"""Log tail tool for reading log files."""

import subprocess
from langchain_core.tools import BaseTool


class LogTailTool(BaseTool):
    """Tail the last N lines from a log file."""

    name: str = "tail_log"
    description: str = "Tail the last N lines of a log file given its path and optional number of lines."

    def _run(self, path: str, lines: int = 500):  # type: ignore[override]
        """Run the tool to tail log files."""
        try:
            return subprocess.check_output(["tail", "-n", str(lines), path], text=True)
        except subprocess.CalledProcessError as e:
            return f"Error reading log file {path}: {e}"
        except FileNotFoundError:
            return f"Log file not found: {path}"

    async def _arun(self, *args, **kwargs):  # noqa: D401
        """Async version not implemented."""
        raise NotImplementedError("Use the synchronous version of this tool.")