from langchain_core.embeddings import Embeddings
from langchain_ollama import OllamaEmbeddings
from langchain_openai import OpenAIEmbeddings
from pydantic import SecretStr

from api.config import get_settings
from rag.hf_hub_inference import HubInferenceEmbeddings


def create_embedding_function() -> Embeddings:
    settings = get_settings()
    provider = settings.llm_provider.lower()

    if provider == "openai":
        if not settings.openai_api_key:
            raise ValueError("OPENAI_API_KEY is required when LLM_PROVIDER=openai")
        return OpenAIEmbeddings(
            model=settings.openai_embedding_model,
            api_key=SecretStr(settings.openai_api_key),
        )
    if provider == "huggingface":
        if not settings.huggingface_api_key:
            raise ValueError(
                "A Hugging Face token is required when LLM_PROVIDER=huggingface "
                "(set HUGGINGFACE_API_KEY or HF_TOKEN / HUGGING_FACE_HUB_TOKEN on Spaces)."
            )
        return HubInferenceEmbeddings(
            model=settings.huggingface_embedding_model,
            api_token=settings.huggingface_api_key,
        )
    if provider == "ollama":
        return OllamaEmbeddings(
            model=settings.ollama_embedding_model,
            base_url=settings.ollama_base_url,
        )
    raise ValueError(f"Unsupported LLM_PROVIDER: {settings.llm_provider}")