"""Merge phase 2 datasets generated separately (different seeds) into one.

Uses LeRobot's aggregate_datasets, then joins the per-episode notes
(phase2_episodes.jsonl, renumbered in merged order) and the generation summaries.

Run:  .venv/bin/python sim/merge_datasets.py data/so101_chess_sim_all data/so101_chess_sim data/so101_chess_sim_b
"""
from __future__ import annotations

import argparse
import json
from pathlib import Path


def main():
    from lerobot.datasets.aggregate import aggregate_datasets
    from lerobot.datasets.lerobot_dataset import LeRobotDataset

    ap = argparse.ArgumentParser(description=__doc__)
    ap.add_argument("out")
    ap.add_argument("parts", nargs="+")
    args = ap.parse_args()
    parts = [Path(p) for p in args.parts]
    out = Path(args.out)
    aggregate_datasets(repo_ids=[f"local/part{i}" for i in range(len(parts))], aggr_repo_id="local/so101_chess_sim",
                       roots=parts, aggr_root=out)
    offset, lines, summaries = 0, [], []
    for p in parts:
        recs = [json.loads(line) for line in (p / "phase2_episodes.jsonl").read_text().splitlines()]
        for r in recs:
            r["part"] = p.name
            r["episode_index"] = offset + r["episode_index"]
            lines.append(json.dumps(r))
        offset += len(recs)
        summaries.append(json.loads((p / "phase2_summary.json").read_text()))
    (out / "phase2_episodes.jsonl").write_text("\n".join(lines) + "\n")
    total = dict(episodes=sum(s["episodes"] for s in summaries), attempts=sum(s["attempts"] for s in summaries),
                 minutes=round(sum(s["minutes"] for s in summaries), 1), parts=[p.name for p in parts],
                 config=summaries[-1].get("config"))
    total["success_rate"] = round(total["episodes"] / total["attempts"], 4)
    (out / "phase2_summary.json").write_text(json.dumps(total, indent=2))
    ds = LeRobotDataset("local/so101_chess_sim", root=out)
    print(f"{out}: {ds.num_episodes} episodes, {ds.num_frames} frames; notes {len(lines)}")


if __name__ == "__main__":
    main()