fix: F12 P2 follow-up — batch imports set departmentId, optimize getDescendantIds, enforce campus root invariant

apps/server/src/departments/departments.service.ts

@@ -2,6 +2,7 @@ import { Injectable, NotFoundException, ConflictException } from '@nestjs/common
 import { InjectRepository } from '@nestjs/typeorm';
 import { Repository } from 'typeorm';
 import { Department } from '../entities/department.entity';
+import { DepartmentType } from '../entities/department.entity';
 import { UserDepartment } from '../entities/user-department.entity';
 import { CreateDepartmentDto, UpdateDepartmentDto, AssignUserDto } from './dto/department.dto';
 
@@ -58,6 +59,9 @@ export class DepartmentsService {
   }
 
   async create(dto: CreateDepartmentDto): Promise<Department> {
+    if (dto.type === DepartmentType.CAMPUS && dto.parentId) {
+      throw new ConflictException('校区类型的部门必须是根部门，不能设置上级');
+    }
     const dept = this.deptRepo.create(dto);
     return this.deptRepo.save(dept);
   }
@@ -65,6 +69,12 @@ export class DepartmentsService {
   async update(id: number, dto: UpdateDepartmentDto): Promise<Department> {
     const dept = await this.findOne(id);
 
+    const effectiveType = dto.type ?? dept.type;
+    const effectiveParentId = dto.parentId !== undefined ? dto.parentId : dept.parentId;
+    if (effectiveType === DepartmentType.CAMPUS && effectiveParentId) {
+      throw new ConflictException('校区类型的部门必须是根部门，不能设置上级');
+    }
+
     // Prevent parent cycles: parentId must not be the dept itself or one of its descendants
     if (dto.parentId !== undefined && dto.parentId !== null) {
       const newParentId = dto.parentId;
@@ -93,14 +103,21 @@ export class DepartmentsService {
 
   /** 获取部门的所有子部门 ID（递归，含自身） */
   async getDescendantIds(departmentId: number): Promise<number[]> {
-    const ids = [departmentId];
-    const children = await this.deptRepo.find({
-      where: { parentId: departmentId, status: 'active' },
-    });
-    for (const child of children) {
-      const childIds = await this.getDescendantIds(child.id);
-      ids.push(...childIds);
+    const all = await this.deptRepo.find({ where: { status: 'active' }, select: ['id', 'parentId'] });
+    const byParent = new Map<number | null, number[]>();
+    for (const d of all) {
+      const key = d.parentId ?? null;
+      byParent.set(key, [...(byParent.get(key) ?? []), d.id]);
     }
+    const ids: number[] = [departmentId];
+    const collect = (parentId: number) => {
+      const children = byParent.get(parentId) ?? [];
+      for (const childId of children) {
+        ids.push(childId);
+        collect(childId);
+      }
+    };
+    collect(departmentId);
     return ids;
   }