#!/usr/bin/env python3
"""Restore LlamaFactory JSONL files from this downloaded dataset repository."""
import argparse
import hashlib
import json
import shutil
from pathlib import Path

import pyarrow.parquet as pq


def main():
    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument('--output-dir', type=Path, required=True)
    args = parser.parse_args()
    root = Path(__file__).resolve().parent
    provenance = json.loads((root / 'provenance.json').read_text())
    args.output_dir.mkdir(parents=True, exist_ok=True)
    for split, filename in [('train', 'train.jsonl'), ('validation', 'holdout.sharegpt.jsonl')]:
        info = provenance['splits'][split]
        destination = args.output_dir / filename
        if destination.exists():
            raise FileExistsError(destination)
        digest, count = hashlib.sha256(), 0
        with destination.open('x', encoding='utf-8') as stream:
            for shard in info['shards']:
                for batch in pq.ParquetFile(root / shard['path']).iter_batches(batch_size=1000):
                    for row in batch.to_pylist():
                        line = json.dumps(row, ensure_ascii=False, sort_keys=True, separators=(',', ':')) + '\n'
                        stream.write(line)
                        digest.update(line.encode())
                        count += 1
        assert count == info['rows']
        assert digest.hexdigest() == info['canonical_rows_sha256']
        print(f'{filename}: {count} verified rows')
    shutil.copy2(root / 'llamafactory/dataset_info.json', args.output_dir / 'dataset_info.json')
    for name in ('exception_tokens.json', 'exception_tokens.yaml'):
        shutil.copy2(root / name, args.output_dir / name)


if __name__ == '__main__':
    main()