feat: 스터디 수료 및 철회 API 구현

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

@@ -0,0 +1,39 @@
+package com.gdschongik.gdsc.domain.study.api;
+
+import com.gdschongik.gdsc.domain.study.application.MentorStudyHistoryService;
+import com.gdschongik.gdsc.domain.study.dto.request.StudyCompletionRequest;
+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.PatchMapping;
+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 Study History", description = "멘토 스터디 수강 이력 API입니다.")
+@RestController
+@RequestMapping("/mentor/study-history")
+@RequiredArgsConstructor
+public class MentorStudyHistoryController {
+
+    private final MentorStudyHistoryService mentorStudyHistoryService;
+
+    @Operation(summary = "스터디 수료 처리", description = "스터디 수료 처리합니다.")
+    @PatchMapping("/complete")
+    public ResponseEntity<Void> completeStudy(
+            @RequestParam(name = "studyId") Long studyId, @Valid @RequestBody StudyCompletionRequest request) {
+        mentorStudyHistoryService.completeStudy(studyId, request);
+        return ResponseEntity.ok().build();
+    }
+
+    @Operation(summary = "스터디 수료 철회", description = "스터디 수료 처리를 철회합니다.")
+    @PatchMapping("/withdraw-completion")
+    public ResponseEntity<Void> withdrawStudyCompletion(
+            @RequestParam(name = "studyId") Long studyId, @Valid @RequestBody StudyCompletionRequest request) {
+        mentorStudyHistoryService.withdrawStudyCompletion(studyId, request);
+        return ResponseEntity.ok().build();
+    }
+}

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

@@ -0,0 +1,61 @@
+package com.gdschongik.gdsc.domain.study.application;
+
+import static com.gdschongik.gdsc.global.exception.ErrorCode.*;
+
+import com.gdschongik.gdsc.domain.member.domain.Member;
+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.StudyHistory;
+import com.gdschongik.gdsc.domain.study.domain.StudyHistoryValidator;
+import com.gdschongik.gdsc.domain.study.domain.StudyValidator;
+import com.gdschongik.gdsc.domain.study.dto.request.StudyCompletionRequest;
+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 MentorStudyHistoryService {
+
+    private final MemberUtil memberUtil;
+    private final StudyValidator studyValidator;
+    private final StudyHistoryValidator studyHistoryValidator;
+    private final StudyRepository studyRepository;
+    private final StudyHistoryRepository studyHistoryRepository;
+
+    @Transactional
+    public void completeStudy(Long studyId, StudyCompletionRequest request) {
+        Member currentMember = memberUtil.getCurrentMember();
+        Study study = studyRepository.findById(studyId).orElseThrow(() -> new CustomException(STUDY_NOT_FOUND));
+        List<StudyHistory> studyHistories = studyHistoryRepository.findAllById(request.studentIds());
+
+        studyValidator.validateStudyMentor(currentMember, study);
+        studyHistoryValidator.validateAppliedToStudy(
+                studyHistories.size(), request.studentIds().size());
+
+        studyHistories.forEach(StudyHistory::complete);
+
+        log.info("[MentorStudyHistoryService] 스터디 수료 처리: studyId={}, studentIds={}", studyId, request.studentIds());
+    }
+
+    @Transactional
+    public void withdrawStudyCompletion(Long studyId, StudyCompletionRequest request) {
+        Member currentMember = memberUtil.getCurrentMember();
+        Study study = studyRepository.findById(studyId).orElseThrow(() -> new CustomException(STUDY_NOT_FOUND));
+        List<StudyHistory> studyHistories = studyHistoryRepository.findAllById(request.studentIds());
+
+        studyValidator.validateStudyMentor(currentMember, study);
+        studyHistoryValidator.validateAppliedToStudy(
+                studyHistories.size(), request.studentIds().size());
+
+        studyHistories.forEach(StudyHistory::withdrawCompletion);
+
+        log.info("[MentorStudyHistoryService] 스터디 수료 철회: studyId={}, studentIds={}", studyId, request.studentIds());
+    }
+}

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

@@ -78,6 +78,13 @@ public void complete() {
         studyHistoryStatus = COMPLETED;
     }
 
+    /**
+     * 스터디 수료 철회
+     */
+    public void withdrawCompletion() {
+        studyHistoryStatus = NONE;
+    }
+
     // 데이터 전달 로직
     public boolean isWithinApplicationAndCourse() {
         return study.isWithinApplicationAndCourse();

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

@@ -0,0 +1,5 @@
+package com.gdschongik.gdsc.domain.study.dto.request;
+
+import java.util.List;
+
+public record StudyCompletionRequest(List<Long> studentIds) {}

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

@@ -55,4 +55,27 @@ class 스터디_수료시 {
             assertThat(studyHistory.getStudyHistoryStatus()).isEqualTo(COMPLETED);
         }
     }
+
+    @Nested
+    class 스터디_수료_철회시 {
+
+        @Test
+        void 수료상태는_NONE이다() {
+            // given
+            Member student = fixtureHelper.createRegularMember(1L);
+            Member mentor = fixtureHelper.createRegularMember(2L);
+            LocalDateTime now = LocalDateTime.now();
+            Study study = fixtureHelper.createStudy(
+                    mentor, Period.of(now.plusDays(5), now.plusDays(10)), Period.of(now.minusDays(5), now));
+
+            StudyHistory studyHistory = StudyHistory.create(student, study);
+            studyHistory.complete();
+
+            // when
+            studyHistory.withdrawCompletion();
+
+            // then
+            assertThat(studyHistory.getStudyHistoryStatus()).isEqualTo(NONE);
+        }
+    }
 }