import argparse
from torch.utils.data import Dataset, DataLoader
from glob import glob
import os, os.path as osp
from tqdm import tqdm
import webdataset as wds

from kn_util.data.video import read_frames_decord, get_frame_indices, fill_temporal_param, save_video_imageio, array_to_video_bytes
from kn_util.data.transforms.video import Compose, Resize, ToStackedArray, CenterCrop
from kn_util.data.transforms.video.functional import split_array


class VideoDataset(Dataset):
    def __init__(self, root_dir, fps=8, size=256):
        self.transform = Compose(
            [
                Resize(size),
                ToStackedArray(),
            ]
        )
        self.video_files = glob(osp.join(root_dir, "**/*.mp4"))
        self.fps = fps

    def __getitem__(self, idx):
        video_file = self.video_files[idx]

        frames = read_frames_decord(video_file, fps=self.fps, output_format="thwc")
        frames = split_array(frames)
        frames = self.transform(frames)
        return video_file, frames

    def __len__(self):
        return len(self.video_files)


if __name__ == "__main__":
    parser = argparse.ArgumentParser()
    parser.add_argument("--root_dir", type=str)
    parser.add_argument("--output_dir", type=str, default="outputs")
    parser.add_argument("--fps", type=int, default=8)
    parser.add_argument("--size", type=int, default=256)
    parser.add_argument("--output_format", type=str, default="tar")
    args = parser.parse_args()

    dataset = VideoDataset(root_dir=args.root_dir, fps=args.fps, size=args.size)
    dataloader = DataLoader(
        dataset,
        batch_size=1,
        shuffle=False,
        collate_fn=lambda x: x[0],
        num_workers=32,
        pin_memory=True,
    )

    dataset_name = args.root_dir.strip("/")
    tar_path = osp.join(args.output_dir, f"{dataset_name}.%02d.tar")
    os.makedirs(args.output_dir, exist_ok=True)

    if args.output_format == "files":
        for video_path, frames in tqdm(dataloader):
            output_path = osp.join(args.output_dir, video_path)
            os.makedirs(osp.dirname(output_path), exist_ok=True)
            save_video_imageio(frames, output_path, fps=args.fps, input_format="thwc")

    if args.output_format == "tar":
        writer = wds.ShardWriter(tar_path, maxcount=4000000000)
        for video_path, frames in tqdm(dataloader):
            video_filename = osp.basename(video_path).split(".")[0]
            writer.write({"mp4": array_to_video_bytes(frames), "__key__": video_filename})
        writer.close()