from fastapi import APIRouter, HTTPException
from pydantic import BaseModel
from typing import List, Optional
import uuid

from bd import Settings
from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker

from bd.tables.poll import Poll
from bd.tables.question import Question
from bd.tables.response import Response, Answer

router = APIRouter(tags=["responses"], prefix="/polls")


class AnswerIn(BaseModel):
    question_id: str
    choice_id: Optional[str]
    text: Optional[str]


class ResponseIn(BaseModel):
    user_id: Optional[str]
    answers: List[AnswerIn]


def get_session():
    settings = Settings()
    engine = create_engine(settings.DATABASE_URL_syncpg, future=True)
    return sessionmaker(bind=engine, future=True)


@router.post("/{poll_id}/responses", status_code=201)
def submit_response(poll_id: str, payload: ResponseIn):
    Session = get_session()
    try:
        pid = uuid.UUID(poll_id)
    except Exception:
        raise HTTPException(status_code=400, detail="Invalid poll UUID")
    with Session() as session:
        poll = session.get(Poll, pid)
        if not poll:
            raise HTTPException(status_code=404, detail="Poll not found")
        resp = Response(poll_id=pid)
        if payload.user_id:
            try:
                resp.user_id = uuid.UUID(payload.user_id)
            except Exception:
                raise HTTPException(status_code=400, detail="Invalid user_id UUID")
        session.add(resp)
        # validate answers
        for a in payload.answers:
            try:
                qid = uuid.UUID(a.question_id)
            except Exception:
                raise HTTPException(status_code=400, detail="Invalid question_id UUID")
            question = session.get(Question, qid)
            if not question or question.poll_id != pid:
                raise HTTPException(status_code=400, detail="Question does not belong to poll")
            choice_uuid = None
            if a.choice_id:
                try:
                    choice_uuid = uuid.UUID(a.choice_id)
                except Exception:
                    raise HTTPException(status_code=400, detail="Invalid choice_id UUID")
            answer = Answer(response=resp, question_id=qid, choice_id=choice_uuid, text=a.text)
            session.add(answer)
        session.commit()
        session.refresh(resp)
        return {"id": str(resp.id)}


@router.get("/{poll_id}/responses")
def list_responses(poll_id: str):
    Session = get_session()
    try:
        pid = uuid.UUID(poll_id)
    except Exception:
        raise HTTPException(status_code=400, detail="Invalid poll UUID")
    with Session() as session:
        rows = session.query(Response).filter(Response.poll_id == pid).all()
        return [{"id": str(r.id), "user_id": str(r.user_id) if r.user_id else None, "submitted_at": r.submitted_at.isoformat()} for r in rows]


@router.get("/responses/{response_id}")
def get_response(response_id: str):
    Session = get_session()
    try:
        rid = uuid.UUID(response_id)
    except Exception:
        raise HTTPException(status_code=400, detail="Invalid UUID")
    with Session() as session:
        r = session.get(Response, rid)
        if not r:
            raise HTTPException(status_code=404, detail="Response not found")
        return {"id": str(r.id), "poll_id": str(r.poll_id), "user_id": str(r.user_id) if r.user_id else None, "submitted_at": r.submitted_at.isoformat(), "answers": [{"id": str(a.id), "question_id": str(a.question_id), "choice_id": str(a.choice_id) if a.choice_id else None, "text": a.text} for a in r.answers]}