feat: 多班级版班级管理系统 v2.0

技术栈：Go (Gin + GORM) + PHP + MySQL 5.7 + Redis

主要功能：
- 多班级完全隔离（class_id 贯穿全系统）
- 后端从 Python FastAPI 重写为 Go Gin（端口 56789）
- 超级管理员独立登录（env 配置路径，默认账密 admin/Admin123）
- 科任老师/课代表新角色
- 课代表作业管理页面
- 排行榜分项排行（操行分/考勤/作业）
- 角色加减分上下限由班主任配置
- 家长改密功能（可开关）
- 班级角色按需开关
- 宿舍号格式：南0-000
- 周度/月度重置功能
- MySQL 5.7 兼容
- Nginx 反向代理部署

开发者: Canglan
版权归属: Sea Network Technology Studio
许可证: Apache License 2.0

backend-go/internal/repository/assignment_repo.go

@@ -0,0 +1,168 @@
+// ===========================================
+// 多班级版班级管理系统 - Go 后端
+//
+// 开发者: Canglan
+// 联系方式: admin@sea-studio.top
+// 版权归属: Sea Network Technology Studio
+// 许可证: Apache License 2.0
+//
+// 版权所有 © Sea Network Technology Studio
+// ===========================================
+
+package repository
+
+import (
+	"time"
+
+	"gorm.io/gorm"
+
+	"hz-gitea.sea-studio.top/canglan/SharedClassManager/internal/model"
+)
+
+// AssignmentRepo 作业数据访问层
+type AssignmentRepo struct {
+	db *gorm.DB
+}
+
+// NewAssignmentRepo 创建作业 Repository
+func NewAssignmentRepo(db *gorm.DB) *AssignmentRepo {
+	return &AssignmentRepo{db: db}
+}
+
+// ========== Assignment 操作 ==========
+
+// CreateAssignment 创建作业
+func (r *AssignmentRepo) CreateAssignment(assignment *model.Assignment) (int, error) {
+	if err := r.db.Create(assignment).Error; err != nil {
+		return 0, err
+	}
+	return assignment.AssignmentID, nil
+}
+
+// GetAssignmentByID 根据ID获取作业
+func (r *AssignmentRepo) GetAssignmentByID(assignmentID int) (*model.Assignment, error) {
+	var assignment model.Assignment
+	if err := r.db.Where("assignment_id = ?", assignmentID).First(&assignment).Error; err != nil {
+		return nil, err
+	}
+	return &assignment, nil
+}
+
+// GetAssignmentsByClass 获取班级作业列表
+func (r *AssignmentRepo) GetAssignmentsByClass(classID int, subjectID int, page, pageSize int) ([]model.Assignment, int64, error) {
+	var assignments []model.Assignment
+	var total int64
+
+	query := r.db.Model(&model.Assignment{}).Where("class_id = ?", classID)
+	if subjectID > 0 {
+		query = query.Where("subject_id = ?", subjectID)
+	}
+
+	if err := query.Count(&total).Error; err != nil {
+		return nil, 0, err
+	}
+
+	offset := (page - 1) * pageSize
+	if err := query.Order("created_at DESC").
+		Limit(pageSize).
+		Offset(offset).
+		Find(&assignments).Error; err != nil {
+		return nil, 0, err
+	}
+
+	return assignments, total, nil
+}
+
+// GetAssignmentsBySubject 获取科目关联的作业列表
+func (r *AssignmentRepo) GetAssignmentsBySubject(subjectID int) ([]model.Assignment, error) {
+	var assignments []model.Assignment
+	if err := r.db.Where("subject_id = ?", subjectID).
+		Order("created_at DESC").
+		Find(&assignments).Error; err != nil {
+		return nil, err
+	}
+	return assignments, nil
+}
+
+// DeleteAssignment 删除作业
+func (r *AssignmentRepo) DeleteAssignment(assignmentID int) error {
+	return r.db.Where("assignment_id = ?", assignmentID).Delete(&model.Assignment{}).Error
+}
+
+// GetHomeworkStatsByDateRange 通过作业截止日期范围查询学生作业提交统计
+func (r *AssignmentRepo) GetHomeworkStatsByDateRange(startDate, endDate time.Time) ([]struct {
+	StudentID int
+	Status    string
+	Count     int64
+}, error) {
+	var stats []struct {
+		StudentID int
+		Status    string
+		Count     int64
+	}
+	err := r.db.Table("homework_submissions hs").
+		Select("hs.student_id, hs.status, COUNT(*) as count").
+		Joins("JOIN assignments a ON hs.assignment_id = a.assignment_id").
+		Where("a.deadline BETWEEN ? AND ?", startDate, endDate).
+		Group("hs.student_id, hs.status").
+		Find(&stats).Error
+	if err != nil {
+		return nil, err
+	}
+	return stats, nil
+}
+
+// ========== AssignmentSubmission 操作 ==========
+
+// CreateSubmission 创建作业提交记录
+func (r *AssignmentRepo) CreateSubmission(submission *model.AssignmentSubmission) (int, error) {
+	if err := r.db.Create(submission).Error; err != nil {
+		return 0, err
+	}
+	return submission.SubmissionID, nil
+}
+
+// GetSubmissionByAssignmentAndStudent 获取指定作业和学生的提交记录
+func (r *AssignmentRepo) GetSubmissionByAssignmentAndStudent(assignmentID, studentID int) (*model.AssignmentSubmission, error) {
+	var submission model.AssignmentSubmission
+	if err := r.db.Where("assignment_id = ? AND student_id = ?", assignmentID, studentID).
+		First(&submission).Error; err != nil {
+		return nil, err
+	}
+	return &submission, nil
+}
+
+// GetSubmissionsByAssignment 获取作业的所有提交记录
+func (r *AssignmentRepo) GetSubmissionsByAssignment(assignmentID int) ([]model.AssignmentSubmission, error) {
+	var submissions []model.AssignmentSubmission
+	if err := r.db.Where("assignment_id = ?", assignmentID).
+		Find(&submissions).Error; err != nil {
+		return nil, err
+	}
+	return submissions, nil
+}
+
+// GetSubmissionsByStudent 获取学生的所有提交记录
+func (r *AssignmentRepo) GetSubmissionsByStudent(studentID int) ([]model.AssignmentSubmission, error) {
+	var submissions []model.AssignmentSubmission
+	if err := r.db.Where("student_id = ?", studentID).
+		Find(&submissions).Error; err != nil {
+		return nil, err
+	}
+	return submissions, nil
+}
+
+// UpdateSubmission 更新提交记录
+func (r *AssignmentRepo) UpdateSubmission(submissionID int, updates map[string]interface{}) error {
+	return r.db.Model(&model.AssignmentSubmission{}).
+		Where("submission_id = ?", submissionID).
+		Updates(updates).Error
+}
+
+// BatchCreateSubmissions 批量创建提交记录
+func (r *AssignmentRepo) BatchCreateSubmissions(submissions []model.AssignmentSubmission) error {
+	if len(submissions) == 0 {
+		return nil
+	}
+	return r.db.Create(&submissions).Error
+}