import torch
from torch.autograd import Variable as V
import torchvision.models as models
from torchvision import transforms as trn
from torch.nn import functional as F
import os
import numpy as np
import cv2
from PIL import Image



def recursion_change_bn(module):
    if isinstance(module, torch.nn.BatchNorm2d):
        module.track_running_stats = 1
    else:
        for i, (name, module1) in enumerate(module._modules.items()):
            module1 = recursion_change_bn(module1)
    return module

def load_labels():
    # prepare all the labels
    # scene category relevant
    file_name_category = 'categories_places365.txt'
    classes = list()
    with open(file_name_category) as class_file:
        for line in class_file:
            classes.append(line.strip().split(' ')[0][3:])
    classes = tuple(classes)

    # indoor and outdoor relevant
    file_name_IO = 'IO_places365.txt'
    with open(file_name_IO) as f:
        lines = f.readlines()
        labels_IO = []
        for line in lines:
            items = line.rstrip().split()
            labels_IO.append(int(items[-1]) -1) # 0 is indoor, 1 is outdoor
    labels_IO = np.array(labels_IO)

    # scene attribute relevant
    file_name_attribute = 'labels_sunattribute.txt'
    with open(file_name_attribute) as f:
        lines = f.readlines()
        labels_attribute = [item.rstrip() for item in lines]
    file_name_W = 'W_sceneattribute_wideresnet18.npy'
    W_attribute = np.load(file_name_W)

    return classes, labels_IO, labels_attribute, W_attribute

def hook_feature(module, input, output):
    return np.squeeze(output.data.cpu().numpy())

def returnCAM(feature_conv, weight_softmax, class_idx):
    # generate the class activation maps upsample to 256x256
    size_upsample = (256, 256)
    nc, h, w = feature_conv.shape
    output_cam = []
    for idx in class_idx:
        cam = weight_softmax[class_idx].dot(feature_conv.reshape((nc, h*w)))
        cam = cam.reshape(h, w)
        cam = cam - np.min(cam)
        cam_img = cam / np.max(cam)
        cam_img = np.uint8(255 * cam_img)
        output_cam.append(cv2.resize(cam_img, size_upsample))
    return output_cam

def returnTF():
# load the image transformer
    tf = trn.Compose([
        trn.Resize((224,224)),
        trn.ToTensor(),
        trn.Normalize([0.485, 0.456, 0.406], [0.229, 0.224, 0.225])
    ])
    return tf


def load_model():
    # this model has a last conv feature map as 14x14

    model_file = 'wideresnet18_places365.pth.tar'
    import wideresnet
    model = wideresnet.resnet18(num_classes=365)
    checkpoint = torch.load(model_file, map_location=lambda storage, loc: storage)
    state_dict = {str.replace(k,'module.',''): v for k,v in checkpoint['state_dict'].items()}
    model.load_state_dict(state_dict)
    
    # hacky way to deal with the upgraded batchnorm2D and avgpool layers...
    for i, (name, module) in enumerate(model._modules.items()):
        module = recursion_change_bn(model)
    model.avgpool = torch.nn.AvgPool2d(kernel_size=14, stride=1, padding=0)
    
    model.eval()

    # hook the feature extractor
    features_names = ['layer4','avgpool'] # this is the last conv layer of the resnet
    for name in features_names:
        model._modules.get(name).register_forward_hook(hook_feature)
    return model

# load the labels
classes, labels_IO, labels_attribute, W_attribute = load_labels()

# load the model
features_blobs = []
model = load_model()


# load the transformer
tf = returnTF() # image transformer

# get the softmax weight
params = list(model.parameters())
weight_softmax = params[-2].data.numpy()
weight_softmax[weight_softmax<0] = 0

def predict(img):
    #img = Image.open('6.jpg')
    input_img = V(tf(img).unsqueeze(0))
    logit = model.forward(input_img)
    h_x = F.softmax(logit, 1).data.squeeze()
    probs, idx = h_x.sort(0, True)
    probs = probs.numpy()
    idx = idx.numpy()
    io_image = np.mean(labels_IO[idx[:10]]) # vote for the indoor or outdoor
    env_image = []
    if io_image < 0.5:
        env_image.append('Indoor')
        #print('--TYPE OF ENVIRONMENT: indoor')
    else:
        env_image.append('Outdoor')
        #print('--TYPE OF ENVIRONMENT: outdoor')

    # output the prediction of scene category
    #print('--SCENE CATEGORIES:')
    scene_cat=[]
    for i in range(0, 5):
        scene_cat.append('{:.3f} -> {}'.format(probs[i], classes[idx[i]]))
        #print('{:.3f} -> {}'.format(probs[i], classes[idx[i]]))
        
    return env_image,scene_cat