import pytorch_lightning as pl
import torch
from torch.utils.data import DataLoader, Dataset, random_split

from lit_module import LitModule
from logger import TBLogger

from wit.configuration import ModelConfig

pretrain_model_name = None  # "qwen/Qwen-1_8B-Chat"
learning_rate = 0.0001
use_tril_attention_mask = None
precision = "32-true"  # "precision:bf16-mixed,16-mixed,32-true"
train_batch_size = 4
val_batch_size = 8
num_proc = 8
max_epochs = 1000
strategy = "auto"
resume_from_ckpt_path = None
seed = 42


class StressDataset(Dataset):
    def __init__(self, start=1, end=128, size=32768):  # 1048576 32768
        self.size = size
        self.features = []
        self.data = torch.randint(start, end, [size, 2048]).long()

    def __len__(self):
        return self.size

    def __getitem__(self, idx):
        output = {}
        data = self.data[idx]
        output["input_ids"] = data
        output["labels"] = data.clone()
        output["token_type_ids"] = torch.zeros(data.shape)
        return output


if __name__ == "__main__":
    torch.manual_seed(seed)

    config = ModelConfig()
    config.vocab_size = 4096
    config.hidden_size = 1024  # 128 1024 2048  32
    config.num_hidden_layers = 6  # 6 12 24  3
    config.num_attention_heads = 8  # 8 8 16

    lit_module = LitModule(pretrain_model_name, learning_rate, config, use_tril_attention_mask)

    raw_dataset = StressDataset()
    train_dataset, val_dataset = random_split(raw_dataset, [0.95, 0.05])

    train_dataloader = DataLoader(
        train_dataset,
        batch_size=train_batch_size,
        num_workers=num_proc,
        persistent_workers=True,
        shuffle=True,
    )
    val_dataloader = DataLoader(
        val_dataset,
        batch_size=val_batch_size,
        num_workers=num_proc,
        persistent_workers=True,
    )

    lit_trainer = pl.Trainer(
        accelerator="gpu",
        devices=2,
        precision=precision,
        logger=TBLogger("./", default_hp_metric=False),
        strategy=strategy,
        max_epochs=max_epochs,
    )
    lit_trainer.fit(
        lit_module,
        train_dataloaders=train_dataloader,
        val_dataloaders=val_dataloader,
        ckpt_path=resume_from_ckpt_path,
    )