"""Abstract base class for LLM backends."""

from abc import ABC, abstractmethod
from typing import Optional


class LLMBackend(ABC):
    """Abstract base class for LLM backends."""

    @abstractmethod
    def generate(self, prompt: str) -> str:
        """Generate a response from the LLM.

        Args:
            prompt: The prompt to send to the LLM.

        Returns:
            The generated response text.
        """
        pass

    @abstractmethod
    def is_available(self) -> bool:
        """Check if the backend is available.

        Returns:
            True if the backend can be used.
        """
        pass

    @abstractmethod
    def get_model_name(self) -> str:
        """Get the name of the currently loaded model.

        Returns:
            Model name string.
        """
        pass

    @abstractmethod
    def set_model(self, model: str) -> None:
        """Set the model to use.

        Args:
            model: Name of the model to load.
        """
        pass

    @abstractmethod
    def close(self) -> None:
        """Clean up resources."""
        pass