#!/usr/bin/env python3

# This file is a helper script to calculate the hash for cache key
# in the CI. It is not used in the build process.

from hashlib import sha256
from pathlib import Path


def hash_file(filename):
    with open(filename, "rb") as f:
        return sha256(f.read()).hexdigest()


def get_ignore_pattern(root: Path) -> list[str]:
    ignorefile = root / ".gitignore"
    if not ignorefile.exists():
        raise RuntimeError("No .gitignore file found in root directory")

    return ignorefile.read_text().splitlines()


def main():
    import pathspec  # pip install pathspec

    root: Path = Path(__file__).parent.parent
    targets: list[Path] = [
        root / "Makefile",
        root / "Makefile.envs",
        root / "packages" / "Makefile",
        root / "tools",
    ]

    ignore_pattern = get_ignore_pattern(root)
    ignore_spec = pathspec.PathSpec.from_lines("gitwildmatch", ignore_pattern)

    hash_candidates: list[Path] = []
    for target in targets:
        if target.is_file():
            hash_candidates.append(target)
        else:
            hash_candidates.extend(list(target.glob("**/*")))

    hash_candidates_filtered = sorted(
        list(
            filter(
                lambda file: file.is_file() and not ignore_spec.match_file(str(file)),
                hash_candidates,
            )
        )
    )

    hashes = []
    for file in hash_candidates_filtered:
        hashes.append(hash_file(file))

    print("".join(hashes))


if __name__ == "__main__":
    main()