"""_utils.py – shared helpers for file-ops tools."""

from __future__ import annotations

import posixpath

_MAX_OUTPUT_LINES = 200
_MAX_OUTPUT_CHARS = 20_000
_TRUNCATION_NOTICE = "\n... [output truncated] ..."


def truncate_output(output: str) -> str:
    """Truncate *output* to avoid hitting token limits."""
    lines = output.splitlines(keepends=True)
    if len(lines) > _MAX_OUTPUT_LINES:
        output = "".join(lines[:_MAX_OUTPUT_LINES]) + _TRUNCATION_NOTICE
    if len(output) > _MAX_OUTPUT_CHARS:
        output = output[:_MAX_OUTPUT_CHARS] + _TRUNCATION_NOTICE
    return output


def _parent(path: str) -> str:
    """Return the parent directory of *path* (best-effort, no I/O)."""
    parent = posixpath.dirname(path.rstrip("/"))
    return parent or "."