feat: implement course listing and retrieval API with dedicated controller, service, and types.

Backend/src/services/courses.service.ts

@@ -0,0 +1,40 @@
+import { prisma } from '../config/database';
+import { Prisma } from '@prisma/client';
+import { config } from '../config';
+import { logger } from '../config/logger';
+import jwt from 'jsonwebtoken';
+import { createCourse, createCourseResponse, listCourseResponse, getCourseResponse } from '../types/courses.types';
+import { UnauthorizedError, ValidationError, ForbiddenError } from '../middleware/errorHandler';
+
+export class CoursesService {
+    async ListCourses(): Promise<listCourseResponse> {
+        try {
+            const courses = await prisma.course.findMany();
+            return {
+                code: 200,
+                message: 'Courses fetched successfully',
+                total: courses.length,
+                data: courses,
+
+            };
+        } catch (error) {
+            logger.error('Failed to fetch courses', { error });
+            throw error;
+        }
+    }
+
+    async GetCourseById(id: number): Promise<getCourseResponse> {
+        try {
+            const course = await prisma.course.findUnique({ where: { id } });
+            return {
+                code: 200,
+                message: 'Course fetched successfully',
+                data: course,
+
+            };
+        } catch (error) {
+            logger.error('Failed to fetch course', { error });
+            throw error;
+        }
+    }
+}