#!/usr/bin/env python3
"""Hash every materialized source file for an auditable release manifest."""

from __future__ import annotations

import argparse
import hashlib
from pathlib import Path


def sha256(path: Path) -> str:
    h = hashlib.sha256()
    with path.open("rb") as f:
        for block in iter(lambda: f.read(8 * 1024 * 1024), b""):
            h.update(block)
    return h.hexdigest()


def main() -> int:
    ap = argparse.ArgumentParser()
    ap.add_argument("--source-root", type=Path, required=True)
    ap.add_argument("--release-root", type=Path, required=True)
    args = ap.parse_args()
    source = args.source_root.resolve()
    paths = sorted(
        p for split in ("training", "validation")
        for p in (source / split).rglob("*")
        if p.is_file()
    )
    output = args.release_root / "SOURCE_FILES.sha256"
    with output.open("w", encoding="utf-8") as f:
        for path in paths:
            rel = path.relative_to(source).as_posix()
            f.write(f"{sha256(path)}  {rel}\n")
    print(f"wrote {len(paths)} source-file hashes to {output}")
    return 0


if __name__ == "__main__":
    raise SystemExit(main())