refactor: updateTag 로직 수정 validator에서 update할 tag의 index를 가져옴

backend/src/main/java/kernel360/techpick/feature/tag/service/TagService.java

@@ -1,7 +1,8 @@
 package kernel360.techpick.feature.tag.service;
 
+import java.util.ArrayList;
+import java.util.Comparator;
 import java.util.List;
-import java.util.Map;
 
 import org.springframework.stereotype.Service;
 import org.springframework.transaction.annotation.Transactional;
@@ -41,7 +42,7 @@ public TagResponse createTag(Long userId, TagCreateRequest request) throws ApiTa
 	@Transactional(readOnly = true)
 	public List<TagResponse> getTagListByUser(Long userId) {
 
-		List<Tag> tagList = tagProvider.findAllByUserId(userId);
+		List<Tag> tagList = tagProvider.findAllByUserIdOrderByTagOrder(userId);
 
 		return tagList.stream()
 			.map(tagMapper::createTagResponse)
@@ -52,18 +53,21 @@ public List<TagResponse> getTagListByUser(Long userId) {
 	public List<TagResponse> updateTagList(Long userId, List<TagUpdateRequest> tagUpdateRequests) throws
 		ApiTagException {
 
-		Map<Long, Tag> tagMap = tagProvider.getTagMapByUserId(userId);
-
-		for (var req : tagUpdateRequests) {
-			// 만약 자신의 태그가 아니라면 tagMap.get(req.id()) == null
-			tagValidator.validateTagAccess(userId, tagMap.get(req.id()));
-			tagMapper.updateTag(req, tagMap.get(req.id()));
+		// immutable list로 들어올 경우 sort가 불가능해 ArrayList로 변환
+		// 항상 mutable list라는것이 보장된다면 삭제해주세요..
+		List<TagUpdateRequest> mutableTagUpdateRequests = new ArrayList<>(tagUpdateRequests);
+		mutableTagUpdateRequests.sort(Comparator.comparingLong(TagUpdateRequest::id));
+
+		List<Tag> userTagList = tagProvider.findAllByUserIdOrderByTagId(userId);
+
+		int idx = 0;
+		for (var req : mutableTagUpdateRequests) {
+			idx = tagValidator.findUpdateTagIdx(idx, req, userTagList);
+			tagMapper.updateTag(req, userTagList.get(idx));
+			idx++;
 		}
 
-		// 수정한 태그들 중 order 가 중복되는지 검증
-		tagValidator.validateTagOrder(tagMap);
-
-		return tagProvider.saveAll(tagMap.values())
+		return tagProvider.saveAll(userTagList)
 			.stream()
 			.map(tagMapper::createTagResponse)
 			.toList();

backend/src/main/java/kernel360/techpick/feature/tag/validator/TagValidator.java

@@ -1,15 +1,14 @@
 package kernel360.techpick.feature.tag.validator;
 
-import java.util.HashSet;
-import java.util.Map;
+import java.util.List;
 import java.util.Objects;
-import java.util.Set;
 
 import org.springframework.stereotype.Component;
 
 import kernel360.techpick.core.exception.feature.tag.ApiTagException;
 import kernel360.techpick.core.model.tag.Tag;
 import kernel360.techpick.feature.tag.model.TagProvider;
+import kernel360.techpick.feature.tag.model.dto.TagUpdateRequest;
 import lombok.RequiredArgsConstructor;
 
 @Component
@@ -32,16 +31,17 @@ public void validateTagNameExists(Long userId, String name) throws ApiTagExcepti
 		}
 	}
 
-	public void validateTagOrder(Map<Long, Tag> tagMap) throws ApiTagException {
+	// 업데이트 대상이 되는 태그의 userTagList에서의 index 반환
+	// 만약 userTagList에 업데이트 하려는 태그가 존재하지 않으면,
+	// 본인이 등록하지 않은 태그에 접근하려는 것이므로 ApiTagException.UNAUTHORIZED_TAG_ACCESS() 발생
+	public int findUpdateTagIdx(int startIdx, TagUpdateRequest req, List<Tag> userTagList) throws ApiTagException {
 
-		Set<Integer> orderSet = new HashSet<>();
-
-		for (Tag tag : tagMap.values()) {
-			// 중복되거나 음수면 유효하지 않은 tag order
-			if (!orderSet.add(tag.getOrder()) || tag.getOrder() < 0) {
-				throw ApiTagException.TAG_INVALID_ORDER();
+		for (int i = startIdx; i < userTagList.size(); i++) {
+			if (req.id().equals(userTagList.get(i).getId())) {
+				return i;
 			}
 		}
+		throw ApiTagException.UNAUTHORIZED_TAG_ACCESS();
 	}
 
 }