# scripts/lib/git_ops.py
"""Narrow git wrapper: subprocess calls, no third-party library."""
from __future__ import annotations

import subprocess
from pathlib import Path
from typing import Iterable


def _run(args: list[str], *, cwd: Path | None = None, check: bool = True) -> subprocess.CompletedProcess:
    return subprocess.run(
        ["git", *args], cwd=cwd, check=check, capture_output=True, text=True
    )


def current_commit() -> str:
    return _run(["rev-parse", "HEAD"]).stdout.strip()


def worktree_clean(*, allowlist: Iterable[str] | None = None) -> bool:
    """True if `git status --porcelain=v1` is empty after filtering allowlisted paths.

    Allowlist entries match either an exact path or a directory prefix (`<entry>/...`).

    Limitations:
    - Renames (`R old -> new` lines) are not parsed; a rename of an allowlisted path
      will be reported as unclean. Callers in this project don't rename tracked
      paths during /refresh, so this is acceptable.
    - Paths containing spaces or non-ASCII characters may be quoted by git
      (`core.quotepath` default), breaking exact-match comparison. Project-controlled
      paths (index/, derived/, surfaces/, STATE.json) are ASCII without spaces.
    """
    out = _run(["status", "--porcelain=v1"]).stdout
    if not out.strip():
        return True
    if allowlist is None:
        return False
    allowed = set(allowlist)
    for line in out.splitlines():
        path = line[3:].strip()
        if path not in allowed and not any(path.startswith(p + "/") for p in allowed):
            return False
    return True


def pull() -> None:
    _run(["pull", "--ff-only"])


def push() -> None:
    _run(["push"])


def add_and_commit(paths: list[str], message: str) -> None:
    _run(["add", "--", *paths])
    _run(["commit", "-m", message])


def add_and_commit_if_changes(paths: list[str], message: str) -> bool:
    """Stage paths and commit only if there are staged changes. Returns True if a commit was made."""
    _run(["add", "--", *paths])
    # `git diff --cached --quiet` exits 0 if no staged changes, 1 if there are staged changes.
    result = _run(["diff", "--cached", "--quiet", "--", *paths], check=False)
    if result.returncode == 0:
        return False
    _run(["commit", "-m", message])
    return True