# retrievers.py
import pickle
from langchain.vectorstores import FAISS
from langchain.retrievers import EnsembleRetriever
from kiwipiepy import Kiwi
from config import FAISS_DB_INDEX, BM25_INDEX


def load_retrievers(embeddings):
    faiss_db = FAISS.load_local(
        FAISS_DB_INDEX, embeddings, allow_dangerous_deserialization=True
    )
    faiss_retriever = faiss_db.as_retriever(search_type="mmr", search_kwargs={"k": 10})

    with open(BM25_INDEX, "rb") as f:
        bm25_retriever = pickle.load(f)

    return EnsembleRetriever(
        retrievers=[bm25_retriever, faiss_retriever],
        weights=[0.7, 0.3],
        search_type="mmr",
    )