重构项目结构，移除Assignment相关功能，优化Submission模块

TechHelper.Server/Services/Lesson/ILessonService.cs

@@ -0,0 +1,11 @@
+using Entities.DTO;
+
+namespace TechHelper.Services.Beta
+{
+    /// <summary>
+    /// Lesson服务接口
+    /// </summary>
+    public interface ILessonService : IBaseService<LessonDto, Guid>
+    {
+    }
+}

TechHelper.Server/Services/Lesson/LessonService.cs

@@ -0,0 +1,167 @@
+using AutoMapper;
+using Entities.Contracts;
+using Entities.DTO;
+using SharedDATA.Api;
+
+namespace TechHelper.Services.Beta
+{
+    /// <summary>
+    /// Lesson服务实现类
+    /// </summary>
+    public class LessonService : ILessonService
+    {
+        private readonly IUnitOfWork _work;
+        private readonly IMapper _mapper;
+
+        public LessonService(IUnitOfWork work, IMapper mapper)
+        {
+            _work = work;
+            _mapper = mapper;
+        }
+
+        public async Task<ApiResponse> GetAllAsync(QueryParameter query)
+        {
+            try
+            {
+                var repository = _work.GetRepository<Lesson>();
+
+                if (query.Search != null && !string.IsNullOrWhiteSpace(query.Search))
+                {
+                    var lessons = await repository.GetPagedListAsync(
+                        predicate: l => l.Title.Contains(query.Search),
+                        pageSize: query.PageSize,
+                        pageIndex: query.PageIndex
+                    );
+                    var lessonDtosFiltered = _mapper.Map<IEnumerable<LessonResponseDto>>(lessons.Items);
+                    return new ApiResponse(true, lessonDtosFiltered);
+                }
+                else
+                {
+                    var lessons = await repository.GetPagedListAsync(
+                        pageSize: query.PageSize,
+                        pageIndex: query.PageIndex
+                    );
+                    var lessonDtos = _mapper.Map<IEnumerable<LessonResponseDto>>(lessons.Items);
+                    return new ApiResponse(true, lessonDtos);
+                }
+            }
+            catch (Exception ex)
+            {
+                return new ApiResponse($"获取所有课程时发生错误: {ex.Message}");
+            }
+        }
+
+        public async Task<ApiResponse> GetAsync(Guid id)
+        {
+            try
+            {
+                var lesson = await _work.GetRepository<Lesson>().GetFirstOrDefaultAsync(
+                    predicate: l => l.Id == id);
+
+                if (lesson == null)
+                {
+                    return new ApiResponse("课程未找到。");
+                }
+
+                var lessonDto = _mapper.Map<LessonResponseDto>(lesson);
+                return new ApiResponse(true, lessonDto);
+            }
+            catch (Exception ex)
+            {
+                return new ApiResponse($"获取课程时发生错误: {ex.Message}");
+            }
+        }
+
+        public async Task<ApiResponse> AddAsync(LessonDto model)
+        {
+            try
+            {
+                // 检查是否已存在同名课程
+                var existingLesson = await _work.GetRepository<Lesson>().GetFirstOrDefaultAsync(
+                    predicate: l => l.Title == model.Title && l.TextbookID == model.TextBookId);
+
+                if (existingLesson != null)
+                {
+                    return new ApiResponse($"课程 '{model.Title}' 在该教材中已存在。");
+                }
+
+                var lesson = _mapper.Map<Lesson>(model);
+
+                await _work.GetRepository<Lesson>().InsertAsync(lesson);
+
+                if (await _work.SaveChangesAsync() > 0)
+                {
+                    return new ApiResponse(true, lesson.Id);
+                }
+                return new ApiResponse("添加课程失败。");
+            }
+            catch (Exception ex)
+            {
+                return new ApiResponse($"添加课程时发生错误: {ex.Message}");
+            }
+        }
+
+        public async Task<ApiResponse> UpdateAsync(LessonDto model)
+        {
+            try
+            {
+                var existingLesson = await _work.GetRepository<Lesson>().GetFirstOrDefaultAsync(
+                    predicate: l => l.Id == model.Id);
+
+                if (existingLesson == null)
+                {
+                    return new ApiResponse("课程未找到。");
+                }
+
+                // 检查是否要修改为已存在的课程名称（排除当前课程）
+                var lessonWithSameName = await _work.GetRepository<Lesson>().GetFirstOrDefaultAsync(
+                    predicate: l => l.Title == model.Title && l.TextbookID == model.TextBookId && l.Id != model.Id);
+
+                if (lessonWithSameName != null)
+                {
+                    return new ApiResponse($"课程名称 '{model.Title}' 在该教材中已被其他课程使用。");
+                }
+
+                _mapper.Map(model, existingLesson);
+                _work.GetRepository<Lesson>().Update(existingLesson);
+
+                if (await _work.SaveChangesAsync() > 0)
+                {
+                    var lessonDto = _mapper.Map<LessonResponseDto>(existingLesson);
+                    return new ApiResponse(true, lessonDto);
+                }
+                return new ApiResponse("更新课程失败。");
+            }
+            catch (Exception ex)
+            {
+                return new ApiResponse($"更新课程时发生错误: {ex.Message}");
+            }
+        }
+
+        public async Task<ApiResponse> DeleteAsync(Guid id)
+        {
+            try
+            {
+                var existingLesson = await _work.GetRepository<Lesson>().GetFirstOrDefaultAsync(
+                    predicate: l => l.Id == id);
+
+                if (existingLesson == null)
+                {
+                    return new ApiResponse("课程未找到。");
+                }
+
+                _work.GetRepository<Lesson>().Delete(existingLesson);
+
+                if (await _work.SaveChangesAsync() > 0)
+                {
+                    return new ApiResponse(true, "课程删除成功。");
+                }
+                return new ApiResponse("删除课程失败。");
+            }
+            catch (Exception ex)
+            {
+                return new ApiResponse($"删除课程时发生错误: {ex.Message}");
+            }
+        }
+    }
+}