修复学期功能

backend/models/semester.py

@@ -51,14 +51,26 @@ class SemesterModel:
     
     @staticmethod
     async def get_active() -> Optional[Dict[str, Any]]:
-        """获取当前活跃学期"""
-        sql = """
-            SELECT semester_id, semester_name, start_date, end_date,
-                   is_active, is_archived, created_at
+        """获取当前活跃学期（优先 is_active 标记，降级为日期范围匹配）"""
+        fields = "semester_id, semester_name, start_date, end_date, is_active, is_archived, created_at"
+        # 第一优先级：is_active 标记
+        sql = f"""
+            SELECT {fields}
             FROM semesters
             WHERE is_active = 1 AND is_archived = 0
             LIMIT 1
         """
+        result = await execute_one(sql)
+        if result:
+            return result
+        # 第二优先级：日期范围匹配
+        # 注：无日期的学期不会自动匹配为活跃学期（需手动激活）
+        sql = f"""
+            SELECT {fields}
+            FROM semesters
+            WHERE is_archived = 0 AND start_date <= CURDATE() AND (end_date IS NULL OR end_date >= CURDATE())
+            LIMIT 1
+        """
         return await execute_one(sql)
     
     @staticmethod
@@ -102,6 +114,29 @@ class SemesterModel:
         sql = "SELECT semester_id FROM conduct_records WHERE record_id = %s"
         result = await execute_one(sql, (record_id,))
         return result['semester_id'] if result else None
+    
+    @staticmethod
+    async def get_attendance_stats_by_semester(semester_id: int, start_date: str, end_date: str) -> List[Dict]:
+        """批量查询学期内所有学生的考勤统计"""
+        sql = """
+            SELECT student_id, status, COUNT(*) as cnt
+            FROM attendance_records
+            WHERE (semester_id = %s OR (semester_id IS NULL AND `date` BETWEEN %s AND %s))
+            GROUP BY student_id, status
+        """
+        return await execute_query(sql, (semester_id, start_date, end_date))
+    
+    @staticmethod
+    async def get_homework_stats_by_date_range(start_date: str, end_date: str) -> List[Dict]:
+        """通过作业截止日期范围查询所有学生的作业提交统计"""
+        sql = """
+            SELECT hs.student_id, hs.status, COUNT(*) as cnt
+            FROM homework_submissions hs
+            JOIN assignments a ON hs.assignment_id = a.assignment_id
+            WHERE a.deadline BETWEEN %s AND %s
+            GROUP BY hs.student_id, hs.status
+        """
+        return await execute_query(sql, (start_date, end_date))
 
 
 class SemesterArchiveModel:
@@ -114,25 +149,39 @@ class SemesterArchiveModel:
             return 0
         sql = """
             INSERT INTO semester_archives
-            (semester_id, student_id, student_no, student_name, final_points, rank_position, total_students)
-            VALUES (%s, %s, %s, %s, %s, %s, %s)
+            (semester_id, student_id, student_no, student_name, final_points, rank_position, total_students,
+             attendance_present, attendance_absent, attendance_late, attendance_leave,
+             homework_submitted, homework_not_submitted, homework_late)
+            VALUES (%s, %s, %s, %s, %s, %s, %s, %s, %s, %s, %s, %s, %s, %s)
         """
         params_list = [
             (
                 a['semester_id'], a['student_id'], a['student_no'],
                 a['student_name'], a['final_points'],
-                a.get('rank_position'), a.get('total_students')
+                a.get('rank_position', 0), a.get('total_students', 0),
+                a.get('attendance_present', 0), a.get('attendance_absent', 0),
+                a.get('attendance_late', 0), a.get('attendance_leave', 0),
+                a.get('homework_submitted', 0), a.get('homework_not_submitted', 0),
+                a.get('homework_late', 0)
             )
             for a in archives_data
         ]
         return await execute_many(sql, params_list)
     
+    @staticmethod
+    async def delete_by_semester(semester_id: int) -> int:
+        """删除指定学期的所有归档数据（用于归档操作的幂等性）"""
+        sql = "DELETE FROM semester_archives WHERE semester_id = %s"
+        return await execute_update(sql, (semester_id,))
+    
     @staticmethod
     async def get_by_semester(semester_id: int) -> List[Dict[str, Any]]:
         """获取学期的归档数据"""
         sql = """
             SELECT archive_id, semester_id, student_id, student_no,
-                   student_name, final_points, rank_position, total_students, archived_at
+                   student_name, final_points, rank_position, total_students,
+                   attendance_present, attendance_absent, attendance_late, attendance_leave,
+                   homework_submitted, homework_not_submitted, homework_late, archived_at
             FROM semester_archives
             WHERE semester_id = %s
             ORDER BY rank_position ASC
@@ -156,7 +205,10 @@ class SemesterArchiveModel:
         sql = """
             SELECT sa.archive_id, sa.semester_id, sa.student_id, sa.student_no,
                    sa.student_name, sa.final_points, sa.rank_position,
-                   sa.total_students, sa.archived_at,
+                   sa.total_students, sa.attendance_present, sa.attendance_absent,
+                   sa.attendance_late, sa.attendance_leave,
+                   sa.homework_submitted, sa.homework_not_submitted, sa.homework_late,
+                   sa.archived_at,
                    s.semester_name, s.start_date, s.end_date
             FROM semester_archives sa
             JOIN semesters s ON sa.semester_id = s.semester_id