
    L = (L + 1.) * 50.
    ab = ab * 110.
    Lab = torch.cat([L, ab], dim=1).permute(0, 2, 3, 1).cpu().numpy()
    rgb_imgs = []
    for img in Lab:
        img_rgb = lab2rgb(img)
        rgb_imgs.append(img_rgb)
    return np.stack(rgb_imgs, axis=0)
    
def visualize(model, data, dims):
    model.net_G.eval()
    with torch.no_grad():
        model.setup_input(data)
        model.forward()
    model.net_G.train()
    fake_color = model.fake_color.detach()
    real_color = model.ab
    L = model.L
    fake_imgs = lab_to_rgb(L, fake_color)
    real_imgs = lab_to_rgb(L, real_color)
    for i in range(1):
        # t_img = transforms.Resize((dims[0], dims[1]))(t_img)
        img = Image.fromarray(np.uint8(fake_imgs[i]))
        img = cv.resize(fake_imgs[i], dsize=(dims[1], dims[0]), interpolation=cv.INTER_CUBIC)
        # st.text(f"Size of fake image {fake_imgs[i].shape} \n Type of image = {type(fake_imgs[i])}")
        st.image(img, caption="Output image", use_column_width='auto', clamp=True)
        
def log_results(loss_meter_dict):
    for loss_name, loss_meter in loss_meter_dict.items():
        print(f"{loss_name}: {loss_meter.avg:.5f}")

# pip install fastai==2.4
from fastai.vision.learner import create_body
from torchvision.models.resnet import resnet18
from fastai.vision.models.unet import DynamicUnet

def build_res_unet(n_input=1, n_output=2, size=256):
    device = torch.device("cuda" if torch.cuda.is_available() else "cpu")
    body = create_body(resnet18(), pretrained=True, n_in=n_input, cut=-2)
    net_G = DynamicUnet(body, n_output, (size, size)).to(device)
    return net_G

net_G = build_res_unet(n_input=1, n_output=2, size=256)
net_G.load_state_dict(torch.load("res18-unet.pt", map_location=device))
model = MainModel(net_G=net_G)
model.load_state_dict(torch.load("final_model_weights.pt", map_location=device))

class MyDataset(torch.utils.data.Dataset):
    def __init__(self, img_list):
        super(MyDataset, self).__init__()
        self.img_list = img_list
        self.augmentations = transforms.Resize((SIZE, SIZE),  Image.BICUBIC)


    def __len__(self):
        return len(self.img_list)

    def __getitem__(self, idx):
        img = self.img_list[idx].convert("RGB")
        # img = self.img_list[idx]
        img = self.augmentations(img)
        img = np.array(img)
        # print(img)
        img_lab = rgb2lab(img).astype("float32") # Converting RGB to L*a*b
        img_lab = transforms.ToTensor()(img_lab)
        L = img_lab[[0], ...] / 50. - 1. # Between -1 and 1
        ab = img_lab[[1, 2], ...] / 110.
        return {'L': L, 'ab': ab}

def make_dataloaders2(batch_size=16, n_workers=4, pin_memory=True, **kwargs): # A handy function to make our dataloaders
    dataset = MyDataset(**kwargs)
    dataloader = DataLoader(dataset, batch_size=batch_size, num_workers=n_workers,
                            pin_memory=pin_memory)
    return dataloader

file_up = st.file_uploader("Upload an jpg image", type=['png', 'jpeg', 'jpg'])
if file_up is not None: 
    im = Image.open(file_up)
    st.text(body=f"Size of uploaded image {im.shape}")
    a = im.shape
    st.image(im, caption="Uploaded Image.", use_column_width='auto')
    test_dl = make_dataloaders2(img_list=[im])
    for data in test_dl:
        model.setup_input(data)
        model.optimize()
        visualize(model, data, a)