[feat] 스터디 가입 요청, 수락, 거절 API 추가

src/main/java/com/flytrap/venusplanner/api/join_request/business/service/JoinRequestCurdFacadeService.java

@@ -0,0 +1,76 @@
+package com.flytrap.venusplanner.api.join_request.business.service;
+
+import static com.flytrap.venusplanner.api.join_request.exception.JoinRequestExceptionType.DuplicateJoinRequestException;
+import static com.flytrap.venusplanner.api.join_request.exception.JoinRequestExceptionType.JoinRequestAlreadyHandledException;
+import static com.flytrap.venusplanner.api.study.exception.StudyExceptionType.StudyAlreadyJoinedException;
+import static com.flytrap.venusplanner.api.study.exception.StudyExceptionType.StudyMismatchException;
+
+import com.flytrap.venusplanner.api.join_request.domain.JoinRequest;
+import com.flytrap.venusplanner.api.member_study.business.service.MemberStudyValidator;
+import com.flytrap.venusplanner.api.study.business.service.StudyValidator;
+import lombok.RequiredArgsConstructor;
+import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
+
+@Service
+@RequiredArgsConstructor
+@Transactional(readOnly = true)
+public class JoinRequestCurdFacadeService {
+
+    private final JoinRequestUpdater joinRequestUpdater;
+    private final JoinRequestValidator joinRequestValidator;
+    private final StudyValidator studyValidator;
+    private final MemberStudyValidator memberStudyValidator;
+
+    @Transactional
+    public JoinRequest createJoinRequest(Long studyId, Long memberId) {
+        studyValidator.validateStudyExists(studyId);
+
+        if (memberStudyValidator.validateMemberBelongsToStudy(memberId, studyId)) {
+            throw StudyAlreadyJoinedException();
+        }
+
+        if (joinRequestValidator.validateWaitingJoinRequestExists(studyId, memberId)) {
+            throw DuplicateJoinRequestException();
+        }
+
+        return joinRequestUpdater.saveJoinRequest(studyId, memberId);
+    }
+
+    @Transactional
+    public void acceptJoinRequest(Long studyId, Long requestId, Long memberId) {
+        studyValidator.validateStudyExists(studyId);
+        memberStudyValidator.validateMemberCanAcceptJoinRequest(memberId, studyId);
+
+        JoinRequest joinRequest = joinRequestValidator.findById(requestId);
+
+        if (!joinRequest.validateStudyIdMatch(studyId)) {
+            throw StudyMismatchException("요청한 스터디 ID와 가입 요청의 스터디 ID가 일치하지 않습니다.");
+        }
+
+        if (!joinRequest.isWaiting()) {
+            throw JoinRequestAlreadyHandledException();
+        }
+
+        joinRequest.accept();
+    }
+
+    @Transactional
+    public void rejectJoinRequest(Long studyId, Long requestId, Long memberId) {
+        studyValidator.validateStudyExists(studyId);
+        memberStudyValidator.validateMemberCanRejectJoinRequest(memberId, studyId);
+
+        JoinRequest joinRequest = joinRequestValidator.findById(requestId);
+
+        if (!joinRequest.validateStudyIdMatch(studyId)) {
+            throw StudyMismatchException("요청한 스터디 ID와 가입 요청의 스터디 ID가 일치하지 않습니다.");
+        }
+
+        if (!joinRequest.isWaiting()) {
+            throw JoinRequestAlreadyHandledException();
+        }
+
+        joinRequest.reject();
+    }
+
+}

src/main/java/com/flytrap/venusplanner/api/join_request/business/service/JoinRequestService.java

