feat: 班级小助手 阶段1-3（monorepo + 后端 REST/Socket.IO + Web 管理端）

packages/server/src/modules/courses/courses.service.ts

@@ -0,0 +1,53 @@
+import type { CourseDto } from '@classhelper/shared';
+import { assertClassWritable, classScopeWhere, resolveClassScope } from '../../lib/access.js';
+import { prisma } from '../../lib/db.js';
+import { ApiError } from '../../lib/http.js';
+import type { TokenPayload } from '../../lib/jwt.js';
+import { toCourseDto } from '../../lib/mappers.js';
+import type { CreateCourseInput, UpdateCourseInput } from './courses.schemas.js';
+
+const teacherSelect = { select: { id: true, name: true, username: true } } as const;
+
+export async function listCourses(user: TokenPayload, classId?: string): Promise<CourseDto[]> {
+  const scope = await resolveClassScope(user, classId);
+  const courses = await prisma.course.findMany({
+    where: classScopeWhere(scope),
+    include: { teacher: teacherSelect },
+    orderBy: [{ classId: 'asc' }, { name: 'asc' }],
+  });
+  return courses.map(toCourseDto);
+}
+
+export async function createCourse(user: TokenPayload, input: CreateCourseInput): Promise<CourseDto> {
+  await assertClassWritable(user, input.classId);
+
+  const created = await prisma.course.create({
+    data: { name: input.name, classId: input.classId, teacherId: user.sub },
+    include: { teacher: teacherSelect },
+  });
+  return toCourseDto(created);
+}
+
+export async function updateCourse(
+  user: TokenPayload,
+  courseId: string,
+  input: UpdateCourseInput,
+): Promise<CourseDto> {
+  const course = await prisma.course.findUnique({ where: { id: courseId } });
+  if (!course) throw ApiError.notFound('课程不存在');
+  await assertClassWritable(user, course.classId);
+
+  const updated = await prisma.course.update({
+    where: { id: courseId },
+    data: { ...(input.name ? { name: input.name } : {}) },
+    include: { teacher: teacherSelect },
+  });
+  return toCourseDto(updated);
+}
+
+export async function deleteCourse(user: TokenPayload, courseId: string): Promise<void> {
+  const course = await prisma.course.findUnique({ where: { id: courseId } });
+  if (!course) throw ApiError.notFound('课程不存在');
+  await assertClassWritable(user, course.classId);
+  await prisma.course.delete({ where: { id: courseId } });
+}