# dao/teachers_dao.py
# 本文件封装对 Teacher 表的所有数据库操作（增、删、改、查）
from sqlalchemy.orm import Session
from sqlalchemy_fastapi_demo_1.scheme.teachers import TeacherAdd, TeacherUpdate
from sqlalchemy_fastapi_demo_1.model.teachers import Teacher
from sqlalchemy_fastapi_demo_1.model.c_lass import Classinfo

class TeacherDAO:
    @staticmethod
    def add_teacher(db:Session,teacher_data:TeacherAdd): # 前端返回的teacher_data是1个Pydantic对象
        db_teacher=Teacher(**(teacher_data.model_dump()))
        db.add(db_teacher)
        db.commit()
        db.refresh(db_teacher)
        return db_teacher
    @staticmethod
    def inspect_teacher_id_unq(db: Session, teacher_id: int):
        """
        根据教师ID获取教师对象（用于主键唯一性检查，查询结果包含被软删除的对象）
        """
        return db.query(Teacher).filter(Teacher.teacher_id == teacher_id).first()
    @staticmethod
    def inspect_class_id_unq(db: Session, class_id: int):
        """
        根据班级ID获取班级对象（用于外键检查，查询结果排除被软删除对象，即不包括is_deleted=1的对象）
        """
        return db.query(Classinfo).filter(Classinfo.class_id == class_id,Classinfo.is_deleted==0).first()
    @staticmethod
    def delete_light(db: Session, teacher_id: int):
        """
        删除教师
        :return: True 表示删除成功，False 表示教师ID不存在，已被软删除或硬删除
        """
        db_teacher = TeacherDAO.inspect_teacher_id_unq(db, teacher_id)
        if (not db_teacher) or db_teacher.is_deleted==1:
            return False
        db_teacher.is_deleted=1  # 标记为1逻辑删除
        db.commit()  # 提交事务
        return True

    @staticmethod
    def update(db: Session,teacher_id:int,teacher_data: TeacherUpdate):
        """
        更新用户信息（只更新传入的非空字段）
        :param db: 数据库会话
        :param teacher_data: 包含要更新字段的 Pydantic 模型
        :return: 更新后的 User 对象，如果用户不存在则返回 None
        """
        # 只更新客户端显式传入的字段（exclude_unset=True 排除未设置的字段,不排除设置了None的字段）
        update_data = teacher_data.model_dump(exclude_unset=True) # 返回要更新字段的字典
        db_teacher=TeacherDAO.inspect_teacher_id_unq(db, teacher_id)
        for key, value in update_data.items():
            setattr(db_teacher, key, value)  # 动态设置属性
        db.commit()  # 提交事务
        db.refresh(db_teacher)  # 刷新对象，获取 onupdate 时间等
        return db_teacher
    @staticmethod
    def get_all(db: Session, skip: int = 0, limit: int = 100):
        """
        获取所有用户（支持分页，不显示软删除）
        :param db: 数据库会话
        :param skip: 偏移量（跳过前 skip 条，从skip+1条开始返回）
        :param limit: 最大返回条数
        :return: 用老师对象列表
        """
        return db.query(Teacher).filter(Teacher.is_deleted==0).offset(skip).limit(limit).all()