"""
LLM provider interface.

The rest of the application (router, chat endpoints, evaluation) must
NEVER call a specific model directly. Everything goes through
generate(prompt) on whatever provider is configured via
config.LLM_PROVIDER. Switching from local Mistral to Groq or OpenAI later
should require changing config only — no changes to callers.
"""

from abc import ABC, abstractmethod


class LLMProvider(ABC):
    """Base interface every provider (local, groq, openai, ...) must implement."""

    @abstractmethod
    def generate(self, prompt: str, stream: bool = False):
        """
        Args:
            prompt: the fully-constructed prompt string (see llm/prompts.py).
            stream: if True, returns a generator yielding text chunks as
                    they're produced, instead of a single string. Providers
                    that can't stream should fall back to yielding the full
                    response once.

        Returns:
            str if stream=False, otherwise a generator[str].
        """
        raise NotImplementedError

    def name(self) -> str:
        return self.__class__.__name__