import torch
from torch import nn


class SymbolNet(nn.Module):
    def __init__(self, num_classes=4, image_size=(28, 28, 1)):
        super(SymbolNet, self).__init__()
        self.conv1 = nn.Sequential(
            nn.Conv2d(1, 32, 5, stride=1),
            nn.ReLU(),
            nn.MaxPool2d(kernel_size=2, stride=2),
            nn.BatchNorm2d(32, momentum=0.99, eps=0.001),
        )
        self.conv2 = nn.Sequential(
            nn.Conv2d(32, 64, 5, padding=2, stride=1),
            nn.ReLU(),
            nn.MaxPool2d(kernel_size=2, stride=2),
            nn.BatchNorm2d(64, momentum=0.99, eps=0.001),
        )

        num_features = 64 * (image_size[0] // 4 - 1) * (image_size[1] // 4 - 1)
        self.fc1 = nn.Sequential(nn.Linear(num_features, 120), nn.ReLU())
        self.fc2 = nn.Sequential(nn.Linear(120, 84), nn.ReLU())
        self.fc3 = nn.Sequential(nn.Linear(84, num_classes))

    def forward(self, x):
        x = self.conv1(x)
        x = self.conv2(x)
        x = torch.flatten(x, 1)
        x = self.fc1(x)
        x = self.fc2(x)
        x = self.fc3(x)
        return x