from typing import Optional
from fastapi import APIRouter, Depends, HTTPException, Query
from sqlalchemy.orm import Session
from database import get_db
from models.essay import EssayGrade
from models.user import User
from schemas.essay import EssayGradeCreate, EssayGradeOut
from services.auth import get_current_user
from services.ai_service import AIService
from services.credits import spend_credits

router = APIRouter(prefix="/api/essay-grades", tags=["作文批改"])
ai_service = AIService()


@router.post("/", response_model=EssayGradeOut, status_code=201)
async def create_essay_grade(
    data: EssayGradeCreate,
    current_user: User = Depends(get_current_user),
    db: Session = Depends(get_db),
):
    """Submit an essay for AI grading; the result is persisted automatically."""
    account = spend_credits(db, current_user, "essay_grade", f"作文批改：{data.title[:40]}")
    db.commit()

    result = await ai_service.grade_essay(
        essay_text=data.essay_text, grade_level=data.grade_level,
        essay_type=data.essay_type, total_score=data.total_score,
    )

    item = EssayGrade(
        user_id=current_user.id,
        title=data.title,
        essay_text=data.essay_text,
        grade_level=data.grade_level,
        essay_type=data.essay_type,
        total_score=data.total_score,
        result=result,
    )
    db.add(item)
    db.commit()
    db.refresh(item)
    return item


@router.get("/", response_model=list[EssayGradeOut])
def list_essay_grades(
    keyword: Optional[str] = None,
    skip: int = Query(0, ge=0),
    limit: int = Query(20, ge=1, le=100),
    current_user: User = Depends(get_current_user),
    db: Session = Depends(get_db),
):
    query = db.query(EssayGrade).filter(EssayGrade.user_id == current_user.id)
    if keyword:
        query = query.filter(EssayGrade.title.contains(keyword))
    return query.order_by(EssayGrade.updated_at.desc()).offset(skip).limit(limit).all()


@router.get("/{grade_id}", response_model=EssayGradeOut)
def get_essay_grade(
    grade_id: int,
    current_user: User = Depends(get_current_user),
    db: Session = Depends(get_db),
):
    item = db.query(EssayGrade).filter(EssayGrade.id == grade_id, EssayGrade.user_id == current_user.id).first()
    if not item:
        raise HTTPException(status_code=404, detail="批改记录不存在")
    return item


@router.delete("/{grade_id}", status_code=204)
def delete_essay_grade(
    grade_id: int,
    current_user: User = Depends(get_current_user),
    db: Session = Depends(get_db),
):
    item = db.query(EssayGrade).filter(EssayGrade.id == grade_id, EssayGrade.user_id == current_user.id).first()
    if not item:
        raise HTTPException(status_code=404, detail="批改记录不存在")
    db.delete(item)
    db.commit()
    return None