#!/usr/bin/env python3
"""Install checkmake if it is not already present.

Tries to install via Go if available, otherwise downloads the latest
pre-built Linux binary from the official GitHub releases.
"""

from __future__ import annotations

import platform
import shutil
import subprocess  # nosec B404
import urllib.request
from pathlib import Path

import click

CHECKMAKE_VERSION = "0.3.2"
RELEASE_URL_TEMPLATE = (
    "https://github.com/checkmake/checkmake/releases/download/"
    f"v{CHECKMAKE_VERSION}/checkmake-v{CHECKMAKE_VERSION}.linux.{{arch}}"
)
TARGET_PATH = Path("/usr/local/bin/checkmake")


def _arch() -> str:
    """Return the architecture string used by checkmake releases."""
    machine = platform.machine().lower()
    if machine in {"x86_64", "amd64"}:
        return "amd64"
    if machine in {"aarch64", "arm64"}:
        return "arm64"
    raise click.ClickException(
        f"Unsupported architecture: {machine}"
    )


def _install_with_go() -> bool:
    """Install checkmake using go install if Go is available."""
    go_bin = shutil.which("go")
    if go_bin is None:
        return False
    subprocess.run(  # nosec B603
        [
            go_bin,
            "install",
            "github.com/checkmake/checkmake/cmd/checkmake@latest",
        ],
        check=True,
    )
    return True


def _download_binary() -> None:
    """Download the prebuilt checkmake binary for the current architecture."""
    url = RELEASE_URL_TEMPLATE.format(arch=_arch())
    urllib.request.urlretrieve(url, TARGET_PATH)  # nosec B310
    TARGET_PATH.chmod(0o755)


def main() -> None:
    """Install checkmake if not already present."""
    if shutil.which("checkmake") is not None:
        return

    if not _install_with_go():
        _download_binary()


if __name__ == "__main__":  # pragma: no cover
    main()  # pragma: no cover