✨ Feat/#330 학생 알림 api 연동

backend/src/main/java/org/example/backend/domain/lecture/entity/Lecture.java

@@ -10,6 +10,7 @@
 
 import org.example.backend.domain.classroom.entity.Classroom;
 import org.example.backend.domain.lectureNoteMapping.entity.LectureNoteMapping;
+import org.example.backend.domain.notification.entity.Notification;
 import org.example.backend.domain.question.entity.Question;
 import org.example.backend.domain.quiz.entity.Quiz;
 import org.example.backend.domain.studentClass.entity.StudentClass;
@@ -65,4 +66,7 @@ public class Lecture extends BaseEntity {
     @OneToMany(mappedBy = "lecture", cascade = CascadeType.ALL, orphanRemoval = true)
     private List<Question> questions = new ArrayList<>();
 
+    @OneToMany(mappedBy = "lecture", cascade = CascadeType.ALL, orphanRemoval = true)
+    private List<Notification> notification = new ArrayList<>();
+
 }

backend/src/main/java/org/example/backend/domain/lecture/service/LectureScheduler.java

@@ -37,6 +37,13 @@ public void notifyProfessorBeforeLecture() {
                     "시스템",
                     lecture.getLectureName() + " 강의가 10분 후 시작됩니다."
             );
+
+            notificationService.sendAlarmToAllStudentsInLecture(
+                    lecture.getId(),
+                    AlarmType.startLecture,
+                    "시스템",
+                    lecture.getLectureName() + " 수업이 10분 후 시작됩니다."
+            );
         }
     }
 }

backend/src/main/java/org/example/backend/domain/lectureNote/service/LectureNoteServiceImpl.java

@@ -13,9 +13,11 @@
 import org.example.backend.domain.lectureNote.repository.LectureNoteRepository;
 import org.example.backend.domain.lectureNoteMapping.entity.LectureNoteMapping;
 import org.example.backend.domain.lectureNoteMapping.repository.LectureNoteMappingRepository;
+import org.example.backend.domain.notification.service.NotificationService;
 import org.example.backend.global.S3.service.S3Service;
 import org.springframework.stereotype.Service;
 import org.springframework.web.multipart.MultipartFile;
+import org.example.backend.domain.notification.entity.AlarmType;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -29,22 +31,24 @@ public class LectureNoteServiceImpl implements LectureNoteService {
 
     private final S3Service s3Service;
     private final LectureNoteRepository lectureNoteRepository;
-    private final ClassroomRepository classroomRepository; // ✅ 추가
+    private final ClassroomRepository classroomRepository;
     private final LectureNoteMappingRepository lectureNoteMappingRepository;
+    private final NotificationService notificationService;
 
     public List<LectureNote> uploadLectureNotes(UUID classId, List<MultipartFile> files) throws IOException {
         // 1. 여러 파일에 대해 처리
         List<LectureNote> lectureNotes = new ArrayList<>();
 
+        // 2) classId로 Classroom 엔티티 조회
+        Classroom classroom = classroomRepository.findById(classId)
+                .orElseThrow(() -> new ClassroomException(ClassroomErrorCode.CLASS_NOT_FOUND));
+
         // 2. 각 파일 업로드 처리
         for (MultipartFile file : files) {
             // 1) S3에 업로드
             String key = "lecture_note/" + classId + "/" + UUID.randomUUID() + "/" + file.getOriginalFilename();
             String fileUrl = s3Service.uploadFile(file, key);
 
-            // 2) classId로 Classroom 엔티티 조회
-            Classroom classroom = classroomRepository.findById(classId)
-                    .orElseThrow(() -> new ClassroomException(ClassroomErrorCode.CLASS_NOT_FOUND));
 
             // 3) LectureNote 객체 생성
             LectureNote lectureNote = LectureNote.builder()
@@ -56,6 +60,13 @@ public List<LectureNote> uploadLectureNotes(UUID classId, List<MultipartFile> fi
             lectureNotes.add(lectureNoteRepository.save(lectureNote));
         }
 
+        notificationService.sendAlarmToAllStudentsInClass(
+                classId,
+                AlarmType.lectureNoteUpload,          // enum에 없다면 추가 필요
+                "시스템",
+                classroom.getClassName() + " 강의자료가 업로드되었습니다."
+        );
+
         return lectureNotes;
     }
 

backend/src/main/java/org/example/backend/domain/notification/entity/Notification.java

