feat: 우수 스터디원 지정 및 철회 API 구현

src/main/java/com/gdschongik/gdsc/domain/study/api/MentorStudyAchievementController.java

@@ -0,0 +1,40 @@
+package com.gdschongik.gdsc.domain.study.api;
+
+import com.gdschongik.gdsc.domain.study.application.MentorStudyAchievementService;
+import com.gdschongik.gdsc.domain.study.dto.request.OutstandingStudentRequest;
+import io.swagger.v3.oas.annotations.Operation;
+import io.swagger.v3.oas.annotations.tags.Tag;
+import jakarta.validation.Valid;
+import lombok.RequiredArgsConstructor;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.DeleteMapping;
+import org.springframework.web.bind.annotation.PostMapping;
+import org.springframework.web.bind.annotation.RequestBody;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RequestParam;
+import org.springframework.web.bind.annotation.RestController;
+
+@Tag(name = "Mentor StudyAchievement", description = "멘토 스터디 우수 스터디원 관리 API입니다.")
+@RestController
+@RequestMapping("/mentor/study-achievements")
+@RequiredArgsConstructor
+public class MentorStudyAchievementController {
+
+    private final MentorStudyAchievementService mentorStudyAchievementService;
+
+    @Operation(summary = "우수 스터디원 지정", description = "우수 스터디원으로 지정합니다.")
+    @PostMapping
+    public ResponseEntity<Void> designateOutstandingStudent(
+            @RequestParam(name = "studyId") Long studyId, @Valid @RequestBody OutstandingStudentRequest request) {
+        mentorStudyAchievementService.designateOutstandingStudent(studyId, request);
+        return ResponseEntity.ok().build();
+    }
+
+    @Operation(summary = "우수 스터디원 철회", description = "우수 스터디원 지정을 철회합니다.")
+    @DeleteMapping
+    public ResponseEntity<Void> withdrawOutstandingStudent(
+            @RequestParam(name = "studyId") Long studyId, @Valid @RequestBody OutstandingStudentRequest request) {
+        mentorStudyAchievementService.withdrawOutstandingStudent(studyId, request);
+        return ResponseEntity.ok().build();
+    }
+}

src/main/java/com/gdschongik/gdsc/domain/study/application/MentorStudyAchievementService.java

@@ -0,0 +1,74 @@
+package com.gdschongik.gdsc.domain.study.application;
+
+import static com.gdschongik.gdsc.global.exception.ErrorCode.*;
+
+import com.gdschongik.gdsc.domain.member.dao.MemberRepository;
+import com.gdschongik.gdsc.domain.member.domain.Member;
+import com.gdschongik.gdsc.domain.study.dao.StudyAchievementRepository;
+import com.gdschongik.gdsc.domain.study.dao.StudyHistoryRepository;
+import com.gdschongik.gdsc.domain.study.dao.StudyRepository;
+import com.gdschongik.gdsc.domain.study.domain.Study;
+import com.gdschongik.gdsc.domain.study.domain.StudyAchievement;
+import com.gdschongik.gdsc.domain.study.domain.StudyHistoryValidator;
+import com.gdschongik.gdsc.domain.study.domain.StudyValidator;
+import com.gdschongik.gdsc.domain.study.dto.request.OutstandingStudentRequest;
+import com.gdschongik.gdsc.global.exception.CustomException;
+import com.gdschongik.gdsc.global.util.MemberUtil;
+import java.util.List;
+import lombok.RequiredArgsConstructor;
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
+
+@Slf4j
+@Service
+@RequiredArgsConstructor
+public class MentorStudyAchievementService {
+
+    private final MemberUtil memberUtil;
+    private final StudyValidator studyValidator;
+    private final StudyHistoryValidator studyHistoryValidator;
+    private final StudyRepository studyRepository;
+    private final StudyHistoryRepository studyHistoryRepository;
+    private final StudyAchievementRepository studyAchievementRepository;
+    private final MemberRepository memberRepository;
+
+    @Transactional
+    public void designateOutstandingStudent(Long studyId, OutstandingStudentRequest request) {
+        Member currentMember = memberUtil.getCurrentMember();
+        Study study = studyRepository.findById(studyId).orElseThrow(() -> new CustomException(STUDY_NOT_FOUND));
+        Long countByStudyIdAndStudentIds =
+                studyHistoryRepository.countByStudyIdAndStudentIds(studyId, request.studentIds());
+
+        studyValidator.validateStudyMentor(currentMember, study);
+        studyHistoryValidator.validateAppliedToStudy(
+                countByStudyIdAndStudentIds, request.studentIds().size());
+
+        List<Member> outstandingStudents = memberRepository.findAllById(request.studentIds());
+        List<StudyAchievement> studyAchievements = outstandingStudents.stream()
+                .map(member -> StudyAchievement.create(member, study, request.achievementType()))
+                .toList();
+        studyAchievementRepository.saveAll(studyAchievements);
+
+        log.info(
+                "[MentorStudyAchievementService] 우수 스터디원 지정: studyId={}, studentIds={}", studyId, request.studentIds());
+    }
+
+    @Transactional
+    public void withdrawOutstandingStudent(Long studyId, OutstandingStudentRequest request) {
+        Member currentMember = memberUtil.getCurrentMember();
+        Study study = studyRepository.findById(studyId).orElseThrow(() -> new CustomException(STUDY_NOT_FOUND));
+        long countByStudyIdAndStudentIds =
+                studyHistoryRepository.countByStudyIdAndStudentIds(studyId, request.studentIds());
+
+        studyValidator.validateStudyMentor(currentMember, study);
+        studyHistoryValidator.validateAppliedToStudy(
+                countByStudyIdAndStudentIds, request.studentIds().size());
+
+        studyAchievementRepository.deleteByStudyAndAchievementTypeAndMemberIds(
+                studyId, request.achievementType(), request.studentIds());
+
+        log.info(
+                "[MentorStudyAchievementService] 우수 스터디원 철회: studyId={}, studentIds={}", studyId, request.studentIds());
+    }
+}

