import torch
from torch.utils.data import DataLoader
from dataloaders.dataloader_msvd_retrieval import MSVD_DataLoader


def dataloader_msvd_train(args, tokenizer):
    msvd_dataset = MSVD_DataLoader(
        subset="train",
        data_path=args.data_path,
        features_path=args.features_path,
        csv_path=args.train_csv,
        max_words=args.max_words,
        feature_framerate=args.feature_framerate,
        tokenizer=tokenizer,
        max_frames=args.max_frames,
        frame_order=args.train_frame_order,
        slice_framepos=args.slice_framepos,
    )

    train_sampler = torch.utils.data.distributed.DistributedSampler(msvd_dataset)
    dataloader = DataLoader(
        msvd_dataset,
        batch_size=args.batch_size // args.n_gpu,
        num_workers=args.num_thread_reader,
        pin_memory=False,
        shuffle=(train_sampler is None),
        sampler=train_sampler,
        drop_last=True,
    )

    return dataloader, len(msvd_dataset), train_sampler

def dataloader_msvd_test(args, tokenizer, subset="test"):
    msvd_testset = MSVD_DataLoader(
        subset=subset,
        data_path=args.data_path,
        features_path=args.features_path,
        csv_path=args.val_csv,
        max_words=args.max_words,
        feature_framerate=args.feature_framerate,
        tokenizer=tokenizer,
        max_frames=args.max_frames,
        frame_order=args.eval_frame_order,
        slice_framepos=args.slice_framepos,
    )
    dataloader_msrvtt = DataLoader(
        msvd_testset,
        batch_size=args.batch_size_val,
        num_workers=args.num_thread_reader,
        shuffle=False,
        drop_last=False,
    )
    return dataloader_msrvtt, len(msvd_testset)


DATALOADER_DICT = {}
DATALOADER_DICT["msvd"] = {"train":dataloader_msvd_train, "val":dataloader_msvd_test, "test":dataloader_msvd_test}