@@ -26,8 +26,8 @@ public class Notification extends BaseEntity {
     @JoinColumn(name = "user_id", nullable = false)
     private User user;
 
-    @ManyToOne
-    @JoinColumn(name = "lecture_id", nullable = false)
+    @ManyToOne(fetch = FetchType.LAZY, optional = true)
+    @JoinColumn(name = "lecture_id", nullable = true)
     private Lecture lecture;
 
     @Enumerated(EnumType.STRING)

backend/src/main/java/org/example/backend/domain/notification/service/NotificationService.java

@@ -1,6 +1,7 @@
 package org.example.backend.domain.notification.service;
 
 import lombok.RequiredArgsConstructor;
+import lombok.extern.slf4j.Slf4j;
 import org.example.backend.domain.classroom.entity.Classroom;
 import org.example.backend.domain.classroom.repository.ClassroomRepository;
 import org.example.backend.domain.lecture.entity.Lecture;
@@ -12,13 +13,17 @@
 import org.example.backend.domain.notification.repository.NotificationRepository;
 import org.example.backend.domain.notificationSetting.service.FcmService;
 import org.example.backend.domain.notificationSetting.service.NotificationTemplateService;
+import org.example.backend.domain.studentClass.repository.StudentClassRepository;
+import org.example.backend.domain.user.entity.User;
+import org.example.backend.domain.user.repository.UserRepository;
 import org.example.backend.global.userdeviceToken.repository.UserDeviceTokenRepository;
 import org.springframework.stereotype.Service;
 import org.springframework.transaction.annotation.Transactional;
 
 import java.util.List;
 import java.util.UUID;
 
+@Slf4j
 @RequiredArgsConstructor
 @Service
 public class NotificationService implements NotificationServiceImpl{
@@ -29,6 +34,8 @@ public class NotificationService implements NotificationServiceImpl{
     private final NotificationTemplateService templateService;
     private final UserDeviceTokenRepository tokenRepository;
     private final FcmService fcmService;
+    private final StudentClassRepository studentClassRepository;
+    private final UserRepository userRepository;
 
     public List<NotificationResponseDTO> getNotificationsByUserId(UUID userId) {
         List<Notification> notificationList =
@@ -71,6 +78,137 @@ public void sendAlarmToProfessor(UUID lectureId, AlarmType type, String senderNa
         notificationRepository.save(notification);
     }
 
