import torch
from torch import nn


class EmbeddingMLP(nn.Module):
    def __init__(self, size=4):
        super().__init__()
        self.net = nn.Sequential(
            nn.Linear(768 * size, 900 * size),
            nn.BatchNorm1d(900 * size),
            nn.ReLU(),
            nn.Linear(900 * size, 300 * size)
        )

    def forward(self, data):
        res = self.net(data)
        return res


class PairClassifier(nn.Module):
    def __init__(self, size=4):
        super().__init__()
        self.encoder = EmbeddingMLP(size)
        self.net = nn.Sequential(
            nn.Linear(300 * size * 2, 3000),
            nn.ReLU(),
            nn.Linear(3000, 1000),
            nn.ReLU(),
            nn.Linear(1000, 2),
        )

    def forward(self, data):
        e1 = self.encoder(data[:, :768 * 4])
        e2 = self.encoder(data[:, 768 * 4:])
        twins = torch.cat([e1, e2], dim=1)
        res = self.net(twins)
        return res