src/main/java/com/gdschongik/gdsc/domain/study/dao/StudyAchievementCustomRepository.java

@@ -1,8 +1,12 @@
 package com.gdschongik.gdsc.domain.study.dao;
 
+import com.gdschongik.gdsc.domain.study.domain.AchievementType;
 import com.gdschongik.gdsc.domain.study.domain.StudyAchievement;
 import java.util.List;
 
 public interface StudyAchievementCustomRepository {
     List<StudyAchievement> findByStudyIdAndMemberIds(Long studyId, List<Long> memberIds);
+
+    void deleteByStudyAndAchievementTypeAndMemberIds(
+            Long studyId, AchievementType achievementType, List<Long> memberIds);
 }

src/main/java/com/gdschongik/gdsc/domain/study/dao/StudyAchievementCustomRepositoryImpl.java

@@ -2,6 +2,7 @@
 
 import static com.gdschongik.gdsc.domain.study.domain.QStudyAchievement.*;
 
+import com.gdschongik.gdsc.domain.study.domain.AchievementType;
 import com.gdschongik.gdsc.domain.study.domain.StudyAchievement;
 import com.querydsl.core.types.dsl.BooleanExpression;
 import com.querydsl.jpa.impl.JPAQueryFactory;
@@ -21,6 +22,18 @@ public List<StudyAchievement> findByStudyIdAndMemberIds(Long studyId, List<Long>
                 .fetch();
     }
 
+    @Override
+    public void deleteByStudyAndAchievementTypeAndMemberIds(
+            Long studyId, AchievementType achievementType, List<Long> memberIds) {
+        queryFactory
+                .delete(studyAchievement)
+                .where(
+                        eqStudyId(studyId),
+                        studyAchievement.achievementType.eq(achievementType),
+                        studyAchievement.student.id.in(memberIds))
+                .execute();
+    }
+
     private BooleanExpression eqStudyId(Long studyId) {
         return studyId != null ? studyAchievement.study.id.eq(studyId) : null;
     }

src/main/java/com/gdschongik/gdsc/domain/study/dao/StudyHistoryCustomRepository.java

@@ -0,0 +1,8 @@
+package com.gdschongik.gdsc.domain.study.dao;
+
+import java.util.List;
+
+public interface StudyHistoryCustomRepository {
+
+    long countByStudyIdAndStudentIds(Long studyId, List<Long> studentIds);
+}

src/main/java/com/gdschongik/gdsc/domain/study/dao/StudyHistoryCustomRepositoryImpl.java

@@ -0,0 +1,27 @@
+package com.gdschongik.gdsc.domain.study.dao;
+
+import static com.gdschongik.gdsc.domain.study.domain.QStudyHistory.*;
+
+import com.querydsl.core.types.dsl.BooleanExpression;
+import com.querydsl.jpa.impl.JPAQueryFactory;
+import java.util.List;
+import lombok.RequiredArgsConstructor;
+
+@RequiredArgsConstructor
+public class StudyHistoryCustomRepositoryImpl implements StudyHistoryCustomRepository {
+
+    private final JPAQueryFactory queryFactory;
+
+    @Override
+    public long countByStudyIdAndStudentIds(Long studyId, List<Long> studentIds) {
+        return (long) queryFactory
+                .select(studyHistory.count())
+                .from(studyHistory)
+                .where(eqStudyId(studyId), studyHistory.student.id.in(studentIds))
+                .fetchOne();
+    }
+
+    private BooleanExpression eqStudyId(Long studyId) {
+        return studyHistory.study.id.eq(studyId);
+    }
+}

src/main/java/com/gdschongik/gdsc/domain/study/dao/StudyHistoryRepository.java

@@ -9,7 +9,7 @@
 import org.springframework.data.domain.Pageable;
 import org.springframework.data.jpa.repository.JpaRepository;
 
