from app.services.ai.base import AIProvider


def get_provider(ai_config: dict) -> AIProvider:
    """
    Factory: return an AIProvider instance based on the 'provider' key in the AI config section.
    ai_config is the 'ai' section of doc_service_config.json, loaded fresh per processing job.
    """
    provider_name = ai_config.get("provider", "anthropic")
    provider_cfg = ai_config.get(provider_name, {})

    match provider_name:
        case "anthropic":
            from app.services.ai.anthropic_provider import AnthropicProvider
            return AnthropicProvider(provider_cfg)
        case "ollama" | "lmstudio":
            from app.services.ai.openai_compat import OpenAICompatProvider
            return OpenAICompatProvider(provider_cfg)
        case _:
            raise ValueError(f"Unknown AI provider: {provider_name!r}")


__all__ = ["AIProvider", "get_provider"]