_DOCKERFILE_TEXT = """
FROM busybox
COPY . /build-context
WORKDIR /build-context
CMD find .
"""

def _dockerignore_check(args):
    if len(args) != 1:
        print("Must specify only one argument: The dockerignore file.")
        return

    ignore_file = Path(args[0])

    if not ignore_file.exists():
        print(f"Dockerignore file {ignore_file} doesn't exist.")

    import tempfile
    import shutil

    with tempfile.TemporaryDirectory() as td:
        dpath = Path(td)

        docker_path = dpath / "Dockerfile"
        ignore_path = dpath / "Dockerfile.dockerignore"
        docker_path.write_text(_DOCKERFILE_TEXT)
        shutil.copyfile(ignore_file, ignore_path)

        $DOCKER_BUILDKIT=1
        docker image build --no-cache -t dockerignore-build-context -f @(docker_path) . &>/dev/null
        docker run -it --rm dockerignore-build-context
        docker image rm dockerignore-build-context &> /dev/null

aliases["ditest"] = _dockerignore_check