[EDMT-457] 회원 포인트 시스템 구현 및 AI 생성 시 포인트 차감 기능 추가 (#78)

* [feat] add point column to Member entity and initialize with default value

* [feat] implement point validation for member actions

* [feat] implement point deduction logic in Member and PointService

* [feat] implement pessimistic locking for point deduction in PointService

* [refac] update deductPoints method to return Member object in PointService

Author: kgy1008

edukit-api/src/main/java/com/edukit/studentrecord/facade/StudentRecordAIFacade.java

@@ -3,6 +3,7 @@
 import com.edukit.common.annotation.AIGenerationMetrics;
 import com.edukit.core.member.db.entity.Member;
 import com.edukit.core.member.service.MemberService;
+import com.edukit.core.member.service.PointService;
 import com.edukit.core.studentrecord.db.entity.StudentRecord;
 import com.edukit.core.studentrecord.db.entity.StudentRecordAITask;
 import com.edukit.core.studentrecord.service.AITaskService;
@@ -22,16 +23,20 @@
 public class StudentRecordAIFacade {
 
     private final MemberService memberService;
+    private final PointService pointService;
     private final AITaskService aiTaskService;
     private final StudentRecordService studentRecordService;
     private final SSEChannelManager sseChannelManager;
     private final ApplicationEventPublisher eventPublisher;
 
+    private static final int DEDUCTED_POINTS = 100;
+
     @Transactional
     @AIGenerationMetrics
     public StudentRecordTaskResponse createTaskId(final long memberId, final long recordId, final int byteCount,
                                                   final String userPrompt) {
-        Member member = memberService.getMemberById(memberId);
+        Member member = pointService.deductPoints(memberId, DEDUCTED_POINTS);
+
         StudentRecord studentRecord = studentRecordService.getRecordDetail(memberId, recordId);
 
         String requestPrompt = AIPromptGenerator.createStreamingPrompt(studentRecord.getStudentRecordType(), byteCount, userPrompt);

edukit-api/src/main/resources/db/migration/V10__Add_member_point.sql

@@ -0,0 +1,3 @@
+-- Add point column to member table
+alter table member
+    add column point int not null default 1000;

edukit-core/src/main/java/com/edukit/core/member/db/entity/Member.java

@@ -58,6 +58,9 @@ public class Member extends BaseTimeEntity {
     @Enumerated(EnumType.STRING)
     private MemberRole role;
 
+    @Column(nullable = false)
+    private int point;
+
     @Column
     private LocalDateTime verifiedAt;
 
@@ -66,16 +69,19 @@ public class Member extends BaseTimeEntity {
 
     private LocalDateTime deletedAt;
 
+    private static final int INITIAL_POINT = 1000;
+
     @Builder(access = AccessLevel.PRIVATE)
     private Member(final Subject subject, final String email, final String password, final String nickname,
                    final School school, final MemberRole role, final LocalDateTime verifiedAt, final boolean isDeleted,
-                   final LocalDateTime deletedAt, final String memberUuid) {
+                   final LocalDateTime deletedAt, final String memberUuid, final int point) {
         this.subject = subject;
         this.email = email;
         this.password = password;
         this.nickname = nickname;
         this.school = school;
         this.role = role;
+        this.point = point;
         this.verifiedAt = verifiedAt;
         this.isDeleted = isDeleted;
         this.deletedAt = deletedAt;
@@ -92,6 +98,7 @@ public static Member create(final Subject subject, final String email, final Str
                 .school(school)
                 .role(memberRole)
                 .isDeleted(false)
+                .point(INITIAL_POINT)
                 .memberUuid(UUID.randomUUID().toString())
                 .build();
     }
@@ -139,4 +146,8 @@ public void updateEmailAndChangeVerifyStatus(final String email) {
         this.email = email;
         this.role = MemberRole.PENDING_TEACHER;
     }
+
+    public void deductPoints(final int pointsToDeduct) {
+        this.point -= pointsToDeduct;
+    }
 }

edukit-core/src/main/java/com/edukit/core/member/db/repository/MemberRepository.java

@@ -1,8 +1,10 @@
 package com.edukit.core.member.db.repository;
 
 import com.edukit.core.member.db.entity.Member;
+import jakarta.persistence.LockModeType;
 import java.util.Optional;
 import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.data.jpa.repository.Lock;
 import org.springframework.data.jpa.repository.Query;
 import org.springframework.data.repository.query.Param;
 
@@ -20,4 +22,8 @@ public interface MemberRepository extends JpaRepository<Member, Long> {
 
     @Query("SELECT m FROM Member m JOIN FETCH m.subject WHERE m.id = :id AND m.isDeleted = :isDeleted")
     Optional<Member> findByIdAndIsDeletedFetchJoinSubject(@Param("id") long id, @Param("isDeleted") boolean isDeleted);
+
+    @Lock(LockModeType.PESSIMISTIC_WRITE)
+    @Query("SELECT m FROM Member m WHERE m.id = :id AND m.isDeleted = false")
+    Optional<Member> findByIdWithLock(@Param("id") Long id);
 }

edukit-core/src/main/java/com/edukit/core/member/exception/MemberErrorCode.java

@@ -15,7 +15,8 @@ public enum MemberErrorCode implements ErrorCode {
     DUPLICATED_NICKNAME("M-40005", "입력하신 닉네임은 중복된 닉네임입니다."),
     INVALID_CURRENT_PASSWORD("M-40006", "현재 비밀번호가 일치하지 않습니다. 다시 입력해주세요."),
     SAME_PASSWORD("M-40007", "새로운 비밀번호는 기존 비밀번호와 같을 수 없습니다."),
-    DUPLICATED_EMAIL("M-40908", "이미 등록된 이메일입니다.");
+    DUPLICATED_EMAIL("M-40908", "이미 등록된 이메일입니다."),
+    INSUFFICIENT_POINTS("M-40009", "포인트가 부족합니다.");
 
     private final String code;
     private final String message;

edukit-core/src/main/java/com/edukit/core/member/service/PointService.java

@@ -0,0 +1,31 @@
+package com.edukit.core.member.service;
+
+import com.edukit.core.member.db.entity.Member;
+import com.edukit.core.member.db.repository.MemberRepository;
+import com.edukit.core.member.exception.MemberErrorCode;
+import com.edukit.core.member.exception.MemberException;
+import lombok.RequiredArgsConstructor;
+import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
+
+@Service
+@RequiredArgsConstructor
+public class PointService {
+
+    private final MemberRepository memberRepository;
+
+    @Transactional
+    public Member deductPoints(final Long memberId, final int pointsToDeduct) {
+        Member member = memberRepository.findByIdWithLock(memberId)
+                .orElseThrow(() -> new MemberException(MemberErrorCode.MEMBER_NOT_FOUND));
+
+        int currentPoint = member.getPoint();
+
+        if (currentPoint < pointsToDeduct) {
+            throw new MemberException(MemberErrorCode.INSUFFICIENT_POINTS);
+        }
+
+        member.deductPoints(pointsToDeduct);
+        return member;
+    }
+}