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

TechHelper.Server/Services/Textbook/ITextbookService.cs

@@ -0,0 +1,12 @@
+using Entities.DTO;
+using TechHelper.Services;
+
+namespace TechHelper.Services.Beta
+{
+    /// <summary>
+    /// 教材服务接口
+    /// </summary>
+    public interface ITextbookService : IBaseService<TextbookDto, Guid>
+    {
+    }
+}

TechHelper.Server/Services/Textbook/TextbookService.cs

@@ -0,0 +1,186 @@
+using AutoMapper;
+using Entities.Contracts;
+using Entities.DTO;
+using Microsoft.EntityFrameworkCore;
+using SharedDATA.Api;
+using TechHelper.Services.Beta;
+
+namespace TechHelper.Services.Beta
+{
+    /// <summary>
+    /// 教材服务实现类
+    /// </summary>
+    public class TextbookService : ITextbookService
+    {
+        private readonly IUnitOfWork _work;
+        private readonly IMapper _mapper;
+
+        public TextbookService(IUnitOfWork work, IMapper mapper)
+        {
+            _work = work;
+            _mapper = mapper;
+        }
+
+        public async Task<ApiResponse> GetAllAsync(QueryParameter query)
+        {
+            try
+            {
+                var repository = _work.GetRepository<Textbook>();
+
+                if (query.Search != null && !string.IsNullOrWhiteSpace(query.Search))
+                {
+                    var textbooks = await repository.GetPagedListAsync(
+                        predicate: t => t.Title.Contains(query.Search) || 
+                                       t.Grade.ToString().Contains(query.Search) ||
+                                       t.Publisher.ToString().Contains(query.Search) ||
+                                       t.SubjectArea.ToString().Contains(query.Search),
+                        pageSize: query.PageSize,
+                        pageIndex: query.PageIndex
+                    );
+                    var textbookDtosFiltered = _mapper.Map<IEnumerable<TextbookResponseDto>>(textbooks.Items);
+                    return new ApiResponse(true, textbookDtosFiltered);
+                }
+                else
+                {
+                    var textbooks = await repository.GetPagedListAsync(
+                        pageSize: query.PageSize,
+                        pageIndex: query.PageIndex
+                    );
+                    var textbookDtos = _mapper.Map<IEnumerable<TextbookResponseDto>>(textbooks.Items);
+                    return new ApiResponse(true, textbookDtos);
+                }
+            }
+            catch (Exception ex)
+            {
+                return new ApiResponse($"获取所有教材时发生错误: {ex.Message}");
+            }
+        }
+
+        public async Task<ApiResponse> GetAsync(Guid id)
+        {
+            try
+            {
+                var textbook = await _work.GetRepository<Textbook>().GetFirstOrDefaultAsync(
+                    predicate: t => t.Id == id,
+                    include: i => i
+                        .Include(t => t.Lessons));
+
+                if (textbook == null)
+                {
+                    return new ApiResponse("教材未找到。");
+                }
+
+                var textbookDto = _mapper.Map<TextbookResponseDto>(textbook);
+                return new ApiResponse(true, textbookDto);
+            }
+            catch (Exception ex)
+            {
+                return new ApiResponse($"获取教材时发生错误: {ex.Message}");
+            }
+        }
+
+        public async Task<ApiResponse> AddAsync(TextbookDto model)
+        {
+            try
+            {
+                // 检查是否已存在同名教材（考虑年级和学科领域）
+                var existingTextbook = await _work.GetRepository<Textbook>().GetFirstOrDefaultAsync(
+                    predicate: t => t.Title == model.Title && 
+                                   t.Grade.ToString() == model.Grade && 
+                                   t.SubjectArea.ToString() == model.SubjectArea);
+
+                if (existingTextbook != null)
+                {
+                    return new ApiResponse($"教材 '{model.Title}' 在该年级和学科领域已存在。");
+                }
+
+                var textbook = _mapper.Map<Textbook>(model);
+
+                await _work.GetRepository<Textbook>().InsertAsync(textbook);
+
+                if (await _work.SaveChangesAsync() > 0)
+                {
+                    return new ApiResponse(true, textbook.Id);
+                }
+                return new ApiResponse("添加教材失败。");
+            }
+            catch (Exception ex)
+            {
+                return new ApiResponse($"添加教材时发生错误: {ex.Message}");
+            }
+        }
+
+        public async Task<ApiResponse> UpdateAsync(TextbookDto model)
+        {
+            try
+            {
+                var existingTextbook = await _work.GetRepository<Textbook>().GetFirstOrDefaultAsync(
+                    predicate: t => t.Id == model.Id);
+
+                if (existingTextbook == null)
+                {
+                    return new ApiResponse("教材未找到。");
+                }
+
+                // 检查是否要修改为已存在的教材名称（排除当前教材）
+                var textbookWithSameName = await _work.GetRepository<Textbook>().GetFirstOrDefaultAsync(
+                    predicate: t => t.Title == model.Title && 
+                                   t.Grade.ToString() == model.Grade && 
+                                   t.SubjectArea.ToString() == model.SubjectArea && 
+                                   t.Id != model.Id);
+
+                if (textbookWithSameName != null)
+                {
+                    return new ApiResponse($"教材名称 '{model.Title}' 在该年级和学科领域已被其他教材使用。");
+                }
+
+                _mapper.Map(model, existingTextbook);
+                _work.GetRepository<Textbook>().Update(existingTextbook);
+
+                if (await _work.SaveChangesAsync() > 0)
+                {
+                    var textbookDto = _mapper.Map<TextbookResponseDto>(existingTextbook);
+                    return new ApiResponse(true, textbookDto);
+                }
+                return new ApiResponse("更新教材失败。");
+            }
+            catch (Exception ex)
+            {
+                return new ApiResponse($"更新教材时发生错误: {ex.Message}");
+            }
+        }
+
+        public async Task<ApiResponse> DeleteAsync(Guid id)
+        {
+            try
+            {
+                var existingTextbook = await _work.GetRepository<Textbook>().GetFirstOrDefaultAsync(
+                    predicate: t => t.Id == id);
+
+                if (existingTextbook == null)
+                {
+                    return new ApiResponse("教材未找到。");
+                }
+
+                // 检查是否有相关课程
+                var hasLessons = existingTextbook.Lessons.Any();
+                if (hasLessons)
+                {
+                    return new ApiResponse("无法删除该教材，因为它包含相关课程。");
+                }
+
+                _work.GetRepository<Textbook>().Delete(existingTextbook);
+
+                if (await _work.SaveChangesAsync() > 0)
+                {
+                    return new ApiResponse(true, "教材删除成功。");
+                }
+                return new ApiResponse("删除教材失败。");
+            }
+            catch (Exception ex)
+            {
+                return new ApiResponse($"删除教材时发生错误: {ex.Message}");
+            }
+        }
+    }
+}