# dao/teacher_dao.py
# 教师信息数据访问层

from typing import List, Optional, Tuple

from sqlalchemy.orm import Session

from dao.exceptions import ConflictError, NotFoundError
from dao.pagination import paginate
from model.teacher_model import Teacher


def assert_teacher_alive(db: Session, tea_id: str, detail: Optional[str] = None) -> Teacher:
    """
    确认教师存在且未删除，否则抛 NotFoundError。
    供班级模块复用作外键校验。
    """
    teacher = db.query(Teacher).filter(Teacher.id == tea_id, Teacher.is_deleted == 0).first()
    if not teacher:
        raise NotFoundError(detail or f"教师 {tea_id} 不存在")
    return teacher


def list_teachers(
    db: Session,
    page: int,
    size: int,
    name: Optional[str] = None,
    type: Optional[str] = None,
) -> Tuple[int, List[Teacher]]:
    """分页查询教师，支持按姓名模糊、按职位过滤。"""
    query = db.query(Teacher).filter(Teacher.is_deleted == 0)
    if name:
        query = query.filter(Teacher.name.like(f"%{name}%"))
    if type:
        query = query.filter(Teacher.type == type)
    return paginate(query, page, size, order_by=Teacher.id)


def create_teacher(db: Session, data: dict) -> Teacher:
    """新增教师：校验编号与电话唯一。"""
    # 编号是主键，已软删除的记录同样占用该编号，所以这里不加 is_deleted 过滤
    if db.query(Teacher).filter(Teacher.id == data["id"]).first():
        raise ConflictError("教师编号已存在")

    if db.query(Teacher).filter(Teacher.phone == data["phone"], Teacher.is_deleted == 0).first():
        raise ConflictError("电话已被使用")

    teacher = Teacher(**data)
    db.add(teacher)
    db.commit()
    db.refresh(teacher)
    return teacher


def update_teacher(db: Session, tea_id: str, data: dict) -> Teacher:
    """更新教师：若改电话需重新校验唯一。"""
    teacher = assert_teacher_alive(db, tea_id, "教师不存在或已删除")

    new_phone = data.get("phone")
    if new_phone and new_phone != teacher.phone:
        if db.query(Teacher).filter(Teacher.phone == new_phone, Teacher.is_deleted == 0).first():
            raise ConflictError("电话已被使用")

    for field, value in data.items():
        setattr(teacher, field, value)

    db.commit()
    db.refresh(teacher)
    return teacher


def soft_delete_teacher(db: Session, tea_id: str) -> None:
    """软删除教师：仅置 is_deleted 标记，数据保留。"""
    teacher = assert_teacher_alive(db, tea_id, "教师不存在或已删除")
    teacher.is_deleted = 1
    db.commit()