"""Build a minimal, offline, hand-rolled npm package and its registry
metadata document, for integration-testing the `npm` module of
id-configurator.

No network access and no build backend (npm/node) is used: the tarball is a
plain gzipped tar assembled with the standard library only, so this script
can run in a minimal Python image with nothing installed.
"""

from __future__ import annotations

import base64
import hashlib
import io
import json
import pathlib
import tarfile

PACKAGE = "idconfiguratortestpkg"
VERSION = "0.0.1"
TARBALL_NAME = f"{PACKAGE}-{VERSION}.tgz"
OUT_DIR = pathlib.Path("/srv")

PACKAGE_JSON = json.dumps({"name": PACKAGE, "version": VERSION})
MARKER = "test-only package served by the id-configurator integration tests\n"


def _add_file(archive: tarfile.TarFile, name: str, content: bytes) -> None:
    info = tarfile.TarInfo(name=f"package/{name}")
    info.size = len(content)
    archive.addfile(info, io.BytesIO(content))


def build_tarball() -> bytes:
    buffer = io.BytesIO()
    with tarfile.open(fileobj=buffer, mode="w:gz") as archive:
        _add_file(archive, "package.json", PACKAGE_JSON.encode("utf-8"))
        _add_file(archive, "marker.txt", MARKER.encode("utf-8"))
    return buffer.getvalue()


def write_registry_metadata(out_dir: pathlib.Path, tarball: bytes) -> None:
    # npm requires a fully-qualified tarball URL, so this bakes in a
    # placeholder that nginx's sub_filter rewrites to the real
    # https://<host used by the client>/ at request time (see
    # npm-repo.nginx.conf) - the host and port this fixture is actually
    # reached on aren't known at image-build time.
    sha1 = hashlib.sha1(tarball).hexdigest()  # nosec B324
    sha512_b64 = base64.b64encode(hashlib.sha512(tarball).digest()).decode("ascii")
    metadata = {
        "name": PACKAGE,
        "dist-tags": {"latest": VERSION},
        "versions": {
            VERSION: {
                "name": PACKAGE,
                "version": VERSION,
                "dist": {
                    "shasum": sha1,
                    "integrity": f"sha512-{sha512_b64}",
                    "tarball": f"__BASE_URL__/{TARBALL_NAME}",
                },
            }
        },
    }
    (out_dir / PACKAGE).write_text(json.dumps(metadata, indent=2), encoding="utf-8")


def main() -> None:
    OUT_DIR.mkdir(parents=True, exist_ok=True)
    tarball = build_tarball()
    (OUT_DIR / TARBALL_NAME).write_bytes(tarball)
    write_registry_metadata(OUT_DIR, tarball)


if __name__ == "__main__":
    main()