-public interface StudyHistoryRepository extends JpaRepository<StudyHistory, Long> {
+public interface StudyHistoryRepository extends JpaRepository<StudyHistory, Long>, StudyHistoryCustomRepository {
 
     List<StudyHistory> findAllByStudent(Member member);
 

src/main/java/com/gdschongik/gdsc/domain/study/domain/StudyHistoryValidator.java

@@ -51,4 +51,10 @@ public void validateUpdateRepository(
             throw new CustomException(STUDY_HISTORY_REPOSITORY_NOT_UPDATABLE_OWNER_MISMATCH);
         }
     }
+
+    public void validateAppliedToStudy(long countStudyHistory, int studentCount) {
+        if (countStudyHistory != studentCount) {
+            throw new CustomException(STUDY_HISTORY_NOT_APPLIED_STUDENT_EXISTS);
+        }
+    }
 }

src/main/java/com/gdschongik/gdsc/domain/study/dto/request/OutstandingStudentRequest.java

@@ -0,0 +1,6 @@
+package com.gdschongik.gdsc.domain.study.dto.request;
+
+import com.gdschongik.gdsc.domain.study.domain.AchievementType;
+import java.util.List;
+
+public record OutstandingStudentRequest(List<Long> studentIds, AchievementType achievementType) {}

src/main/java/com/gdschongik/gdsc/global/exception/ErrorCode.java

@@ -124,6 +124,7 @@ public enum ErrorCode {
     STUDY_HISTORY_REPOSITORY_NOT_UPDATABLE_ASSIGNMENT_ALREADY_SUBMITTED(
             HttpStatus.CONFLICT, "이미 제출한 과제가 있으므로 레포지토리를 수정할 수 없습니다."),
     STUDY_HISTORY_REPOSITORY_NOT_UPDATABLE_OWNER_MISMATCH(HttpStatus.CONFLICT, "레포지토리 소유자가 현재 멤버와 다릅니다."),
+    STUDY_HISTORY_NOT_APPLIED_STUDENT_EXISTS(HttpStatus.CONFLICT, "해당 스터디에 신청하지 않은 멤버가 있습니다."),
 
     // StudyAnnouncement
     STUDY_ANNOUNCEMENT_NOT_FOUND(HttpStatus.NOT_FOUND, "존재하지 않는 스터디 공지입니다."),

src/test/java/com/gdschongik/gdsc/domain/study/application/MentorStudyAchievementServiceTest.java

@@ -0,0 +1,82 @@
+package com.gdschongik.gdsc.domain.study.application;
+
+import static com.gdschongik.gdsc.domain.study.domain.AchievementType.*;
+import static org.assertj.core.api.Assertions.*;
+
+import com.gdschongik.gdsc.domain.member.domain.Member;
+import com.gdschongik.gdsc.domain.recruitment.domain.vo.Period;
+import com.gdschongik.gdsc.domain.study.domain.Study;
+import com.gdschongik.gdsc.domain.study.domain.StudyAchievement;
+import com.gdschongik.gdsc.domain.study.dto.request.OutstandingStudentRequest;
+import com.gdschongik.gdsc.helper.IntegrationTest;
+import java.time.LocalDateTime;
+import java.util.List;
+import org.junit.jupiter.api.Nested;
+import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+
+public class MentorStudyAchievementServiceTest extends IntegrationTest {
+
+    @Autowired
+    private MentorStudyAchievementService mentorStudyAchievementService;
+
+    @Nested
+    class 우수_스터디원_지정시 {
+
+        @Test
+        void 성공한다() {
+            // given
+            LocalDateTime now = LocalDateTime.now();
+            Member mentor = createMentor();
+            Study study = createStudy(
+                    mentor,
+                    Period.createPeriod(now.plusDays(5), now.plusDays(10)),
+                    Period.createPeriod(now.minusDays(5), now));
+
+            Member student = createRegularMember();
+            createStudyHistory(student, study);
+
+            logoutAndReloginAs(mentor.getId(), mentor.getRole());
+            OutstandingStudentRequest request =
+                    new OutstandingStudentRequest(List.of(student.getId()), FIRST_ROUND_OUTSTANDING_STUDENT);
+
+            // when
+            mentorStudyAchievementService.designateOutstandingStudent(study.getId(), request);
+
+            // then
+            List<StudyAchievement> studyAchievements =
+                    studyAchievementRepository.findByStudyIdAndMemberIds(study.getId(), request.studentIds());
+            assertThat(studyAchievements).hasSize(request.studentIds().size());
+        }
+    }
+
+    @Nested
+    class 우수_스터디원_철회시 {
+
+        @Test
+        void 성공한다() {
+            // given
+            Member student = createRegularMember();
+            LocalDateTime now = LocalDateTime.now();
+            Member mentor = createMentor();
+            Study study = createStudy(
+                    mentor,
+                    Period.createPeriod(now.plusDays(5), now.plusDays(10)),
+                    Period.createPeriod(now.minusDays(5), now));
+            createStudyHistory(student, study);
+            createStudyAchievement(student, study, FIRST_ROUND_OUTSTANDING_STUDENT);
+
+            logoutAndReloginAs(mentor.getId(), mentor.getRole());
+            OutstandingStudentRequest request =
+                    new OutstandingStudentRequest(List.of(student.getId()), FIRST_ROUND_OUTSTANDING_STUDENT);
+
+            // when
+            mentorStudyAchievementService.withdrawOutstandingStudent(study.getId(), request);
+
+            // then
+            List<StudyAchievement> studyAchievements =
+                    studyAchievementRepository.findByStudyIdAndMemberIds(study.getId(), request.studentIds());
+            assertThat(studyAchievements).isEmpty();
+        }
+    }
+}

