"""
"Import/Convert" an **existing local LeRobot dataset directory** to LeRobot's standard cache location
`$HF_LEROBOT_HOME/<repo_id>` (OpenPi/LeRobot loads datasets from here by repo_id by default).

The requirement is to import:
`/workspace/ghsun/libero_plus_lerobot_ori_10pct`
into `$HF_LEROBOT_HOME` (or a specified output directory), so it can be loaded directly by LeRobot/OpenPi via `repo_id`.

Usage example:

```bash
python openpi/convert_libero_plus.py \
  --src_dir /workspace/ghsun/libero_plus_lerobot_ori_10pct \
  --repo_id local/libero_plus_lerobot_ori_10pct
```

Notes:
- If `--hardlink=True` and source/destination are on the same filesystem, hard links will be preferred for speed and to save disk space;
  otherwise, it automatically falls back to standard copy.
- This script **does not modify data content**, it only handles the "placement into standard location" conversion/transfer.
"""

from __future__ import annotations

import argparse
import os
import shutil
from pathlib import Path

def _default_hf_lerobot_home() -> Path:
    """
    Try to align with LeRobot's default behavior:
    - Prioritize environment variable HF_LEROBOT_HOME
    - Otherwise use HF_HOME/lerobot (if huggingface_hub is available)
    - Otherwise fallback to ~/.cache/huggingface/lerobot
    """
    env = os.getenv("HF_LEROBOT_HOME")
    if env:
        return Path(env).expanduser()
    try:
        from huggingface_hub.constants import HF_HOME  # type: ignore

        return (Path(HF_HOME) / "lerobot").expanduser()
    except Exception:  # noqa: BLE001
        return Path.home() / ".cache" / "huggingface" / "lerobot"


HF_LEROBOT_HOME = _default_hf_lerobot_home()


def _copytree(src: Path, dst: Path, *, hardlink: bool) -> None:
    def _copy_or_link(s: str, d: str) -> str:
        if hardlink:
            try:
                os.link(s, d)
                return d
            except OSError:
                # May fail across filesystems, fallback to copy
                pass
        shutil.copy2(s, d)
        return d

    shutil.copytree(src, dst, copy_function=_copy_or_link, dirs_exist_ok=False)


def main() -> None:
    parser = argparse.ArgumentParser(description="Import local LeRobot dataset to $HF_LEROBOT_HOME/<repo_id>")
    parser.add_argument(
        "--src_dir",
        type=str,
        default="/workspace/ghsun/libero_plus_lerobot_ori_10pct",
        help="Root directory of the dataset to import (should contain meta/info.json)",
    )
    parser.add_argument(
        "--repo_id",
        type=str,
        default="local/libero_plus_lerobot_ori_10pct",
        help="Target repo_id under the output root directory after import (will become a directory)",
    )
    parser.add_argument(
        "--output_root",
        type=str,
        default=None,
        help="Output root directory; if not provided, uses $HF_LEROBOT_HOME (default: ~/.cache/huggingface/lerobot)",
    )
    parser.add_argument("--overwrite", action="store_true", help="Delete and overwrite if target already exists")
    parser.add_argument("--no-overwrite", dest="overwrite", action="store_false", help="Raise error if target already exists")
    parser.set_defaults(overwrite=True)
    parser.add_argument("--hardlink", action="store_true", help="Prefer hard links (fallback to copy on failure)")
    parser.add_argument("--no-hardlink", dest="hardlink", action="store_false", help="Disable hard links, copy only")
    parser.set_defaults(hardlink=True)
    args = parser.parse_args()

    src = Path(args.src_dir).expanduser().resolve()
    if not src.exists():
        raise FileNotFoundError(f"src_dir does not exist: {src}")
    if not (src / "meta" / "info.json").exists():
        raise FileNotFoundError(f"LeRobot meta info file not found: {src / 'meta' / 'info.json'}")

    output_root = Path(args.output_root).expanduser().resolve() if args.output_root else HF_LEROBOT_HOME
    dst = (output_root / args.repo_id).resolve()

    if dst.exists():
        if not args.overwrite:
            raise FileExistsError(f"Target already exists and overwrite=False: {dst}")
        shutil.rmtree(dst)

    dst.parent.mkdir(parents=True, exist_ok=True)
    _copytree(src, dst, hardlink=args.hardlink)

    print(f"Done: Imported to {dst}")
    print(f"You can now load it in OpenPi using repo_id='{args.repo_id}' (default root={output_root})")


if __name__ == "__main__":
    main()