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

# 坚决把下面这三行开头的 sqlalchemy_fastapi_demo. 全删掉！
from scheme.teachers import TeacherAdd, TeacherResponse, TeacherUpdate
from database import get_db
from dao.teachers_dao import TeacherDAO
router=APIRouter()
# ---------- 创建新教师 ----------
@router.post("/teacher/add",response_model=TeacherResponse)
async def add_teacher(teacher:TeacherAdd,db:Session=Depends(get_db)):
    existing_foreign_key=TeacherDAO.inspect_class_id_unq(db,teacher.class_id)
    if existing_foreign_key:# 外键校验
        existing_teacher_id=TeacherDAO.inspect_teacher_id_unq(db,teacher.teacher_id)
        if existing_teacher_id:# 主键校验
            raise HTTPException(status_code=409, detail="主键教师ID已被占用，包括软删除") # 资源冲突
        return TeacherDAO.add_teacher(db,teacher)
    else:
        raise HTTPException(status_code=404, detail="班级ID不存在，数据库无数据，或已被软删除") # 关联资源不存在
# ---------- 软删除教师 ----------
@router.delete("/teacher/delete", status_code=204)
async def light_delete_teacher(teacher_id:int=Query(...,ge=1,description='输入想要删除的教师ID'),
                         db:Session=Depends(get_db)):
    """
    删除用户，成功返回 204 No Content
    """
    success = TeacherDAO.delete_light(db, teacher_id)
    if not success: # 目标删除教师ID不存在（被硬删除或软删除）
        raise HTTPException(status_code=404, detail="教师ID不存在") # 关联资源不存在
    # 返回 None 表示目标教师ID已删除
    return None
# ---------- 更新教师信息 ----------
@router.put("/teacher/update",response_model=TeacherResponse)
async def update_teacher(
    teacher_data: TeacherUpdate,
    teacher_id:int=Query(...,ge=1,description='输入教师想要更新的教师ID'),
    db: Session = Depends(get_db)
):
    """
    更新用户信息（只更新传入的字段,也就是非None）
    """
    # 检查教师ID是否存在
    existing_teacher_id = TeacherDAO.inspect_teacher_id_unq(db,teacher_id)
    if (not existing_teacher_id) or (existing_teacher_id.is_deleted==1):
        raise HTTPException(status_code=404, detail="教师ID不存在，已被硬删除或软删除") # 关联资源不存在
    # 更新班级ID
    if teacher_data.class_id is not None:
        # 校验外键，校验班级ID是否在Class表存在
        existing_foreign_key=TeacherDAO.inspect_class_id_unq(db,teacher_data.class_id)
        if not existing_foreign_key:
            raise HTTPException(status_code=404, detail="班级ID不存在，已被硬删除或软删除")  # 关联资源不存在
        updated = TeacherDAO.update(db, teacher_id, teacher_data)
        return updated
    updated = TeacherDAO.update(db, teacher_id, teacher_data)
    return updated
# ---------- 查询所有教师（分页） ----------
@router.get("/teacher/total_query",response_model=List[TeacherResponse])
async def get_teachers(
    skip: int = Query(0, ge=0, description="跳过的记录数"),
    limit: int = Query(100, ge=1, le=200, description="返回的最大记录数"),
    db: Session = Depends(get_db)   # 依赖注入获得数据库会话
):
    """
    获取用户列表，支持分页，从skip+1条开始返回
    """
    users = TeacherDAO.get_all(db, skip=skip, limit=limit)
    return users   # FastAPI 自动根据 response_model 转换为 JSON
# ---------- 根据 ID 查询单个教师 ----------
@router.get("/teacher/single_query", response_model=TeacherResponse)
async def get_teacher(
    teacher_id: int,
    db: Session = Depends(get_db)
):
    """
    根据用户 ID 获取详细信息，不显示软删除
    """
    teacher = TeacherDAO.inspect_teacher_id_unq(db, teacher_id)
    if (not teacher) or teacher.is_deleted==1:
        raise HTTPException(status_code=404, detail="教师ID不存在") # 关联资源不存在
    return teacher