#!/usr/bin/env python3
"""CI entry point for commit-message lint.

This file only locates and delegates. Every rule, the type/emoji mapping and
the policy schema belong to the commit-message skill validator, which reads
`skills/commit-message/references/commit_policy.json`.

Do not reimplement validation here and do not parse rules out of
`docs/common/commit_message.md`: that document is human guidance, not a machine
policy source. See `skills/commit-message/references/ci-wiring.md`.
"""
from __future__ import annotations

import os
import pathlib
import subprocess
import sys

VALIDATOR_CANDIDATES = (
    ("skills", "commit-message", "scripts", "validate_commit_message.py"),
    (
        "docs",
        "standards",
        "playbook",
        "skills",
        "commit-message",
        "scripts",
        "validate_commit_message.py",
    ),
)


def _eprint(*args: object) -> None:
    print(*args, file=sys.stderr)


def _repo_root() -> pathlib.Path:
    output = subprocess.check_output(
        ["git", "rev-parse", "--show-toplevel"], text=True
    )
    return pathlib.Path(output.strip())


def _find_validator(root: pathlib.Path) -> pathlib.Path:
    tried: list[pathlib.Path] = []
    for parts in VALIDATOR_CANDIDATES:
        path = root.joinpath(*parts)
        tried.append(path)
        if path.is_file():
            return path
    raise FileNotFoundError(
        "commit-message skill validator not found; expected one of:\n"
        + "\n".join(f"- {path}" for path in tried)
    )


def main() -> int:
    try:
        root = _repo_root()
    except Exception as exc:
        _eprint(f"ERROR: not a git repository: {exc}")
        return 2

    os.chdir(root)

    try:
        validator = _find_validator(root)
    except FileNotFoundError as exc:
        _eprint(f"ERROR: {exc}")
        return 2

    print(f"validator: {validator}")
    sys.stdout.flush()
    # No arguments: the validator selects its CI input mode from the event
    # payload. Exit codes pass through unchanged (0 pass / 1 lint / 2 input).
    return subprocess.run([sys.executable, str(validator)], cwd=root).returncode


if __name__ == "__main__":
    raise SystemExit(main())