"""Helpers for WebUI-managed Hermes Agent git worktrees."""

from __future__ import annotations

import subprocess
import time
from contextlib import redirect_stderr, redirect_stdout
from io import StringIO
from pathlib import Path

import logging

logger = logging.getLogger(__name__)


def find_git_repo_root(workspace: str | Path) -> Path:
    """Return the enclosing git repo root for *workspace*.

    Use git itself instead of checking ``workspace/.git`` so nested workspaces
    and linked git worktrees are both handled correctly.
    """
    ws = Path(workspace).expanduser().resolve()
    if not ws.is_dir():
        raise ValueError("Workspace path does not exist or is not a directory")
    try:
        result = subprocess.run(
            ["git", "rev-parse", "--show-toplevel"],
            cwd=ws,
            text=True,
            capture_output=True,
            timeout=5,
            check=False,
        )
    except (OSError, subprocess.TimeoutExpired) as exc:
        raise ValueError("Workspace is not inside a git repository") from exc
    if result.returncode != 0:
        raise ValueError("Workspace is not inside a git repository")
    root = result.stdout.strip()
    if not root:
        raise ValueError("Workspace is not inside a git repository")
    return Path(root).expanduser().resolve()


def _setup_agent_worktree(repo_root: str) -> dict:
    try:
        import api.config  # noqa: F401  # ensure Hermes Agent dir is on sys.path
        from cli import _setup_worktree
    except Exception as exc:
        raise RuntimeError("Hermes Agent worktree helper is unavailable") from exc
    output = StringIO()
    with redirect_stdout(output), redirect_stderr(output):
        info = _setup_worktree(repo_root)
    emitted = output.getvalue().strip()
    if emitted:
        logger.debug("Hermes Agent worktree helper output: %s", emitted)
    if not info:
        raise RuntimeError("Hermes Agent failed to create a git worktree")
    return info


def create_worktree_for_workspace(workspace: str | Path) -> dict:
    repo_root = find_git_repo_root(workspace)
    info = _setup_agent_worktree(str(repo_root))
    path = info.get("path")
    branch = info.get("branch")
    if not path or not branch:
        raise RuntimeError("Hermes Agent returned incomplete worktree metadata")
    return {
        "path": str(Path(path).expanduser().resolve()),
        "branch": str(branch),
        "repo_root": str(Path(info.get("repo_root") or repo_root).expanduser().resolve()),
        "created_at": time.time(),
    }