#!/usr/bin/env python3
"""Detect whether the latest git commit is a release commit.

Release commits have the format ``release: vX.Y.Z [skip ci]``.
This script writes ``is-release=true`` or ``is-release=false`` to
``$GITHUB_OUTPUT`` for use in CI workflow conditionals.

Usage::

    python3 scripts/ci/detect_release_commit.py
"""

from __future__ import annotations

import os
import re
import subprocess  # nosec B404

import click

RELEASE_RE = re.compile(r"^release: v\d+\.\d+\.\d+")


def get_commit_message() -> str:
    """Get the subject of the latest git commit."""
    result = subprocess.run(  # nosec B603 B607
        ["git", "log", "-1", "--pretty=%s"],
        capture_output=True,
        text=True,
        check=False,
    )
    if result.returncode != 0:
        raise click.ClickException(f"git log failed: {result.stderr.strip()}")
    return result.stdout.strip()


def is_release_commit(message: str) -> bool:
    """Check if a commit message matches the release commit format."""
    return bool(RELEASE_RE.match(message))


def write_github_output(key: str, value: str) -> None:
    """Append a key=value line to the $GITHUB_OUTPUT file."""
    gh_output = os.environ.get("GITHUB_OUTPUT")
    if not gh_output:
        raise click.ClickException("GITHUB_OUTPUT environment variable is not set")
    with open(gh_output, "a") as f:  # noqa: PTH123
        f.write(f"{key}={value}\n")


@click.command()
def main() -> None:
    """Detect if the latest commit is a release commit and set GITHUB_OUTPUT."""
    msg = get_commit_message()
    click.echo(f"Commit message: {msg}")
    is_release = is_release_commit(msg)
    write_github_output("is-release", "true" if is_release else "false")
    if is_release:
        click.echo("Release commit — skipping all post-merge jobs.")
    else:
        click.echo("Regular merge commit — running all post-merge jobs.")


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