@@ -0,0 +1,36 @@
+package com.flytrap.venusplanner.api.join_request.business.service;
+
+import static com.flytrap.venusplanner.api.join_request.exception.JoinRequestExceptionType.JoinRequestNotFoundException;
+
+import com.flytrap.venusplanner.api.join_request.domain.JoinRequest;
+import com.flytrap.venusplanner.api.join_request.domain.JoinRequestState;
+import com.flytrap.venusplanner.api.join_request.infrastructure.repository.JoinRequestRepository;
+import lombok.RequiredArgsConstructor;
+import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
+
+@Service
+@RequiredArgsConstructor
+@Transactional(readOnly = true)
+public class JoinRequestService implements JoinRequestUpdater, JoinRequestValidator {
+
+    private final JoinRequestRepository joinRequestRepository;
+
+    @Override
+    @Transactional
+    public JoinRequest saveJoinRequest(Long studyId, Long memberId) {
+        return joinRequestRepository.save(JoinRequest.create(studyId, memberId));
+    }
+
+    @Override
+    public boolean validateWaitingJoinRequestExists(Long studyId, Long memberId) {
+        return joinRequestRepository.existsByMemberIdAndStudyIdAndState(
+                memberId, studyId, JoinRequestState.WAIT);
+    }
+
+    @Override
+    public JoinRequest findById(Long joinRequestId) {
+        return joinRequestRepository.findById(joinRequestId)
+                .orElseThrow(() -> JoinRequestNotFoundException(joinRequestId));
+    }
+}

src/main/java/com/flytrap/venusplanner/api/join_request/business/service/JoinRequestUpdater.java

@@ -0,0 +1,8 @@
+package com.flytrap.venusplanner.api.join_request.business.service;
+
+import com.flytrap.venusplanner.api.join_request.domain.JoinRequest;
+
+public interface JoinRequestUpdater {
+
+    JoinRequest saveJoinRequest(Long studyId, Long memberId);
+}

src/main/java/com/flytrap/venusplanner/api/join_request/business/service/JoinRequestValidator.java

@@ -0,0 +1,8 @@
+package com.flytrap.venusplanner.api.join_request.business.service;
+
+import com.flytrap.venusplanner.api.join_request.domain.JoinRequest;
+
+public interface JoinRequestValidator {
+    boolean validateWaitingJoinRequestExists(Long studyId, Long memberId);
+    JoinRequest findById(Long joinRequestId);
+}

src/main/java/com/flytrap/venusplanner/api/join_request/domain/JoinRequest.java

@@ -0,0 +1,65 @@
+package com.flytrap.venusplanner.api.join_request.domain;
+
+import com.flytrap.venusplanner.global.entity.TimeAuditingBaseEntity;
+import jakarta.persistence.Entity;
+import jakarta.persistence.EnumType;
+import jakarta.persistence.Enumerated;
+import jakarta.persistence.GeneratedValue;
+import jakarta.persistence.GenerationType;
+import jakarta.persistence.Id;
+import jakarta.validation.constraints.NotNull;
+import java.util.Objects;
+import lombok.AccessLevel;
+import lombok.Builder;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+
+@Entity
+@Getter
+@NoArgsConstructor(access = AccessLevel.PROTECTED)
+public class JoinRequest extends TimeAuditingBaseEntity {
+
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private Long id;
+
+    @NotNull
+    private Long memberId;
+
+    @NotNull
+    private Long studyId;
+
+    @Enumerated(EnumType.STRING)
+    private JoinRequestState state;
+
+    @Builder
+    private JoinRequest(Long memberId, Long studyId, JoinRequestState state) {
+        this.memberId = memberId;
+        this.studyId = studyId;
+        this.state = state;
+    }
+
+    public static JoinRequest create(Long studyId, Long memberId) {
+        return JoinRequest.builder()
+                .studyId(studyId).memberId(memberId)
+                .state(JoinRequestState.WAIT)
+                .build();
+    }
+
+    public boolean isWaiting() {
+        return this.state == JoinRequestState.WAIT;
+    }
+
+    public boolean validateStudyIdMatch(Long studyId) {
+        return Objects.equals(this.studyId, studyId);
+    }
+
+    public void accept() {
+        this.state = JoinRequestState.ACCEPT;
+    }
+
+    public void reject() {
+        this.state = JoinRequestState.REJECT;
+    }
+
+}

src/main/java/com/flytrap/venusplanner/api/join_request/domain/JoinRequestState.java

@@ -0,0 +1,5 @@
+package com.flytrap.venusplanner.api.join_request.domain;
+
+public enum JoinRequestState {
+    WAIT, ACCEPT, REJECT
+}

src/main/java/com/flytrap/venusplanner/api/join_request/exception/JoinRequestExceptionType.java

