"""Merge Chrono part directories into one (episodes.jsonl concatenated, per-policy trajectory npz merged).
Usage: python merge_chrono_parts.py out_dir part_dir [part_dir ...]. Refuses duplicates."""
import json
import sys
from pathlib import Path

import numpy as np

out = Path(sys.argv[1])
parts = [Path(p) for p in sys.argv[2:]]
(out / 'traj').mkdir(parents=True, exist_ok=False)
seen, rows, traj = set(), [], {}
for d in parts:
    for line in open(d / 'episodes.jsonl'):
        r = json.loads(line)
        key = (r['policy'], r['goal_id'])
        if key in seen:
            raise SystemExit(f'duplicate {key} in {d}')
        seen.add(key)
        rows.append(line if line.endswith('\n') else line + '\n')
    for f in (d / 'traj').glob('*.npz'):
        traj.setdefault(f.stem, {}).update(dict(np.load(f)))
(out / 'episodes.jsonl').write_text(''.join(rows))
for pol, dd in traj.items():
    np.savez_compressed(out / 'traj' / f'{pol}.npz', **dd)
(out / 'MERGED_FROM.txt').write_text('\n'.join(str(p) for p in parts) + '\n')
print(len(rows), 'episodes;', sum(len(v) for v in traj.values()), 'trajectories ->', out)