import os
from pathlib import Path

from fastapi import FastAPI, File, HTTPException, UploadFile
from pydantic import BaseModel

from rag import answer_question, index_pdf


BASE_DIR = Path(__file__).resolve().parent.parent
DATA_DIR = Path(os.getenv("DATA_DIR", BASE_DIR / "data"))
UPLOAD_DIR = DATA_DIR / "uploads"
UPLOAD_DIR.mkdir(parents=True, exist_ok=True)

app = FastAPI(title="PDF RAG Chatbot")


class AskRequest(BaseModel):
    question: str


@app.get("/health")
def health():
    return {"status": "ok"}


@app.post("/upload")
async def upload_pdf(file: UploadFile = File(...)):
    if not file.filename.lower().endswith(".pdf"):
        raise HTTPException(status_code=400, detail="PDF 파일만 업로드할 수 있습니다.")

    save_path = UPLOAD_DIR / file.filename
    content = await file.read()
    save_path.write_bytes(content)

    try:
        result = index_pdf(save_path)
    except RuntimeError as error:
        raise HTTPException(status_code=500, detail=str(error)) from error

    return {
        "filename": file.filename,
        "chunks": result["chunks"],
        "message": "PDF 업로드 및 인덱싱이 완료되었습니다.",
    }


@app.post("/ask")
def ask(request: AskRequest):
    if not request.question.strip():
        raise HTTPException(status_code=400, detail="질문을 입력해 주세요.")

    try:
        return answer_question(request.question)
    except RuntimeError as error:
        raise HTTPException(status_code=500, detail=str(error)) from error