from fastapi import APIRouter, Depends, HTTPException
from sqlalchemy.orm import Session
from typing import List, Optional

from database import get_db
from models import Class, Teacher
from schemas import ClassCreate, ClassUpdate, ClassBase

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


@router.get("/", response_model=List[ClassBase])
def list_classes(db: Session = Depends(get_db), skip: int = 0, limit: int = 100):
    classes = db.query(Class).filter(Class.is_deleted == False).offset(skip).limit(limit).all()
    return classes


@router.get("/{class_id}", response_model=ClassBase)
def get_class(class_id: int, db: Session = Depends(get_db)):
    cls = db.query(Class).filter(Class.id == class_id, Class.is_deleted == False).first()
    if not cls:
        raise HTTPException(status_code=404, detail="班级不存在")
    return cls


@router.post("/", response_model=ClassBase)
def create_class(data: ClassCreate, db: Session = Depends(get_db)):
    existing = db.query(Class).filter(Class.num == data.num, Class.is_deleted == False).first()
    if existing:
        raise HTTPException(status_code=400, detail="班级编号已存在")

    # Validate foreign keys exist
    if data.head_teacher_id:
        if not db.query(Teacher).filter(Teacher.id == data.head_teacher_id, Teacher.is_deleted == False).first():
            raise HTTPException(status_code=400, detail="班主任教师不存在")
    if data.coach_teacher_id:
        if not db.query(Teacher).filter(Teacher.id == data.coach_teacher_id, Teacher.is_deleted == False).first():
            raise HTTPException(status_code=400, detail="授课老师不存在")
    if data.tutor_teacher_id:
        if not db.query(Teacher).filter(Teacher.id == data.tutor_teacher_id, Teacher.is_deleted == False).first():
            raise HTTPException(status_code=400, detail="助教老师不存在")

    cls = Class(**data.model_dump())
    db.add(cls)
    db.commit()
    db.refresh(cls)
    return cls


@router.put("/{class_id}", response_model=ClassBase)
def update_class(class_id: int, data: ClassUpdate, db: Session = Depends(get_db)):
    cls = db.query(Class).filter(Class.id == class_id, Class.is_deleted == False).first()
    if not cls:
        raise HTTPException(status_code=404, detail="班级不存在")

    if data.head_teacher_id is not None:
        if not db.query(Teacher).filter(Teacher.id == data.head_teacher_id, Teacher.is_deleted == False).first():
            raise HTTPException(status_code=400, detail="班主任教师不存在")
    if data.coach_teacher_id is not None:
        if not db.query(Teacher).filter(Teacher.id == data.coach_teacher_id, Teacher.is_deleted == False).first():
            raise HTTPException(status_code=400, detail="授课老师不存在")
    if data.tutor_teacher_id is not None:
        if not db.query(Teacher).filter(Teacher.id == data.tutor_teacher_id, Teacher.is_deleted == False).first():
            raise HTTPException(status_code=400, detail="助教老师不存在")

    for key, value in data.model_dump(exclude_unset=True).items():
        setattr(cls, key, value)
    db.commit()
    db.refresh(cls)
    return cls


@router.delete("/{class_id}")
def delete_class(class_id: int, db: Session = Depends(get_db)):
    cls = db.query(Class).filter(Class.id == class_id, Class.is_deleted == False).first()
    if not cls:
        raise HTTPException(status_code=404, detail="班级不存在")
    cls.is_deleted = True
    db.commit()
    return {"message": "删除成功"}