import torch
import torch.nn as nn
import torch.nn.functional as F


class mfm(nn.Module):
    def __init__(self, in_channels, out_channels, kernel_size=3, stride=1, padding=1, type=1):
        super(mfm, self).__init__()
        self.out_channels = out_channels
        if type == 1:
            self.filter = nn.Conv2d(in_channels, 2 * out_channels, kernel_size=kernel_size, stride=stride,
                                    padding=padding)
        else:
            self.filter = nn.Linear(in_channels, 2 * out_channels)

    def forward(self, x):
        x = self.filter(x)
        out = torch.split(x, self.out_channels, 1)
        return torch.max(out[0], out[1])


class group(nn.Module):
    def __init__(self, in_channels, out_channels, kernel_size, stride, padding):
        super(group, self).__init__()
        self.conv_a = mfm(in_channels, in_channels, 1, 1, 0)
        self.conv = mfm(in_channels, out_channels, kernel_size, stride, padding)

    def forward(self, x):
        x = self.conv_a(x)
        x = self.conv(x)
        return x


class resblock(nn.Module):
    def __init__(self, in_channels, out_channels):
        super(resblock, self).__init__()
        self.conv1 = mfm(in_channels, out_channels, kernel_size=3, stride=1, padding=1)
        self.conv2 = mfm(out_channels, out_channels, kernel_size=3, stride=1, padding=1)

    def forward(self, x):
        res = x
        out = self.conv1(x)
        out = self.conv2(out)
        out = out + res
        return out


class network_29layers_v2(nn.Module):
    def __init__(self, block, layers, is_train=False, num_classes=80013):
        super(network_29layers_v2, self).__init__()
        self.is_train = is_train
        self.conv1 = mfm(1, 48, 5, 1, 2)
        self.block1 = self._make_layer(block, layers[0], 48, 48)
        self.group1 = group(48, 96, 3, 1, 1)
        self.block2 = self._make_layer(block, layers[1], 96, 96)
        self.group2 = group(96, 192, 3, 1, 1)
        self.block3 = self._make_layer(block, layers[2], 192, 192)
        self.group3 = group(192, 128, 3, 1, 1)
        self.block4 = self._make_layer(block, layers[3], 128, 128)
        self.group4 = group(128, 128, 3, 1, 1)
        self.fc = nn.Linear(8 * 8 * 128, 256)

        if self.is_train:
            self.fc2_ = nn.Linear(256, num_classes, bias=False)

    def _make_layer(self, block, num_blocks, in_channels, out_channels):
        layers = []
        for i in range(0, num_blocks):
            layers.append(block(in_channels, out_channels))
        return nn.Sequential(*layers)

    def forward(self, x):
        x = self.conv1(x)
        x = F.max_pool2d(x, 2) + F.avg_pool2d(x, 2)

        x = self.block1(x)
        x = self.group1(x)
        x = F.max_pool2d(x, 2) + F.avg_pool2d(x, 2)

        x = self.block2(x)
        x = self.group2(x)
        x = F.max_pool2d(x, 2) + F.avg_pool2d(x, 2)

        x = self.block3(x)
        x = self.group3(x)
        x = self.block4(x)
        x = self.group4(x)
        x = F.max_pool2d(x, 2) + F.avg_pool2d(x, 2)

        x = x.view(x.size(0), -1)
        fc = self.fc(x)

        if self.is_train:
            x = F.dropout(fc, training=self.training)
            out = self.fc2_(x)
            return out, fc
        else:
            return fc