import os
from fastapi import FastAPI, File, UploadFile
from langchain_community.document_loaders import PyMuPDFLoader
from langchain.text_splitter import RecursiveCharacterTextSplitter
from langchain_community.embeddings import HuggingFaceEmbeddings
from langchain_community.vectorstores import Chroma

app = FastAPI()

@app.post("/upload")
async def upload_pdf(file: UploadFile = File(...)):
    file_location = f"uploads/{file.filename}"
    with open(file_location, "wb") as f:
        f.write(await file.read())

    loader = PyMuPDFLoader(file_location)
    docs = loader.load()

    splitter = RecursiveCharacterTextSplitter(chunk_size=1000, chunk_overlap=200)
    chunks = splitter.split_documents(docs)

    embedding = HuggingFaceEmbeddings(model_name="all-MiniLM-L6-v2")
    vectordb = Chroma.from_documents(chunks, embedding, persist_directory="chroma_db")
    vectordb.persist()

    return {"message": f"✅ {file.filename} uploaded and processed into vector DB."}