src/test/java/com/gdschongik/gdsc/domain/study/domain/StudyHistoryValidatorTest.java

@@ -124,4 +124,21 @@ class 레포지토리_입력시 {
                     .hasMessage(STUDY_HISTORY_REPOSITORY_NOT_UPDATABLE_OWNER_MISMATCH.getMessage());
         }
     }
+
+    @Nested
+    class 스터디_수강신청_여부_확인시 {
+
+        @Test
+        void 해당_스터디를_신청하지_않은_멤버가_있다면_실패한다() {
+            // given
+            Long countStudyHistory = 1L;
+            int requestStudentCount = 2;
+
+            // when & then
+            assertThatThrownBy(
+                            () -> studyHistoryValidator.validateAppliedToStudy(countStudyHistory, requestStudentCount))
+                    .isInstanceOf(CustomException.class)
+                    .hasMessage(STUDY_HISTORY_NOT_APPLIED_STUDENT_EXISTS.getMessage());
+        }
+    }
 }

src/test/java/com/gdschongik/gdsc/helper/IntegrationTest.java

@@ -30,10 +30,15 @@
 import com.gdschongik.gdsc.domain.recruitment.domain.RecruitmentRound;
 import com.gdschongik.gdsc.domain.recruitment.domain.RoundType;
 import com.gdschongik.gdsc.domain.recruitment.domain.vo.Period;
+import com.gdschongik.gdsc.domain.study.dao.StudyAchievementRepository;
 import com.gdschongik.gdsc.domain.study.dao.StudyDetailRepository;
+import com.gdschongik.gdsc.domain.study.dao.StudyHistoryRepository;
 import com.gdschongik.gdsc.domain.study.dao.StudyRepository;
+import com.gdschongik.gdsc.domain.study.domain.AchievementType;
 import com.gdschongik.gdsc.domain.study.domain.Study;
+import com.gdschongik.gdsc.domain.study.domain.StudyAchievement;
 import com.gdschongik.gdsc.domain.study.domain.StudyDetail;
+import com.gdschongik.gdsc.domain.study.domain.StudyHistory;
 import com.gdschongik.gdsc.global.security.PrincipalDetails;
 import com.gdschongik.gdsc.infra.feign.payment.client.PaymentClient;
 import com.gdschongik.gdsc.infra.github.client.GithubClient;
@@ -81,6 +86,12 @@ public abstract class IntegrationTest {
     @Autowired
     protected StudyDetailRepository studyDetailRepository;
 
+    @Autowired
+    protected StudyHistoryRepository studyHistoryRepository;
+
+    @Autowired
+    protected StudyAchievementRepository studyAchievementRepository;
+
     @MockBean
     protected OnboardingRecruitmentService onboardingRecruitmentService;
 
@@ -262,6 +273,16 @@ protected StudyDetail createNewStudyDetail(Long week, Study study, LocalDateTime
         return studyDetailRepository.save(studyDetail);
     }
 
+    protected StudyHistory createStudyHistory(Member member, Study study) {
+        StudyHistory studyHistory = StudyHistory.create(member, study);
+        return studyHistoryRepository.save(studyHistory);
+    }
+
+    protected StudyAchievement createStudyAchievement(Member member, Study study, AchievementType achievementType) {
+        StudyAchievement studyAchievement = StudyAchievement.create(member, study, achievementType);
+        return studyAchievementRepository.save(studyAchievement);
+    }
+
     protected StudyDetail publishAssignment(StudyDetail studyDetail) {
         studyDetail.publishAssignment(ASSIGNMENT_TITLE, studyDetail.getPeriod().getEndDate(), DESCRIPTION_LINK);
         return studyDetailRepository.save(studyDetail);