@@ -0,0 +1,21 @@
+package com.flytrap.venusplanner.api.join_request.exception;
+
+import com.flytrap.venusplanner.api.join_request.domain.JoinRequest;
+import com.flytrap.venusplanner.global.exception.CustomException;
+import com.flytrap.venusplanner.global.exception.GeneralExceptionType;
+
+public class JoinRequestExceptionType extends GeneralExceptionType {
+
+    public static CustomException JoinRequestNotFoundException(Long joinRequestId) {
+        return DomainNotFoundException(JoinRequest.class, joinRequestId);
+    }
+
+    public static CustomException DuplicateJoinRequestException() {
+        return DuplicateDomainException("이미 가입 요청된 상태입니다.");
+    }
+
+    public static CustomException JoinRequestAlreadyHandledException() {
+        return DuplicateDomainException("이미 처리된 가입 요청입니다");
+    }
+
+}

src/main/java/com/flytrap/venusplanner/api/join_request/infrastructure/repository/JoinRequestRepository.java

@@ -0,0 +1,10 @@
+package com.flytrap.venusplanner.api.join_request.infrastructure.repository;
+
+import com.flytrap.venusplanner.api.join_request.domain.JoinRequest;
+import com.flytrap.venusplanner.api.join_request.domain.JoinRequestState;
+import org.springframework.data.jpa.repository.JpaRepository;
+
+public interface JoinRequestRepository extends JpaRepository<JoinRequest, Long> {
+
+    boolean existsByMemberIdAndStudyIdAndState(Long memberId, Long studyId, JoinRequestState state);
+}

src/main/java/com/flytrap/venusplanner/api/join_request/presentation/controller/JoinRequestController.java

@@ -0,0 +1,56 @@
+package com.flytrap.venusplanner.api.join_request.presentation.controller;
+
+import com.flytrap.venusplanner.api.join_request.business.service.JoinRequestCurdFacadeService;
+import com.flytrap.venusplanner.api.join_request.domain.JoinRequest;
+import com.flytrap.venusplanner.api.join_request.presentation.dto.response.JoinRequestCreateResponse;
+import com.flytrap.venusplanner.global.auth.annotation.SignIn;
+import com.flytrap.venusplanner.global.auth.dto.SessionMember;
+import lombok.RequiredArgsConstructor;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.PatchMapping;
+import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.bind.annotation.PostMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+@RestController
+@RequiredArgsConstructor
+public class JoinRequestController {
+
+    private final JoinRequestCurdFacadeService joinRequestCrudService;
+
+    @PostMapping("/api/v1/studies/{studyId}/join-requests")
+    public ResponseEntity<JoinRequestCreateResponse> requestToJoinStudy(
+            @PathVariable Long studyId,
+            @SignIn SessionMember sessionMember
+    ) {
+        JoinRequest joinRequest = joinRequestCrudService
+                .createJoinRequest(studyId, sessionMember.id());
+
+        return ResponseEntity.status(HttpStatus.CREATED)
+                .body(new JoinRequestCreateResponse(joinRequest.getId()));
+    }
+
+    @PatchMapping("/api/v1/studies/{studyId}/join-requests/{requestId}/accept")
+    public ResponseEntity<Void> acceptJoinRequest(
+            @PathVariable Long studyId,
+            @PathVariable Long requestId,
+            @SignIn SessionMember sessionMember
+    ) {
+        joinRequestCrudService.acceptJoinRequest(studyId, requestId, sessionMember.id());
+
+        return ResponseEntity.ok(null);
+    }
+
+    @PatchMapping("/api/v1/studies/{studyId}/join-requests/{requestId}/reject")
+    public ResponseEntity<Void> rejectJoinRequest(
+            @PathVariable Long studyId,
+            @PathVariable Long requestId,
+            @SignIn SessionMember sessionMember
+    ) {
+        joinRequestCrudService.rejectJoinRequest(studyId, requestId, sessionMember.id());
+
+        return ResponseEntity.ok(null);
+    }
+
+}

src/main/java/com/flytrap/venusplanner/api/join_request/presentation/dto/response/JoinRequestCreateResponse.java

@@ -0,0 +1,6 @@
+package com.flytrap.venusplanner.api.join_request.presentation.dto.response;
+
+public record JoinRequestCreateResponse(
+        Long id
+) {
+}

src/main/java/com/flytrap/venusplanner/api/member_study/business/service/MemberStudyService.java

