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

TechHelper.Server/Services/Grade/GradeService.cs

@@ -0,0 +1,155 @@
+using AutoMapper;
+using Entities.Contracts;
+using Entities.DTO;
+using Microsoft.EntityFrameworkCore;
+using SharedDATA.Api;
+
+namespace TechHelper.Services.Beta
+{
+    public class GradeService : IGradeService
+    {
+        private readonly IUnitOfWork _work;
+        private readonly IMapper _mapper;
+
+        public GradeService(IUnitOfWork work, IMapper mapper)
+        {
+            _work = work;
+            _mapper = mapper;
+        }
+
+        public async Task<ApiResponse> GetAllAsync(QueryParameter query)
+        {
+            try
+            {
+                var repository = _work.GetRepository<Grade>();
+
+                if (query.Search != null && !string.IsNullOrWhiteSpace(query.Search))
+                {
+                    var grades = await repository.GetPagedListAsync(
+                        predicate: g => g.GradeName.Contains(query.Search),
+                        pageSize: query.PageSize,
+                        pageIndex: query.PageIndex
+                    );
+                    var gradeDtosFiltered = _mapper.Map<IEnumerable<GradeDto>>(grades);
+                    return new ApiResponse(true, gradeDtosFiltered);
+                }
+                else
+                {
+                    var grades = await repository.GetPagedListAsync(
+                        pageSize: query.PageSize,
+                        pageIndex: query.PageIndex
+                    );
+                    var gradeDtos = _mapper.Map<IEnumerable<GradeDto>>(grades);
+                    return new ApiResponse(true, gradeDtos);
+                }
+            }
+            catch (Exception ex)
+            {
+                return new ApiResponse($"获取所有年级时发生错误: {ex.Message}");
+            }
+        }
+
+        public async Task<ApiResponse> GetAsync(Guid id)
+        {
+            try
+            {
+                var grade = await _work.GetRepository<Grade>().GetFirstOrDefaultAsync(
+                    predicate: g => g.Id == id,
+                    include: i => i.Include(g => g.School));
+
+                if (grade == null)
+                {
+                    return new ApiResponse("年级未找到。");
+                }
+
+                var gradeDto = _mapper.Map<GradeDto>(grade);
+                return new ApiResponse(true, gradeDto);
+            }
+            catch (Exception ex)
+            {
+                return new ApiResponse($"获取年级时发生错误: {ex.Message}");
+            }
+        }
+
+        public async Task<ApiResponse> AddAsync(GradeDto model)
+        {
+            try
+            {
+                // 检查是否已存在相同学校下的同名年级
+                var existingGrade = await _work.GetRepository<Grade>().GetFirstOrDefaultAsync(
+                    predicate: g => g.SchoolId == model.SchoolId && g.GradeName == model.GradeName && g.GradeLevel == model.GradeLevel);
+
+                if (existingGrade != null)
+                {
+                    return new ApiResponse($"在当前学校下，年级 '{model.GradeName}' 已存在。");
+                }
+
+                var grade = _mapper.Map<Grade>(model);
+                await _work.GetRepository<Grade>().InsertAsync(grade);
+
+                if (await _work.SaveChangesAsync() > 0)
+                {
+                    return new ApiResponse(true, _mapper.Map<GradeDto>(grade));
+                }
+                return new ApiResponse("添加年级失败。");
+            }
+            catch (Exception ex)
+            {
+                return new ApiResponse($"添加年级时发生错误: {ex.Message}");
+            }
+        }
+
+        public async Task<ApiResponse> UpdateAsync(GradeDto model)
+        {
+            try
+            {
+                var existingGrade = await _work.GetRepository<Grade>().GetFirstOrDefaultAsync(
+                    predicate: g => g.Id == model.Id);
+
+                if (existingGrade == null)
+                {
+                    return new ApiResponse("年级未找到。");
+                }
+
+                _mapper.Map(model, existingGrade);
+                _work.GetRepository<Grade>().Update(existingGrade);
+
+                if (await _work.SaveChangesAsync() > 0)
+                {
+                    return new ApiResponse(true, _mapper.Map<GradeDto>(existingGrade));
+                }
+                return new ApiResponse("更新年级失败。");
+            }
+            catch (Exception ex)
+            {
+                return new ApiResponse($"更新年级时发生错误: {ex.Message}");
+            }
+        }
+
+        public async Task<ApiResponse> DeleteAsync(Guid id)
+        {
+            try
+            {
+                var existingGrade = await _work.GetRepository<Grade>().GetFirstOrDefaultAsync(
+                    predicate: g => g.Id == id);
+
+                if (existingGrade == null)
+                {
+                    return new ApiResponse("年级未找到。");
+                }
+
+                _work.GetRepository<Grade>().Delete(existingGrade);
+
+                if (await _work.SaveChangesAsync() > 0)
+                {
+                    return new ApiResponse(true, "年级删除成功。");
+                }
+                return new ApiResponse("删除年级失败。");
+            }
+            catch (Exception ex)
+            {
+                return new ApiResponse($"删除年级时发生错误: {ex.Message}");
+            }
+        }
+    }
+}