from model.all_model import ClassManagement
from fastapi import HTTPException
from schema.cla_schema import claRequest
from datetime import datetime
from sqlalchemy.exc import SQLAlchemyError
import logging

logger = logging.getLogger(__name__)


def add_class_dao(c: claRequest, session):
    try:
        # ---------- 校验：班级名称不能重复 ----------
        # 只查未删除的记录，含义是：已逻辑删除的班级允许重建同名
        exists = (
            session.query(ClassManagement)
            .filter(ClassManagement.class_name == c.class_name)
            .filter(ClassManagement.delete_status == 0)
            .first()
        )
        if exists:
            raise HTTPException(400, f"班级 '{c.class_name}' 已存在，不能重复添加")

        # 班主任和授课教师可以是同一个人，无需校验

        data = c.model_dump()
        d = ClassManagement(**data)
        session.add(d)
        session.commit()
        session.refresh(d)
        return d

    except HTTPException:
        raise
    except SQLAlchemyError as e:
        session.rollback()
        logger.error(f"新增班级失败: {e}")
        raise HTTPException(400, "输入有误，请重新添加班级！")


def get_class_dao(n: int, m: int, session):
    try:
        if n < 1 or m < 1:
            return []
        class_list = (
            session.query(ClassManagement)
            .filter(ClassManagement.delete_status == 0)
            .offset((n - 1) * m)
            .limit(m)
            .all()
        )
        return class_list
    except SQLAlchemyError as e:
        logger.error(f"查询班级列表失败: {e}")
        raise HTTPException(status_code=400, detail="查询失败，请稍后重试！")


def update_class_dao(class_id: int, req: claRequest, session):
    try:
        rows = (
            session.query(ClassManagement)
            .filter(ClassManagement.class_id == class_id)
            .filter(ClassManagement.delete_status == 0)
            .update(req.model_dump(exclude_unset=True), synchronize_session=False)
        )
        session.commit()
        if rows == 0:
            raise HTTPException(status_code=404, detail="该班级不存在或已被删除")
    except HTTPException:
        session.rollback()
        raise
    except SQLAlchemyError as e:
        session.rollback()
        logger.error(f"更新班级失败: {e}")
        raise HTTPException(status_code=400, detail="更新失败，请检查参数")
    return {"code": 200, "msg": "更新成功"}


def delete_class_dao(class_id: int, session):
    try:
        # 先按 class_id 查记录，再判断状态，从而区分"不存在"和"已删除"
        obj = (
            session.query(ClassManagement)
            .filter(ClassManagement.class_id == class_id)
            .first()
        )

        # 情况 1：记录不存在
        if obj is None:
            raise HTTPException(status_code=404, detail="该班级不存在")

        # 情况 2：记录存在但已删除 → 提示"已删除"
        if obj.delete_status == 1:
            raise HTTPException(status_code=400, detail="该班级已被删除，请勿重复操作")

        # 情况 3：执行逻辑删除
        obj.delete_status = 1
        obj.delete_time = datetime.now()
        session.commit()

    except HTTPException:
        session.rollback()
        raise
    except SQLAlchemyError as e:
        session.rollback()
        logger.error(f"删除班级失败: {e}")
        raise HTTPException(status_code=400, detail="删除异常，请核对后重试！")

    return {"code": 200, "msg": "删除成功"}