import torch
import torch.nn as nn
import torchvision


class Discriminator_VGG_128(nn.Module):
    # input_img_factor = multiplier to support images over 128x128. Only certain factors are supported.
    def __init__(self, in_nc, nf, input_img_factor=1, extra_conv=False):
        super(Discriminator_VGG_128, self).__init__()
        # [64, 128, 128]
        self.conv0_0 = nn.Conv2d(in_nc, nf, 3, 1, 1, bias=True)
        self.conv0_1 = nn.Conv2d(nf, nf, 4, 2, 1, bias=False)
        self.bn0_1 = nn.BatchNorm2d(nf, affine=True)
        # [64, 64, 64]
        self.conv1_0 = nn.Conv2d(nf, nf * 2, 3, 1, 1, bias=False)
        self.bn1_0 = nn.BatchNorm2d(nf * 2, affine=True)
        self.conv1_1 = nn.Conv2d(nf * 2, nf * 2, 4, 2, 1, bias=False)
        self.bn1_1 = nn.BatchNorm2d(nf * 2, affine=True)
        # [128, 32, 32]
        self.conv2_0 = nn.Conv2d(nf * 2, nf * 4, 3, 1, 1, bias=False)
        self.bn2_0 = nn.BatchNorm2d(nf * 4, affine=True)
        self.conv2_1 = nn.Conv2d(nf * 4, nf * 4, 4, 2, 1, bias=False)
        self.bn2_1 = nn.BatchNorm2d(nf * 4, affine=True)
        # [256, 16, 16]
        self.conv3_0 = nn.Conv2d(nf * 4, nf * 8, 3, 1, 1, bias=False)
        self.bn3_0 = nn.BatchNorm2d(nf * 8, affine=True)
        self.conv3_1 = nn.Conv2d(nf * 8, nf * 8, 4, 2, 1, bias=False)
        self.bn3_1 = nn.BatchNorm2d(nf * 8, affine=True)
        # [512, 8, 8]
        self.conv4_0 = nn.Conv2d(nf * 8, nf * 8, 3, 1, 1, bias=False)
        self.bn4_0 = nn.BatchNorm2d(nf * 8, affine=True)
        self.conv4_1 = nn.Conv2d(nf * 8, nf * 8, 4, 2, 1, bias=False)
        self.bn4_1 = nn.BatchNorm2d(nf * 8, affine=True)
        final_nf = nf * 8

        self.extra_conv = extra_conv
        if self.extra_conv:
            self.conv5_0 = nn.Conv2d(nf * 8, nf * 16, 3, 1, 1, bias=False)
            self.bn5_0 = nn.BatchNorm2d(nf * 16, affine=True)
            self.conv5_1 = nn.Conv2d(nf * 16, nf * 16, 4, 2, 1, bias=False)
            self.bn5_1 = nn.BatchNorm2d(nf * 16, affine=True)
            input_img_factor = input_img_factor // 2
            final_nf = nf * 16

        self.linear1 = nn.Linear(final_nf * 4 * input_img_factor * 4 * input_img_factor, 100)
        self.linear2 = nn.Linear(100, 1)

        # activation function
        self.lrelu = nn.LeakyReLU(negative_slope=0.2, inplace=True)

    def forward(self, x):
        x = x[0]
        fea = self.lrelu(self.conv0_0(x))
        fea = self.lrelu(self.bn0_1(self.conv0_1(fea)))

        #fea = torch.cat([fea, skip_med], dim=1)
        fea = self.lrelu(self.bn1_0(self.conv1_0(fea)))
        fea = self.lrelu(self.bn1_1(self.conv1_1(fea)))

        #fea = torch.cat([fea, skip_lo], dim=1)
        fea = self.lrelu(self.bn2_0(self.conv2_0(fea)))
        fea = self.lrelu(self.bn2_1(self.conv2_1(fea)))

        fea = self.lrelu(self.bn3_0(self.conv3_0(fea)))
        fea = self.lrelu(self.bn3_1(self.conv3_1(fea)))

        fea = self.lrelu(self.bn4_0(self.conv4_0(fea)))
        fea = self.lrelu(self.bn4_1(self.conv4_1(fea)))

        if self.extra_conv:
            fea = self.lrelu(self.bn5_0(self.conv5_0(fea)))
            fea = self.lrelu(self.bn5_1(self.conv5_1(fea)))

        fea = fea.contiguous().view(fea.size(0), -1)
        fea = self.lrelu(self.linear1(fea))
        out = self.linear2(fea)
        return out