import random

from fastapi import APIRouter, Depends
from sqlalchemy.orm import Session

from backend.auth import get_current_user
from backend.database import get_db
from backend.models import Question
from backend.schemas import PracticeCheckRequest, PracticeStartRequest

router = APIRouter(dependencies=[Depends(get_current_user)])


@router.post("/start")
def start_practice(payload: PracticeStartRequest, db: Session = Depends(get_db)) -> dict:
    query = db.query(Question)
    if payload.chapter:
        query = query.filter(Question.chapter == payload.chapter)
    if payload.secondary_knowledge:
        query = query.filter(Question.secondary_knowledge == payload.secondary_knowledge)
    if payload.question_type:
        query = query.filter(Question.question_type == payload.question_type)
    if payload.difficulty:
        query = query.filter(Question.difficulty == payload.difficulty)
    items = query.all()
    if payload.random_mode:
        random.shuffle(items)
    items = items[: payload.limit]
    return {
        "total": len(items),
        "items": [
            {
                "id": i.id,
                "stem": i.stem,
                "option_a": i.option_a,
                "option_b": i.option_b,
                "option_c": i.option_c,
                "option_d": i.option_d,
                "question_type": i.question_type,
            }
            for i in items
        ],
    }


@router.post("/check")
def check_answer(payload: PracticeCheckRequest, db: Session = Depends(get_db)) -> dict:
    item = db.get(Question, payload.question_id)
    if not item:
        return {"correct": False, "message": "题目不存在"}
    user_answer = payload.user_answer.strip().upper()
    right_answer = item.answer.strip().upper()
    return {
        "correct": user_answer == right_answer,
        "right_answer": right_answer,
        "explanation": item.explanation,
    }