#!/usr/bin/env python3
"""Dataset cleanup & re-index tool.

Usage:
    python scripts/cleanup_reindex.py

This script performs the following:
1. Delete episodes 000000-000009 from data & videos.
2. Rename remaining episodes (000010-000049 → 000000-000039).
3. Update meta JSONL / JSON files accordingly.

Designed for one-off use; idempotency is *not* guaranteed.
"""
from __future__ import annotations

import json
import shutil
from pathlib import Path
from typing import Dict, List

ROOT = Path(__file__).resolve().parent.parent  # project root
DATA_DIR = ROOT / "data" / "chunk-000"
VIDEO_DIR = ROOT / "videos" / "chunk-000"
META_DIR = ROOT / "meta"

DELETE_RANGE = range(0, 10)  # episodes 0-9, inclusive
OLD_START = 10               # first episode kept
TOTAL_EPISODES_OLD = 50
TOTAL_EPISODES_NEW = 40

# -----------------------------------------------------------------------------
# Helper functions
# -----------------------------------------------------------------------------

def delete_episode_files(idx: int) -> None:
    """Remove parquet & mp4 files for a given episode index."""
    ep_str = f"episode_{idx:06d}"
    parquet = DATA_DIR / f"{ep_str}.parquet"
    for p in [parquet]:
        if p.exists():
            p.unlink()
            print(f"[DEL] {p.relative_to(ROOT)}")

    for cam in ["observation.images.laptop", "observation.images.phone"]:
        mp4 = VIDEO_DIR / cam / f"{ep_str}.mp4"
        if mp4.exists():
            mp4.unlink()
            print(f"[DEL] {mp4.relative_to(ROOT)}")


def rename_episode_files(old_idx: int, new_idx: int) -> None:
    """Rename parquet & mp4 files old_idx → new_idx."""
    old_ep = f"episode_{old_idx:06d}"
    new_ep = f"episode_{new_idx:06d}"

    # Parquet
    src_parquet = DATA_DIR / f"{old_ep}.parquet"
    dst_parquet = DATA_DIR / f"{new_ep}.parquet"
    if src_parquet.exists():
        src_parquet.rename(dst_parquet)
        print(f"[MV ] {src_parquet.relative_to(ROOT)} → {dst_parquet.relative_to(ROOT)}")

    # Videos
    for cam in ["observation.images.laptop", "observation.images.phone"]:
        src_mp4 = VIDEO_DIR / cam / f"{old_ep}.mp4"
        dst_mp4 = VIDEO_DIR / cam / f"{new_ep}.mp4"
        if src_mp4.exists():
            src_mp4.rename(dst_mp4)
            print(f"[MV ] {src_mp4.relative_to(ROOT)} → {dst_mp4.relative_to(ROOT)}")


def update_episodes_jsonl() -> int:
    """Trim first 10 lines & re-index episode_index.

    Returns
    -------
    int
        Total frames across remaining episodes (sum of `length`).
    """
    path = META_DIR / "episodes.jsonl"
    new_lines: List[str] = []
    total_frames = 0
    with path.open() as fh:
        for line in fh:
            data = json.loads(line)
            idx = data["episode_index"]
            if idx in DELETE_RANGE:
                continue  # skip
            new_idx = idx - OLD_START
            data["episode_index"] = new_idx
            total_frames += data.get("length", 0)
            new_lines.append(json.dumps(data, ensure_ascii=False))

    # Overwrite
    path.write_text("\n".join(new_lines) + "\n")
    print(f"[OK ] episodes.jsonl updated (total_frames={total_frames})")
    return total_frames


def update_episodes_stats_jsonl() -> None:
    """Trim & re-index episode_index field only."""
    path = META_DIR / "episodes_stats.jsonl"
    new_lines: List[str] = []
    with path.open() as fh:
        for line in fh:
            data = json.loads(line)
            idx = data.get("episode_index")
            if idx in DELETE_RANGE:
                continue
            new_idx = idx - OLD_START
            data["episode_index"] = new_idx
            new_lines.append(json.dumps(data, ensure_ascii=False))
    path.write_text("\n".join(new_lines) + "\n")
    print("[OK ] episodes_stats.jsonl updated")


def update_info_json(total_frames: int) -> None:
    path = META_DIR / "info.json"
    info: Dict = json.loads(path.read_text())
    info["total_episodes"] = TOTAL_EPISODES_NEW
    info["total_videos"] = TOTAL_EPISODES_NEW * 2
    info["total_frames"] = total_frames
    # Update splits
    if "splits" in info and "train" in info["splits"]:
        info["splits"]["train"] = "0:40"
    path.write_text(json.dumps(info, ensure_ascii=False, indent=4) + "\n")
    print("[OK ] info.json updated")


# -----------------------------------------------------------------------------
# Main
# -----------------------------------------------------------------------------

def main() -> None:
    # 1. Delete unwanted episodes
    print("=== Deleting episodes 0-9 ===")
    for idx in DELETE_RANGE:
        delete_episode_files(idx)

    # 2. Rename remaining episodes
    print("\n=== Renaming remaining episodes ===")
    for old_idx in range(OLD_START, TOTAL_EPISODES_OLD):
        rename_episode_files(old_idx, old_idx - OLD_START)

    # 3. Update meta files
    print("\n=== Updating meta files ===")
    total_frames = update_episodes_jsonl()
    update_episodes_stats_jsonl()
    update_info_json(total_frames)

    print("\nAll tasks completed.")


if __name__ == "__main__":
    main()