from transformers import BertTokenizer, BertForSequenceClassification, TrainingArguments, Trainer
import random
import torch

with open('train/in.tsv') as f:
    data_train_X = f.readlines()

with open('train/expected.tsv') as f:
    data_train_Y = f.readlines()

with open('dev-0/in.tsv') as f:
    data_dev_X = f.readlines()

with open('test-A/in.tsv') as f:
    data_test_X = f.readlines()

class CustomDataset(torch.utils.data.Dataset):
    def __init__(self, encodings, labels=None):
        self.encodings = encodings
        self.labels = labels

    def __getitem__(self, idx):
        item = {key: torch.tensor(val[idx]) for key, val in self.encodings.items()}
        if self.labels:
            item["labels"] = torch.tensor(self.labels[idx])
        return item

    def __len__(self):
        return len(self.encodings["input_ids"])

data_train = list(zip(data_train_X, data_train_Y))
data_train = random.sample(data_train, 50000)

tokenizer = BertTokenizer.from_pretrained("bert-base-uncased")
train_X = tokenizer([text[0] for text in data_train], truncation=True, padding=True)
train_Y = [int(text[1]) for text in data_train]

train_dataset = CustomDataset(train_X, train_Y)

model = BertForSequenceClassification.from_pretrained("bert-base-uncased", num_labels=2)

training_args = TrainingArguments("model")
trainer = Trainer(
    model=model, args=training_args, train_dataset=train_dataset)
trainer.train()