"""Verify the release inventory; optionally check file SHA256 digests."""

import argparse
import hashlib
import json
from pathlib import Path, PurePosixPath


def sha(path):
    with Path(path).open("rb") as stream:
        return hashlib.file_digest(stream, "sha256").hexdigest()


def safe_path(root, name):
    relative = PurePosixPath(name)
    if (not name or "\\" in name or relative.is_absolute()
            or any(part in {".", ".."} for part in name.split("/"))):
        raise ValueError(f"Invalid release path: {name}")
    result = root.joinpath(*relative.parts)
    if not result.resolve().is_relative_to(root.resolve()) or result.is_symlink():
        raise ValueError(f"Unsafe release path: {name}")
    return result


def verify(directory, hashes=False):
    root = Path(directory).resolve()
    manifest = json.loads((root / "RELEASE.json").read_text(encoding="utf-8"))
    if manifest.get("format") != "vimeml_hf_release_v1" or manifest.get("license") != "gpl-2.0":
        raise ValueError("Unsupported release format or license.")
    sums = {}
    for line in (root / "SHA256SUMS.txt").read_text(encoding="utf-8").splitlines():
        digest, name = line.split("  ", 1)
        if len(digest) != 64 or any(c not in "0123456789abcdef" for c in digest) or name in sums:
            raise ValueError("Invalid checksum entry.")
        sums[name] = digest
    if set(sums) != set(manifest["files"]) | {"RELEASE.json"}:
        raise ValueError("Checksum inventory differs from RELEASE.json.")
    for name, digest in sums.items():
        path = safe_path(root, name)
        if not path.is_file():
            raise ValueError(f"Missing release file: {name}")
        if name != "RELEASE.json":
            entry = manifest["files"][name]
            if entry["bytes"] != path.stat().st_size or entry["sha256"] != digest:
                raise ValueError(f"Release inventory mismatch: {name}")
        if hashes and sha(path) != digest:
            raise ValueError(f"Release checksum mismatch: {name}")
    expected = set(sums) | {"SHA256SUMS.txt"}
    actual = {p.relative_to(root).as_posix() for p in root.rglob("*") if p.is_file()
              and ".cache" not in p.relative_to(root).parts
              and "__pycache__" not in p.relative_to(root).parts
              and p.suffix != ".pyc" and p.relative_to(root).as_posix() != ".gitattributes"}
    if actual != expected:
        raise ValueError("Unexpected release file inventory.")
    return manifest, sorted(expected)


def main():
    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument("--release", type=Path, default=Path(__file__).resolve().parent)
    parser.add_argument("--hashes", action="store_true", help="Also read and hash every payload file.")
    args = parser.parse_args()
    manifest, files = verify(args.release, hashes=args.hashes)
    print(f"Verified {len(files)} files: {manifest['repo_id']} / source {manifest['source_commit']}")


if __name__ == "__main__":
    main()