"""Custom exceptions for Unraid MCP Server.

This module defines custom exception classes for consistent error handling
throughout the application, with proper integration to FastMCP's error system.
"""

import contextlib
import logging
from collections.abc import Generator

from fastmcp.exceptions import ToolError as FastMCPToolError


class ToolError(FastMCPToolError):
    """User-facing error that MCP clients can handle.

    This is the main exception type used throughout the application for
    errors that should be presented to the user/LLM in a friendly way.

    Inherits from FastMCP's ToolError to ensure proper MCP protocol handling.
    """

    pass


@contextlib.contextmanager
def tool_error_handler(
    tool_name: str,
    action: str,
    logger: logging.Logger,
) -> Generator[None]:
    """Context manager that standardizes tool error handling.

    Re-raises ToolError as-is. Catches all other exceptions, logs them
    with full traceback, and wraps them in ToolError with a descriptive message.

    Args:
        tool_name: The tool name for error messages (e.g., "docker", "vm").
        action: The current action being executed.
        logger: The logger instance to use for error logging.
    """
    try:
        yield
    except ToolError:
        raise
    except Exception as e:
        logger.error(f"Error in unraid_{tool_name} action={action}: {e}", exc_info=True)
        raise ToolError(f"Failed to execute {tool_name}/{action}: {e!s}") from e