"""Convert a parquet HF RGBD-GSD dataset back to raw image files.

Restores the original structure:
  {out}/{split}/images/{id}.jpg
  {out}/{split}/masks/{id}.png
  {out}/{split}/depths/{id}.png

Usage
-----
# From HuggingFace Hub:
python parquet_to_raw.py --repo garrying/RGBD-GSD

# From a local save_to_disk() directory:
python parquet_to_raw.py --local ./rgbd_gsd_disk

# Restore only the test split:
python parquet_to_raw.py --repo garrying/RGBD-GSD --splits test

# Change output directory:
python parquet_to_raw.py --repo garrying/RGBD-GSD --out RGBD-GSD_raw
"""
import argparse
from pathlib import Path
from datasets import load_dataset, load_from_disk

SPLITS = ["train", "test"]


def save_split(ds, split: str, out_dir: Path):
    split_dir = out_dir / split
    img_dir   = split_dir / "images"; img_dir.mkdir(parents=True, exist_ok=True)
    mask_dir  = split_dir / "masks";  mask_dir.mkdir(parents=True, exist_ok=True)
    depth_dir = split_dir / "depths"; depth_dir.mkdir(parents=True, exist_ok=True)

    for i, sample in enumerate(ds):
        stem = sample.get("image_id") or f"{i:08d}"
        sample["image"].save(img_dir   / f"{stem}.jpg")
        sample["mask"].save(mask_dir   / f"{stem}.png")
        sample["depth"].save(depth_dir / f"{stem}.png")

        if (i + 1) % 100 == 0:
            print(f"  {i + 1}/{len(ds)}")

    print(f"  saved {len(ds)} samples -> {split_dir}")


def main():
    parser = argparse.ArgumentParser(
        description="Convert parquet RGBD-GSD back to raw image files."
    )
    src = parser.add_mutually_exclusive_group(required=True)
    src.add_argument("--repo",  help="HuggingFace repo ID (e.g. garrying/RGBD-GSD)")
    src.add_argument("--local", help="Path to a save_to_disk() directory")
    parser.add_argument("--out",    default="RGBD-GSD",
                        help="Output root directory (default: RGBD-GSD)")
    parser.add_argument("--splits", nargs="+", choices=SPLITS, default=SPLITS,
                        help="Which splits to restore (default: all)")
    args = parser.parse_args()

    out_dir = Path(args.out)
    out_dir.mkdir(parents=True, exist_ok=True)

    for split in args.splits:
        print(f"\nLoading {split}...")
        if args.repo:
            ds = load_dataset(args.repo, split=split)
        else:
            ds = load_from_disk(str(Path(args.local) / split))
        print(f"  {len(ds)} samples — saving images...")
        save_split(ds, split, out_dir)

    print(f"\nDone!  Raw files in: {out_dir.resolve()}")


if __name__ == "__main__":
    main()