@@ -1,5 +1,7 @@
 package com.flytrap.venusplanner.api.member_study.business.service;
 
+import static com.flytrap.venusplanner.global.exception.GeneralExceptionType.ForbiddenException;
+
 import com.flytrap.venusplanner.api.member_study.domain.MemberStudy;
 import com.flytrap.venusplanner.api.member_study.infrastructure.repository.MemberStudyRepository;
 import com.flytrap.venusplanner.api.study.domain.Study;
@@ -11,7 +13,7 @@
 @Service
 @RequiredArgsConstructor
 @Transactional(readOnly = true)
-public class MemberStudyService {
+public class MemberStudyService implements MemberStudyValidator {
 
     private final MemberStudyRepository memberStudyRepository;
 
@@ -22,4 +24,29 @@ public void saveLeaderStudy(SessionMember leader, Study study) {
         );
         memberStudyRepository.save(memberStudy);
     }
+
+    @Override
+    public boolean validateMemberBelongsToStudy(Long memberId, Long studyId) {
+        return memberStudyRepository.existsByStudyIdAndMemberId(studyId, memberId);
+    }
+
+    @Override
+    public void validateMemberCanAcceptJoinRequest(Long memberId, Long studyId) {
+        MemberStudy memberStudy = memberStudyRepository.findByStudyIdAndMemberId(studyId, memberId)
+                .orElseThrow(() -> ForbiddenException("스터디 멤버가 아닙니다."));
+
+        if (!memberStudy.canAcceptStudyJoinRequest()) {
+            throw ForbiddenException("수락 권한이 없습니다.");
+        }
+    }
+
+    @Override
+    public void validateMemberCanRejectJoinRequest(Long memberId, Long studyId) {
+        MemberStudy memberStudy = memberStudyRepository.findByStudyIdAndMemberId(studyId, memberId)
+                .orElseThrow(() -> ForbiddenException("스터디 멤버가 아닙니다."));
+
+        if (!memberStudy.canAcceptStudyJoinRequest()) {
+            throw ForbiddenException("거절 권한이 없습니다.");
+        }
+    }
 }

src/main/java/com/flytrap/venusplanner/api/member_study/business/service/MemberStudyValidator.java

@@ -0,0 +1,8 @@
+package com.flytrap.venusplanner.api.member_study.business.service;
+
+public interface MemberStudyValidator {
+
+    boolean validateMemberBelongsToStudy(Long memberId, Long studyId);
+    void validateMemberCanAcceptJoinRequest(Long memberId, Long studyId);
+    void validateMemberCanRejectJoinRequest(Long memberId, Long studyId);
+}

src/main/java/com/flytrap/venusplanner/api/member_study/domain/MemberStudy.java

@@ -9,6 +9,7 @@
 import jakarta.persistence.GenerationType;
 import jakarta.persistence.Id;
 import jakarta.persistence.ManyToOne;
+import java.util.Objects;
 import lombok.AccessLevel;
 import lombok.Builder;
 import lombok.Getter;
@@ -47,4 +48,16 @@ public static MemberStudy fromLeader(Long leaderId, Study study) {
                 .permissionId(Permission.EDIT.getId())
                 .build();
     }
+
+    public boolean isLeader() {
+        return Objects.equals(rollId, Roll.LEADER.getId());
+    }
+
+    public boolean canAcceptStudyJoinRequest() {
+        return isLeader();
+    }
+
+    public boolean canRejectStudyJoinRequest() {
+        return isLeader();
+    }
 }

src/main/java/com/flytrap/venusplanner/api/member_study/infrastructure/repository/MemberStudyRepository.java

@@ -1,9 +1,13 @@
 package com.flytrap.venusplanner.api.member_study.infrastructure.repository;
 
 import com.flytrap.venusplanner.api.member_study.domain.MemberStudy;
+import java.util.Optional;
 import org.springframework.data.jpa.repository.JpaRepository;
 import org.springframework.stereotype.Repository;
 
 @Repository
 public interface MemberStudyRepository extends JpaRepository<MemberStudy, Long> {
+
+    boolean existsByStudyIdAndMemberId(Long studyId, Long memberId);
+    Optional<MemberStudy> findByStudyIdAndMemberId(Long studyId, Long memberId);
 }