from datetime import datetime, timezone

from fastapi import APIRouter, Depends, HTTPException, Query
from sqlmodel import Session, select, func

from ..database import get_session
from ..models import Novel
from ..schemas import NovelCreate, NovelUpdate, NovelRead, NovelList

router = APIRouter(prefix="/api/novels", tags=["novels"])


def _get_novel_or_404(novel_id: int, session: Session) -> Novel:
    novel = session.get(Novel, novel_id)
    if not novel:
        raise HTTPException(status_code=404, detail="小说不存在")
    return novel


@router.get("", response_model=NovelList)
def list_novels(
    skip: int = Query(0, ge=0),
    limit: int = Query(20, ge=1, le=100),
    session: Session = Depends(get_session),
):
    total = session.exec(select(func.count(Novel.id))).one()
    novels = session.exec(
        select(Novel).order_by(Novel.updated_at.desc()).offset(skip).limit(limit)
    ).all()
    items = [NovelRead.model_validate(n, from_attributes=True) for n in novels]
    return NovelList(items=items, total=total)


@router.post("", response_model=NovelRead, status_code=201)
def create_novel(data: NovelCreate, session: Session = Depends(get_session)):
    novel = Novel(**data.model_dump())
    session.add(novel)
    session.commit()
    session.refresh(novel)
    return novel


@router.get("/{novel_id}", response_model=NovelRead)
def get_novel(novel_id: int, session: Session = Depends(get_session)):
    return _get_novel_or_404(novel_id, session)


@router.patch("/{novel_id}", response_model=NovelRead)
def update_novel(
    novel_id: int, data: NovelUpdate, session: Session = Depends(get_session)
):
    novel = _get_novel_or_404(novel_id, session)
    update_data = data.model_dump(exclude_unset=True)
    for key, value in update_data.items():
        setattr(novel, key, value)
    novel.updated_at = datetime.now(timezone.utc)
    session.add(novel)
    session.commit()
    session.refresh(novel)
    return novel


@router.delete("/{novel_id}", status_code=204)
def delete_novel(novel_id: int, session: Session = Depends(get_session)):
    novel = _get_novel_or_404(novel_id, session)
    session.delete(novel)
    session.commit()