from sqlalchemy.orm import Session

from model.wl_emp_model import Emp
from model.wl_student_model import Student
from scheme.wl_emp_scheme import EmpCreate, EmpUpdate


class EmpDAO:

    @staticmethod
    def get_student(db: Session, stu_no: str):
        """按学号查未删除的学生"""
        return db.query(Student).filter(
            Student.stu_no == stu_no,
            Student.is_deleted == 0,
        ).first()

    @staticmethod
    def list_emps(db: Session, skip: int = 0, limit: int = 100, company_name: str = None):
        """查询就业列表"""
        q = db.query(Emp).filter(Emp.is_deleted == 0)
        if company_name:
            q = q.filter(Emp.company_name.like(f"%{company_name}%"))

        emp_list = q.offset(skip).limit(limit).all()
        for e in emp_list:
            e.stu_name = e.student.stu_name
        return emp_list

    @staticmethod
    def get_emp(db: Session, stu_no: str):
        """按学号查就业信息"""
        emp = db.query(Emp).filter(
            Emp.stu_no == stu_no,
            Emp.is_deleted == 0,
        ).first()
        emp.stu_name =emp.student.stu_name
        return emp

    @staticmethod
    def create_emp(db: Session, emp_data: EmpCreate):
        """新增就业信息；如果这个学生之前被删过，就把那条记录复活"""
        # stu_no 是主键，已删除的记录也占着这个主键，所以查的时候要连已删除的一起查
        exist = db.query(Emp).filter(Emp.stu_no == emp_data.stu_no).first()
        if exist and exist.is_deleted == 0:
            raise ValueError("该学生的就业信息已存在")

        # exclude_none：没传的字段不写进去，交给数据库默认值
        data = emp_data.model_dump(exclude_none=True)
        stu = EmpDAO.get_student(db, emp_data.stu_no)

        if exist:
            # 复活旧记录
            for k, v in data.items():
                setattr(exist, k, v)
            exist.is_deleted = 0
            db.commit()
            db.refresh(exist)
            exist.stu_name = stu.stu_name if stu else None
            return exist

        db_emp = Emp(**data)
        db.add(db_emp)
        db.commit()
        db.refresh(db_emp)
        db_emp.stu_name = stu.stu_name if stu else None
        return db_emp

    @staticmethod
    def update_emp(db: Session, stu_no: str, emp_data: EmpUpdate):
        """修改就业信息"""
        db_emp = EmpDAO.get_emp(db, stu_no)
        if not db_emp:
            return None

        update_dict = emp_data.model_dump(exclude_unset=True)
        for k, v in update_dict.items():
            setattr(db_emp, k, v)

        db.commit()
        db.refresh(db_emp)
        return db_emp

    @staticmethod
    def delete_emp(db: Session, stu_no: str):
        """逻辑删除，修改 is_deleted=1"""
        db_emp = EmpDAO.get_emp(db, stu_no)
        if not db_emp:
            return None

        db_emp.is_deleted = 1
        db.commit()
        return db_emp