"""Validate this Hugging Face distribution's SHA-256 manifest (standard library only)."""
from pathlib import Path
import hashlib

ROOT = Path(__file__).resolve().parent


def main():
    count = 0
    seen = set()
    for line in (ROOT / 'SHA256SUMS.txt').read_text(encoding='utf-8').splitlines():
        if not line.strip():
            continue
        digest, name = line.split('  ', 1)
        path = (ROOT / name).resolve()
        if name in seen or len(digest) != 64 or any(c not in '0123456789abcdef' for c in digest):
            raise SystemExit('Invalid or duplicate manifest entry: ' + name)
        if not path.is_relative_to(ROOT) or not path.is_file():
            raise SystemExit('Missing file or unsafe path: ' + name)
        actual = hashlib.sha256(path.read_bytes()).hexdigest()
        if actual != digest:
            raise SystemExit('SHA-256 mismatch: ' + name)
        seen.add(name)
        count += 1
    if not count:
        raise SystemExit('Manifest is empty.')
    print(f'PASS: {count} distribution file hashes match.')
    print('Integrity verifies bytes; it does not certify mathematical correctness.')


if __name__ == '__main__':
    main()