from sqlalchemy.orm import Session
from sqlalchemy import func
from model.wl_student_model import Student
from model.wl_class_model import Class_   # 你同学写的
from scheme.wl_student_scheme import StudentCreate, StudentUpdate


# ---- 学号生成 ----
def generate_stu_no(db: Session, class_id: int, seq: int = None) -> str:
    #没选班级和班级不存在给不同的提示，前端能直接展示给用户看
    if class_id is None:
        raise ValueError("请先选择班级")
    #非测试就解除下面5行测试，注释date_str = "20260912"
    cls = db.query(Class_).filter_by(class_id=class_id).first()
    if not cls or not cls.start_time:
        raise ValueError("班级不存在或未设置开班时间")
    date_str = cls.start_time.strftime("%Y%m%d")
    # 直接写死一个日期字符串用于测试
    # date_str = "20260912"

    if seq is None:
        count = db.query(func.count(Student.stu_id)) \
                  .filter(Student.class_id == class_id).scalar() or 0
        seq = count + 1
    return f"{date_str}{seq:03d}"


# ---- 增 ----
def create_student(db: Session, data: StudentCreate) -> Student:
    stu_no = generate_stu_no(db, data.class_id)
    stu = Student(stu_no=stu_no, **data.model_dump())
    db.add(stu)
    db.commit()
    db.refresh(stu)
    return stu


# ---- 查（多条件）----
def search_students(db: Session, stu_no=None, stu_name=None,
                    class_id=None, advisor_id=None, status=None):
    q = db.query(Student).filter(Student.is_deleted == 0)   # 若加了逻辑删除字段
    if stu_no:
        q = q.filter(Student.stu_no.like(f"%{stu_no}%"))
    if stu_name:
        q = q.filter(Student.stu_name.like(f"%{stu_name}%"))
    if class_id:
        q = q.filter(Student.class_id == class_id)
    if advisor_id:
        q = q.filter(Student.advisor_id == advisor_id)
    #学生model没有status，先注释
    # if status:
    #     q = q.filter(Student.status == status)
    return q.all()


def get_student_by_no(db: Session, stu_no: str) -> Student | None:
    return db.query(Student).filter(
        Student.stu_no == stu_no,
        Student.is_deleted == 0
    ).first()


# ---- 改 ----
def update_student(db: Session, stu_no: str, data: StudentUpdate) -> Student | None:
    stu = get_student_by_no(db, stu_no)
    if not stu:
        return None
    for k, v in data.model_dump(exclude_unset=True).items():
        setattr(stu, k, v)
    db.commit()
    db.refresh(stu)
    return stu


# ---- 逻辑删 ----
def delete_student(db: Session, stu_no: str) -> bool:
    stu = get_student_by_no(db, stu_no)
    if not stu:
        return False
    stu.is_deleted = 1
    db.commit()
    return True