+    @Transactional
+    public void sendAlarmToStudentInLecture(UUID lectureId, UUID studentUserId,
+                                            AlarmType type, String senderName, String extra) {
+        Lecture lecture = lectureRepository.findById(lectureId)
+                .orElseThrow(() -> new RuntimeException("Lecture not found"));
+
+        UUID classId = lecture.getClassroom().getId();
+
+        // 수강 검증 (해당 반의 학생인지)
+        if (!studentClassRepository.existsByClassIdAndUserId(classId, studentUserId)) {
+            throw new RuntimeException("Student does not belong to this class");
+        }
+
+        String title = templateService.getTitle(type);
+        String body  = templateService.getBody(type, senderName, extra);
+
+        sendToUser(studentUserId, title, body);
+
+        User student = userRepository.findById(studentUserId)
+                .orElseThrow(() -> new RuntimeException("User not found"));
+        Notification notification = Notification.builder()
+                .user(student)
+                .lecture(lecture)
+                .alarmType(type)
+                .isRead(false)
+                .build();
+        notificationRepository.save(notification);
+    }
+
+    @Transactional
+    public void sendAlarmToAllStudentsInLecture(UUID lectureId,
+                                                AlarmType type, String senderName, String extra) {
+        Lecture lecture = lectureRepository.findById(lectureId)
+                .orElseThrow(() -> new RuntimeException("Lecture not found"));
+
+        UUID classId = lecture.getClassroom().getId();
+
+        String title = templateService.getTitle(type);
+        String body  = templateService.getBody(type, senderName, extra);
+
+        // 이 반에 속한 모든 학생 userId
+        List<UUID> studentIds = studentClassRepository.findUserIdsByClassId(classId);
+
+        log.info("[Notification] classId={}, lectureId={}, studentCount={}", classId, lectureId, studentIds);
+        log.debug("[Notification] studentIds={}", studentIds);
+
+        // (간단 버전) 각 유저별 토큰 찾아 전송
+        studentIds.stream().distinct().forEach(id -> sendToUser(id, title, body));
+
+        List<Notification> notifications = studentIds.stream()
+                .distinct()
+                .map(id -> Notification.builder()
+                        .user(userRepository.getReferenceById(id))
+                        .lecture(lecture)
+                        .alarmType(type)
+                        .isRead(false)
+                        .build()
+                ).toList();
+
+        notificationRepository.saveAll(notifications);
+    }
+
+    /** 공통 전송 헬퍼: 유저의 활성 FCM 토큰 전부에 발송 */
+    private void sendToUser(UUID userId, String title, String body) {
+        var tokens = tokenRepository.findAllByUserIdAndIsActiveTrue(userId);
+        tokens.forEach(token -> fcmService.sendNotification(token.getFcmToken(), title, body));
+    }
+    @Transactional
+    public void sendAlarmToAllStudentsInClass(UUID classId,
+                                              AlarmType type,
+                                              String senderName,
+                                              String extra) {
+        // 1) 반 로딩
+        Classroom classroom = classroomRepository.findById(classId)
+                .orElseThrow(() -> new RuntimeException("Classroom not found"));
+
+        // 2) 템플릿 생성
+        String title = templateService.getTitle(type);
+        String body  = templateService.getBody(type, senderName, extra);
+
+        // 3) 학생 userId 조회 (null 제거 + 중복 제거)
+        List<UUID> studentIds = studentClassRepository.findUserIdsByClassId(classId)
+                .stream()
+                .filter(java.util.Objects::nonNull)
+                .distinct()
+                .toList();
+
+        log.info("[Notification] classId={}, studentCount={}", classId, studentIds.size());
+        log.debug("[Notification] studentIds={}", studentIds);
+
+        if (studentIds.isEmpty()) return;
+
+        // 4) 푸시 발송 (유저별 활성 토큰에 전송)
+        studentIds.forEach(id -> sendToUser(id, title, body));
+
+        // 5) Notification 저장 (lecture는 클래스 단위이므로 null 가능해야 함)
+        var students = userRepository.findAllById(studentIds);
+        var userMap = students.stream().collect(
+                java.util.stream.Collectors.toMap(
+                        org.example.backend.domain.user.entity.User::getId,
+                        java.util.function.Function.identity()
+                )
+        );
+
+        List<Notification> notifications = studentIds.stream()
+                .map(id -> {
+                    User u = userMap.get(id);
+                    if (u == null) {
+                        log.warn("[Notification] user not found for userId={} (skipped)", id);
+                        return null;
+                    }
+                    return Notification.builder()
+                            .user(u)
+                            .lecture(null)     // 특정 회차가 없으므로 null (엔티티가 nullable이어야 함)
+                            .alarmType(type)
+                            .isRead(false)
+                            .build();
+                })
+                .filter(java.util.Objects::nonNull)
+                .toList();
+
+        notificationRepository.saveAll(notifications);
+        log.info("[Notification] saved notifications={}", notifications.size());
+    }
+
+
+
+
+
+
+
     @Transactional
     public void markAllAsRead(UUID userId) {
         notificationRepository.markAllAsReadByUserId(userId);

backend/src/main/java/org/example/backend/domain/notificationSetting/entity/NotificationSetting.java

@@ -4,6 +4,8 @@
 import lombok.*;
 import org.example.backend.global.entitiy.BaseEntity;
 
+import java.util.UUID;
+
 @Entity
 @Table(name = "notification_setting")
 @Data
@@ -14,7 +16,7 @@ public class NotificationSetting extends BaseEntity {
 
     @Id
     @Column(name = "user_id")
-    private String userId;
+    private UUID userId;
 
 
     @Column(name = "quiz_upload", nullable = false)

backend/src/main/java/org/example/backend/domain/notificationSetting/repository/NotificationSettingRepository.java

@@ -3,5 +3,8 @@
 import org.example.backend.domain.notificationSetting.entity.NotificationSetting;
 import org.springframework.data.jpa.repository.JpaRepository;
 
-public interface NotificationSettingRepository extends JpaRepository<NotificationSetting, String> {
+import java.util.UUID;
+
+public interface NotificationSettingRepository extends JpaRepository<NotificationSetting, UUID> {
+    boolean existsByUserId(UUID userId);
 }

backend/src/main/java/org/example/backend/domain/notificationSetting/service/NotificationSettingService.java

