"""Provider resolution: Settings -> LLMClient."""

from tutor.config import Settings
from tutor.services.llm.base import LLMClient
from tutor.services.llm.fake import FakeLLMClient
from tutor.services.llm.openai_compat import OpenAICompatClient

GEMINI_OPENAI_BASE_URL = "https://generativelanguage.googleapis.com/v1beta/openai/"

_PRESET_BASE_URLS: dict[str, str | None] = {
    "gemini": GEMINI_OPENAI_BASE_URL,
    "mistral": "https://api.mistral.ai/v1",
    "ollama": "http://localhost:11434/v1",  # premium mode: reached over Tailscale in M5
    "openai": None,  # SDK default
}


def create_llm_client(settings: Settings) -> LLMClient:
    if settings.llm_provider == "fake":
        return FakeLLMClient()

    api_key = settings.llm_api_key.get_secret_value() if settings.llm_api_key else None
    if settings.llm_provider == "ollama":
        api_key = api_key or "ollama"  # local servers accept any non-empty key
    if not api_key:
        msg = f"LLM_API_KEY is required for provider '{settings.llm_provider}'"
        raise ValueError(msg)

    return OpenAICompatClient(
        model=settings.llm_model,
        api_key=api_key,
        base_url=settings.llm_base_url or _PRESET_BASE_URLS[settings.llm_provider],
        timeout_s=settings.llm_timeout_s,
    )