# Copyright 2021 Huawei Technologies Co., Ltd
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

import torch, pdb
import torchvision
import torch.nn.modules


class vgg16bn(torch.nn.Module):
    def __init__(self, pretrained=False):
        super(vgg16bn, self).__init__()
        model = list(torchvision.models.vgg16_bn(pretrained=pretrained).features.children())
        model = model[:33] + model[34:43]
        self.model = torch.nn.Sequential(*model)

    def forward(self, x):
        return self.model(x)


class resnet(torch.nn.Module):
    def __init__(self, layers, pretrained=False):
        super(resnet, self).__init__()
        if layers == '18':
            # model = torchvision.models.resnet18(pretrained=pretrained)
            model=torchvision.models.resnet18(pretrained=False)
            model.load_state_dict(torch.load('backbone/resnet18-5c106cde.pth'),strict=True)
        elif layers == '34':
            model = torchvision.models.resnet34(pretrained=pretrained)
        elif layers == '50':
            model = torchvision.models.resnet50(pretrained=pretrained)
        elif layers == '101':
            model = torchvision.models.resnet101(pretrained=pretrained)
        elif layers == '152':
            model = torchvision.models.resnet152(pretrained=pretrained)
        elif layers == '50next':
            model = torchvision.models.resnext50_32x4d(pretrained=pretrained)
        elif layers == '101next':
            model = torchvision.models.resnext101_32x8d(pretrained=pretrained)
        elif layers == '50wide':
            model = torchvision.models.wide_resnet50_2(pretrained=pretrained)
        elif layers == '101wide':
            model = torchvision.models.wide_resnet101_2(pretrained=pretrained)
        else:
            raise NotImplementedError

        self.conv1 = model.conv1
        self.bn1 = model.bn1
        self.relu = model.relu
        self.maxpool = model.maxpool
        self.layer1 = model.layer1
        self.layer2 = model.layer2
        self.layer3 = model.layer3
        self.layer4 = model.layer4

    def forward(self, x):
        x = self.conv1(x)
        x = self.bn1(x)
        x = self.relu(x)
        x = self.maxpool(x)
        x = self.layer1(x)
        x2 = self.layer2(x)
        x3 = self.layer3(x2)
        x4 = self.layer4(x3)
        return x2, x3, x4