@@ -17,9 +17,9 @@ public class NotificationSettingService implements NotificationSettingServiceImp
 
     @Override
     public NotificationSettingResponseDTO getNotiSetting(UUID userId) {
-        NotificationSetting setting = notificationSettingRepository.findById(userId.toString())
+        NotificationSetting setting = notificationSettingRepository.findById(userId)
                 .orElseGet(() -> NotificationSetting.builder()
-                        .userId(userId.toString())
+                        .userId(userId)
                         .quizUpload(true)
                         .quizAnswerUpload(true)
                         .lectureNoteUpload(true)
@@ -32,7 +32,7 @@ public NotificationSettingResponseDTO getNotiSetting(UUID userId) {
 
     @Transactional
     public void patchSettings(UUID userId, NotificationSettingPatchRequest req) {
-        NotificationSetting entity = notificationSettingRepository.findById(userId.toString())
+        NotificationSetting entity = notificationSettingRepository.findById(userId)
                 .orElseThrow(() -> new IllegalArgumentException("알림 설정이 존재하지 않습니다."));
 
         if (req.quizUpload() != null) entity.setQuizUpload(req.quizUpload());
@@ -41,4 +41,20 @@ public void patchSettings(UUID userId, NotificationSettingPatchRequest req) {
         if (req.lectureUpload() != null) entity.setLectureUpload(req.lectureUpload());
         if (req.recordUpload() != null) entity.setRecordUpload(req.recordUpload());
     }
+
+    public void initializeDefaultSettings(UUID userId) {
+        // 이미 존재하는 설정이 있으면 중복 생성 방지
+        if (notificationSettingRepository.existsByUserId(userId)) return;
+
+        NotificationSetting notificationSetting = NotificationSetting.builder()
+                .userId(userId)
+                .quizUpload(true)
+                .quizAnswerUpload(true)
+                .lectureNoteUpload(true)
+                .lectureUpload(true)
+                .recordUpload(true)
+                .build();
+
+        notificationSettingRepository.save(notificationSetting);
+    }
 }

backend/src/main/java/org/example/backend/domain/notificationSetting/service/NotificationSettingServiceImpl.java

@@ -9,4 +9,5 @@ public interface NotificationSettingServiceImpl {
     NotificationSettingResponseDTO getNotiSetting(UUID userId);
 
     void patchSettings(UUID userId, NotificationSettingPatchRequest req);
+    void initializeDefaultSettings(UUID userId);
 }

backend/src/main/java/org/example/backend/domain/quiz/service/QuizServiceImpl.java

@@ -181,6 +181,12 @@ public QuizSaveResponseDTO saveQuiz(UUID lectureId, QuizSaveRequestDTO request)
                 }
             }
         }
+        notificationService.sendAlarmToAllStudentsInLecture(
+                lecture.getId(),
+                AlarmType.quizUpload,
+                "시스템",
+                lecture.getLectureName() + " 퀴즈가 게시되었습니다. 풀어보러 갈까요?."
+        );
         scheduleQuizAnswerUploadNotification(lecture);
 
 
@@ -206,6 +212,13 @@ private void scheduleQuizAnswerUploadNotification(Lecture lecture) {
                     "시스템",
                     lecture.getLectureName() + " 퀴즈 대시보드가 업로드 되었습니다."
             );
+
+            notificationService.sendAlarmToAllStudentsInLecture(
+                    lecture.getId(),
+                    AlarmType.quizAnswerUpload,
+                    "시스템",
+                    lecture.getLectureName() + " 퀴즈 정답이 공개되었습니다."
+            );
         }, triggerTime);
     }
 

backend/src/main/java/org/example/backend/domain/studentClass/repository/StudentClassRepository.java

@@ -34,4 +34,11 @@ SELECT CASE WHEN COUNT(sc) > 0 THEN TRUE ELSE FALSE END
       )
 """)
     boolean existsByUserIdAndLectureId(@Param("userId") UUID userId, @Param("lectureId") UUID lectureId);
+
+    // 해당 클래스에 속한 학생들의 userId만 조회
+    @Query("select sc.userId from StudentClass sc where sc.classId = :classId")
+    List<UUID> findUserIdsByClassId(UUID classId);
+
+    // 특정 학생이 해당 클래스에 속해있는지 여부
+    boolean existsByClassIdAndUserId(UUID classId, UUID userId);
 }